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26 results on '"Sahakyan, N."'

1. Broad-band study of gamma-ray blazars at redshifts z = 2.0–2.5.

Author

Sahakyan, N, Harutyunyan, G, Gasparyan, S, and Israyelyan, D

Subjects
*BL Lacertae objects, *REDSHIFT, *SPECTRAL energy distribution, *INVERSE Compton scattering, *PHOTON flux, *MAGNETIC fields
Abstract

High redshift blazars are among the most powerful non-explosive sources in the Universe and play a crucial role in understanding the evolution of relativistic jets. To understand these bright objects, we performed a detailed investigation of the multiwavelength properties of 79 γ-ray blazars with redshifts ranging from z = 2.0 to 2.5, using data from Fermi LAT, Swift XRT / UVOT , and NuSTAR observations. In the γ-ray band, the spectral analysis revealed a wide range of flux and photon indices, from 5.32 × 10−10 to 3.40 × 10−7 photon cm−2 s−1 and from 1.66 to 3.15, respectively, highlighting the diverse nature of these sources. The detailed temporal analysis showed that flaring activities were observed in 31 sources. Sources such as 4C+71.07, PKS 1329-049, and 4C + 01.02, demonstrated significant increase in the γ-ray luminosity and flux variations, reaching peak luminosity exceeding 1050 erg s−1. The temporal analysis extended to X-ray and optical/ultraviolet (UV) bands, showed clear flux changes in some sources in different observations. The time-averaged properties of high redshift blazars were derived through modeling the spectral energy distributions with a one-zone leptonic scenario, assuming the emission region is within the broad-line region (BLR) and the X-ray and γ-ray emissions are due to inverse Compton scattering of synchrotron and BLR-reflected photons. This modeling allowed us to constrain the emitting particle distribution, estimate the magnetic field inside the jet, and evaluate the jet luminosity, which is discussed in comparison with the disc luminosity derived from fitting the excess in the UV band. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Long-term multi-wavelength study of 1ES 0647+250

Author

MAGIC Collaboration, Acciari, V. A., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Arcaro, C., Artero, M., Asano, K., Baack, D., Babić, A., Baquero, A., de Almeida, U. Barres, Barrio, J. A., Batković, I., González, J. Becerra, Bednarek, W., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bökenkamp, H., Bonnoli, G., Bošnjak, Ž., Burelli, I., Busetto, G., Carosi, R., Carretero-Castrillo, M., Ceribella, G., Chai, Y., Chilingarian, A., Cikota, S., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Del Popolo, A., Delfino, M., Delgado, J., Mendez, C. Delgado, Depaoli, D., Di Pierro, F., Di Venere, L., Espiñeira, E. Do Souto, Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., Emery, G., Ramazani, V. Fallah, Fariña, L., Fattorini, A., Font, L., Fruck, C., Fukami, S., Fukazawa, Y., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Paiva, J. G. Giesbrecht, Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Hassan, T., Heckmann, L., Herrera, J., Hrupec, D., Hütten, M., Inada, T., Iotov, R., Ishio, K., Iwamura, Y., Martínez, I. Jiménez, Jormanainen, J., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Lyard, E., Fraga, B. Machado de Oliveira, Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mangano, S., Mannheim, K., Mariotti, M., Martínez, M., Aguilar, A. Mas, Mazin, D., Menchiari, S., Mender, S., Mićanović, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., Molina, E., Mondal, H. A., Moralejo, A., Morcuende, D., Moreno, V., Nakamori, T., Nanci, C., Nava, L., Neustroev, V., Rosillo, M. Nievas, Nigro, C., Nilsson, K., Nishijima, K., Ekoume, T. Njoh, Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Persic, M., Pihet, M., Podobnik, F., Moroni, P. G. Prada, Prandini, E., Principe, G., Priyadarshi, C., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sitarek, J., Sliusar, V., Sobczynska, D., Spolon, A., Stamerra, A., Strišković, J., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Vanzo, G., Acosta, M. Vazquez, Ventura, S., Verguilov, V., Viale, I., Vigorito, C. F., Vitale, V., Vovk, I., Walter, R., Will, M., Wunderlich, C., Yamamoto, T., Zarić, D., Acosta-Pulido, J. A., D'Ammando, F., Hovatta, T., Kiehlmann, S., Liodakis, I., Leto, C., Max-Moerbeck, W., Pacciani, L., Perri, M., Readhead, A. C. S., Reeves, R. A., Verrecchia, F., University of La Laguna, National Institute for Astrophysics, University of Udine, Max-Planck-Institut für Physik, University of Padova, Institute for High Energy Physics, The University of Tokyo, Dortmund University, University of Zagreb, Universidad Complutense de Madrid, Centro Brasileiro de Pesquisas Físicas, University of Łódź, Metsähovi Radio Observatory, Aalto-yliopisto, and Aalto University

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), galaxies [Gamma rays], individual: 1ES 0647+250 [BL Lacertae objects], galaxies: active, FOS: Physical sciences, Astronomy and Astrophysics, galaxies: jets, BL Lacertae objects: individual: 1ES 0647+250, Active [Galaxies], Space and Planetary Science, gamma rays: galaxies, Galaxies: active, BL Lacertae objects: individual: 1ES 0647+250, galaxies: jets, gamma rays: galaxies, jets [Galaxies], Astrophysics - High Energy Astrophysical Phenomena, active, BL Lacertae objects: individual: 1ES 0647+250 [galaxies]
Abstract

Context. The BL Lac object 1ES 0647+250 is one of the few distant γ-ray emitting blazars detected at very high energies (VHEs; ≳100 GeV) during a non-flaring state. It was detected with the MAGIC telescopes during a period of low activity in the years 2009−2011 as well as during three flaring activities in the years 2014, 2019, and 2020, with the highest VHE flux in the last epoch. An extensive multi-instrument data set was collected as part of several coordinated observing campaigns over these years. Aims. We aim to characterise the long-term multi-band flux variability of 1ES 0647+250, as well as its broadband spectral energy distribution (SED) during four distinct activity states selected in four different epochs, in order to constrain the physical parameters of the blazar emission region under certain assumptions. Methods. We evaluated the variability and correlation of the emission in the different energy bands with the fractional variability and the Z-transformed discrete correlation function, as well as its spectral evolution in X-rays and γ rays. Owing to the controversy in the redshift measurements of 1ES 0647+250 reported in the literature, we also estimated its distance in an indirect manner through a comparison of the GeV and TeV spectra from simultaneous observations with Fermi-LAT and MAGIC during the strongest flaring activity detected to date. Moreover, we interpret the SEDs from the four distinct activity states within the framework of one-component and two-component leptonic models, proposing specific scenarios that are able to reproduce the available multi-instrument data. Results. We find significant long-term variability, especially in X-rays and VHE γ rays. Furthermore, significant (3−4σ) correlations were found between the radio, optical, and high-energy (HE) γ-ray fluxes, with the radio emission delayed by about ∼400 days with respect to the optical and γ-ray bands. The spectral analysis reveals a harder-when-brighter trend during the non-flaring state in the X-ray domain. However, no clear patterns were observed for either the enhanced states or the HE (30 MeV < E < 100 GeV) and VHE γ-ray emission of the source. The indirect estimation of the redshift yielded a value of z = 0.45 ± 0.05, which is compatible with some of the values reported in the literature. The SEDs related to the low-activity state and the three flaring states of 1ES 0647+250 can be described reasonably well with the both one-component and two-component leptonic scenarios. However, the long-term correlations indicate the need for an additional radio-producing region located about 3.6 pc downstream from the gamma-ray producing region., Astronomy & Astrophysics, 670, ISSN:0004-6361, ISSN:1432-0746

Published
2023

3. A lower bound on intergalactic magnetic fields from time variability of 1ES 0229+200 from MAGIC and Fermi/LAT observations

Author

Acciari, V. A., Agudo, I., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Artero, M., Asano, K., Baack, D., Babic, A., Baquero, A., de Almeida, U. Barres, Barrio, J. A., Batkovic, I., González, J. Becerra, Bednarek, W., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bökenkamp, H., Bonnoli, G., Bošnjak, Ž., Burelli, I., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Del Popolo, A., Delfino, M., Delgado, J., Mendez, C. Delgado, Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espiñeira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fariña, L., Fattorini, A., Font, L., Fruck, C., Fukami, S., Fukazawa, Y., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovic, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Hassan, T., Heckmann, L., Herrera, J., Hrupec, D., Hütten, M., Inada, T., Iotov, R., Ishio, K., Iwamura, Y., Martínez, I. Jiménez, Jormanainen, J., Jouvin, L., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Linhoff, L., Liodakis, I., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., de Oliveira Fraga, B. Machado, Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Mariotti, M., Martínez, M., Aguilar, A. Mas, Mazin, D., Menchiari, S., Mender, S., Micanovic, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., Molina, E., Mondal, H. A., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Nakamori, T., Nanci, C., Nava, L., Neustroev, V., Nievas Rosillo, M., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletic, L., Peñil, P., Persic, M., Pihet, M., Prada Moroni, P. G., Prandini, E., Priyadarshi, C., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sitarek, J., Šnidaric, I., Sobczynska, D., Spolon, A., Stamerra, A., Striškovic, J., Strom, D., Strzys, M., Suda, Y., Suric, T., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Viale, I., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Yamamoto, T., Zaric, D., Neronov, A., Semikoz, D., Korochkin, A., MAGIC Collaboration, Département de Physique des Particules (ex SPP) (DPhP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), MAGIC, and HEP, INSPIRE

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Cosmology and Nongalactic Astrophysics (astro-ph.CO), galaxies: active, intergalactic magnetic fields, FOS: Physical sciences, Astronomy and Astrophysics, early Universe, magic, fermi, Space and Planetary Science, gamma rays: galaxies, ddc:520, intergalactic medium, Early Universe, Galaxies: active, Gamma rays: galaxies, Intergalactic medium, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Astronomy and astrophysics 670, A145 (2023). doi:10.1051/0004-6361/202244126, Context. Extended and delayed emission around distant TeV sources induced by the effects of propagation of γ ray s through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF).Aims. We search for delayed GeV emission from the hard-spectrum TeV γ-ray emitting blazar 1ES 0229+200, with the goal of detecting or constraining the IGMF-dependent secondary flux generated during the propagation of TeV γ rays through the intergalactic medium.Methods. We analysed the most recent MAGIC observations over a 5 year time span, and complemented them with historic data of the H.E.S.S. and VERITAS telescopes, along with a 12-year-long exposure of the Fermi/LAT telescope. We used them to trace source evolution in the GeV–TeV band over a decade and a half. We used Monte Carlo simulations to predict the delayed secondary γ-ray flux, modulated by the source variability, as revealed by TeV-band observations. We then compared these predictions for various assumed IGMF strengths to all available measurements of the γ-ray flux evolution.Results. We find that the source flux in the energy range above 200 GeV experiences variations around its average on the 14-year time span of observations. No evidence for the flux variability is found in the 1 − 100 GeV energy range accessible to Fermi/LAT. The non-detection of variability due to delayed emission from electromagnetic cascade developing in the intergalactic medium imposes a lower bound of B > 1.8 × 10´$^{−17}$ G for the long-correlation-length IGMF and B > 10$^{−14}$ G for an IGMF of cosmological origin. Though weaker than the one previously derived from the analysis of Fermi/LAT data, this bound is more robust, being based on a conservative intrinsic source spectrum estimate and accounting for the details of source variability in the TeV energy band. We discuss implications of this bound for cosmological magnetic fields that might explain the baryon asymmetry of the Universe., Published by EDP Sciences, Les Ulis

Published
2023
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4. Origin of multiwavelength emission from flaring high redshift blazar PKS 0537−286.

Author

Sahakyan, N, Harutyunyan, G, and Israyelyan, D

Subjects
*BL Lacertae objects, *INVERSE Compton scattering, *RADIO jets (Astrophysics), *SPECTRAL energy distribution, *SUPERMASSIVE black holes, *SOLAR flares, *SYNCHROTRON radiation, *REDSHIFT
Abstract

The high redhsift blazars powered by supermassive black holes with masses exceeding 109 M⊙ have the highest jet power and luminosity and are important probes to test the physics of relativistic jets at the early epochs of the Universe. We present a multifrequency spectral and temporal study of high redshift blazar PKS 0537−286 by analysing data from Fermi - LAT, NuSTAR Swift XRT , and UVOT. Although the time averaged γ-ray spectrum of the source is relatively soft (indicating the high-energy emission peak is below the GeV range), several prominent flares were observed when the spectrum hardened and the luminosity increased above 1049 erg s−1. The X-ray emission of the source varies in different observations and is characterized by a hard spectrum ≤1.38 with a luminosity of >1047 erg s−1. The broad-band spectral energy distribution in the quiescent and flaring periods was modelled within a one-zone leptonic scenario assuming different locations of the emission region and considering both internal (synchrotron radiation) and external (from the disc, broad-line region, and dusty torus) photon fields for the inverse Compton scattering. The modelling shows that the most optimistic scenario, from the energy requirement point of view, is when the jet energy dissipation occurs within the broad-line region. The comparison of the model parameters obtained for the quiescent and flaring periods suggests that the flaring activities are most likely caused by the hardening of the emitting electron spectral index and shifting of the cut-off energy to higher values. [ABSTRACT FROM AUTHOR]

Published
2023
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5. Gradient boosting decision trees classification of blazars of uncertain type in the fourth Fermi-LAT catalogue.

Author

Sahakyan, N, Vardanyan, V, and Khachatryan, M

Subjects
*DECISION trees, *BL Lacertae objects, *MACHINE learning, *CLASSIFICATION algorithms, *ARTIFICIAL neural networks, *CLASSIFICATION, *CATALOGS
Abstract

The deepest all-sky survey available in the γ-ray band – the last release of the Fermi-LAT catalogue (4FGL-DR3) based on the data accumulated in 12 years contains more than 6600 sources. The largest population among the sources is blazar subclass – 3743, 60.1 per cent of which are classified as BL Lacertae objects (BL Lacs) or Flat Spectrum Radio Quasars (FSRQs), while the rest are listed as blazar candidates of uncertain type (BCU) as their firm optical classification is lacking. The goal of this study is to classify BCUs using different machine learning algorithms, which are trained on the spectral and temporal properties of already classified BL Lacs and FSRQs. Artificial Neural Networks, XGBoost , and LightGBM algorithms are employed to construct predictive models for BCU classification. Using 18 input parameters of 2219 BL Lacs and FSRQs, we train (80 per cent of the sample) and test (20 per cent) these algorithms and find that LightGBM model, state-of-the-art classification algorithm based on gradient boosting decision trees, provides the highest performance. Based on our best model, we classify 825 BCUs as BL Lac candidates and 405 as FSRQ candidates, however, 190 remain without a clear prediction, but the percentage of BCUs in 4FGL is reduced to 5.1 per cent. The γ-ray photon index, synchrotron peak frequency, and high-energy peak frequency of a large sample are used to investigate the relationship between FSRQs and BL Lacs (LBLs, IBLs, and HBLs). [ABSTRACT FROM AUTHOR]

Published
2023
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6. An intermittent extreme BL Lac: MWL study of 1ES 2344+514 in anenhanced state

Author

A Acciari, Magic Collaboration V., Ansoldi, S., A Antonelli, L., Arbet&nbsp, A, Engels, Babić, A., Banerjee, B., Barres&nbsp, U, Almeida, Nbsp, A Barrio, J., Becerra&nbsp, J, González, Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bonnoli, G., Bošnjak, Ž, Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingaryan, A., Cikota, S., M Colak, S., Colin, U., Colombo, E., L Contreras, J., Cortina, J., Covino, S., Elia do Souto Espiñeira, Da&nbsp, P, Vela, Dazzi, F., De&nbsp, Angelis, B, Lotto, Delfino, M., Delgado, J., Depaoli, D., Di&nbsp, F, Pierro, L, Venere, Do&nbsp, E, Espiñeira, Souto Nbsp, Dominis&nbsp, D, Prester, Donini, A., Doro, M., Elsaesser, D., Fallah&nbsp, V, Ramazani, Fattorini, A., Ferrara, G., Foffano, L., V Fonseca, M., Font, L., Fruck, C., Fukami, S., García Nbsp, J., R, López, Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinović, N., Gliwny, P., Green, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kajiwara, Y., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Loporchio, S., Machado&nbsp, Oliveira&nbsp, de&nbsp, Fraga, Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Mender, S., Mićanović, S., Miceli, D., Miener, T., Minev, M., M Miranda, J., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., M Paredes, J., Pavletić, L., Peñil, P., Peresano, M., Persic, M., Prada Nbsp, G., Moroni, Prandini, E., Puljak, I., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tosti, L., van&nbsp, Scherpenberg, Vanzo, G., Vazquez&nbsp, M, Acosta, Ventura, S., Verguilov, V., F Vigorito, C., Vitale, V., Vovk, I., Will, M., Zarić, D., D Baack, Fact Collaboration, Balbo, M., Beck, M., Biederbeck, N., Biland, A., Blank, M., Bretz, T., Bruegge, K., Bulinski, M., Buss, J., Doerr, M., Dorner, D., Hildebrand, D., Iotov, R., Klinger, M., Mannheim, K., Achim&nbsp, S, Mueller, Neise, D., Neronov, A., Nöthe, M., Paravac, A., Rhode, W., Sedlaczek, K., Shukla, A., Sliusar, V., Tani, L., Theissen, F., Walter, R., Acosta Nbsp, J., Mwl, Collaborators, Pulido, V Filippenko, A., Hovatta, T., Kiehlmann, S., M Larionov, V., Max-Moerbeck, W., M Raiteri, C., S Readhead, A. C., Šegon, M., Villata, M., Zheng, W., German Research Foundation, Swiss National Science Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Department of Atomic Energy (India), Japan Society for the Promotion of Science, Academy of Finland, Croatian Science Foundation, University of Rijeka, Ministerio de Economía y Competitividad (España), Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Babic, A., Banerjee, B., Barres de Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingaryan, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contrera, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Foffano, L., Fonsec, M. V., Font, L., Fruck, C., Fukami, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinovic, N., Gliwny, P., Green, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kajiwara, Y., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Mender, S., Micanovic, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Parede, J. M., Pavletic, L., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suric, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tosti, L., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zaric, D., Baack, D., Balbo, M., Beck, M., Biederbeck, N., Biland, A., Blank, M., Bretz, T., Bruegge, K., Bulinski, M., Buss, J., Doerr, M., Dorner, D., Hildebrand, D., Iotov, R., Klinger, M., Mannheim, K., Achim Mueller, S., Neise, D., Neronov, A., Nothe, M., Paravac, A., Rhode, W., Sedlaczek, K., Shukla, A., Sliusar, V., Tani, L., Theissen, F., Walter, R., Acosta Pulido, J., Filippenko, A. V., Hovatta, T., Kiehlmann, S., Larionov, V. M., Max-Moerbeck, W., Raiteri, C. M., Readhead, A. C. S., Segon, M., Villata, M., Zheng, W., Metsähovi Radio Observatory, Aalto-yliopisto, and Aalto University

Subjects
Flux, OBSERVATORY SUPERNOVA SEARCH, Astrophysics, 7. Clean energy, 01 natural sciences, law.invention, law, MAGIC (telescope), 010303 astronomy & astrophysics, BL Lacertae objects: individual: 1ES 2344+514 – galaxies: active –gamma-rays: galaxies, individuals: 1Es 2344+514 [BL Lacertae objects], High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Physics, BL Lacertae objects: Individual: 1ES 2344+514, BL Lacertae objects: individuals: 1Es 2344+514, Galaxies: active, GALAXIES, active [galaxies], SPECTRAL VARIABILITY, Spectral energy distribution, Electrónica, OBJECTS, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Flare, BL Lac object, Gamma-rays: galaxies, Astrophysics and Astronomy, TELESCOPE, Astrophysics::High Energy Astrophysical Phenomena, MODELS, FOS: Physical sciences, CONNECTION, Telescope, 0103 physical sciences, Galaxies: Active, Gamma-rays: Galaxies, 010308 nuclear & particles physics, active, BL Lacertae objects: individual: 1ES 2344+514, gamma-rays: galaxies, Astrophysics - High Energy Astrophysical Phenomena [galaxies], Astronomy and Astrophysics, Light curve, individual: 1ES 2344+514 [BL Lacertae objects], Crab Nebula, galaxies [gamma-rays], Space and Planetary Science, DISCOVERY, RADIATION, ddc:520, galaxies: active, GAMMA-RAY EMISSION
Abstract

Extreme High-frequency BL~Lacs (EHBL) feature their synchrotron peak of the broadband spectral energy distribution (SED) at $\nu_{\rm s} \geq $10$^{17}$\,Hz. The BL~Lac object 1ES~2344+514 was included in the EHBL family because of its impressive shift of the synchrotron peak in 1996. During the following years, the source appeared to be in a low state without showing any extreme behaviours. In August 2016, 1ES~2344+514 was detected with the ground-based $\gamma$-ray telescope FACT during a high $\gamma$-ray state, triggering multi-wavelength (MWL) observations. We studied the MWL light curves of 1ES~2344+514 during the 2016 flaring state, using data from radio to VHE $\gamma$ rays taken with OVRO, KAIT, KVA, NOT, some telescopes of the GASP-WEBT collaboration at the Teide, Crimean, and St. Petersburg observatories, \textit{Swift}-UVOT, \textit{Swift}-XRT, \textit{Fermi}-LAT, FACT and MAGIC. With simultaneous observations of the flare, we built the broadband SED and studied it in the framework of a leptonic and an hadronic model. The VHE $\gamma$-ray observations show a flux level of 55\% of the Crab Nebula flux above 300\,GeV, similar to the historical maximum of 1995. The combination of MAGIC and \textit{Fermi}-LAT spectra provides an unprecedented characterization of the inverse-Compton peak for this object during a flaring episode. The $\Gamma$ index of the intrinsic spectrum in the VHE $\gamma$-ray band is $2.04\pm0.12_{\rm stat}\pm0.15_{\rm sys}$. We find the source in an extreme state with a shift of the position of the synchrotron peak to frequencies above or equal to $10^{18}$\,Hz, Comment: Accepted in MNRAS. Corresponding authors: M. Manganaro, A. Arbet Engels, D. Dorner

Published
2021
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7. Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and γ-ray activity in 2015-2016

Author

Banerjee, B., Terzić, T., Paneque, D., Majumdar, P., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Artero, M., Asano, K., Babić, A., Banrje, B., Baquero, A., Barres Almeida, U., Barrio, J. A., Batković, I., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bökenkamp, H., Bonnoli, G., Bošnjak, Ž, Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Giacomo D'Amico, D’elia, V., Da Vela, P., Dazzi, F., Angelis, A., Lotto, B., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espiñeira, E., Dominis Prester, D., Donini, A., Doro, M., Fallah Ramazani, V., Fattorini, A., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Fukazawa, Y., García López, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Ishio, K., Iwamura, Y., Jiménez Martínez, I., Jormanainen, J., Jouvin, L., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Machado Oliveira Fraga, B., Maggio, C., Righini, S., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Menchiari, S., Mender, S., Mićanović, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Nakamori, T., Nava, L., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Vera, R. J. C., Paoletti, R., Paredes, J. M., Pavletić, L., Peñil, P., Persic, M., Pihet, M., Prada Moroni, P. G., Prandini, E., Priyadarshi, C., Puljak, I., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Lien, A. Y., Schmidt, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Spolon, A., Stamerra, A., Strišković, J., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Järvelä, E., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Yamamoto, T., Zarić, D., Arbet-Engels, A., Baack, D., Balbo, M., Biland, A., Bretz, T., Buss, J., Dorner, D., Eisenberger, L., Elsaesser, D., Hildebrand, D., Iotov, R., Kalenski, A., Mannheim, K., Mitchell, A., Neise, D., Noethe, M., Paravac, A., Rhode, W., Schleicher, B., Sliusar, V., Walter, R., Valverde, J., Horan, D., Giroletti, M., Perri, M., Verrecchia, F., Leto, C., Sadun, A. C., Moody, J. W., Joner, M., Marscher, A. P., Jorstad, S. G., Lähteenmäki, A., Tornikoski, M., Ramakrishnan, V., Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), MAGIC, ITA, USA, GBR, DEU, ARM, BRA, CHL, HRV, FIN, JPN, IND, POL, RUS, CHE, German Research Foundation, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Department of Atomic Energy (India), Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), Ministry of Education, Youth and Science (Bulgaria), Academy of Finland, University of Tokyo, La Caixa, University of Rijeka, Polish National Agency for Academic Exchange, Ministério da Ciência e Tecnologia (Brasil), Croatian Science Foundation, Department of Electronics and Nanoengineering, Metsähovi Radio Observatory, Aalto-yliopisto, Aalto University, Acciari, Va, Ansoldi, S, Antonelli, La, Asano, K, Babic, A, Banerjee, B, Baquero, A, de Almeida, Ub, Barrio, Ja, Gonzalez, Jb, Bednarek, W, Bellizzi, L, Bernardini, E, Bernardos, M, Berti, A, Besenrieder, J, Bhattacharyya, W, Bigongiari, C, Blanch, O, Bonnoli, G, Bosnjak, Z, Busetto, G, Carosi, R, Ceribella, G, Cerruti, M, Chai, Y, Chilingarian, A, Cikota, S, Colak, Sm, Colombo, E, Contreras, Jl, Cortina, J, Covino, S, D'Amico, G, D'Elia, V, Da Vela, P, Dazzi, F, De Angelis, A, De Lotto, B, Delfino, M, Delgado, J, Mendez, Cd, Depaoli, D, Di Girolamo, T, Di Pierro, F, Di Venere, L, Neira, Ede, Prester, Dd, Donini, A, Doro, M, Ramazani, Vf, Fattorini, A, Ferrara, G, Foffano, L, Fonseca, Mv, Font, L, Fruck, C, Fukami, S, Lopez, Rjg, Garczarczyk, M, Gasparyan, S, Gaug, M, Giglietto, N, Giordano, F, Gliwny, P, Green, Jg, Green, D, Hadasch, D, Hahn, A, Heckmann, L, Herrera, J, Hoang, J, Hrupec, D, Hutten, M, Inada, T, Inoue, S, Ishio, K, Iwamura, Y, Jormanainen, J, Jouvin, L, Kajiwara, Y, Karjalainen, M, Kerszberg, D, Kobayashi, Y, Kubo, H, Kushida, J, Lamastra, A, Lelas, D, Leone, F, Lindfors, E, Lombardi, S, Longo, F, Lopez, M, Lopez-Coto, R, Lopez-Oramas, A, Loporchio, S, Fraga, Bmd, Maggio, C, Majumdar, P, Makariev, M, Mallamaci, M, Maneva, G, Manganaro, M, Maraschi, L, Mariotti, M, Martinez, M, Mazin, D, Mender, S, Micanovic, S, Miceli, D, Miener, T, Minev, M, Miranda, Jm, Mirzoyan, R, Molina, E, Moralejo, A, Morcuende, D, Moreno, V, Moretti, E, Munar-Adrover, P, Neustroev, V, Nigro, C, Nilsson, K, Ninci, D, Nishijima, K, Noda, K, Nozaki, S, Ohtani, Y, Oka, T, Otero-Santos, J, Palatiello, M, Paneque, D, Paoletti, R, Paredes, Jm, Pavletic, L, Penil, P, Perennes, C, Persic, M, Moroni, Pgp, Prandini, E, Priyadarshi, C, Puljak, I, Rhode, W, Ribo, M, Rico, J, Righi, C, Rugliancich, A, Saha, L, Sahakyan, N, Saito, T, Sakurai, S, Satalecka, K, Schleicher, B, Schmidt, K, Schweizer, T, Sitarek, J, Snidaric, I, Sobczynska, D, Spolon, A, Stamerra, A, Strom, D, Strzys, M, Suda, Y, Suric, T, Takahashi, M, Tavecchio, F, Temnikov, P, Terzic, T, Teshima, M, Torres-Alba, N, Tosti, L, Truzzi, S, van Scherpenberg, J, Vanzo, G, Acosta, Mv, Ventura, S, Verguilov, V, Vigorito, Cf, Vitale, V, Vovk, I, Will, M, Zaric, D, Arbet-Engels, A, Baack, D, Balbo, M, Beck, M, Biederbeck, N, Biland, A, Bretz, T, Bruegge, K, Buss, J, Dorner, D, Elsaesser, D, Hildebrand, D, Iotov, R, Klinger, M, Mannheim, K, Neise, D, Neronov, A, Noethe, M, Paravac, A, Sliusar, V, Theissen, F, Walter, R, Valverde, J, Horan, D, Giroletti, M, Perri, M, Verrecchia, F, Leto, C, Sadun, Ac, Moody, Jw, Joner, M, Marscher, Ap, Jorstad, Sg, Lahteenmaki, A, Tornikoski, M, Ramakrishnan, V, Jarvela, E, Vera, Rjc, Righini, S, and Lien, Ay

Subjects
BL Lacertae objects: individual: Mrk 421, galaxies: active, methods: data analysis, methods: observational, radiation mechanisms: non-thermal, Non-thermal, Astrophysics, 4/3, GeV, 01 natural sciences, law.invention, Correlation, law, optical, MAGIC (telescope), data analysis [Methods], 010303 astronomy & astrophysics, Physics, individual: Mrk 421 [BL Lacertae objects], radio wave, Gamma ray, Low activity, X-ray, non-thermal [radiation mechanisms], Synchrotron, Log-normal distribution, Electrónica, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Radio wave, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, VHE, GLAST, blazar, Flux (metallurgy), 0103 physical sciences, synchrotron, Radiation mechanisms, TeV, observational [Methods], Blazar, 010308 nuclear & particles physics, Astronomy and Astrophysics, Spectral component, MAGIC, flux, Space and Planetary Science, 13. Climate action, gamma ray, correlation, data analysi [methods], ddc:520, spectral, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Energy (signal processing)
Abstract

Acciari, V. A., et al. (MAGIC Collaboration), We report a characterization of the multiband flux variability and correlations of the nearby (z = 0.031) blazar Markarian 421 (Mrk 421) using data from Metsähovi, Swift, Fermi-LAT, MAGIC, FACT, and other collaborations and instruments from 2014 November till 2016 June. Mrk 421 did not show any prominent flaring activity, but exhibited periods of historically low activity above 1 TeV (F>1 TeV < 1.7 × 10-12 ph cm-2 s-1) and in the 2-10 keV (X-ray) band (F 2-10, keV< 3.6× 10-11 erg cm-2 s-1), during which the Swift-BAT data suggest an additional spectral component beyond the regular synchrotron emission. The highest flux variability occurs in X-rays and very high-energy (E > 0.1 TeV) γ-rays, which, despite the low activity, show a significant positive correlation with no time lag. The HRkeV and HRTeV show the harder-when-brighter trend observed in many blazars, but the trend flattens at the highest fluxes, which suggests a change in the processes dominating the blazar variability. Enlarging our data set with data from years 2007 to 2014, we measured a positive correlation between the optical and the GeV emission over a range of about 60 d centred at time lag zero, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 d centred at a time lag of 43+9-6 d. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions of the jet. The flux distributions are better described with a lognormal function in most of the energy bands probed, indicating that the variability in Mrk 421 is likely produced by a multiplicative process., The financial support of the German BMBF and MPG; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish MINECO (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729-C6-2-R, FPA2017-82729-C6-6-R, FPA2017-82729-C6-5-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2017-87055-C2-2-P, FPA2017-90566-REDC); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant nr. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia ‘Severo Ochoa’ SEV-2016-0588 and SEV-2015-0548, the Unidad de Excelencia ‘María de Maeztu’ MDM-2014-0369 and the ‘la Caixa’ Foundation (fellowship LCF/BQ/PI18/11630012), by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq, and FAPERJ.

Published
2021

8. first hard X-ray spectral catalogue of Blazars observed by NuSTAR.

Author

Middei, R, Giommi, P, Perri, M, Turriziani, S, Sahakyan, N, Chang, Y L, Leto, C, and Verrecchia, F

Subjects
HARD X-rays, SPECTRAL energy distribution, SOLAR flares, ACTIVE galactic nuclei, BL Lacertae objects, DOWNLOADING
Abstract

Blazars are a peculiar class of active galactic nuclei that enlighten the sky at all wavelengths. The electromagnetic emission of these sources is jet-dominated, resulting in a spectral energy distribution (SED) that has a typical double-humped shape. X-ray photons provide a wealth of information on the physics of each source as in the X-ray band, we can observe the tail of SED first peak, the rise of the second one or the transition between the two. NuSTAR , thanks to its capability of focusing X-rays up to 79 keV provides broad-band data particularly suitable to compute SEDs in a still poorly explored part of the spectrum. In the context of the Open Universe initiative, we developed a dedicated pipeline, NuSTAR_Spectra , a shell-script that automatically downloads data from the archive, generates scientific products and carries out a complete spectral analysis. The script homogeneously extracts high level scientific products for both NuSTAR 's telescopes and the spectral characterization is performed testing two phenomenological models. The corresponding X-ray properties are derived from the data best fit, and the SEDs are also computed. The systematic processing of all blazar observations of the NuSTAR public archive allowed us to release the first hard X-ray spectroscopic catalogue of blazars (NuBlazar). The catalogue, updated to 2021 September 30, includes 253 observations of 126 distinct blazars, 30 of which have been multiply observed. [ABSTRACT FROM AUTHOR]

Published
2022
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9. Measurement of the Extragalactic Background Light using MAGIC and Fermi-LAT gamma-ray observations of blazars up to z = 1

Author

Acciari, V A, Ansoldi, S, Antonelli, L A, Arbet&nbsp, Engels, A, Baack, D, Babić, A, Banerjee, B, Barresundefined, deundefined, Almeida, U, Barrio, J A, Becerraundefined, González, J, Bednarek, W, Bellizzi, L, Bernardini, E, Berti, A, Besenrieder, J, Bhattacharyya, W, Bigongiari, C, Biland, A, Blanch, O, Bonnoli, G, Busetto, G, Carosi, R, Ceribella, G, Chai, Y, Cikota, S, Colak, S M, Colin, U, Colombo, E, Contreras, J L, Cortina, J, Covino, S, D’Elia, V, Daundefined, Vela, P, Dazzi, F, Deundefined, Angelis, A, Lotto, B, Delfino, M, Delgado, J, Diundefined, Pierro, F, Doundefined, Soutoundefined, Espiñeira, E, Domínguez, A, Dominisundefined, Prester, D, Dorner, D, Doro, M, Elsaesser, D, Fallahundefined, Ramazani, V, Fattorini, A, Fernández-Barral, A, Ferrara, G, Fidalgo, D, Foffano, L, Fonseca, M V, Font, L, Fruck, C, Galindo, D, Gallozzi, S, Garcíaundefined, López, R J, Garczarczyk, M, Gasparyan, S, Gaug, M, Godinović, N, Green, D, Guberman, D, Hadasch, D, Hahn, A, Hassan, T, Herrera, J, Hoang, J, Hrupec, D, Inoue, S, Ishio, K, Iwamura, Y, Kubo, H, Kushida, J, Lamastra, A, Lelas, D, Leone, F, Lindfors, E, Lombardi, S, Longo, F, López, M, López-Coto, R, López-Oramas, A, Machadoundefined, Oliveiraundefined, Fraga, B, Maggio, C, Majumdar, P, Makariev, M, Mallamaci, M, Maneva, G, Manganaro, M, Mannheim, K, Maraschi, L, Mariotti, M, Martínez, M, Masuda, S, Mazin, D, Mićanović, S, Miceli, D, Minev, M, Miranda, J M, Mirzoyan, R, Molina, E, Moralejo, A, Morcuende, D, Moreno, V, Moretti, E, Munar-Adrover, P, Neustroev, V, Niedzwiecki, A, Nievasundefined, Rosillo, M, Nigro, C, Nilsson, K, Ninci, D, Nishijima, K, Noda, K, Nogués, L, Nöthe, M, Paiano, S, Palacio, J, Palatiello, M, Paneque, D, Paoletti, R, Paredes, J M, Peñil, P, Peresano, M, Persic, M, Pradaundefined, Moroni, P G, Prandini, E, Puljak, I, Rhode, W, Ribó, M, Rico, J, Righi, C, Rugliancich, A, Saha, L, Sahakyan, N, Saito, T, Satalecka, K, Schweizer, T, Sitarek, J, Šnidarić, I, Sobczynska, D, Somero, A, Stamerra, A, Strom, D, Strzys, M, Surić, T, Tavecchio, F, Temnikov, P, Terzić, T, Teshima, M, Torres-Albà, N, Tsujimoto, S, vanundefined, Scherpenberg, J, Vanzo, G, Vázquezundefined, Acosta, M, Vovk, I, Will, M, Zarić, D, Acciar, V. A., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Do Souto Espineira, E., Dominguez, A., Dominis Prester, D., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernandez-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., Gallozzi, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Godinovic, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Herrera, J., Hoang, J., Hrupec, D., Inoue, S., Ishio, K., Iwamura, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., MacHado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Masuda, S., Mazin, D., Micanovic, S., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nothe, M., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Suric, T., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tsujimoto, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vovk, I., Will, M., and Zaric, D.

Subjects
gamma-rays: galaxies, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies [infrared], 01 natural sciences, infrared: galaxies, diffuse background [infrared], 0103 physical sciences, galaxies: active, gamma-rays: galaxies, infrared: diffuse background, infrared: galaxies, galaxie [gamma-rays], Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Luminous infrared galaxy, Physics, infrared: diffuse background, 010308 nuclear & particles physics, Gamma ray, Astronomy and Astrophysics, Galaxy, Redshift, Stars, galaxies [gamma-rays], Extragalactic background light, Space and Planetary Science, active [galaxies], ddc:520, Astrophysics - High Energy Astrophysical Phenomena, Fermi Gamma-ray Space Telescope
Abstract

We present a measurement of the extragalactic background light (EBL) based on a joint likelihood analysis of 32 gamma-ray spectra for 12 blazars in the redshift range z = 0.03 to 0.944, obtained by the MAGIC telescopes and Fermi-LAT. The EBL is the part of the diffuse extragalactic radiation spanning the ultraviolet, visible and infrared bands. Major contributors to the EBL are the light emitted by stars through the history of the universe, and the fraction of it which was absorbed by dust in galaxies and re-emitted at longer wavelengths. The EBL can be studied indirectly through its effect on very-high energy photons that are emitted by cosmic sources and absorbed via photon-photon interactions during their propagation across cosmological distances. We obtain estimates of the EBL density in good agreement with state-of-the-art models of the EBL production and evolution. The 1-sigma upper bounds, including systematic uncertainties, are between 13% and 23% above the nominal EBL density in the models. No anomaly in the expected transparency of the universe to gamma rays is observed in any range of optical depth.We also perform a wavelength-resolved EBL determination, which results in a hint of an excess of EBL in the 0.18 - 0.62 $\mu$m range relative to the studied models, yet compatible with them within systematics., Comment: Accepted by MNRAS

Published
2019

10. The Open Universe survey of Swift-XRT GRB fields: a complete sample of HBL blazars

Author

Giommi, P., Chang, Y. L., Turriziani, S., Glauch, T., Leto, C., Verrecchia, F., Padovani, P., Penacchioni, Ana Virginia, Arneodo, F., Barres de Almeida, U., Brandt, C. H., Capalbi, M., Civitarese, Enrique Osvaldo, D’Elia, V., Di Giovanni, A., De Angelis, M., Del Rio Vera, J., Di Pippo, S., Middei, R., Perri, M., Pollock, A. M. T., Puccetti, S., Ricard, N., Ruffini, R., and Sahakyan, N.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, Física, FOS: Physical sciences, methods: data analysis, galaxies [X-rays], X-rays: galaxies, surveys, active [galaxies], data analysis [methods], Astrophysics - High Energy Astrophysical Phenomena, Ciencias Exactas, catalogs
Abstract

Aims. The sample of serendipitous sources detected in all Swift-XRT images pointing at gamma ray bursts (GRBs) constitutes the largest existing medium-deep survey of the X-ray sky. To build such dataset we analysed all Swift X-ray images centred on GRBs and observed over a period of 15 years using automatic tools that do not require any expertise in X-ray astronomy. Besides presenting a new large X-ray survey and a complete sample of blazars, this work aims to be a step in the direction of achieving the ultimate goal of the Open Universe Initiative, which is to enable non-expert people to benefit fully from space science data, possibly extending the potential for scientific discovery, which is currently confined within a small number of highly specialised teams, to a much larger population. Methods. We used the Swift_deepsky Docker container encapsulated pipeline to build the largest existing flux-limited and unbiased sample of serendipitous X-ray sources. Swift_deepsky runs on any laptop or desktop computer with a modern operating system. The tool automatically downloads the data and the calibration files from the archives, runs the official Swift analysis software, and produces a number of results including images, the list of detected sources, X-ray fluxes, spectral energy distribution data, and spectral slope estimations. Results. We used our source list to build the LogN-LogS of extra-galactic sources, which perfectly matches that estimated by other satellites. Combining our survey with multi-frequency data, we selected a complete radio-flux-density-limited sample of high energy peaked blazars (HBL). The LogN-LogS built with this data set confirms that previous samples are incomplete below ∼20 mJy, Instituto de Física La Plata

Published
2020
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11. X-ray spectra, light curves and SEDs of blazars frequently observed by Swift.

Author

Giommi, Paolo, Perri, M, Capalbi, M, D'Elia, V, Barres de Almeida, U, Brandt, C H, Pollock, A M T, Arneodo, F, Di Giovanni, A, Chang, Y L, Civitarese, O, De Angelis, M, Leto, C, Verrecchia, F, Ricard, N, Di Pippo, S, Middei, R, Penacchioni, A V, Ruffini, R, and Sahakyan, N

Subjects
X-ray spectra, LIGHT curves, BL Lacertae objects, SPECTRAL energy distribution, ASTROPHYSICS, ENERGY bands, COSMIC rays
Abstract

Blazars research is one of the hot topics of contemporary extragalactic astrophysics. That is because these sources are the most abundant type of extragalactic γ-ray sources and are suspected to play a central role in multimessenger astrophysics. We have used Swift |$\_$| xrtproc, a tool to carry out an accurate spectral and photometric analysis of the Swift-XRT data of all blazars observed by Swift at least 50 times between December 2004 and the end of 2020. We present a database of X-ray spectra, best-fit parameter values, count rates and flux estimations in several energy bands of over 31 000 X-ray observations and single snapshots of 65 blazars. The results of the X-ray analysis have been combined with other multifrequency archival data to assemble the broad-band Spectral Energy Distributions (SEDs) and the long-term light curves of all sources in the sample. Our study shows that large X-ray luminosity variability on different time-scales is present in all objects. Spectral changes are also frequently observed with a 'harder-when-brighter' or 'softer-when-brighter' behaviour depending on the SED type of the blazars. The peak energy of the synchrotron component (νpeak) in the SED of HBL blazars, estimated from the log-parabolic shape of their X-ray spectra, also exhibits very large changes in the same source, spanning a range of over two orders of magnitude in Mrk421 and Mrk501, the objects with the best data sets in our sample. [ABSTRACT FROM AUTHOR]

Published
2021
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12. Multiwavelength study of high-redshift blazars.

Author

Sahakyan, N, Israyelyan, D, Harutyunyan, G, Khachatryan, M, and Gasparyan, S

Subjects
*SPECTRAL energy distribution, *X-ray spectra, *COMPTON scattering, *HARD X-rays, *OPTICAL telescopes, *SOLAR flares, *GAMMA ray bursts
Abstract

High-redshift blazars are among the most powerful objects in the Universe. The spectral and temporal properties of 33 distant blazars (z > 2.5) detected in the high-energy γ-ray band are investigated by analysing the Fermi -LAT and Swift Ultraviolet and Optical Telescope/X-ray Telescope (UVOT/XRT) data. The considered sources have soft time-averaged γ-ray spectra (Γγ ≥ 2.2) whereas those that have been observed in the X-ray band have hard X-ray spectra (ΓX = 1.01−1.86). The γ-ray flux of high-redshift blazars ranges from 4.84 × 10−10 to 1.50 × 10−7 photon cm−2 s−1 and the luminosity is within (0.10−5.54) × 1048 erg s−1 which during the γ-ray flares increases up to (0.1−1) × 1050 erg s−1. In the X-ray band, only the emission of PKS 0438−43, B2 0743+25, and TXS 0222+185 is found to vary in different Swift XRT observations whereas in the γ-ray band, the emission is variable for fourteen sources: the flux of B3 1343+451 and PKS 0537−286 changes in sub-day scales, that of PKS 0347−211 and PKS 0451−28 in day scales, while the γ-ray variability of the others is in week or month scales. The properties of distant blazar jets are derived by modelling the multiwavelength spectral energy distributions within a one-zone leptonic scenario assuming that the X-ray and γ-ray emissions are produced from inverse Compton scattering of synchrotron and dusty torus photons. From the fitting, the emission region size is found to be ≤0.05 pc and the magnetic field and the Doppler factor are correspondingly within 0.10−1.74 G and 10.0−27.4. By modelling the optical–UV excess, we found that the central black hole masses and accretion disc luminosities are within L d ≃ (1.09−10.94) × 1046 erg s−1 and (1.69−5.35) × 109 M⊙, respectively. [ABSTRACT FROM AUTHOR]

Published
2020
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13. Open Universe for Blazars: a new generation of astronomical products based on 14 years of Swift-XRT data.

Author

Giommi, P., Brandt, C. H., Barres de Almeida, U., Pollock, A. M. T., Arneodo, F., Chang, Y. L., Civitarese, O., De Angelis, M., D'Elia, V., Del Rio Vera, J., Di Pippo, S., Middei, R., Penacchioni, A. V., Perri, M., Ruffini, R., Sahakyan, N., and Turriziani, S.

Subjects
RADIANT intensity, SPACE sciences, DATA science, UNIVERSE, ASTROPHYSICS, GALACTIC X-ray sources, MACINTOSH (Computer)
Abstract

Aims. Open Universe for Blazars is a set of high-transparency multi-frequency data products for blazar science, and the tools designed to generate them. Blazars are drawing growing interest following the consolidation of their position as the most abundant type of source in the extragalactic very high-energy γ-ray sky, and because of their status as prime candidate sources in the nascent field of multi-messenger astrophysics. As such, blazar astrophysics is becoming increasingly data driven, depending on the integration and combined analysis of large quantities of data from the entire span of observational astrophysics techniques. The project was therefore chosen as one of the pilot activities within the United Nations Open Universe Initiative, whose objective is to stimulate a large increase in the accessibility and ease of utilisation of space science data for the worldwide benefit of scientific research, education, capacity building, and citizen science. Methods. Our aim is to deliver innovative data science tools for multi-messenger astrophysics. In this work we report on a data analysis pipeline called Swift-DeepSky based on the Swift XRTDAS software and the XIMAGE package, encapsulated into a Docker container. Swift-DeepSky downloads and reads low-level data, generates higher level products, detects X-ray sources, and estimates several intensity and spectral parameters for each detection, thus facilitating the generation of complete and up-to-date science-ready catalogues from an entire space-mission data set. Results. As a first application of our innovative approach, we present the results of a detailed X-ray image analysis based on Swift-DeepSky that was run on all Swift-XRT observations including a known blazar, carried out during the first 14 years of operations of the Neil Gehrels Swift Observatory. Short exposures executed within one week of each other have been added to increase sensitivity, which ranges between ∼1 × 10−12 and ∼1 × 10−14 erg cm−2 s−1 (0.3–10.0 keV). After cleaning for problematic fields, the resulting database includes over 27 000 images integrated in different X-ray bands, and a catalogue, called 1OUSXB, that provides intensity and spectral information for 33 396 X-ray sources, 8896 of which are single or multiple detections of 2308 distinct blazars. All the results can be accessed online in a variety of ways, from the Open Universe portal through Virtual Observatory services, via the VOU-Blazar tool and the SSDC SED builder. One of the most innovative aspects of this work is that the results can be easily reproduced and extended by anyone using the Docker version of the Swift-DeepSky pipeline, which runs on Linux, Mac, and Windows machines, and does not require any specific experience in X-ray data analysis. [ABSTRACT FROM AUTHOR]

Published
2019
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14. Dissecting the region around IceCube-170922A: the blazar TXS 0506+056 as the first cosmic neutrino source.

Author

Padovani, P, Giommi, P, Resconi, E, Glauch, T, Arsioli, B, Sahakyan, N, and Huber, M

Subjects
BL Lacertae objects, COSMIC neutrino background, SPACETIME, COSMIC rays, FERMI energy
Abstract

We present the dissection in space, time, and energy of the region around the IceCube-170922A neutrino alert. This study is motivated by: (1) the first association between a neutrino alert and a blazar in a flaring state, TXS 0506+056; (2) the evidence of a neutrino flaring activity during 2014–2015 from the same direction; (3) the lack of an accompanying simultaneous γ-ray enhancement from the same counterpart; (4) the contrasting flaring activity of a neighbouring bright γ-ray source, the blazar PKS 0502+049, during 2014–2015. Our study makes use of multiwavelength archival data accessed through Open Universe tools and includes a new analysis of Fermi -LAT data. We find that PKS 0502+049 contaminates the γ-ray emission region at low energies but TXS 0506+056 dominates the sky above a few GeV. TXS 0506+056, which is a very strong (top percent) radio and γ-ray source, is in a high γ-ray state during the neutrino alert but in a low though hard γ-ray state in coincidence with the neutrino flare. Both states can be reconciled with the energy associated with the neutrino emission and, in particular during the low/hard state, there is evidence that TXS 0506+056 has undergone a hadronic flare with very important implications for blazar modelling. All multimessenger diagnostics reported here support a single coherent picture in which TXS 0506+056, a very high energy γ-ray blazar, is the only counterpart of all the neutrino emissions in the region and therefore the most plausible first non-stellar neutrino and, hence, cosmic ray source. [ABSTRACT FROM AUTHOR]

Published
2018
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15. High energy gamma-ray emission from PKS 1441+25.

Author

Sahakyan, N. and Gasparyan, S.

Subjects
*RADIO sources (Astronomy), *QUASARS, *GAMMA rays, *SPECTRUM analysis, *ASTRONOMICAL research
Abstract

We present theγ -ray observations of the flat-spectrum radio quasar PKS 1441+25 (z=0.939), using the Fermi large Area Telescope data accumulated during 2015 January-December. A γ-ray flare was observed in January 24, when the flux increased up to (2.22 ± 0.38) x 10-6 photon cm-2 s-1 with the flux-doubling time-scale being as short as ∼1.44 d. The spectral analysis shows that from 2015 April 13 to April 28, the MeV-to-GeV photon index has hardened and changes in the range of Γ = (1.73-1.79) for most of the time. The hardest photon index of Γ = 1.54 ± 0.16 has been observed on MJD 57 131.46 with 11.8σ which is not common for flat-spectrum radio quasars. For the same period theγ -ray spectrum shows a possible deviation from a simple power-law shape, indicating a spectral cutoff at Ecut = 17.7 ± 8.9 GeV. The spectral energy distributions during quiescent and flaring states are modelled using one-zone leptonic models that include the synchrotron, synchrotron self Compton and external inverse Compton processes; the model parameters are estimated using the Markov Chain Monte Carlo method. The emission in the flaring states can be modelled assuming that either the bulk Lorentz factor or the magnetic field has increased. The modelling shows that there is a hint of hardening of the low-energy index (∼1.98) of the underlying non-thermal distribution of electrons responsible for the emission in 2015 April. Such hardening agrees with theγ -ray data, which pointed out a significantγ -ray photon index hardening on 2015 April 13 to 28. [ABSTRACT FROM AUTHOR]

Published
2017
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16. Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017

Author

Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Artero, M., Asano, K., Babi��, A., Baquero, A., de Almeida, U. Barres, Barrio, J. A., Batkovi��, I., Gonz��lez, J. Becerra, Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bo��njak, Z., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Mendez, C. Delgado, Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espi��eira, E., Prester, D. Dominis, Donini, A., Doro, M., Ramazani, V. Fallah, Fattorini, A., Ferrara, G., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., L��pez, R. J. Garc��a, Garczarczyk, Markus, Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovi��, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., H��tten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jim��nez, I., Jormanainen, J., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., L��pez-Coto, R., L��pez-Moya, M., L��pez-Oramas, A., Loporchio, S., de Oliveira Fraga, B. Machado, Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Mart��nez, M., Mazin, D., Menchiari, S., Mender, S., Mi��anovi��, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavleti��, L., Pe��il, P., Perennes, C., Persic, M., Moroni, P. G. Prada, Prandini, E., Priyadarshi, C., Puljak, I., Rib��, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schmidt, K., Schweizer, T., Sitarek, J., ��nidari��, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suri��, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzi��, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Vanzo, G., Acosta, M. Vazquez, Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Zari��, D., Baack, D., Balbo, M., Biederbeck, N., Biland, A., Bretz, T., Buss, J., Dorner, D., Eisenberger, L., Elsaesser, D., Hildebrand, D., Iotov, R., Mannheim, K., Neise, D., Noethe, M., Paravac, A., Rhode, W., Schleicher, B., Sliusar, V., Walter, R., D'Ammando, F., Horan, D., Lien, A. Y., Balokovi��, M., Madejski, G. M., Perri, M., Verrecchia, F., Leto, C., L��hteenm��ki, A., Tornikoski, M., Ramakrishnan, V., J��rvel��, E., Vera, R. J. C., Chamani, W., Villata, M., Raiteri, C. M., Gupta, A. C., Pandey, A., Fuentes, A., Agudo, I., Casadio, C., Semkov, E., Ibryamov, S., Marchini, A., Bachev, R., Strigachev, A., Ovcharov, E., Bozhilov, V., Valcheva, A., Zaharieva, E., Damljanovic, G., Vince, O., Larionov, V. M., Borman, G. A., Grishina, T. S., Hagen-Thorn, V. A., Kopatskaya, E. N., Larionova, E. G., Larionova, L. V., Morozova, D. A., Nikiforova, A. A., Savchenko, S. S., Troitskiy, I. S., Troitskaya, Y. V., Vasilyev, A. A., Merkulova, O. A., Chen, W. P., Samal, M., Lin, H. C., Moody, J. W., Sadun, A. C., Jorstad, S. G., Marscher, A. P., Weaver, Z. R., Feige, M., Kania, J., Kopp, M., Kunkel, L., Reinhart, D., Scherbantin, A., Schneider, L., Lorey, C., Acosta-Pulido, J. A., Carnerero, M. I., Carosati, D., Kurtanidze, S. O., Kurtanidze, O. M., Nikolashvili, M. G., Chanishvili, R. G., Chigladze, R. A., Ivanidze, R. Z., Kimeridze, G. N., Sigua, L. A., Joner, M. D., Spencer, M., Giroletti, M., Marchili, N., Righini, S., Rizzi, N., and Bonnoli, G.

Subjects
electron, galaxies: active, flux: correlation, GeV, radiation mechanisms: non-thermal, 7. Clean energy, MAGIC, GLAST, blazar, gamma ray: VHE, ultraviolet, optical, spectral, TeV, BL Lacertae objects: individual: Mrk 421, X-ray: flux, model: leptonic, Lorentz
Abstract

Astronomy and astrophysics 655, A89 (2021). doi:10.1051/0004-6361/202141004, Aims. We present a detailed characterisation and theoretical interpretation of the broadband emission of the paradigmatic TeV blazar Mrk 421, with a special focus on the multi-band flux correlations.Methods. The dataset has been collected through an extensive multi-wavelength campaign organised between 2016 December and 2017 June. The instruments involved are MAGIC, FACT, Fermi-LAT, Swift, GASP-WEBT, OVRO, Medicina, and Mets��hovi. Additionally, four deep exposures (several hours long) with simultaneous MAGIC and NuSTAR observations allowed a precise measurement of the falling segments of the two spectral components.Results. The very-high-energy (VHE; E > 100 GeV) gamma rays and X-rays are positively correlated at zero time lag, but the strength and characteristics of the correlation change substantially across the various energy bands probed. The VHE versus X-ray fluxes follow different patterns, partly due to substantial changes in the Compton dominance for a few days without a simultaneous increase in the X-ray flux (i.e., orphan gamma-ray activity). Studying the broadband spectral energy distribution (SED) during the days including NuSTAR observations, we show that these changes can be explained within a one-zone leptonic model with a blob that increases its size over time. The peak frequency of the synchrotron bump varies by two orders of magnitude throughout the campaign. Our multi-band correlation study also hints at an anti-correlation between UV-optical and X-ray at a significance higher than 3��. A VHE flare observed on MJD 57788 (2017 February 4) shows gamma-ray variability on multi-hour timescales, with a factor ten increase in the TeV flux but only a moderate increase in the keV flux. The related broadband SED is better described by a two-zone leptonic scenario rather than by a one-zone scenario. We find that the flare can be produced by the appearance of a compact second blob populated by high energetic electrons spanning a narrow range of Lorentz factors, from �����$_{min}$=2��10$^4$ to �����$_{max}$=6��10$^5$.Key words: galaxies: active / BL Lacertae objects: individual: Mrk 421 / radiation mechanisms: non-thermal��� Light curves and spectral energy distributions data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/655/A89������ Corresponding authors: A. Arbet Engels and D. Paneque; e-mail: contact.magic@mpp.mpg.de.��������� Also member of the MAGIC Collaboration.������������ Also member of the FACT Collaboration., Published by EDP Sciences, Les Ulis

17. First detection of VHE gamma-ray emission from TXS 1515���273, study of its X-ray variability and spectral energy distribution

Author

Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Artero, M., Asano, K., Baack, D., Babi��, A., Baquero, A., de Almeida, U. Barres, Barrio, J. A., Batkovi��, I., Gonz��lez, J. Becerra, Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bo��njak, ��., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Mendez, C. Delgado, Depaoli, D., Di Pierro, F., Di Venere, L., Espi��eira, E. Do Souto, Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., Ramazani, V. Fallah, Fattorini, A., Ferrara, G., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., L��pez, R. J. Garc��a, Garczarczyk, Markus, Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovi��, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., H��tten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jim��nez, I., Jormanainen, J., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., L��pez-Coto, R., L��pez-Moya, M., L��pez-Oramas, A., Loporchio, S., Fraga, B. Machado de Oliveira, Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Mart��nez, M., Mazin, D., Menchiari, S., Mender, S., Mi��anovi��, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavleti��, L., Pe��il, P., Perennes, C., Persic, M., Moroni, P. G. Prada, Prandini, E., Priyadarshi, C., Puljak, I., Rhode, W., Rib��, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., ��nidari��, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suri��, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzi��, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Vanzo, G., Acosta, M. Vazquez, Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Zaric, D., Bissaldi, E., Bonnoli, G., Cutini, S., D'Ammando, F., Nabizadeh, A., Marchini, A., and Orienti, M.

Subjects
Radiation mechanisms: non-thermal, objects: individual: TXS 1515���273, galaxies: active, 7. Clean energy
Abstract

Monthly notices of the Royal Astronomical Society 507(1), 1528 - 1545 (2021). doi:10.1093/mnras/stab1994, We report here on the first multiwavelength (MWL) campaign on the blazar TXS 1515���273, undertaken in 2019 and extending from radio to very-high-energy gamma-rays (VHE). Up until now, this blazar had not been the subject of any detailed MWL observations. It has a rather hard photon index at GeV energies and was considered a candidate extreme high-synchrotron-peaked source. MAGIC observations resulted in the first-time detection of the source in VHE with a statistical significance of 7.6��. The average integral VHE flux of the source is 6 �� 1 per cent of the Crab nebula flux above 400 GeV. X-ray coverage was provided by Swift-XRT, XMM���Newton, and NuSTAR. The long continuous X-ray observations were separated by ���9 h, both showing clear hour scale flares. In the XMM���Newton data, both the rise and decay time-scales are longer in the soft X-ray than in the hard X-ray band, indicating the presence of a particle cooling regime. The X-ray variability time-scales were used to constrain the size of the emission region and the strength of the magnetic field. The data allowed us to determine the synchrotron peak frequency and classify the source as a flaring high, but not extreme synchrotron-peaked object. Considering the constraints and variability patterns from the X-ray data, we model the broad-band spectral energy distribution. We applied a simple one-zone model, which could not reproduce the radio emission and the shape of the optical emission, and a two-component leptonic model with two interacting components, enabling us to reproduce the emission from radio to VHE band., Published by Oxford Univ. Press, Oxford

18. Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and $\gamma$-ray activity in 2015$-$2016

Author

Acciari, V. A., Ansoldi, S., Antonelli, L. A., Asano, K., Babić, A., Banerjee, Debasish, Baquero, A., Barres de Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, Elisa, Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bonnoli, G., Bošnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Girolamo, T., Di Pierro, F., Di Venere, L., Do Souto Espiñeira, E., Dominis Prester, D., Donini, A., Doro, M., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., García López, R. J., Garczarczyk, Markus, Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jormanainen, J., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Mender, S., Mićanović, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Peñil, P., Perennes, C., Persic, M., Prada Moroni, P. G., Prandini, E., Priyadarshi, C., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, Konstancja, Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tosti, L., Truzzi, S., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zarić, D., Arbet-Engels, A., Baack, D., Balbo, M., Beck, M., Biederbeck, N., Biland, A., Bretz, T., Bruegge, K., Buss, J., Dorner, D., Elsaesser, D., Hildebrand, D., Iotov, R., Klinger, M., Mannheim, K., Neise, D., Neronov, A., Noethe, M., Paravac, A., Sliusar, V., Theissen, F., Walter, R., Valverde, J., Horan, D., Giroletti, M., Perri, M., Verrecchia, F., Leto, C., Sadun, A. C., Moody, J. W., Joner, M., Marscher, A. P., Jorstad, S. G., Lähteenmäki, A., Tornikoski, M., Ramakrishnan, V., Järvelä, E., Vera, R. J. C., Righini, S., and Lien, A. Y.

Subjects
radio wave, galaxies: active, GeV, 4/3, radiation mechanisms: non-thermal, MAGIC, methods: data analysis, GLAST, VHE, blazar, X-ray, flux, 13. Climate action, gamma ray, correlation, synchrotron, optical, TeV, spectral, BL Lacertae objects: individual: Mrk 421, methods: observational
Abstract

Monthly notices of the Royal Astronomical Society 504(1), 1427 (2021). doi:10.1093/mnras/staa3727, We report a characterization of the multiband flux variability and correlations of the nearby (z = 0.031) blazar Markarian 421 (Mrk 421) using data from Metsähovi, Swift, Fermi-LAT, MAGIC, FACT, and other collaborations and instruments from 2014 November till 2016 June. Mrk 421 did not show any prominent flaring activity, but exhibited periods of historically low activity above 1 TeV (F_>1 TeV < 1.7 × 10^−12 ph cm^−2 s^−1) and in the 2–10 keV (X-ray) band (F|$_{2-10\, \mathrm{keV}}\lt 3.6\times 10^{-11}$| erg cm^−2 s^−1), during which the Swift-BAT data suggest an additional spectral component beyond the regular synchrotron emission. The highest flux variability occurs in X-rays and very high-energy (E > 0.1 TeV) γ-rays, which, despite the low activity, show a significant positive correlation with no time lag. The HR_keV and HR_TeV show the harder-when-brighter trend observed in many blazars, but the trend flattens at the highest fluxes, which suggests a change in the processes dominating the blazar variability. Enlarging our data set with data from years 2007 to 2014, we measured a positive correlation between the optical and the GeV emission over a range of about 60 d centred at time lag zero, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 d centred at a time lag of |$43^{+9}_{-6}$| d. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions of the jet. The flux distributions are better described with a lognormal function in most of the energy bands probed, indicating that the variability in Mrk 421 is likely produced by a multiplicative process., Published by Oxford Univ. Press, Oxford

19. An intermittent extreme BL Lac: MWL study of 1ES 2344+514 in an enhanced state

Author

Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Baack, D., Babić, A., Banerjee, B., Barres de Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bonnoli, G., Bošnjak, Ž., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Espiñeira, E. Souto, Dominis Prester, D., Donini, A., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kajiwara, Y., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Loporchio, S., de Oliveira Fraga, B. Machado, Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Mender, S., Mićanović, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Peñil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tosti, L., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zarić, D., Balbo, M., Beck, M., Biederbeck, N., Biland, A., Blank, M., Bretz, T., Bruegge, K., Bulinski, M., Buss, J., Doerr, M., Dorner, D., Hildebrand, D., Iotov, R., Klinger, M., Mannheim, K., Mueller, S. Achim, Neise, D., Neronov, A., Nöthe, M., Paravac, A., Rhode, W., Sedlaczek, K., Shukla, A., Sliusar, V., Tani, L., Theissen, F., Walter, R., MWL Collaborators, Pulido, J. Acosta, Filippenko, A. V., Hovatta, T., Kiehlmann, S., Larionov, V. M., Max-Moerbeck, W., Raiteri, C. M., Readhead, A. C. S., Šegon, M., Villata, M., and Zheng, W.

Subjects
gamma-rays: galaxies, galaxies: active, BL Lacertae objects: individual: 1ES 2344+514, 7. Clean energy
Abstract

Monthly notices of the Royal Astronomical Society 496(3), 3912 - 3928 (2020). doi:10.1093/mnras/staa1702, Extreme high-frequency BL Lacs (EHBL) feature their synchrotron peak of the broad-band spectral energy distribution (SED) at $\nu_s ≥$ 10$^{17}$ Hz. The BL Lac object 1ES 2344+514 was included in the EHBL family because of its impressive shift of the synchrotron peak in 1996. During the following years, the source appeared to be in a low state without showing any extreme behaviours. In 2016 August, 1ES 2344+514 was detected with the ground-based γ-ray telescope FACT during a high γ-ray state, triggering multiwavelength (MWL) observations. We studied the MWL light curves of 1ES 2344+514 during the 2016 flaring state, using data from radio to very-high-energy (VHE) γ-rays taken with OVRO, KAIT, KVA, NOT, some telescopes of the GASP-WEBT collaboration at the Teide, Crimean, and St. Petersburg observatories, Swift-UVOT, Swift-XRT, Fermi-LAT, FACT, and MAGIC. With simultaneous observations of the flare, we built the broad-band SED and studied it in the framework of a leptonic and a hadronic model. The VHE γ-ray observations show a flux level of 55 per cent of the Crab Nebula flux above 300 GeV, similar to the historical maximum of 1995. The combination of MAGIC and Fermi-LAT spectra provides an unprecedented characterization of the inverse-Compton peak for this object during a flaring episode. The Γ index of the intrinsic spectrum in the VHE γ-ray band is 2.04 ± 0.12$_{stat}$ ± 0.15$_{sys}$. We find the source in an extreme state with a shift of the position of the synchrotron peak to frequencies above or equal to 10$^{17}$ Hz., Published by Oxford Univ. Press, Oxford

20. Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017

Author

Katsuaki Asano, I. Jiménez, A. Fuentes, C. M. Raiteri, D. Dominis Prester, E. Molina, E. Colombo, Y. V. Troitskaya, Nikola Godinovic, Sidika Merve Colak, Jenni Jormanainen, Yuki Iwamura, Alessandra Lamastra, Lab Saha, Antoniya Valcheva, Sunay Ibryamov, Elena G. Larionova, B. De Lotto, Evgeni Ovcharov, D. Zarić, Kazuma Ishio, David A. Green, M. Villata, D. Horan, Givi N. Kimeridze, Alexander Hahn, S. Nozaki, M. Perri, Michael D. Joner, D. Neise, S. Loporchio, R. J. García López, Marcello Giroletti, Victor A. Acciari, V. Fallah Ramazani, Tomohiko Oka, Daniela Dorner, Narek Sahakyan, J. Kushida, M. Kopp, Lorenzo Bellizzi, Noah Biederbeck, Joseph Moody, M. Gaug, L. Schneider, A. López-Oramas, Daniel Morcuende, N. Rizzi, Jose Luis Contreras, G. Vanzo, Rodolfo Carosi, L. Maraschi, Andrés Baquero, M. I. Carnerero, R. Iotov, Mosè Mariotti, A. Paravac, John Hoang, Ashwani Pandey, Z. R. Weaver, Francesco Longo, F. D'Ammando, S. Paiano, Elina Lindfors, Moritz Hütten, J. Herrera, Koji Noda, Abelardo Moralejo, Laura Eisenberger, E. Moretti, Julian Sitarek, Marcos López-Moya, Wlodek Bednarek, L. Di Venere, Ashot Chilingarian, U. Barres de Almeida, Elisa Bernardini, I. Agudo, M. Feige, R. Z. Ivanidze, O. A. Merkulova, D. Depaoli, M. Spencer, Massimo Persic, J. van Scherpenberg, Pratik Majumdar, L. Kunkel, K. Nishijima, Stefano Ansoldi, Juan Cortina, Kai Phillip Schmidt, A. Berti, Riccardo Paoletti, Saverio Lombardi, Daniel Mazin, M. V. Fonseca, Damir Lelas, R. J. C. Vera, Sanae Inoue, Giacomo D'Amico, Dominik Baack, C. Perennes, A. A. Nikiforova, Yating Chai, Stefan Cikota, G. M. Madejski, A. Arbet Engels, Daniel Kerszberg, Manuel Artero, E. Do Souto Espiñeira, Tomislav Terzić, J. Becerra González, Martin Makariev, R. Mirzoyan, Yoshiki Ohtani, G. A. Borman, Pawel Gliwny, Jose Miguel Miranda, A. De Angelis, Vitaly Neustroev, Wara Chamani, Oscar Blanch, T. S. Grishina, Martin Will, M. Vazquez Acosta, Nicola Giglietto, L. V. Larionova, Lea Heckmann, Francesco Gabriele Saturni, Jorge Otero-Santos, R. A. Chigladze, M. Balbo, N. Marchili, D. Hadasch, P. G. Prada Moroni, A. A. Vasilyev, M. G. Nikolashvili, Jordi Delgado, V. Ramakrishnan, Christian Fruck, G. Busetto, Victoria Moreno, Luca Tosti, A. Rugliancich, C. Nigro, Marina Manganaro, Valeri M. Larionov, M. Balokovic, Manuel Delfino, A. Strigachev, J. M. Paredes, Manash R. Samal, Stefano Covino, I. Vovk, H. C. Lin, Ž. Bošnjak, Stefano Menchiari, Rumen Bachev, Marc Ribó, Dorota Sobczyńska, Carolin Wunderlich, Bernd Schleicher, M. Minev, Antonio Stamerra, Maria-Isabel Bernardos, I. S. Troitskiy, Merja Tornikoski, E. N. Kopatskaya, Shunsuke Sakurai, Camilla Maggio, Chiara Righi, F. Verrecchia, P. Temnikov, S. G. Jorstad, T. Schweizer, Hidetoshi Kubo, Lluis Font, A. Y. Lien, Toshiaki Inada, A. Scherbantin, Lorand A. Sigua, G. Maneva, Stefano Truzzi, B. Machado de Oliveira Fraga, V. Bozhilov, M. Palatiello, Alessandro Marchini, Chaitanya Priyadarshi, Alessia Spolon, Léa Jouvin, Konstancja Satalecka, Tomoki Saito, Giovanni Ceribella, Michele Doro, S. O. Kurtanidze, Carlo Vigorito, Pablo Peñil, D. Strom, Giacomo Bonnoli, Adrian Biland, Ana Babić, Alicia Fattorini, D. Hildebrand, Satoshi Fukami, G. Ferrara, Y. Kajiwara, Matteo Cerruti, P. Da Vela, Vassil Verguilov, Lovro Pavletić, C. Delgado Mendez, Emilia Järvelä, S. Mićanović, Sergey S. Savchenko, Ivica Puljak, M. Noethe, Simone Mender, Francesco Dazzi, V. Vitale, Manuela Mallamaci, Ivana Batković, F. Leone, M. I. Martínez, J. Rico, Alan P. Marscher, C. Lorey, S. Ventura, Tjark Miener, Anne Lähteenmäki, David Paneque, Masahiro Teshima, Jarred Gershon Green, Wrijupan Bhattacharyya, Kari Nilsson, R. Walter, M. Strzys, D. Reinhart, E. Zaharieva, Wen Ping Chen, Vitalii Sliusar, Jürgen Besenrieder, Francesco Giordano, Antonio Tutone, Thomas Bretz, J. Buss, Alok C. Gupta, Simona Righini, O. M. Kurtanidze, Ciro Bigongiari, O. Vince, D. Elsaesser, C. Leto, M. Garczarczyk, Sargis Gasparyan, J. Kania, Dario Hrupec, R. López-Coto, Wolfgang Rhode, I. Snidaric, D. A. Morozova, Vladimir A. Hagen-Thorn, Mitsunari Takahashi, J. A. Acosta-Pulido, E. Prandini, Marie Karjalainen, D. Miceli, Goran Damljanović, Evgeni Semkov, Alice Donini, L. A. Antonelli, J. A. Barrio, Y. Suda, D. Carosati, V. D'Elia, Fabrizio Tavecchio, A. C. Sadun, Tihomir Surić, C. Casadio, Karl Mannheim, Santiago Ubach, Y. Kobayashi, F. Di Pierro, European Commission, European Research Council, Ministerio de Ciencia e Innovación (España), Generalitat de Catalunya, Federal Ministry of Education and Research (Germany), German Research Foundation, Swiss National Science Foundation, Croatian Science Foundation, Ministry of Education, Science and Technological Development (Serbia), Bulgarian National Science Fund, National Aeronautics and Space Administration (US), Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Artero, M., Asano, K., Babi??, A., Baquero, A., Barres de Almeida, U., Barrio, J. A., Batkovi??, I., Becerra Gonz??lez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bo??njak, ??., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D???amico, G., D???elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espi??eira, E., Dominis Prester, D., Donini, A., Doro, M., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garc??a L??pez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovi??, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., H??tten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jim??nez, I., Jormanainen, J., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., L??pez-Coto, R., L??pez-Moya, M., L??pez-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Mart??nez, M., Mazin, D., Menchiari, S., Mender, S., Mi??anovi??, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavleti??, L., Pe??il, P., Perennes, C., Persic, M., Prada Moroni, P. G., Prandini, E., Priyadarshi, C., Puljak, I., Rib??, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schmidt, K., Schweizer, T., Sitarek, J., nidari??, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suri??, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzi??, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Zari??, D., Baack, D., Balbo, M., Biederbeck, N., Biland, A., Bretz, T., Buss, J., Dorner, D., Eisenberger, L., Elsaesser, D., Hildebrand, D., Iotov, R., Mannheim, K., Neise, D., Noethe, M., Paravac, A., Rhode, W., Schleicher, B., Sliusar, V., Walter, R., D???ammando, F., Horan, D., Lien, A. Y., Balokovi??, M., Madejski, G. M., Perri, M., Verrecchia, F., Leto, C., L??hteenm??ki, A., Tornikoski, M., Ramakrishnan, V., J??rvel??, E., Vera, R. J. C., Chamani, W., Villata, M., Raiteri, C. M., Gupta, A. C., Pandey, A., Fuentes, A., Agudo, I., Casadio, C., Semkov, E., Ibryamov, S., Marchini, A., Bachev, R., Strigachev, A., Ovcharov, E., Bozhilov, V., Valcheva, A., Zaharieva, E., Damljanovic, G., Vince, O., Larionov, V. M., Borman, G. A., Grishina, T. S., Hagen-Thorn, V. A., Kopatskaya, E. N., Larionova, E. G., Larionova, L. V., Morozova, D. A., Nikiforova, A. A., Savchenko, S. S., Troitskiy, I. S., Troitskaya, Y. V., Vasilyev, A. A., Merkulova, O. A., Chen, W. P., Samal, M., Lin, H. C., Moody, J. W., Sadun, A. C., Jorstad, S. G., Marscher, A. P., Weaver, Z. R., Feige, M., Kania, J., Kopp, M., Kunkel, L., Reinhart, D., Scherbantin, A., Schneider, L., Lorey, C., Acosta-Pulido, J. A., Carnerero, M. I., Carosati, D., Kurtanidze, S. O., Kurtanidze, O. M., Nikolashvili, M. G., Chigladze, R. A., Ivanidze, R. Z., Kimeridze, G. N., Sigua, L. A., Joner, M. D., Spencer, M., Giroletti, M., Marchili, N., Righini, S., Rizzi, N., Bonnoli, G., Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), MAGIC, FACT, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University

Subjects
electron, PARTICLE-ACCELERATION, ELECTRON ACCELERATION, Radiation mechanisms: non-thermal, RAY, VHE [gamma ray], galaxies: active, BL Lacertae objects: individual: Mrk 421, radiation mechanisms: non-thermal, Electron, Astrophysics, GeV, 01 natural sciences, 7. Clean energy, LARGE-AREA TELESCOPE, law.invention, OBSERVATIONS, law, ultraviolet, optical, MAGIC (telescope), correlation [flux], 010303 astronomy & astrophysics, X-ray: flux, model: leptonic, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), BL-LACERTAE, individual: Mrk 421 [BL Lacertae objects], flux [X-ray], Gamma ray, flux: correlation, Galaxies: active, non-thermal [radiation mechanisms], Synchrotron, SWIFT OBSERVATIONS, active [galaxies], Spectral energy distribution, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, Lorentz, Flare, LOG-PARABOLIC SPECTRA, ACTIVE GALACTIC NUCLEI, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, radiation, mechanisms: non-thermal, LIGHT CURVES, X-RAY, MULTIWAVELENGTH, GLAST, leptonic [model], blazar, 0103 physical sciences, TeV, Blazar, 010308 nuclear & particles physics, Astronomy and Astrophysics, MAGIC, gamma ray: VHE, Space and Planetary Science, ddc:520, spectral, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope
Abstract

Full list of authors: Acciari, V. A.; Ansoldi, S.; Antonelli, L. A.; Arbet Engels, A.; Artero, M.; Asano, K.; Babić, A.; Baquero, A.; Barres de Almeida, U.; Barrio, J. A.; Batković, I.; Becerra González, J.; Bednarek, W.; Bellizzi, L.; Bernardini, E.; Bernardos, M.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Blanch, O.; Bošnjak, Ž.; Busetto, G.; Carosi, R.; Ceribella, G.; Cerruti, M.; Chai, Y.; Chilingarian, A.; Cikota, S.; Colak, S. M.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Lotto, B.; Delfino, M.; Delgado, J.; Delgado Mendez, C.; Depaoli, D.; di Pierro, F.; di Venere, L.; Do Souto Espiñeira, E.; Dominis Prester, D.; Donini, A.; Doro, M.; Fallah Ramazani, V.; Fattorini, A.; Ferrara, G.; Fonseca, M. V.; Font, L.; Fruck, C.; Fukami, S.; García López, R. J.; Garczarczyk, M.; Gasparyan, S.; Gaug, M.; Giglietto, N.; Giordano, F.; Gliwny, P.; Godinović, N.; Green, J. G.; Green, D.; Hadasch, D.; Hahn, A.; Heckmann, L.; Herrera, J.; Hoang, J.; Hrupec, D.; Hütten, M.; Inada, T.; Inoue, S.; Ishio, K.; Iwamura, Y.; Jiménez, I.; Jormanainen, J.; Jouvin, L.; Kajiwara, Y.; Karjalainen, M.; Kerszberg, D.; Kobayashi, Y.; Kubo, H.; Kushida, J.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Lombardi, S.; Longo, F.; López-Coto, R.; López-Moya, M.; López-Oramas, A.; Loporchio, S.; Machado de Oliveira Fraga, B.; Maggio, C.; Majumdar, P.; Makariev, M.; Mallamaci, M.; Maneva, G.; Manganaro, M.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menchiari, S.; Mender, S.; Mićanović, S.; Miceli, D.; Miener, T.; Minev, M.; Miranda, J. M.; Mirzoyan, R.; Molina, E.; Moralejo, A.; Morcuende, D.; Moreno, V.; Moretti, E.; Neustroev, V.; Nigro, C.; Nilsson, K.; Nishijima, K.; Noda, K.; Nozaki, S.; Ohtani, Y.; Oka, T.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pavletić, L.; Peñil, P.; Perennes, C.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Priyadarshi, C.; Puljak, I.; Ribó, M.; Rico, J.; Righi, C.; Rugliancich, A.; Saha, L.; Sahakyan, N.; Saito, T.; Sakurai, S.; Satalecka, K.; Saturni, F. G.; Schmidt, K.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Spolon, A.; Stamerra, A.; Strom, D.; Strzys, M.; Suda, Y.; Surić, T.; Takahashi, M.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Teshima, M.; Tosti, L.; Truzzi, S.; Tutone, A.; Ubach, S.; van Scherpenberg, J.; Vanzo, G.; Vazquez Acosta, M.; Ventura, S.; Verguilov, V.; Vigorito, C. F.; Vitale, V.; Vovk, I.; Will, M.; Wunderlich, C.; Zarić, D.; Baack, D.; Balbo, M.; Biederbeck, N.; Biland, A.; Bretz, T.; Buss, J.; Dorner, D.; Eisenberger, L.; Elsaesser, D.; Hildebrand, D.; Iotov, R.; Mannheim, K.; Neise, D.; Noethe, M.; Paravac, A.; Rhode, W.; Schleicher, B.; Sliusar, V.; Walter, R.; D'Ammando, F.; Horan, D.; Lien, A. Y.; Baloković, M.; Madejski, G. M.; Perri, M.; Verrecchia, F.; Leto, C.; Lähteenmäki, A.; Tornikoski, M.; Ramakrishnan, V.; Järvelä, E.; Vera, R. J. C.; Chamani, W.; Villata, M.; Raiteri, C. M.; Gupta, A. C.; Pandey, A.; Fuentes, A.; Agudo, I.; Casadio, C.; Semkov, E.; Ibryamov, S.; Marchini, A.; Bachev, R.; Strigachev, A.; Ovcharov, E.; Bozhilov, V.; Valcheva, A.; Zaharieva, E.; Damljanovic, G.; Vince, O.; Larionov, V. M.; Borman, G. A.; Grishina, T. S.; Hagen-Thorn, V. A.; Kopatskaya, E. N.; Larionova, E. G.; Larionova, L. V.; Morozova, D. A.; Nikiforova, A. A.; Savchenko, S. S.; Troitskiy, I. S.; Troitskaya, Y. V.; Vasilyev, A. A.; Merkulova, O. A.; Chen, W. P; Samal, M.; Lin, H. C.; Moody, J. W.; Sadun, A. C.; Jorstad, S. G.; Marscher, A. P.; Weaver, Z. R.; Feige, M.; Kania, J.; Kopp, M.; Kunkel, L.; Reinhart, D.; Scherbantin, A.; Schneider, L.; Lorey, C.; Acosta-Pulido, J. A.; Carnerero, M. I.; Carosati, D.; Kurtanidze, S. O.; Kurtanidze, O. M.; Nikolashvili, M. G.; Chigladze, R. A.; Ivanidze, R. Z.; Kimeridze, G. N.; Sigua, L. A.; Joner, M. D.; Spencer, M.; Giroletti, M.; Marchili, N.; Righini, S.; Rizzi, N.; Bonnoli, G.; MAGIC Collaboration; Fact Collaboration.-- This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., Aims. We present a detailed characterisation and theoretical interpretation of the broadband emission of the paradigmatic TeV blazar Mrk 421, with a special focus on the multi-band flux correlations. Methods. The dataset has been collected through an extensive multi-wavelength campaign organised between 2016 December and 2017 June. The instruments involved are MAGIC, FACT, Fermi-LAT, Swift, GASP-WEBT, OVRO, Medicina, and Metsahovi. Additionally, four deep exposures (several hours long) with simultaneous MAGIC and NuSTAR observations allowed a precise measurement of the falling segments of the two spectral components. Results. The very-high-energy (VHE; E 100 GeV) gamma rays and X-rays are positively correlated at zero time lag, but the strength and characteristics of the correlation change substantially across the various energy bands probed. The VHE versus X-ray fluxes follow dierent patterns, partly due to substantial changes in the Compton dominance for a few days without a simultaneous increase in the X-ray flux (i.e., orphan gamma-ray activity). Studying the broadband spectral energy distribution (SED) during the days including NuSTAR observations, we show that these changes can be explained within a one-zone leptonic model with a blob that increases its size over time. The peak frequency of the synchrotron bump varies by two orders of magnitude throughout the campaign. Our multi-band correlation study also hints at an anti-correlation between UV-optical and X-ray at a significance higher than 3. A VHE flare observed on MJD 57788 (2017 February 4) shows gamma-ray variability on multi-hour timescales, with a factor ten increase in the TeV flux but only a moderate increase in the keV flux. The related broadband SED is better described by a two-zone leptonic scenario rather than by a one-zone scenario.We find that the flare can be produced by the appearance of a compact second blob populated by high energetic electrons spanning a narrow range of Lorentz factors, from 0 min = 2104 to 0 max = 6105. © 2021 Georg Thieme Verlag. All rights reserved., The MAGIC Collaboration would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF, MPG and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish Ministerio de Ciencia e Innovación (MICINN) (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729-C6-5-R, FPA2017-90566-REDC, PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-105510GB-C31,PID2019-107847RB-C41, PID2019-107847RB-C42, PID2019-107847RB-C44, PID2019-107988GB-C22); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant nr. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588, SEV-2017-0709 and CEX2019-000920-S, and “María de Maeztu” CEX2019-000918-M, the Unidad de Excelencia “María de Maeztu” MDM-2015-0509-18-2 and the “la Caixa” Foundation (fellowship LCF/BQ/PI18/11630012) and by the CERCA program of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02; by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3; the Polish National Research Centre grant UMO-2016/22/M/ST9/00382; and by the Brazilian MCTIC, CNPq and FAPERJ. The important contributions from ETH Zurich grants ETH-10.08-2 and ETH-27.12-1 as well as the funding by the Swiss SNF and the German BMBF (Verbundforschung Astro- und Astroteilchenphysik) and HAP (Helmoltz Alliance for Astroparticle Physics) are gratefully acknowledged. Part of this work is supported by Deutsche Forschungsgemeinschaft (DFG) within the Collaborative Research Center SFB 876 “Providing Information by Resource-Constrained Analysis”, project C3. We are thankful for the very valuable contributions from E. Lorenz, D. Renker and G. Viertel during the early phase of the project. We thank the Instituto de Astrofísica de Canarias for allowing us to operate the telescope at the Observatorio del Roque de los Muchachos in La Palma, the Max-Planck-Institut für Physik for providing us with the mount of the former HEGRA CT3 telescope, and the MAGIC collaboration for their support. The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515. This work made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC; Italy) and the California Institute of Technology (USA). This research has also made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy. A.A.E and D.P acknowledge support from the Deutsche Forschungs gemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC-2094 – 390783311. M. B. acknowledges support from the YCAA Prize Postdoctoral Fellowship and from the Black Hole Initiative at Harvard University, which is funded in part by the Gordon and Betty Moore Foundation (grant GBMF8273) and in part by the John Templeton Foundation. This publication makes use of data obtained at the Metsähovi Radio Observatory, operated by Aalto University in Finland. This research has made use of data from the OVRO 40-m monitoring program (Richards et al. 2011) which is supported in part by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G and NSF grants AST-0808050 and AST-1109911. I.A. acknowledges financial support from the Spanish “Ministerio de Ciencia e Innovación” (MCINN) through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía-CSIC (SEV-2017-0709). Acquisition and reduction of the MAPCAT data was supported in part by MICINN through grants AYA2016-80889-P and PID2019-107847RB-C44. The MAPCAT observations were carried out at the German-Spanish Calar Alto Observatory, which is jointly operated by Junta de Andalucía and Consejo Superior de Investigaciones Científicas. C.C. acknowledges support from the European Research Council (ERC) under the European Union Horizon 2020 research and innovation program under the grant agreement No 771282. This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grants KP-06-H28/3 (2018), KP-06-H38/4 (2019) and KP-06-KITAJ/2 (2020). We acknowledge support by Bulgarian National Science Fund under grant DN18-10/2017 and National RI Roadmap Projects DO1-277/16.12.2019 and DO1-268/16.12.2019 of the Ministry of Education and Science of the Republic of Bulgaria. This research was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (contract No 451-03-68/2020-14/200002). G.D. acknowledges observing grant support from the Institute of Astronomy and Rozhen NAO BAS through the bilateral joint research project “Gaia Celestial Reference Frame (CRF) and fast variable astronomical objects” (2020–2022, head – G. Damljanovic). The BU group was supported in part by NASA Fermi guest investigator program grants 80NSSC19K1505 and 80NSSC20K1566. This study was based in part on observations conducted using the 1.8 m Perkins Telescope Observatory (PTO) in Arizona, which is owned and operated by Boston University. This article is partly based on observations made with the LCOGT Telescopes, one of whose nodes is located at the Observatorios de Canarias del IAC on the island of Tenerife in the Observatorio del Teide. This article is also based partly on data obtained with the STELLA robotic telescopes in Tenerife, an AIP facility jointly operated by AIP and IAC. The Abastumani team acknowledges financial support by the Shota Rustaveli National Science Foundation under contract FR-19-6174. Based on observations with the Medicina telescope operated by INAF – Istituto di Radioastronomia.

Published
2021

21. First detection of VHE gamma-ray emission from TXS 1515-273, study of its X-ray variability and spectral energy distribution

Author

M. I. Martínez, V. Neustroev, Francesco Longo, Maria-Isabel Bernardos, Alessandro Marchini, Alicia Fattorini, Tomohiko Oka, Katsuaki Asano, U. Barres de Almeida, Damir Lelas, Adrian Biland, D. Hadasch, D. Miceli, Sanae Inoue, Giacomo D'Amico, Yating Chai, Stefan Cikota, Pawel Gliwny, I. Vovk, David A. Green, R. J. García López, Narek Sahakyan, Stefano Covino, Lea Heckmann, Francesco Gabriele Saturni, J. Becerra González, Armin Nabizadeh, F. D'Ammando, J. Rico, M. Vazquez Acosta, Nicola Giglietto, Alexander Hahn, Nikola Godinovic, Dorota Sobczyńska, G. Ferrara, G. Busetto, E. Molina, Satoshi Fukami, Shunsuke Sakurai, Jarred Gershon Green, Elisabetta Bissaldi, C. Perennes, D. Strom, Yusuke Suda, E. Colombo, Lab Saha, Alice Donini, Kazuma Ishio, Massimo Persic, L. A. Antonelli, Martin Makariev, Dominik Baack, P. G. Prada Moroni, J. Kushida, Ivica Puljak, Victor Moreno, Oscar Blanch, S. Ventura, C. Nigro, Carlo Vigorito, F. Leone, D. Dominis Prester, Alessandra Lamastra, J. A. Barrio, John Hoang, V. Verguilov, Tomoki Saito, J. M. Paredes, Antonio Stamerra, Giovanni Ceribella, Rodolfo Carosi, I. Jiménez, V. D'Elia, Pratik Majumdar, M. V. Fonseca, Daniel Morcuende, Jose Luis Contreras, Jenni Jormanainen, Vincenzo Vitale, T. Schweizer, A. Arbet Engels, S. Loporchio, A. Rugliancich, Marina Manganaro, A. De Angelis, M. Karjalainen, Sargis Gasparyan, Stefano Menchiari, Y. Kajiwara, Fabrizio Tavecchio, M. Palatiello, Manuela Mallamaci, Masahiro Teshima, S. Paiano, Luca Tosti, I. Snidaric, Mosè Mariotti, Martin Will, M. Orienti, S. Mićanović, Ashot Chilingarian, Wolfgang Rhode, Lluis Font, B. Machado de Oliveira Fraga, Tihomir Surić, Manuel Artero, Juan Cortina, Toshiaki Inada, Yuki Iwamura, Stefano Truzzi, D. Zarić, Saverio Lombardi, Francesco Dazzi, Simone Mender, E. Do Souto Espiñeira, Tomislav Terzić, Dario Hrupec, Pablo Peñil, Konstancja Satalecka, L. Maraschi, Giacomo Bonnoli, Sidika Merve Colak, Elina Lindfors, Marcos López-Moya, G. Maneva, Karl Mannheim, Wlodek Bednarek, L. Di Venere, Mitsunari Takahashi, Michele Doro, J. van Scherpenberg, Stefano Ansoldi, Daniel Mazin, Riccardo Paoletti, Christian Fruck, Ivana Batković, E. Prandini, Wrijupan Bhattacharyya, Julian Sitarek, Santiago Ubach, Y. Kobayashi, F. Di Pierro, Jürgen Besenrieder, Lorenzo Bellizzi, Francesco Giordano, Antonio Tutone, J. Otero-Santos, K. Nishijima, Jose Miguel Miranda, Kai Phillip Schmidt, A. Berti, Yoshiki Ohtani, Tjark Miener, David Paneque, D. Elsaesser, Jordi Delgado, Ž. Bošnjak, Matteo Cerruti, Chiara Righi, V. Fallah Ramazani, V. A. Acciari, P. Temnikov, P. Da Vela, Manuel Delfino, Lovro Pavletić, Moritz Hütten, Chaitanya Priyadarshi, Carolin Wunderlich, Ana Babić, C. Delgado Mendez, M. Strzys, Kari Nilsson, Camilla Maggio, Daniela Dorner, Gaia Vanzo, M. Gaug, J. Herrera, Koji Noda, Elisa Bernardini, Alessia Spolon, Léa Jouvin, A. López-Oramas, S. Cutini, Daniel Kerszberg, Marc Ribó, B. De Lotto, S. Nozaki, Andrés Baquero, Hidetoshi Kubo, Abelardo Moralejo, E. Moretti, D. Depaoli, Bernd Schleicher, M. Minev, R. Mirzoyan, Ciro Bigongiari, M. Garczarczyk, R. López-Coto, German Research Foundation, Swiss National Science Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Department of Atomic Energy (India), Institute for Cosmic Ray Research (Japan), University of Tokyo, Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), Ministry of Education and Research (Romania), Academy of Finland, La Caixa, Croatian Science Foundation, University of Rijeka, Polish National Agency for Academic Exchange, European Commission, Ministerio de Economía y Competitividad (España), Istituto Nazionale di Astrofisica, Acciari, Va, Ansoldi, S, Antonelli, La, Engels, Aa, Artero, M, Asano, K, Baack, D, Babic, A, Baquero, A, de Almeida, Ub, Barrio, Ja, Batkovic, I, Gonzalez, Jb, Bednarek, W, Bellizzi, L, Bernardini, E, Bernardos, M, Berti, A, Besenrieder, J, Bhattacharyya, W, Bigongiari, C, Biland, A, Blanch, O, Bosnjak, Z, Busetto, G, Carosi, R, Ceribell, G, Cerruti, M, Chai, Y, Chilingarian, A, Cikota, S, Colak, Sm, Colombo, E, Contreras, Jl, Cortina, J, Covino, S, D'Amico, G, D'Elia, V, Da Vela, P, Dazzi, F, De Angelis, A, De Lotto, B, Delfino, M, Delgado, J, Mendez, Cd, Depaoli, D, Di Pierro, F, Di Venere, L, Espineira, Ed, Prester, Dd, Donini, A, Dorner, D, Doro, M, Elsaesser, D, Ramazani, Vf, Fattorini, A, Ferrara, G, Fonseca, Mv, Font, L, Fruck, C, Fukami, S, Lopez, Rjg, Garczarczyk, M, Gasparyan, S, Gaug, M, Giglietto, N, Giordano, F, Gliwny, P, Godinovic, N, Green, Jg, Green, D, Hadasch, D, Hahn, A, Heckmann, L, Herrera, J, Hoang, J, Hrupec, D, Hutten, M, Inada, T, Inoue, S, Ishio, K, Iwamura, Y, Jimenez, I, Jormanainen, J, Jouvin, L, Kajiwara, Y, Karjalainen, M, Kerszberg, D, Kobayashi, Y, Kubo, H, Kushida, J, Lamastra, A, Lelas, D, Leone, F, Lindfors, E, Lombardi, S, Longo, F, Lopez-Coto, R, Lopez-Moya, M, Lopez-Oramas, A, Loporchio, S, Fraga, Bmd, Maggio, C, Majumdar, P, Makariev, M, Mallamaci, M, Maneva, G, Manganaro, M, Mannheim, K, Maraschi, L, Mariotti, M, Martinez, M, Mazin, D, Menchiari, S, Mender, S, Micanovic, S, Miceli, D, Miener, T, Minev, M, Miranda, Jm, Mirzoyan, R, Molina, E, Moralejo, A, Morcuende, D, Moreno, V, Moretti, E, Neustroev, V, Nigro, C, Nilsson, K, Nishijima, K, Noda, K, Nozaki, S, Ohtani, Y, Oka, T, Otero-Santos, J, Paiano, S, Palatiello, M, Paneque, D, Paoletti, R, Paredes, Jm, Pavletic, L, Penil, P, Perennes, C, Moroni, Pgp, Prandini, E, Priyadarshi, C, Puljak, I, Rhode, W, Ribo, M, Rico, J, Righi, C, Rugliancich, A, Saha, L, Sahakyan, N, Saito, T, Sakurai, S, Satalecka, K, Saturni, Fg, Schleicher, B, Schmidt, K, Schweizer, T, Sitarek, J, Snidaric, I, Sobczynska, D, Spolon, A, Stamerra, A, Strom, D, Strzys, M, Suda, Y, Suric, T, Takahashi, M, Tavecchio, F, Temnikov, P, Terzic, T, Teshima, M, Tosti, L, Truzzi, S, Tutone, A, Ubach, S, Vanscherpenberg, J, Vanzo, G, Acosta, Mv, Ventura, S, Verguilov, V, Vigorito, Cf, Vitale, V, Vovk, I, Will, M, Wunderlich, C, Zaric, D, Bissaldi, E, Bonnoli, G, Cutini, S, D'Ammando, F, Nabizadeh, A, Marchini, A, and Orienti, M

Subjects
Photon, 010504 meteorology & atmospheric sciences, active [Galaxies], Radiation mechanisms: non-thermal, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, Objects: individual: TXS 1515–273, FOS: Physical sciences, Flux, Astrophysics, 01 natural sciences, 7. Clean energy, law.invention, law, objects: individual: TXS 1515-273, 0103 physical sciences, individual: TXS 1515-273 [Objects], MAGIC (telescope), Blazar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, non-thermal [Radiation mechanisms], individual: TXS 1515–273 [objects], Gamma ray, Astronomy and Astrophysics, Synchrotron, Crab Nebula, Space and Planetary Science, ddc:520, Spectral energy distribution, Física nuclear, objects: individual: TXS 1515–273, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Full list of authors: Acciari, V. A.; Ansoldi, S.; Antonelli, L. A.; Arbet Engels, A. ; Artero, M.; Asano, K.; Baack, D.; Babić, A.; Baquero, A.; Barres de Almeida, U.; Barrio, J. A.; Batković, I.; Becerra González, J.; Bednarek, W.; Bellizzi, L.; Bernardini, E.; Bernardos, M.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Biland, A.; Blanch, O.; Bošnjak, Ž.; Busetto, G.; Carosi, R.; Ceribella, G.; Cerruti, M.; Chai, Y.; Chilingarian, A.; Cikota, S.; Colak, S. M.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Lotto, B.; Delfino, M.; Delgado, J.; Delgado Mendez, C.; Depaoli, D.; Pierro, F. Di; Venere, L. Di; Do Souto Espiñeira, E.; Dominis Prester, D.; Donini, A.; Dorner, D.; Doro, M.; Elsaesser, D.; Fallah Ramazani, V.; Fattorini, A.; Ferrara, G.; Fonseca, M. V.; Font, L.; Fruck, C.; Fukami, S.; García López, R. J.; Garczarczyk, M.; Gasparyan, S.; Gaug, M.; Giglietto, N.; Giordano, F.; Gliwny, P.; Godinović, N.; Green, J. G.; Green, D.; Hadasch, D.; Hahn, A.; Heckmann, L.; Herrera, J.; Hoang, J.; Hrupec, D.; Hütten, M.; Inada, T.; Inoue, S.; Ishio, K.; Iwamura, Y.; Jiménez, I.; Jormanainen, J.; Jouvin, L.; Kajiwara, Y.; Karjalainen, M.; Kerszberg, D.; Kobayashi, Y.; Kubo, H.; Kushida, J.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Lombardi, S.; Longo, F.; López-Coto, R.; López-Moya, M.; López-Oramas, A.; Loporchio, S.; Machado de Oliveira Fraga, B.; Maggio, C.; Majumdar, P.; Makariev, M.; Mallamaci, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menchiari, S.; Mender, S.; Mićanović, S.; Miceli, D.; Miener, T.; Minev, M.; Miranda, J. M.; Mirzoyan, R.; Molina, E.; Moralejo, A.; Morcuende, D.; Moreno, V.; Moretti, E.; Neustroev, V.; Nigro, C.; Nilsson, K.; Nishijima, K.; Noda, K.; Nozaki, S.; Ohtani, Y.; Oka, T.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pavletić, L.; Peñil, P.; Perennes, C.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Priyadarshi, C.; Puljak, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Rugliancich, A.; Saha, L.; Sahakyan, N.; Saito, T.; Sakurai, S.; Satalecka, K.; Saturni, F. G.; Schleicher, B.; Schmidt, K.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Spolon, A.; Stamerra, A.; Strom, D.; Strzys, M.; Suda, Y.; Surić, T.; Takahashi, M.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Teshima, M.; Tosti, L.; Truzzi, S.; Tutone, A.; Ubach, S.; van Scherpenberg, J.; Vanzo, G.; Vazquez Acosta, M.; Ventura, S.; Verguilov, V.; Vigorito, C. F.; Vitale, V.; Vovk, I.; Will, M.; Wunderlich, C.; Zarić, D.; Bissaldi, E.; Bonnoli, G.; Cutini, S.; D'Ammando, F.; Nabizadeh, A.; Marchini, A.; Orienti, M.; MAGIC Collaboration., We report here on the first multiwavelength (MWL) campaign on the blazar TXS 1515-273, undertaken in 2019 and extending from radio to very-high-energy gamma-rays (VHE). Up until now, this blazar had not been the subject of any detailed MWL observations. It has a rather hard photon index at GeV energies and was considered a candidate extreme high-synchrotron-peaked source. MAGIC observations resulted in the first-time detection of the source in VHE with a statistical significance of 7.6σ. The average integral VHE flux of the source is 6 ± 1 per cent of the Crab nebula flux above 400 GeV. X-ray coverage was provided by Swift-XRT, XMM-Newton, and NuSTAR. The long continuous X-ray observations were separated by ∼9 h, both showing clear hour scale flares. In the XMM-Newton data, both the rise and decay time-scales are longer in the soft X-ray than in the hard X-ray band, indicating the presence of a particle cooling regime. The X-ray variability time-scales were used to constrain the size of the emission region and the strength of the magnetic field. The data allowed us to determine the synchrotron peak frequency and classify the source as a flaring high, but not extreme synchrotron-peaked object. Considering the constraints and variability patterns from the X-ray data, we model the broad-band spectral energy distribution. We applied a simple one-zone model, which could not reproduce the radio emission and the shape of the optical emission, and a two-component leptonic model with two interacting components, enabling us to reproduce the emission from radio to VHE band. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society., The financial support of the German BMBF, MPG, and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish Ministerio de Ciencia e Innovacion (MICINN) (FPA201787859-P, FPA2017-85668-P, FPA2017-82729-C6-5-R, FPA201790566-REDC, PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-105510GB-C31, PID2019-107847RB-C41, PID2019107847RB-C42, PID2019-107847RB-C44, PID2019-107988GBC22); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1268/16.12.2019 and the Academy of Finland grant nr. 317637 and 320045 are gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia `Severo Ochoa' SEV-20160588, SEV-2017-0709 and CEX2019-000920-S, and `Maria de Maeztu' CEX2019-000918-M, the Unidad de Excelencia `Maria de Maeztu' MDM-2015-0509-18-2 and the `la Caixa' Foundation (fellowshipLCF/BQ/PI18/11630012), by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq, and FAPERJ. The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, theCommissariat à l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase from the following agencies is also gratefully acknowledged: the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Etudes Spatiales in France.

Published
2021

22. H.e.s.s. And magic observations of a sudden cessation of a very-high-energy γ -ray flare in PKS 1510-089 in May 2016

Author

A. Yusafzai, J. van Scherpenberg, M. Büchele, B. Boccardi, S. Caroff, S. J. Fegan, Daniela Dorner, T. Schweizer, Mosè Mariotti, Gaia Vanzo, Tom Armstrong, Nu. Komin, Pratik Majumdar, M. V. Fonseca, Matteo Cerruti, A. Lemiere, F. Eichhorn, J. Devin, C. Trichard, Michael Punch, Stefano Gabici, M. Palatiello, V. A. Acciari, F. Schüssler, Sylvia Zhu, P. J. Meintjes, Werner Hofmann, Samuel Timothy Spencer, Y. Kajiwara, J. Zorn, D. Dominis Prester, S. Bonnefoy, Constantin Steppa, G. Maurin, Adrian Biland, J. M. Paredes, Antonio Stamerra, U. Barres de Almeida, Tadayuki Takahashi, Damir Lelas, Victor Doroshenko, Davide Depaoli, Dmitriy Kostunin, R. Mirzoyan, T. Surić, D. Gottschall, M. Füßling, Moritz Hütten, Lea Heckmann, M. Gaug, J. Herrera, Ullrich Schwanke, C. Arcaro, H. Abdalla, Lorenzo Bellizzi, Thomas P. Krichbaum, Francesco Dazzi, John Hoang, Martin Will, Dominik Baack, L. Maraschi, Elina Lindfors, M. A. Kastendieck, R. Rauth, V. Baghmanyan, D. Ninci, Koji Noda, Michael Backes, S. Raab, Sanae Inoue, Giacomo D'Amico, Manuel Meyer, Q. Remy, L. Olivera-Nieto, Dorota Sobczyńska, Elisa Bernardini, M. Filipovic, Riaan Steenkamp, Davit Zargaryan, Hambeleleni Ndiyavala, Stefan Klepser, G. Vasileiadis, G. Lamanna, S. G. Jorstad, Daniel Mazin, Jacek Niemiec, Kirsty Feijen, Alessandro Montanari, Tim Holch, Seiya Nozaki, Anna Barnacka, M. Hörbe, Giacomo Bonnoli, D. Strom, T. Tavernier, Takeshi Oka, Axel Donath, J. Rico, A. W. Chen, J. Dyks, T. Chand, Jim Hinton, F. Niederwanger, Olaf Reimer, Daniel Kerszberg, Manuel Delfino, Krzysztof Katarzynski, Ivica Puljak, S. Sailer, Dmitry Khangulyan, Christian Fruck, Gavin Rowell, D. A. Sanchez, Maria Haupt, Julian Sitarek, Alan P. Marscher, Stefano Truzzi, Pablo Peñil, E. O. Angüner, Catherine Boisson, S. Ventura, Dieter Horns, M. Bryan, V. Barbosa Martins, L. Sun, Rachel Simoni, Gerard Fontaine, Jacco Vink, P. Reichherzer, Jim Davies, G. Hermann, Regis Terrier, Clemens Hoischen, A. A. Zdziarski, G. Ferrara, Francois Brun, G. Emery, M. de Bony de Lavergne, P. Vincent, Kyoshi Nishijima, Alessandra Lamastra, G. Fichet de Clairfontaine, E. de Oña Wilhelmi, P. Munar-Adrover, Yoshiki Ohtani, Carlo Romoli, Jordi Delgado, Wrijupan Bhattacharyya, L. Di Venere, D. Zarić, Zorawar Wadiasingh, F. Di Pierro, Ž. Bošnjak, Hester Schutte, Isak Delberth Davids, Roberta Zanin, Karl Mannheim, M. Strzys, Łukasz Stawarz, R. J. Tuffs, V. Fallah Ramazani, B. Bi, Marc Ribó, Sabrina Casanova, H. Prokoph, A. Carosi, Stefano Covino, D. J. van der Walt, Thomas Murach, Yating Chai, Saša Mićanović, Jae-Young Kim, V. Vitale, Francesco Longo, R. Konno, Alicia Fattorini, Narek Sahakyan, Y. A. Gallant, R. J. García López, Junko Kushida, Jürgen Besenrieder, Dario Hrupec, P. Da Vela, S. Steinmassl, P. G. Prada Moroni, Jonathan Mackey, Rafal Moderski, Stefan Cikota, Hidetoshi Kubo, Armelle Jardin-Blicq, Monica Barnard, J. Otero-Santos, Mischa Breuhaus, J. Becerra González, Yu. W. Wong, V. Joshi, Samuel Zouari, N. Shafi, Natalia Żywucka, E. Prandini, M. A. Lopez, Gianluca Giavitto, Katsuaki Asano, Mitsunari Takahashi, T. Vuillaume, M. Curyło, P. Morris, K. Egberts, Stefano Ansoldi, M. de Naurois, Pawel Gliwny, L. Pavletić, C. Moore, Alessia Spolon, M. Vazquez Acosta, D. Elsaesser, Tomoki Saito, Giovanni Ceribella, Riccardo Paoletti, Celine Armand, Jhilik Majumdar, Stefan Ohm, G. Busetto, Léa Jouvin, Ana Babić, Frank M. Rieger, A. Dmytriiev, Dorit Glawion, Z. R. Weaver, Włodek Kluźniak, S. Chandra, V. Marandon, A. Djannati-Ataï, E. Moulin, Tomasz Bulik, Alessio Berti, M. Seglar-Arroyo, H. Odaka, Christian Stegmann, Stefan Wagner, C. Perennes, Pierre Brun, Yasunobu Uchiyama, A. Fiasson, U. Colin, David A. Green, Kazuma Ishio, A. Arbet Engels, A. De Angelis, Wlodek Bednarek, Nikola Godinovic, F. Ait Benkhali, Vassil Verguilov, Camilla Maggio, L. Mohrmann, Jean-Pierre Ernenwein, M. Spir-Jacob, M. Karjalainen, Vitaly Neustroev, P. deWilt, M. Scalici, Victoria Moreno, A. Priyana Noel, A. López-Oramas, M. Lemoine-Goumard, N. Torres-Albà, Martin Makariev, C. van Rensburg, Oscar Blanch, S. Pita, Alexander Hahn, V. Sahakian, Yusuke Suda, S. Schwemmer, Thomas Lohse, Misao Sasaki, Daniel Morcuende, Johannes Veh, D. Jankowsky, Michael Kreter, D. Berge, Luca Tosti, R. Marx, F. Werner, V. Poireau, Andrea Santangelo, C. Nigro, Andreas Quirrenbach, Jose Luis Contreras, E. Ruiz-Velasco, Thomas Bylund, M. Tluczykont, V. D'Elia, A. S. Seyffert, Jose Miguel Miranda, Massimo Persic, L. Dirson, Efthalia Traianou, Carlo Vigorito, Sargis Gasparyan, Y. Kobayashi, Jacques Muller, Jeffrey A. Hodgson, Marek Jamrozy, Christoph Deil, I. Jung-Richardt, Joachim Hahn, Mohanraj Senniappan, A. Rugliancich, Marina Manganaro, K. Nakashima, Kleopas Shiningayamwe, Alice Donini, Michelle Tsirou, Yuki Iwamura, G. Maneva, L. A. Antonelli, Juan Cortina, Markus Holler, Michal Ostrowski, Wolfgang Rhode, L. Rinchiuso, Felix Jankowsky, Sebastian Panny, M. I. Martínez, Michael Zacharias, Ferdinando Giordano, Felix Aharonian, Lluis Font, J.-P. Lenain, Merja Tornikoski, B. Machado de Oliveira Fraga, M.-H. Grondin, Lenka Tomankova, Markus Böttcher, Alison Mitchell, Chiara Righi, E. Do Souto Espiñeira, Tomislav Terzić, Alexandre Marcowith, P. Temnikov, Helene Sol, Sabrina Einecke, Iryna Lypova, Toshiaki Inada, Rodolfo Carosi, R. D. Parsons, Yvonne Becherini, Shunsuke Sakurai, L. Giunti, A. Nayerhoda, Arnaud Mares, Chaitanya Priyadarshi, Satoshi Fukami, Konstancja Satalecka, Stefan Funk, Johan Bregeon, Sidika Merve Colak, Alicja Wierzcholska, R. J. White, F. Leone, Michele Doro, D. Huber, Carolina Casadio, Anne Lähteenmäki, Masahiro Teshima, Domenico Tiziani, D. Malyshev, M. Panter, U. Katz, Heinrich J. Völk, G. Martí-Devesa, C. Levy, M. Renaud, J. A. Barrio, Kai Phillip Schmidt, L. Oakes, N. Giglietto, Simone Mender, Paolo Marchegiani, Ashot Chilingarian, Tjark Miener, James E. M. Watson, David Paneque, J. Bolmont, Manuela Mallamaci, Halim Ashkar, A. Sinha, Fabrizio Tavecchio, Kari Nilsson, B. van Soelen, B. Rudak, R. Adam, D. Miceli, M. Mohamed, Saverio Lombardi, E. Molina, P. T. O'Brien, E. Colombo, Lab Saha, Luca Foffano, C. van Eldik, G. Peron, Garret Cotter, D. Hadasch, D. A. Prokhorov, K. Kosack, Konrad Bernlöhr, B. Peyaud, I. Vovk, G. Pühlhofer, A. Reimer, J. F. Glicenstein, Bruno Khelifi, Serena Loporchio, I. Snidaric, Abelardo Moralejo, Andreas Specovius, E. Moretti, Bernd Schleicher, M. Minev, B. De Lotto, Andrés Baquero, A.M. Taylor, J. Damascene Mbarubucyeye, Christo Venter, Ciro Bigongiari, A. Zech, M. Garczarczyk, R. López-Coto, Q. Piel, Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), H.E.S.S., MAGIC, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), German Research Foundation, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Ministerio de Economía y Competitividad (España), Department of Atomic Energy (India), Academy of Finland, University of Tokyo, La Caixa, Croatian Science Foundation, University of Rijeka, Polish National Agency for Academic Exchange, Abdalla, H., Adam, R., Aharonian, F., Ait Benkhali, F., Ang??ner, E. O., Arcaro, C., Armand, C., Armstrong, T., Ashkar, H., Backes, M., Baghmanyan, V., Barbosa Martins, V., Barnacka, A., Barnard, M., Becherini, Y., Berge, D., Bernl??hr, K., Bi, B., B??ttcher, M., Boisson, C., Bolmont, J., Bonnefoy, S., de Bony de Lavergne, M., Bregeon, J., Breuhaus, M., Brun, F., Brun, P., Bryan, M., B??chele, M., Bulik, T., Bylund, T., Caroff, S., Carosi, A., Casanova, S., Chand, T., Chandra, S., Chen, A., Cotter, G., Cury??o, M., Damascene Mbarubucyeye, J., Davids, I. D., Davies, J., Deil, C., Devin, J., Dewilt, P., Dirson, L., Djannati-Ata??, A., Dmytriiev, A., Donath, A., Doroshenko, V., Dyks, J., Egberts, K., Eichhorn, F., Einecke, S., Emery, G., Ernenwein, J. -P., Feijen, K., Fegan, S., Fiasson, A., Fichet de Clairfontaine, G., Filipovic, M., Fontaine, G., Funk, S., F????ling, M., Gabici, S., Gallant, Y. A., Giavitto, G., Giunti, L., Glawion, D., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Hahn, J., Haupt, M., Hermann, G., Hinton, J. A., Hofmann, W., Hoischen, C., Holch, T. L., Holler, M., H??rbe, M., Horns, D., Huber, D., Jamrozy, M., Jankowsky, D., Jankowsky, F., Jardin-Blicq, A., Joshi, V., Jung-Richardt, I., Kastendieck, M. A., Katarzy??ski, K., Katz, U., Khangulyan, D., Kh??lifi, B., Klepser, S., Klu??niak, W., Komin, Nu., Konno, R., Kosack, K., Kostunin, D., Kreter, M., Lamanna, G., Lemi??re, A., Lemoine-Goumard, M., Lenain, J. -P., Levy, C., Lohse, T., Lypova, I., Mackey, J., Majumdar, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Mares, A., Mart??-Devesa, G., Marx, R., Maurin, G., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Montanari, A., Moore, C., Morris, P., Moulin, E., Muller, J., Murach, T., Nakashima, K., Nayerhoda, A., de Naurois, M., Ndiyavala, H., Niederwanger, F., Niemiec, J., Oakes, L., O???brien, P., Odaka, H., Ohm, S., Olivera-Nieto, L., de Ona Wilhelmi, E., Ostrowski, M., Panter, M., Panny, S., Parsons, R. D., Peron, G., Peyaud, B., Piel, Q., Pita, S., Poireau, V., Priyana Noel, A., Prokhorov, D. A., Prokoph, H., P??hlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Rauth, R., Reichherzer, P., Reimer, A., Reimer, O., Remy, Q., Renaud, M., Rieger, F., Rinchiuso, L., Romoli, C., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Sailer, S., Sanchez, D. A., Santangelo, A., Sasaki, M., Scalici, M., Sch??ssler, F., Schutte, H. M., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Senniappan, M., Seyffert, A. S., Shafi, N., Shiningayamwe, K., Simoni, R., Sinha, A., Sol, H., Specovius, A., Spencer, S., Spir-Jacob, M., Stawarz, ??., Sun, L., Steenkamp, R., Stegmann, C., Steinmassl, S., Steppa, C., Takahashi, T., Tavernier, T., Taylor, A. M., Terrier, R., Tiziani, D., Tluczykont, M., Tomankova, L., Trichard, C., Tsirou, M., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Vincent, P., Vink, J., V??lk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Watson, J., Werner, F., White, R., Wierzcholska, A., Wong, Yu. W., Yusafzai, A., Zacharias, M., Zanin, R., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., Zorn, J., Zouari, S., ywucka, N., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Asano, K., Baack, D., Babi??, A., Baquero, A., Barres de Almeida, U., Barrio, J. A., Becerra Gonz??lez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bo??njak, ??., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D???amico, G., D???elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espi??eira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garc??a L??pez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovi??, N., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., H??tten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., L??pez, M., L??pez-Coto, R., L??pez-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Mart??nez, M., Mazin, D., Mender, S., Mi??anovi??, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavleti??, L., Pe??il, P., Perennes, C., Persic, M., Prada Moroni, P. G., Prandini, E., Priyadarshi, C., Puljak, I., Rhode, W., Rib??, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., nidari??, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suri??, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzi??, T., Teshima, M., Torres-Alb??, N., Tosti, L., Truzzi, S., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zari??, D., Jorstad, S. G., Marscher, A. P., Boccardi, B., Casadio, C., Hodgson, J., Kim, J. -Y., Krichbaum, T. P., L??hteenm??ki, A., Tornikoski, M., Traianou, E., Weaver, Z. R., Gravitation and Astroparticle Physics Amsterdam, High Energy Astrophys. & Astropart. Phys (API, FNWI), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University

Subjects
non-thermal, quasars: individual: PKS 1510−089, galaxies: active, relativistic processes, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies [radiation mechanisms], Photon, individual: PKS 1510−089 [quasars], Astrophysics::High Energy Astrophysical Phenomena, Flux, radiation mechanisms: non-thermal / quasars: individual: PKS 1510−089 / galaxies: active / relativistic processes, radiation mechanisms: non-thermal, quasars: individual: PKS 1510-089, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, law, 0103 physical sciences, Galaxies: Active, Quasars: Individual: Pks 1510-089, Radiation mechanisms: Non-thermal, Relativistic processes, individual: PKS 1510-089 [quasars], MAGIC (telescope), 010303 astronomy & astrophysics, Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, Astronomy and Astrophysics, Quasar, Light curve, non-thermal [radiation mechanisms], relativistic processes [radiation mechanisms], Extragalactic background light, Space and Planetary Science, active [galaxies], ddc:520, Física nuclear, quasars: individual: PKS 1510���089, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope, Flare
Abstract

The flat spectrum radio quasar (FSRQ) PKS 1510−089 is known for its complex multiwavelength behaviour and it is one of only a few FSRQs detected in very-high-energy (VHE, E > 100 GeV) γ rays. The VHE γ-ray observations with H.E.S.S. and MAGIC in late May and early June 2016 resulted in the detection of an unprecedented flare, which revealed, for the first time, VHE γ-ray intranight variability for this source. While a common variability timescale of 1.5 h has been found, there is a significant deviation near the end of the flare, with a timescale of ∼20 min marking the cessation of the event. The peak flux is nearly two orders of magnitude above the low-level emission. For the first time, a curvature was detected in the VHE γ-ray spectrum of PKS 1510–089, which can be fully explained by the absorption on the part of the extragalactic background light. Optical R-band observations with ATOM revealed a counterpart of the γ-ray flare, even though the detailed flux evolution differs from the VHE γ-ray light curve. Interestingly, a steep flux decrease was observed at the same time as the cessation of the VHE γ-ray flare. In the high-energy (HE, E > 100 MeV) γ-ray band, only a moderate flux increase was observed with Fermi-LAT, while the HE γ-ray spectrum significantly hardens up to a photon index of 1.6. A search for broad-line region (BLR) absorption features in the γ-ray spectrum indicates that the emission region is located outside of the BLR. Radio very-long-baseline interferometry observations reveal a fast-moving knot interacting with a standing jet feature around the time of the flare. As the standing feature is located ∼50 pc from the black hole, the emission region of the flare may have been located at a significant distance from the black hole. If this is indeed a true correlation, the VHE γ rays must have been produced far down in the jet, where turbulent plasma crosses a standing shock., Astronomy & Astrophysics, 648, ISSN:0004-6361, ISSN:1432-0746

Published
2021

23. Monitoring of the radio galaxy M 87 during a low-emission state from 2012 to 2015 with MAGIC

Author

Acciari, V A, Ansoldi, Antonelli, S, L A, Arbet&nbsp, Engels, Arcaro, A, Baack, C, Babić, D, Banerjee, A, Bangale, B, Barres&nbsp, de&nbsp, Almeida, P, Barrio, U, J A, Becerra&nbsp, González, Bednarek, J, Bellizzi, W, Bernardini, L, Berti, E, Besenrieder, A, Bhattacharyya, J, Bigongiari, W, Biland, C, Blanch, A, Bonnoli, O, Bošnjak, G, Busetto, Ž, Carosi, G, Ceribella, R, Chai, G, Chilingaryan, Y, Cikota, A, Colak, S, S M, Colin, Colombo, U, Contreras, E, J L, Cortina, Covino, J, D’Elia, S, Da&nbsp, Vela, V, Dazzi, P, De&nbsp, Angelis, F, Lotto, A, Delfino, B, Delgado, M, Depaoli, J, Di&nbsp, Pierro, D, Venere, F, Do&nbsp, Souto&nbsp, Espiñeira, L, Dominis&nbsp, Prester, E, Donini, D, Dorner, A, Doro, D, Elsaesser, M, Fallah&nbsp, Ramazani, D, Fattorini, V, Fernández-Barral, A, Ferrara, A, Fidalgo, G, Foffano, D, Fonseca, L, M V, Font, Fruck, L, Fukami, C, García&nbsp, López, S, R J, Garczarczyk, Gasparyan, M, Gaug, S, Giglietto, M, Giordano, N, Godinović, F, Green, N, Guberman, D, Hadasch, D, Hahn, D, Herrera, A, Hoang, J, Hrupec, J, Hütten, D, Inada, M, Inoue, T, Ishio, S, Iwamura, K, Jouvin, Y, Kerszberg, L, Kubo, D, Kushida, H, Lamastra, J, Lelas, A, D, Leone, F., Lindfors, E., Lombardi, Longo, S, López, F, López-Coto, M, López-Oramas, R, Loporchio, A, Machado&nbsp, Oliveira&nbsp, Fraga, S, Maggio, B, Majumdar, C, Makariev, P, Mallamaci, M, Maneva, M, Manganaro, G, Mannheim, M, Maraschi, K, Mariotti, L, Martínez, M, Masuda, M, Mazin, S, Mićanović, D, Miceli, S, Minev, D, Miranda, M, J M, Mirzoyan, Molina, R, Moralejo, E, Morcuende, A, Moreno, D, Moretti, V, Munar-Adrover, E, Neustroev, P, Nigro, V, Nilsson, C, Ninci, K, Nishijima, D, Noda, K, Nogués, K, Nöthe, L, Nozaki, M, Paiano, S, Palacio, S, Palatiello, J, Paneque, M, Paoletti, D, Paredes, R, Peñil, Peresano, P, Persic, M, Prada&nbsp, Moroni, M, P G, Prandini, Puljak, E, Rhode, I, Ribó, W, Rico, M, Righi, J, Rugliancich, C, Saha, A, Sahakyan, L, Saito, N, Sakurai, T, Satalecka, S, Schmidt, K, Schweizer, K, Sitarek, T, Šnidarić, J, Sobczynska, I, Somero, D, Stamerra, A, Strom, A, Strzys, D, Suda, M, Surić, Y, Takahashi, T, Tavecchio, M, Temnikov, F, Terzić, P, Teshima, T, Torres-Albà, M, Tosti, N, Tsujimoto, L, Vagelli, S, van&nbsp, Scherpenberg, V, Vanzo, J, Acosta, G, M Vazquez, Vigorito, C F, Vitale, Vovk, V, Will, I, Zarić, M, Asano, D, Collaborators: K, Hada, Harris, K, D E, Giroletti, Jermak, M, H E, Madrid, J P, Massaro, Richter, F, Spanier, S, Steele, F, I A, Walker, R, C, European Space Agency, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), National Aeronautics and Space Administration (US), Agencia Estatal de Investigación (España), European Commission, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Arcaro, C., Baack, D., Babic, A., Banerjee, B., Bangale, P., Barres de Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Chilingaryan, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., da Vela, P., Dazzi, F., de Angelis, A., de Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernandez-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinovic, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kerszberg, D., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Masuda, S., Mazin, D., Micanovic, S., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nothe, M., Nozaki, S., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suric, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tosti, L., Tsujimoto, S., Vagelli, V., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zaric, D., Asano, K., Hada, K., Harris, D. E., Giroletti, M., Jermak, H. E., Madrid, J. P., Massaro, F., Richter, S., Spanier, F., Steele, I. A., Walker, R. C., 30588766 - Arcaro, Cornelia, 25433822 - Richter, Stephan, and 25161814 - Spanier, Felix Alexander

Subjects
galaxies [Gamma rays], Photon, Radio galaxy, VHE [gamma ray], radiation mechanisms non-thermal, galaxies active, galaxies individual M 87, galaxies jets, gamma rays galaxies, magnetic field, Astrophysics, jet [Galaxies], 01 natural sciences, Power law, law.invention, galaxies: individual: M 87, law, flux [gamma ray], radiation mechanisms: non-thermal, galaxies: active, galaxies: jets, gamma rays: galaxies, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, QC, QB, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Physics, galaxie [Gamma rays], photon, Synchrotron, Magnetic field, Wavelength, Galaxies: active, Galaxies: individual: M 87, Galaxies: jets, Gamma rays: galaxies, Radiation mechanisms: non-thermal, Spectral energy distribution, Astrophysics and Astronomy, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, radio wave [galaxy], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, GLAST, GeneralLiterature_MISCELLANEOUS, Telescope, emission [gamma ray], synchrotron, 0103 physical sciences, Astrophysics::Galaxy Astrophysics, non-thermal [Radiation mechanisms], hybrid, 010308 nuclear & particles physics, ComputingMilieux_PERSONALCOMPUTING, individual: M 87 [galaxies], Astronomy and Astrophysics, MAGIC, monitoring, Space and Planetary Science, ddc:520, spectral, jets [Galaxies], individual: M 87 [Galaxies], non-thermal [adiation mechanisms]
Abstract

MAGIC Collaboration: et al., M 87 is one of the closest (z = 0.004 36) extragalactic sources emitting at very high energies (VHE, E > 100 GeV). The aim of this work is to locate the region of the VHE gamma-ray emission and to describe the observed broad-band spectral energy distribution (SED) during the low VHE gamma-ray state. The data from M 87 collected between 2012 and 2015 as part of a MAGIC monitoring programme are analysed and combined with multiwavelength data from Fermi-LAT, Chandra, HST, EVN, VLBA, and the Liverpool Telescope. The averaged VHE gamma-ray spectrum can be fitted from ∼100 GeV to ∼10 TeV with a simple power law with a photon index of (−2.41 ± 0.07), while the integral flux above 300 GeV is (1.44±0.13)×10−12cm−2s−1⁠. During the campaign between 2012 and 2015, M 87 is generally found in a low-emission state at all observed wavelengths. The VHE gamma-ray flux from the present 2012–2015M 87 campaign is consistent with a constant flux with some hint of variability (⁠∼3σ⁠) on a daily time-scale in 2013. The low-state gamma-ray emission likely originates from the same region as the flare-state emission. Given the broad-band SED, both a leptonic synchrotron self-Compton and a hybrid photohadronic model reproduce the available data well, even if the latter is preferred. We note, however, that the energy stored in the magnetic field in the leptonic scenario is very low, suggesting a matter-dominated emission region., The financial support of the German BMBF and MPG, the Italian Istituto Nazionale di Fisica Nucleare (INFN) and Istituto Nazionale di Astrofisica (INAF), the Swiss National Fund (SNF), the ERDF under the Spanish Ministry of Economy and Competitiveness (MINECO) (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662-C2-2-P, FPA2017-90566-REDC), the Indian Department of Atomic Energy, the Japanese JSPS and MEXT, and the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018, is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia ‘Severo Ochoa’ SEV-2016-0588 and SEV2015-0548, and Unidad de Excelencia ‘Maria de Maeztu’ MDM2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers grants SFB823/C4 and SFB876/C3, by the Polish National Research Centre grant UMO2016/22/M/ST9/00382, and by the Brazilian MCTIC, CNPq, and FAPERJ. The Very Long Baseline Array is operated by the National Radio Astronomy Observatory, which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The work of FM is supported by the ‘Departments of Excellence 2018–2022’ Grant awarded by the Italian Ministry of Education, University and Research (MIUR) (L. 232/2016). His research has made also use of resources provided by the Compagnia di San Paolo for the grant awarded on the BLENV project (S1618 L1 MASF 01) and by the Ministry of Education, Universities and Research for the grant MASF FFABR 17 01. This investigation is supported by the National Aeronautics and Space Administration (NASA) grants GO4-15096X, AR6-17012X, and GO6-17081X. This work made use of the Swinburne University of Technology software correlator, developed as part of the Australian Major National Research Facilities Programme and operated under licence. Based in part on observations made with the NASA/European Space Agency (ESA) Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with programmes GO 12293, 12671, 13061, and 13759.

Published
2020

24. Testing two-component models on very high-energy gamma-ray-emitting BL Lac objects

Author

Razmik Mirzoyan, D. Ninci, Susumu Inoue, Dorota Sobczyńska, V. Verguilov, Chiara Righi, J. van Scherpenberg, I. Šnidarić, John Hoang, Y. Chai, Stefano Covino, A. Babić, F. Di Pierro, D. Strom, Jose Luis Contreras, Petar Temnikov, Elisa Bernardini, C. Arcaro, Y. Iwamura, Ž. Bošnjak, Juan Cortina, Andrei Berdyugin, Bernd Schleicher, L. Jouvin, M. Makariev, Massimo Persic, P. Peñil, Markus Garczarczyk, Antonio Stamerra, J. Becerra González, F. de Palma, A. Arbet Engels, F. Leone, B. Machado de Oliveira Fraga, L. Nogués, Juan Abel Barrio, Sebastian Kiehlmann, A. Rugliancich, Marina Manganaro, S. Ansoldi, J. Rico, Anthony C. S. Readhead, M. Palatiello, H. Kubo, M. Karjalainen, Vitaly Neustroev, Laura Maraschi, Pawel Gliwny, Tomohiro Inada, N. Godinović, Giacomo Bonnoli, L. Bellizzi, Narek Sahakyan, M. Vazquez Acosta, Nicola Giglietto, P. G. Prada Moroni, K. Mannheim, M. Takahashi, Luca Tosti, S. Loporchio, D. Dominis Prester, Miguel Nievas-rosillo, Francesco Giordano, U. Barres de Almeida, C. Nigro, Valerio D'Elia, J. Otero-Santos, M. I. Martínez, Francesco Dazzi, Simone Mender, Alessia Spolon, G. Maneva, D. Hadasch, Elina Lindfors, Konstancja Satalecka, Luca Foffano, R. J. García López, Jenni Jormanainen, Michele Doro, A. Hahn, Takeshi Oka, Rumen Bachev, Kyoshi Nishijima, Daniel Mazin, A. Berti, A. Donini, B. Banerjee, T. Schweizer, Kari Nilsson, K. Noda, Armin Nabizadeh, G. Busetto, Shunsuke Sakurai, Daniel Kerszberg, M. Will, S. Gasparyan, A. Lamastra, M. Delfino, P. Munar-Adrover, A. López-Oramas, V. Fallah Ramazani, Carlo Vigorito, L. Saha, M. Mariotti, Walter Max-Moerbeck, N. Torres-Albà, Sarah M. Wagner, David Paneque, A. Biland, F. D' Ammando, Anton Strigachev, J. Besenrieder, M. Hütten, I. Vovk, C. Maggio, Arto Oksanen, L. Pavletić, D. Elsaesser, Matteo Cerruti, S. Fukami, Christian Fruck, U. Colin, David A. Green, D. Lelas, Kazuma Ishio, V. A. Acciari, W. Bhattacharyya, Yosuke Kobayashi, A. Fattorini, R. Reinthal, D. Zarić, Seiya Nozaki, E. Do Souto Espiñeira, Tomislav Terzić, Y. Kajiwara, Julian Sitarek, A. De Angelis, D. Miceli, M. V. Fonseca, W. Rhode, Francesco Longo, S. Lombardi, B. De Lotto, Roberto Carosi, Elisa Prandini, Sofia Ventura, D. Morcuende, N. Talebpour Sheshvan, W. Bednarek, Saša Mićanović, M. Minev, Riccardo Paoletti, M. Teshima, S. M. Colak, Markus Gaug, M. Peresano, Yoshiki Ohtani, Jordi Delgado, J. Kushida, P. Kehusmaa, Oscar Blanch, Ashot Chilingarian, D. Dorner, L. A. Antonelli, L. O. Takalo, V. Moreno, Giacomo D'Amico, S. Cikota, Kevin Schmidt, Y. Suda, Talvikki Hovatta, Fabrizio Tavecchio, Rodrigo Reeves, Eduardo Colombo, Ll. Font, M. Hodges, G. Ferrara, Dario Hrupec, M. A. Lopez, G. Ceribella, J. M. Paredes, Ciro Bigongiari, M. Mallamaci, R. López-Coto, Abelardo Moralejo, E. Moretti, D. Depaoli, Edgar Molina, G. Vanzo, T. Saito, P. Majumdar, Jose Carlos Herrera, F. Wierda, M. Strzys, L. Di Venere, Vincenzo Vitale, Dominik Baack, Jose Miguel Miranda, Tjark Miener, T. Surić, P. Da Vela, M. Ribó, I. Puljak, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, A., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovic, N., Green, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Loporchio, S., MacHado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Mender, S., Micanovic, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletic, L., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suric, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tosti, L., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zaric, D., Nievas-Rosillo, M., Arcaro, C., D' Ammando, F., De Palma, F., Hodges, M., Hovatta, T., Kiehlmann, S., Max-Moerbeck, W., Readhead, A. C. S., Reeves, R., Takalo, L., Reinthal, R., Jormanainen, J., Wierda, F., Wagner, S. M., Berdyugin, A., Nabizadeh, A., Talebpour Sheshvan, N., Oksanen, A., Bachev, R., Strigachev, A., Kehusmaa, P., 30588766 - Arcaro, Cornelia, Academy of Finland, Ministerio de Economía y Competitividad (España), Swiss National Science Foundation, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Japan Society for the Promotion of Science, Metsähovi Radio Observatory, Aalto-yliopisto, and Aalto University

Subjects
galaxies [Gamma rays], Astronomical databases: miscellaneous, BL Lacertae objects: general, Galaxies: Active, Galaxies: jets, Gamma rays: galaxies, Radiation mechanisms: non-Thermal, SHEATH POLARIZATION STRUCTURES, Astrophysics, Parameter space, galaxies: active, galaxies: jets, astronomical databases: miscellaneous, radiation mechanisms: non-thermal, gamma rays: galaxies, 01 natural sciences, jet [Galaxies], non-Thermal [Radiation mechanisms], 010303 astronomy & astrophysics, LACERTAE OBJECTS, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, TEV BLAZARS, CROSS-CORRELATIONS, galaxie [Gamma rays], 1ES 1959+650, Gamma ray, Active [Galaxies], miscellaneous [Astronomical databases], Spectral energy distribution, Física nuclear, RELATIVISTIC JETS, Astrophysics - High Energy Astrophysical Phenomena, ACTIVE GALACTIC NUCLEI, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, GeneralLiterature_MISCELLANEOUS, 0103 physical sciences, Very-long-baseline interferometry, Blazar, MULTIWAVELENGTH OBSERVATIONS, 010308 nuclear & particles physics, general [BL Lacertae objects], ComputingMilieux_PERSONALCOMPUTING, Astronomy and Astrophysics, Light curve, Space and Planetary Science, X-RAY, ddc:520, jets [Galaxies], miscellaneou [Astronomical databases], COMPLETE SAMPLE, Free parameter
Abstract

MAGIC Collaboration: et al., [Context]: It has become evident that one-zone synchrotron self-Compton models are not always adequate for very high-energy (VHE) gamma-ray-emitting blazars. While two-component models perform better, they are difficult to constrain due to the large number of free parameters., [Aims]: In this work, we make a first attempt at taking into account the observational constraints from very long baseline interferometry (VLBI) data, long-term light curves (radio, optical, and X-rays), and optical polarisation to limit the parameter space for a two-component model and test whether or not it can still reproduce the observed spectral energy distribution (SED) of the blazars., [Methods]: We selected five TeV BL Lac objects based on the availability of VHE gamma-ray and optical polarisation data. We collected constraints for the jet parameters from VLBI observations. We evaluated the contributions of the two components to the optical flux by means of decomposition of long-term radio and optical light curves as well as modelling of the optical polarisation variability of the objects. We selected eight epochs for these five objects based on the variability observed at VHE gamma rays, for which we constructed the SEDs that we then modelled with a two-component model., [Results]: We found parameter sets which can reproduce the broadband SED of the sources in the framework of two-component models considering all available observational constraints from VLBI observations. Moreover, the constraints obtained from the long-term behaviour of the sources in the lower energy bands could be used to determine the region where the emission in each band originates. Finally, we attempt to use optical polarisation data to shed new light on the behaviour of the two components in the optical band. Our observationally constrained two-component model allows explanation of the entire SED from radio to VHE with two co-located emission regions., VFR and EL were supported by Academy of Finland projects 317636 and 320045. We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF and MPG; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish MINECO (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729-C6-2-R, FPA2017-82729-C6-6-R, FPA2017-82729-C6-5-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2017-87055-C2-2-P, FPA2017-90566-REDC); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant nr. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588 and SEV2015-0548, the Unidad de Excelencia “María de Maeztu” MDM-2014-0369 and the “la Caixa” Foundation (fellowship LCF/BQ/PI18/11630012), by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq and FAPERJ.

Published
2020

25. Study of the variable broadband emission of Markarian 501 during the most extreme Swift X-ray activity

Author

Francesco Longo, Yuki Iwamura, Susumu Inoue, L. Nogués, M. I. Martínez, G. Pedaletti, Thomas Bretz, J. Buss, A. Rugliancich, Marina Manganaro, D. Galindo, Merja Tornikoski, Sabrina Einecke, Martin Makariev, Oscar Blanch, C. Leto, Ciro Bigongiari, Adrian Biland, D. Zarić, Andrii Neronov, M. Garczarczyk, Sargis Gasparyan, Konstancja Satalecka, Michele Doro, Marc Ribó, M. Noethe, J. Becerra González, Kazuma Ishio, J. Rico, Christian Fruck, Kyoshi Nishijima, Abelardo Moralejo, E. Moretti, Wolfgang Rhode, Christoph Wendel, Dominik Baack, Satoshi Masuda, Hidetoshi Kubo, Nikola Godinovic, B. Machado de Oliveira Fraga, Alexander Hahn, Manuel Delfino, Daniela Dorner, P. Giammaria, A. Niedzwiecki, Alessio Berti, U. Barres de Almeida, F. Verrecchia, G. Busetto, Lena Linhoff, D. Fidalgo, Damir Lelas, G. Ferrara, Alicia Fattorini, D. Hildebrand, David Paneque, V. A. Acciari, Bernd Schleicher, Gaia Vanzo, M. Peresano, Rodolfo Carosi, M. Perri, Alessandra Lamastra, John Hoang, Marcel Strzys, M. Gaug, Chiara Righi, M. Armas Padilla, D. Ninci, Ana Babić, Michael Blank, Dorota Sobczyńska, D. Dominis Prester, A. De Angelis, Vitaly Neustroev, I. Snidaric, F. Schulz, E. von Willert, D. Guberman, A. Y. Lien, J. Herrera, Juan Abel Barrio, B. Banerjee, J. van Scherpenberg, V. D'Elia, Narek Sahakyan, P. Temnikov, Stefano Ansoldi, R. J. García López, G. Maneva, E. Do Souto Espiñera, B. De Lotto, Elisa Bernardini, Riccardo Paoletti, S. Paiano, Karl Mannheim, Pablo Peñil, A. Shukla, Ivica Puljak, Jose Luis Contreras, D. Neise, Andrea Tramacere, Manuela Mallamaci, A. López-Oramas, Jordi Delgado, V. Fallah Ramazani, Juan Cortina, J. Palacio, P. Colin, R. Walter, J. M. Paredes, F. Di Pierro, Antonio Stamerra, Pratik Majumdar, Camilla Maggio, M. V. Fonseca, Ievgen Vovk, Francesco Dazzi, A. Fernández-Barral, Cosimo Nigro, P. Munar-Adrover, Massimo Persic, Dario Hrupec, L. A. Antonelli, Martin Will, D. Kuveždić, T. Schweizer, F. Leone, Anne Lähteenmäki, Tarek M. Hassan, Fabrizio Tavecchio, Masahiro Teshima, A. Somero, Kari Nilsson, Ll. Font, M. Bulinski, Wlodek Bednarek, Vitalii Sliusar, P. G. Prada Moroni, Junko Kushida, P. Da Vela, E. Prandini, N. Torres-Albà, Joni Tammi, Sebastian Achim Mueller, J. R. Garcia, Giacomo Bonnoli, Manuel Doerr, Stefano Gallozzi, Jose Miguel Miranda, Wrijupan Bhattacharyya, Julian Sitarek, T. Surić, Shimpei Tsujimoto, K. Bruegge, D. Elsaesser, Tomislav Terzić, Jürgen Besenrieder, E. Molina, E. Colombo, Lab Saha, Luca Foffano, Mosè Mariotti, A. Paravac, Saverio Lombardi, M. Nievas Rosillo, M. Minev, M. Balbo, D. Hadasch, R. Mirzoyan, A. Arbet-Engels, K. Sedlaczek, L. Maraschi, Elina Lindfors, Daniel Mazin, Stefan Cikota, M. Vazquez Acosta, Victoria Moreno, Stefano Covino, Tomoki Saito, Giovanni Ceribella, Aaron Dominguez, K. Noda, Sidika Merve Colak, M. López, German Research Foundation, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), Croatian Science Foundation, University of Rijeka, Polish National Agency for Academic Exchange, Ministério da Ciência, Tecnologia e Inovação (Brasil), National Aeronautics and Space Administration (US), Department of Energy (US), Commissariat à l'Ènergie Atomique et aux Ènergies Alternatives (France), Centre National de la Recherche Scientifique (France), Institut National de Physique Nucléaire et de Physique des Particules (France), Agenzia Spaziale Italiana, High Energy Accelerator Research Organization (Japan), Japan Aerospace Exploration Agency, Knut and Alice Wallenberg Foundation, Swedish Research Council, Swedish National Space Board, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bonnoli, G., Busetto, G., Carosi, R., Ceribella, G., Cikota, S., Colak, S. M., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., DI Pierro, F., Do Souto Espinera, E., Dominguez, A., Dominis Prester, D., Doro, M., Fallah Ramazani, V., Fattorini, A., Fernandez-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., Gallozzi, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giammaria, P., Godinovic, N., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Herrera, J., Hoang, J., Hrupec, D., Inoue, S., Ishio, K., Iwamura, Y., Kubo, H., Kushida, J., Kuvecdic, D., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Oramas, A., MacHado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Martinez, M., Masuda, S., Mazin, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Garcia, J. R., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, A., Stamerra, A., Strzys, M., Suric, T., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tsujimoto, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vovk, I., Will, M., Zaric, D., Arbet-Engels, A., Baack, D., Balbo, M., Biland, A., Blank, M., Bretz, T., Bruegge, K., Bulinski, M., Buss, J., Doerr, M., Dorner, D., Einecke, S., Elsaesser, D., Hildebrand, D., Linhoff, L., Mannheim, K., Mueller, S., Neise, D., Neronov, A., Noethe, M., Paravac, A., Rhode, W., Schleicher, B., Schulz, F., Sedlaczek, K., Shukla, A., Sliusar, V., Von Willert, E., Walter, R., Wendel, C., Tramacere, A., Lien, A., Perri, M., Verrecchia, F., Armas Padilla, M., Leto, C., Lahteenmaki, A., Tornikoski, M., Tammi, J., Department of Electronics and Nanoengineering, Metsähovi Radio Observatory, Aalto-yliopisto, and Aalto University

Subjects
galaxies: active, BL Lacertae objects: individual: Mrk 501, gamma rays: galaxies, X-rays: galaxies, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Power law, Spectral line, Galaxies: active, Gamma rays: galaxies, individual: Mrk 501 [BL Lacertae objects], 0103 physical sciences, MAGIC (telescope), Blazar, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, galaxie [Gamma rays], 010308 nuclear & particles physics, Gamma ray, Astronomy and Astrophysics, galaxies [X-rays], Crab Nebula, Space and Planetary Science, active [galaxies], galaxies [gamma rays], ddc:520, Física nuclear, High Energy Astrophysical Phenomena, Astrophysics - High Energy Astrophysical Phenomena
Abstract

[Context] Markarian 501 (Mrk 501) is a very high-energy (VHE) gamma-ray blazar located at z = 0:034, which is regularly monitored by a wide range of multi-wavelength instruments, from radio to VHE gamma rays. During a period of almost two weeks in July 2014, the highest X-ray activity of Mrk 501 was observed in -14 years of operation of the Neil Gehrels Swift Gamma-ray Burst Observatory., [Aims] We characterize the broadband variability of Mrk 501 from radio to VHE gamma rays during the most extreme X-ray activity measured in the last 14 years, and evaluate whether it can be interpreted within theoretical scenarios widely used to explain the broadband emission from blazars., [Methods] The emission of Mrk 501 was measured at radio with Metsähovi, at optical–UV with KVA and Swift/UVOT, at X-ray with Swift/XRT and Swift/BAT, at gamma ray with Fermi-LAT, and at VHE gamma rays with the FACT and MAGIC telescopes. The multi-band variability and correlations were quantified, and the broadband spectral energy distributions (SEDs) were compared with predictions from theoretical models., [Results] The VHE emission of Mrk 501 was found to be elevated during the X-ray outburst, with a gamma-ray flux above 0.15 TeV varying from ∼0.5 to ∼2 times the Crab nebula flux. The X-ray and VHE emission both varied on timescales of 1 day and were found to be correlated. We measured a general increase in the fractional variability with energy, with the VHE variability being twice as large as the X-ray variability. The temporal evolution of the most prominent and variable segments of the SED, characterized on a day-by-day basis from 2014 July 16 to 2014 July 31, is described with a one-zone synchrotron self-Compton model with variations in the break energy of the electron energy distribution (EED), and with some adjustments in the magnetic field strength and spectral shape of the EED. These results suggest that the main flux variations during this extreme X-ray outburst are produced by the acceleration and the cooling of the high-energy electrons. A narrow feature at ∼3 TeV was observed in the VHE spectrum measured on 2014 July 19 (MJD 56857.98), which is the day with the highest X-ray flux (>0.3 keV) measured during the entire Swift mission. This feature is inconsistent with the classical analytic functions to describe the measured VHE spectra (power law, log-parabola, and log-parabola with exponential cutoff) at more than 3σ. A fit with a log-parabola plus a narrow component is preferred over the fit with a single log-parabola at more than 4σ, and a dedicated Monte Carlo simulation estimated the significance of this extra component to be larger than 3σ. Under the assumption that this VHE spectral feature is real, we show that it can be reproduced with three distinct theoretical scenarios: (a) a pileup in the EED due to stochastic acceleration; (b) a structured jet with two-SSC emitting regions, with one region dominated by an extremely narrow EED; and (c) an emission from an IC pair cascade induced by electrons accelerated in a magnetospheric vacuum gap, in addition to the SSC emission from a more conventional region along the jet of Mrk 501., The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish MINECO (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662-C2-2-P, FPA2017-90566-REDC), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588 and SEV-2015-0548, and Unidad de Excelencia “María de Maeztu” MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq and FAPERJ. The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Instituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. The important contributions from ETH Zurich grants ETH-10.08-2 and ETH-27.12-1 as well as the funding by the Swiss SNF and the German BMBF (Ver-bundforschung Astro-und Astroteilchenphysik) and HAP (Helmoltz Alliance for Astroparticle Physics) are gratefully acknowledged. Part of this work is supported by Deutsche Forschungsgemeinschaft (DFG) within the Collaborative Research Center SFB 876, project C3. We thank the Instituto de Astrofisica de Canarias for allowing us to operate the telescope at the Observatorio del Roque de los Muchachos in La Palma, the Max-Planck-Institut fur Physik for providing us with the mount of the former HEGRA CT3 telescope, and the MAGIC Collaboration for their support. JBG acknowledges the support of the Viera y Clavijo program funded by ACIISI and ULL. C. W. is grateful for the support by the project “Promotion inklusive” of the Universität zu Köln and the German Bundesmin-isterium für Arbeit und Soziales. This publication makes use of data obtained at Metsähovi Radio Observatory, operated by Aalto University, Finland.

Published
2020

26. Testing emission models on the extreme blazar 2WHSP J073326.7+515354 detected at very high energies with the MAGIC telescopes

Author

Adrian Biland, J. Becerra González, J. Rico, Satoshi Fukami, Alessandra Lamastra, D. Mazin, G. Busetto, L. Di Venere, Alessio Berti, F. Leone, Neustroev, Kazuma Ishio, R. Mirzoyan, Rodolfo Carosi, Mosè Mariotti, Masahiro Teshima, Manuela Mallamaci, Sargis Gasparyan, Léa Jouvin, John Hoang, Cosimo Nigro, F. D'Ammando, A. Somero, Wolfgang Rhode, L. Nogués, A. Arbet Engels, Juan Abel Barrio, M. Minev, D. Dominis Prester, Giacomo Bonnoli, Stefano Covino, A. López-Oramas, Narek Sahakyan, Daniela Dorner, Luca Tosti, Julian Sitarek, Fallah Ramazani, Tihomir Surić, Pablo Peñil, Lorenzo Bellizzi, Gaia Vanzo, M. Gaug, D. Fidalgo, P. G. Prada Moroni, K. Nishijima, Daniela Hadasch, Francesco Longo, Alicia Fattorini, Tomoki Saito, Giovanni Ceribella, G. Maneva, U. Barres de Almeida, Damir Lelas, S. Paiano, Karl Mannheim, R. J. García López, Katsuaki Asano, David Paneque, Saverio Lombardi, D. Ninci, Wrijupan Bhattacharyya, Koji Noda, Chiara Righi, M. Peresano, Daniel Kerszberg, Pratik Majumdar, D. Guberman, Dorota Sobczyńska, Matteo Cerruti, V. A. Acciari, Yuki Iwamura, Susumu Inoue, Elisa Bernardini, Wlodek Bednarek, M. V. Fonseca, P. Temnikov, A. Rugliancich, Martin Makariev, Marina Manganaro, G. Ferrara, L. Maraschi, Elina Lindfors, Martin Will, D. Zarić, Oscar Blanch, Nikola Godinovic, D. Strom, E. Do Souto Espiñeira, N. Torres-Albà, Ferdinando Giordano, Jordi Delgado, U. Colin, David A. Green, Marc Ribó, M. Palatiello, F. Di Pierro, Ž. Bošnjak, Ivica Puljak, Tomislav Terzić, Alexander Hahn, D. Elsaesser, Toshiaki Inada, B. Banerjee, Shunsuke Sakurai, Kevin Schmidt, Dario Hrupec, E. Molina, Hidetoshi Kubo, M. A. Lopez, Konstancja Satalecka, M. I. Martínez, Michele Doro, Francesco Dazzi, E. Colombo, A. De Angelis, Mitsunari Takahashi, Lab Saha, Luca Foffano, P. Munar-Adrover, Massimo Persic, Stefano Ansoldi, Davide Depaoli, Yating Chai, Junko Kushida, Stefan Cikota, P. Da Vela, Jose Miguel Miranda, Vitale, Riccardo Paoletti, J. van Scherpenberg, Sasa Micanovic, B. Machado de Oliveira Fraga, J. Palacio, E. Prandini, M. Vazquez Acosta, J. M. Paredes, Antonio Stamerra, Moritz Hütten, Vagelli, A. Chilingaryan, Ievgen Vovk, Dominik Baack, Marcel Strzys, Jose Carlos Herrera, Jürgen Besenrieder, T. Schweizer, D’Elia, Camilla Maggio, Christian Fruck, N. Giglietto, Moreno, Yusuke Suda, Carlo Vigorito, Sidika Merve Colak, Manuel Delfino, Alice Donini, L. A. Antonelli, Ana Babić, R. Clavero, Daniel Morcuende, Jose Luis Contreras, Juan Cortina, Fabrizio Tavecchio, Ll. Font, I. Snidaric, Kari Nilsson, D. Miceli, Serena Loporchio, Abelardo Moralejo, E. Moretti, B. De Lotto, S. Nozaki, Ciro Bigongiari, M. Garczarczyk, R. López-Coto, ITA, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babic, A., Banerjee, B., Barres de Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingaryan, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., da Vela, P., Dazzi, F., de Angelis, A., de Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinovic, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kerszberg, D., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Micanovic, S., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nozaki, S., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suric, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tosti, L., Vagelli, V., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zaric, D., Asano, K., D'Ammando, F., and Clavero, R.

Subjects
Astrophysics and Astronomy, galaxie [Gamma-rays], active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Hadron, FOS: Physical sciences, astro-ph.HE, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Jet (particle physics), X-rays: general, 01 natural sciences, 7. Clean energy, law.invention, law, general [X-rays], 0103 physical sciences, MAGIC (telescope), Blazar, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, general [BL Lacertae objects], Gamma ray, BL Lacertae objects: general - galaxies: active - gamma-rays: galaxies - X-rays: general, Astronomy and Astrophysics, alaxies: active, BL Lacertae objects: general, gamma-rays: gala, Galaxies: active, Synchrotron, galaxies [gamma-rays], 13. Climate action, Space and Planetary Science, Spectral energy distribution, ddc:520, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, Gamma-rays: galaxies
Abstract

Extreme high-energy peaked BL Lac objects (EHBLs) are an emerging class of blazars. Their typical two-hump structured spectral energy distribution (SED) peaks at higher energies with respect to conventional blazars. Multi-wavelength (MWL) observations constrain their synchrotron peak in the medium to hard X-ray band. Their gamma-ray SED peaks above the GeV band, and in some objects it extends up to several TeV. Up to now, only a few EHBLs have been detected in the TeV gamma-ray range. In this paper, we report the detection of the EHBL 2WHSP J073326.7+515354, observed and detected during 2018 in TeV gamma rays with the MAGIC telescopes. The broad-band SED is studied within a MWL context, including an analysis of the Fermi-LAT data over ten years of observation and with simultaneous Swift-XRT, Swift-UVOT, and KVA data. Our analysis results in a set of spectral parameters that confirms the classification of the source as an EHBL. In order to investigate the physical nature of this extreme emission, different theoretical frameworks were tested to model the broad-band SED. The hard TeV spectrum of 2WHSP J073326.7+515354 sets the SED far from the energy equipartition regime in the standard one-zone leptonic scenario of blazar emission. Conversely, more complex models of the jet, represented by either a two-zone spine-layer model or a hadronic emission model, better represent the broad-band SED., MNRAS published

Published
2019

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