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Start Over Author "Hovatta, T" Journal monthly notices of the royal astronomical society
104 results on '"Hovatta, T"'

1. Unprecedented extreme high-frequency radio variability in early-stage active galactic nuclei.

Author

Järvelä, E, Savolainen, T, Berton, M, Lähteenmäki, A, Kiehlmann, S, Hovatta, T, Varglund, I, Readhead, A C S, Tornikoski, M, Max-Moerbeck, W, Reeves, R A, and Suutarinen, S

Subjects
ACTIVE galactic nuclei, SHORTWAVE radio, COLLEGE radio stations, ASTROPHYSICAL jets, BRIGHTNESS temperature, BL Lacertae objects, SEYFERT galaxies, RADIO jets (Astrophysics)
Abstract

We report on the discovery of one of the most extreme cases of high-frequency radio variability ever measured in active galactic nuclei (AGNs), observed on time-scales of days and exhibiting variability amplitudes of 3–4 orders of magnitude. These sources, all radio-weak narrow-line Seyfert 1 (NLS1) galaxies, were discovered some years ago at Aalto University Metsähovi Radio Observatory (MRO) based on recurring flaring at 37 GHz, strongly indicating the presence of relativistic jets. In subsequent observations with the Karl G. Jansky Very Large Array (JVLA) at 1.6, 5.2, and 9.0 GHz no signs of jets were seen. To determine the cause of their extraordinary behaviour, we observed them with the JVLA at 10, 15, 22, 33, and 45 GHz, and with the Very Long Baseline Array (VLBA) at 15 GHz. These observations were complemented with single-dish monitoring at 37 GHz at MRO, and at 15 GHz at Owens Valley Radio Observatory (OVRO). Intriguingly, all but one source either have a steep radio spectrum up to 45 GHz, or were not detected at all. Based on the 37 GHz data, the time-scales of the radio flares are a few days, and the derived variability brightness temperatures and variability Doppler factors are comparable to those seen in blazars. We discuss alternative explanations for their extreme behaviour, but so far no definite conclusions can be made. These sources exhibit radio variability at a level rarely, if ever, seen in AGN. They might represent a new type of jetted AGN, or a new variability phenomenon, and thus deserve our continued attention. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Multi-wavelength observations of the lensed quasar PKS 1830−211 during the 2019 γ-ray flare

Author

Vercellone, S, primary, Donnarumma, I, additional, Pittori, C, additional, Capitanio, F, additional, De Rosa, A, additional, Di Gesu, L, additional, Kiehlmann, S, additional, Iacolina, M N, additional, Pellizzoni, P A, additional, Egron, E, additional, Pacciani, L, additional, Piano, G, additional, Puccetti, S, additional, Righini, S, additional, Valente, G, additional, Verrecchia, F, additional, Vittorini, V, additional, Tavani, M, additional, Brocato, E, additional, Chen, A W, additional, Hovatta, T, additional, Melis, A, additional, Max–Moerbeck, W, additional, Perrodin, D, additional, Pilia, M, additional, Pili, M, additional, Readhead, A C S, additional, Reeves, R, additional, Ridolfi, A, additional, Vitali, F, additional, Bulgarelli, A, additional, Cattaneo, P W, additional, Lucarelli, F, additional, Morselli, A, additional, and Trois, A, additional

Published
2023
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4. A Kpc-scale radio polarization study of PG BL Lacs with the uGMRT.

Author

Baghel, Janhavi, Kharb, P, Hovatta, T, Gulati, S, Lindfors, E, and S., Silpa

Subjects
BL Lacertae objects, VERY long baseline interferometry, RADIO galaxies, THERMAL plasmas, ACTIVE galaxies, MAGNETIC cores
Abstract

We present here uGMRT band 4 (∼650 MHz) polarization images of 8 BL Lac objects belonging to the Palomar-Green (PG) 'blazar' sample. A large fraction of the sources (⁠|$\sim 63~{{\ \rm per\ cent}}$|⁠) reveal core-halo radio structures with most of the polarization detected in the inner core-jet regions. PG1101 + 385 and PG2254 + 075 exhibit a 'spine-sheath structure' in polarization. The core-halo and 'spine-sheath' structures are consistent with the Unified Scheme suggestion that BL Lacs are the pole-on beamed counterparts of Fanaroff–Riley (FR) type I radio galaxies. PG1418 + 546 and PG0851 + 203 (OJ287) show the presence of terminal hotspots similar to FR type II radio galaxies. They were also found to be low-spectrally peaked BL Lacs, supportive of the 'blazar envelope' scenario for BL Lacs and quasars. Fractional polarization ranges from 1 to 13 per cent in the cores and 2 to 26 per cent in the inner jets/lobes of the sample BL Lacs. Compared to the varied radio morphology of quasars from the PG 'blazar' sample, the BL Lacs appear to be less diverse. A comparison of the inferred core magnetic (B -) field structures on arcsec- (kpc-) scales w.r.t. the Very Long Baseline Interferometry jet direction does not reveal any preferred orientation, suggesting that if large-scale ordered B -fields exist, they do so on scales smaller than probed by the current observations. However, the presence of polarized emission on arcsec-scales suggests that any mixing of thermal plasma with the synchrotron emitting plasma is insufficient to fully depolarize the emission via the internal depolarization process. [ABSTRACT FROM AUTHOR]

Published
2024
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5. 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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6. Multiwavelength study of the gravitationally lensed blazar QSO B0218+357 between 2016 and 2020

Author

Acciari, V A, primary, Ansoldi, S, additional, Antonelli, L A, additional, Arbet Engels, A, additional, Artero, M, additional, Asano, K, additional, Baack, D, additional, Babić, A, additional, Baquero, A, additional, Barres de Almeida, U, additional, Barrio, J A, additional, Batković, I, additional, Becerra González, J, additional, Bednarek, W, additional, Bellizzi, L, additional, Bernardini, E, additional, Bernardos, M, additional, Berti, A, additional, Besenrieder, J, additional, Bhattacharyya, W, additional, Bigongiari, C, additional, Biland, A, additional, Blanch, O, additional, Bonnoli, G, additional, Bošnjak, Ž, additional, Busetto, G, additional, Carosi, R, additional, Ceribella, G, additional, Cerruti, M, additional, Chai, Y, additional, Chilingarian, A, additional, Cikota, S, additional, Colak, S M, additional, Colombo, E, additional, Contreras, J L, additional, Cortina, J, additional, Covino, S, additional, D’Amico, G, additional, D’Elia, V, additional, Da Vela, P, additional, Dazzi, F, additional, De Angelis, A, additional, De Lotto, B, additional, Delfino, M, additional, Delgado, J, additional, Delgado Mendez, C, additional, Depaoli, D, additional, Di Pierro, F, additional, Di Venere, L, additional, Do Souto Espiñeira, E, additional, Dominis Prester, D, additional, Donini, A, additional, Dorner, D, additional, Doro, M, additional, Elsaesser, D, additional, Fallah Ramazani, V, additional, Fattorini, A, additional, Ferrara, G, additional, Fonseca, M V, additional, Font, L, additional, Fruck, C, additional, Fukami, S, additional, García López, R J, additional, Garczarczyk, M, additional, Gasparyan, S, additional, Gaug, M, additional, Giglietto, N, additional, Giordano, F, additional, Gliwny, P, additional, Godinović, N, additional, Green, J G, additional, Green, D, additional, Hadasch, D, additional, Hahn, A, additional, Heckmann, L, additional, Herrera, J, additional, Hoang, J, additional, Hrupec, D, additional, Hütten, M, additional, Inada, T, additional, Inoue, S, additional, Ishio, K, additional, Iwamura, Y, additional, Jiménez, I, additional, Jormanainen, J, additional, Jouvin, L, additional, Kajiwara, Y, additional, Karjalainen, M, additional, Kerszberg, D, additional, Kobayashi, Y, additional, Kubo, H, additional, Kushida, J, additional, Lamastra, A, additional, Lelas, D, additional, Leone, F, additional, Lindfors, E, additional, Lombardi, S, additional, Longo, F, additional, López-Coto, R, additional, López-Moya, M, additional, López-Oramas, A, additional, Loporchio, S, additional, Machado de Oliveira Fraga, B, additional, Maggio, C, additional, Majumdar, P, additional, Makariev, M, additional, Mallamaci, M, additional, Maneva, G, additional, Manganaro, M, additional, Mannheim, K, additional, Maraschi, L, additional, Mariotti, M, additional, Martínez, M, additional, Mazin, D, additional, Menchiari, S, additional, Mender, S, additional, Mićanović, S, additional, Miceli, D, additional, Miener, T, additional, Minev, M, additional, Miranda, J M, additional, Mirzoyan, R, additional, Molina, E, additional, Moralejo, A, additional, Morcuende, D, additional, Moreno, V, additional, Moretti, E, additional, Neustroev, V, additional, Nigro, C, additional, Nilsson, K, additional, Nishijima, K, additional, Noda, K, additional, Nozaki, S, additional, Ohtani, Y, additional, Oka, T, additional, Otero-Santos, J, additional, Paiano, S, additional, Palatiello, M, additional, Paneque, D, additional, Paoletti, R, additional, Paredes, J M, additional, Pavletić, L, additional, Peñil, P, additional, Perennes, C, additional, Persic, M, additional, Prada Moroni, P G, additional, Prandini, E, additional, Priyadarshi, C, additional, Puljak, I, additional, Rhode, W, additional, Ribó, M, additional, Rico, J, additional, Righi, C, additional, Rugliancich, A, additional, Saha, L, additional, Sahakyan, N, additional, Saito, T, additional, Sakurai, S, additional, Satalecka, K, additional, Saturni, F G, additional, Schleicher, B, additional, Schmidt, K, additional, Schweizer, T, additional, Sitarek, J, additional, Šnidarić, I, additional, Sobczynska, D, additional, Spolon, A, additional, Stamerra, A, additional, Strom, D, additional, Strzys, M, additional, Suda, Y, additional, Surić, T, additional, Takahashi, M, additional, Tavecchio, F, additional, Temnikov, P, additional, Terzić, T, additional, Teshima, M, additional, Tosti, L, additional, Truzzi, S, additional, Tutone, A, additional, Ubach, S, additional, van Scherpenberg, J, additional, Vanzo, G, additional, Vazquez Acosta, M, additional, Ventura, S, additional, Verguilov, V, additional, Vigorito, C F, additional, Vitale, V, additional, Vovk, I, additional, Will, M, additional, Wunderlich, C, additional, Zarić, D, additional, de Palma, F, additional, D’Ammando, F, additional, Barnacka, A, additional, Sahu, D K, additional, Hodges, M, additional, Hovatta, T, additional, Kiehlmann, S, additional, Max-Moerbeck, W, additional, Readhead, A C S, additional, Reeves, R, additional, Pearson, T J, additional, Lähteenmäki, A, additional, Björklund, I, additional, Tornikoski, M, additional, Tammi, J, additional, Suutarinen, S, additional, Hada, K, additional, and Niinuma, K, additional

Published
2021
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8. The time-dependent distribution of optical polarization angle changes in blazars

Author

Kiehlmann, S, primary, Blinov, D, additional, Liodakis, I, additional, Pavlidou, V, additional, Readhead, A C S, additional, Angelakis, E, additional, Casadio, C, additional, Hovatta, T, additional, Kylafis, N, additional, Mahabal, A, additional, Mandarakas, N, additional, Myserlis, I, additional, Panopoulou, G V, additional, Pearson, T J, additional, Ramaprakash, A, additional, Reig, P, additional, Skalidis, R, additional, Słowikowska, A, additional, Tassis, K, additional, and Zensus, J A, additional

Published
2021
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9. The Most Powerful Flaring Activity from the NLSy1 PMN J0948+0022

Author

D'Ammando, F, Orienti, M, Finke, J, Raiteri, C. M, Hovatta, T, Larsson, J, Max-Moerbeck, W, Perkins, J, Readhead, A. C. S, and Richards, J. L

Subjects
Astronomy
Abstract

We report on multifrequency observations performed during 2012 December-2013 August of the first narrow-line Seyfert 1 galaxy detected in gamma rays, PMN J0948+0022 (z equal to 0.5846). A gamma-ray flare was observed by the Large Area Telescope on board Fermi during 2012 December-2013 January, reaching a daily peak flux in the 0.1-100 GeV energy range of (155 plus or minus 31)×10(exp −8) ph cm (exp −2) s (exp −1) on 2013 January 1, corresponding to an apparent isotropic luminosity of approximately 1.5×10)exp 48) erg s(exp −1). The gamma-ray flaring period triggered Swift and VERITAS observations in addition to radio and optical monitoring by OVRO, MOJAVE, and CRTS. A strong flare was observed in optical, UV, and X- rays on 2012 December 30, quasi-simultaneously to the gamma-ray flare, reaching a record flux for this source from optical to gamma rays. VERITAS observations at very high energy (E greater than 100 GeV) during 2013 January 6-17 resulted in an upper limit of F(sub greater than 0.2 TeV) less than 4.0 × 10(exp −12) ph cm(exp −2) s(exp −1). We compared the spectral energy distribution (SED) of the flaring state in 2013 January with that of an intermediate state observed in 2011. The two SEDs, modelled as synchrotron emission and an external Compton scattering of seed photons from a dust torus, can be modelled by changing both the electron distribution parameters and the magnetic field.

Published
2014
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10. RoboPol: AGN polarimetric monitoring data

Author

Blinov, D, primary, Kiehlmann, S, additional, Pavlidou, V, additional, Panopoulou, G V, additional, Skalidis, R, additional, Angelakis, E, additional, Casadio, C, additional, Einoder, E N, additional, Hovatta, T, additional, Kokolakis, K, additional, Kougentakis, A, additional, Kus, A, additional, Kylafis, N, additional, Kyritsis, E, additional, Lalakos, A, additional, Liodakis, I, additional, Maharana, S, additional, Makrydopoulou, E, additional, Mandarakas, N, additional, Maragkakis, G M, additional, Myserlis, I, additional, Papadakis, I, additional, Paterakis, G, additional, Pearson, T J, additional, Ramaprakash, A N, additional, Readhead, A C S, additional, Reig, P, additional, Słowikowska, A, additional, Tassis, K, additional, Xexakis, K, additional, Żejmo, M, additional, and Zensus, J A, additional

Published
2020
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11. An intermittent extreme BL Lac: MWL study of 1ES 2344+514 in an enhanced state

Author

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

Published
2020
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12. decade of joint MOJAVE–Fermi AGN monitoring: localization of the gamma-ray emission region.

Author

Kramarenko, I G, Pushkarev, A B, Kovalev, Y Y, Lister, M L, Hovatta, T, and Savolainen, T

Subjects
GAMMA ray astronomy, BL Lacertae objects, ACTIVE galactic nuclei, QUASARS, GAMMA rays, ASTROPHYSICAL jets, LIGHT curves, ACTINIC flux
Abstract

Within the MOJAVE VLBA programme (Monitoring of Jets in AGN with VLBA Experiments), we have accumulated observational data at 15 GHz for hundreds of jets in gamma-ray bright active galactic nuclei since the beginning of the Fermi scientific observations in 2008 August. We investigated a time delay between the flux density of AGN parsec-scale radio emission at 15 GHz and 0.1–300 GeV Fermi LAT photon flux, taken from constructed light curves using weekly and adaptive binning. The correlation analysis shows that radio is lagging gamma-ray radiation by up to 8 months in the observer's frame, while in the source frame, the typical delay is about 2–3 months. If the jet radio emission, excluding the opaque core, is considered, significant correlation is found at greater time lags. We supplement these results with VLBI kinematics and core shift data to conclude that the dominant high-energy production zone is typically located at a distance of several parsecs from the central nucleus. We also found that quasars have on average more significant correlation peak, more distant gamma-ray emission region from the central engine and shorter variability time-scale compared to those of BL Lacertae objects. [ABSTRACT FROM AUTHOR]

Published
2022
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13. Multiwavelength behaviour of the blazar 3C 279: decade-long study from γ-ray to radio

Author

Larionov, V M, primary, Jorstad, S G, additional, Marscher, A P, additional, Villata, M, additional, Raiteri, C M, additional, Smith, P S, additional, Agudo, I, additional, Savchenko, S S, additional, Morozova, D A, additional, Acosta-Pulido, J A, additional, Aller, M F, additional, Aller, H D, additional, Andreeva, T S, additional, Arkharov, A A, additional, Bachev, R, additional, Bonnoli, G, additional, Borman, G A, additional, Bozhilov, V, additional, Calcidese, P, additional, Carnerero, M I, additional, Carosati, D, additional, Casadio, C, additional, Chen, W-P, additional, Damljanovic, G, additional, Dementyev, A V, additional, Di Paola, A, additional, Frasca, A, additional, Fuentes, A, additional, Gómez, J L, additional, Gónzalez-Morales, P, additional, Giunta, A, additional, Grishina, T S, additional, Gurwell, M A, additional, Hagen-Thorn, V A, additional, Hovatta, T, additional, Ibryamov, S, additional, Joshi, M, additional, Kiehlmann, S, additional, Kim, J-Y, additional, Kimeridze, G N, additional, Kopatskaya, E N, additional, Kovalev, Yu A, additional, Kovalev, Y Y, additional, Kurtanidze, O M, additional, Kurtanidze, S O, additional, Lähteenmäki, A, additional, Lázaro, C, additional, Larionova, L V, additional, Larionova, E G, additional, Leto, G, additional, Marchini, A, additional, Matsumoto, K, additional, Mihov, B, additional, Minev, M, additional, Mingaliev, M G, additional, Mirzaqulov, D, additional, Muñoz Dimitrova, R V, additional, Myserlis, I, additional, Nikiforova, A A, additional, Nikolashvili, M G, additional, Nizhelsky, N A, additional, Ovcharov, E, additional, Pressburger, L D, additional, Rakhimov, I A, additional, Righini, S, additional, Rizzi, N, additional, Sadakane, K, additional, Sadun, A C, additional, Samal, M R, additional, Sanchez, R Z, additional, Semkov, E, additional, Sergeev, S G, additional, Sigua, L A, additional, Slavcheva-Mihova, L, additional, Sola, P, additional, Sotnikova, Yu V, additional, Strigachev, A, additional, Thum, C, additional, Traianou, E, additional, Troitskaya, Yu V, additional, Troitsky, I S, additional, Tsybulev, P G, additional, Vasilyev, A A, additional, Vince, O, additional, Weaver, Z R, additional, Williamson, K E, additional, and Zhekanis, G V, additional

Published
2020
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15. RoboPol: a four-channel optical imaging polarimeter

Author

Ramaprakash, A N, primary, Rajarshi, C V, primary, Das, H K, primary, Khodade, P, primary, Modi, D, primary, Panopoulou, G, primary, Maharana, S, primary, Blinov, D, primary, Angelakis, E, primary, Casadio, C, primary, Fuhrmann, L, primary, Hovatta, T, primary, Kiehlmann, S, primary, King, O G, primary, Kylafis, N, primary, Kougentakis, A, primary, Kus, A, primary, Mahabal, A, primary, Marecki, A, primary, Myserlis, I, primary, Paterakis, G, primary, Paleologou, E, primary, Liodakis, I, primary, Papadakis, I, primary, Papamastorakis, I, primary, Pavlidou, V, primary, Pazderski, E, primary, Pearson, T J, primary, Readhead, A C S, primary, Reig, P, primary, Słowikowska, A, primary, Tassis, K, primary, and Zensus, J A, primary

Published
2019
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17. Radio and γ -ray follow-up of the exceptionally high activity state of PKS 1510-089 in 2011

Author

Orienti, M., Koyama, S., D’Ammando, F., Giroletti, M., Kino, M., Nagai, H., Venturi, T., Dallacasa, D., Giovannini, G., Angelakis, E., Fuhrmann, L., Hovatta, T., Max-Moerbeck, W., Schinzel, F. K., Akiyama, K., Hada, K., Honma, M., Gasparrini, D., Krichbaum, T. P., Nestoras, I., Readhead, A. C. S., Richards, J. L., Riquelme, D., Sievers, A., Ungerechts, H., and Zensus, J. A.

Subjects
galaxies quasars: individual (PKS 1510−089), radio continuum: general, gamma-rays: observations, radiation mechanisms: non-thermal
Published
2013

18. SBS 0846+513: a New Gamma-ray-emitting Narrow-line Seyfert 1 Galaxy

Author

D'Ammando, F., Orienti, M., Finke, J., Raiteri, C. M., Angelakis, E., Fuhrmann, L., Giroletti, M., Hovatta, T., Max-Moerbeck, W., Perkins, J. S., Readhead, A. C. S., Richards, J. L., Stawarz, Lukasz, and Donato, D.

Abstract

著者人数: 14名, Accepted: 2012-07-11, 資料番号: SA1004292000

Published
2012

19. The high brightness temperature of B0529+483 revealed by RadioAstron and implications for interstellar scattering

Author

Pilipenko, S V, primary, Kovalev, Y Y, additional, Andrianov, A S, additional, Bach, U, additional, Buttaccio, S, additional, Cassaro, P, additional, Cimò, G, additional, Edwards, P G, additional, Gawroński, M P, additional, Gurvits, L I, additional, Hovatta, T, additional, Jauncey, D L, additional, Johnson, M D, additional, Kovalev, Yu A, additional, Kutkin, A M, additional, Lisakov, M M, additional, Melnikov, A E, additional, Orlati, A, additional, Rudnitskiy, A G, additional, Sokolovsky, K V, additional, Stanghellini, C, additional, de Vicente, P, additional, Voitsik, P A, additional, Wolak, P, additional, and Zhekanis, G V, additional

Published
2017
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20. RoboPol: connection between optical polarization plane rotations and gamma-ray flares in blazars

Author

Blinov, D., primary, Pavlidou, V., additional, Papadakis, I., additional, Kiehlmann, S., additional, Liodakis, I., additional, Panopoulou, G. V., additional, Angelakis, E., additional, Baloković, M., additional, Hovatta, T., additional, King, O. G., additional, Kus, A., additional, Kylafis, N., additional, Mahabal, A., additional, Maharana, S., additional, Myserlis, I., additional, Paleologou, E., additional, Papamastorakis, I., additional, Pazderski, E., additional, Pearson, T. J., additional, Ramaprakash, A., additional, Readhead, A. C. S., additional, Reig, P., additional, Tassis, K., additional, and Zensus, J. A., additional

Published
2017
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24. RoboPol: the optical polarization of gamma-ray-loud and gamma-ray-quiet blazars

Author

Angelakis, E., primary, Hovatta, T., additional, Blinov, D., additional, Pavlidou, V., additional, Kiehlmann, S., additional, Myserlis, I., additional, Böttcher, M., additional, Mao, P., additional, Panopoulou, G. V., additional, Liodakis, I., additional, King, O. G., additional, Baloković, M., additional, Kus, A., additional, Kylafis, N., additional, Mahabal, A., additional, Marecki, A., additional, Paleologou, E., additional, Papadakis, I., additional, Papamastorakis, I., additional, Pazderski, E., additional, Pearson, T. J., additional, Prabhudesai, S., additional, Ramaprakash, A. N., additional, Readhead, A. C. S., additional, Reig, P., additional, Tassis, K., additional, Urry, M., additional, and Zensus, J. A., additional

Published
2016
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25. RoboPol: do optical polarization rotations occur in all blazars?

Author

Blinov, D., primary, Pavlidou, V., additional, Papadakis, I., additional, Kiehlmann, S., additional, Liodakis, I., additional, Panopoulou, G. V., additional, Pearson, T. J., additional, Angelakis, E., additional, Baloković, M., additional, Hovatta, T., additional, Joshi, V., additional, King, O. G., additional, Kus, A., additional, Kylafis, N., additional, Mahabal, A., additional, Marecki, A., additional, Myserlis, I., additional, Paleologou, E., additional, Papamastorakis, I., additional, Pazderski, E., additional, Prabhudesai, S., additional, Ramaprakash, A., additional, Readhead, A. C. S., additional, Reig, P., additional, Tassis, K., additional, and Zensus, J. A., additional

Published
2016
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26. The RINGO2 and DIPOL optical polarization catalogue of blazars

Author

Jermak, H., primary, Steele, I. A., additional, Lindfors, E., additional, Hovatta, T., additional, Nilsson, K., additional, Lamb, G. P., additional, Mundell, C., additional, Barres de Almeida, U., additional, Berdyugin, A., additional, Kadenius, V., additional, Reinthal, R., additional, and Takalo, L., additional

Published
2016
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28. Erratum: Optical polarization map of the Polaris Flare with RoboPol

Author

Panopoulou, G., primary, Tassis, K., additional, Blinov, D., additional, Pavlidou, V., additional, King, O. G., additional, Paleologou, E., additional, Ramaprakash, A., additional, Angelakis, E., additional, Baloković, M., additional, Das, H. K., additional, Feiler, R., additional, Hovatta, T., additional, Khodade, P., additional, Kiehlmann, S., additional, Kus, A., additional, Kylafis, N., additional, Liodakis, I., additional, Mahabal, A., additional, Modi, D., additional, Myserlis, I., additional, Papadakis, I., additional, Papamastorakis, I., additional, Pazderska, B., additional, Pazderski, E., additional, Pearson, T. J., additional, Rajarshi, C., additional, Readhead, A. C. S., additional, Reig, P., additional, and Zensus, J. A., additional

Published
2016
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29. RoboPol: optical polarization-plane rotations and flaring activity in blazars

Author

Blinov, D., primary, Pavlidou, V., additional, Papadakis, I. E., additional, Hovatta, T., additional, Pearson, T. J., additional, Liodakis, I., additional, Panopoulou, G. V., additional, Angelakis, E., additional, Baloković, M., additional, Das, H., additional, Khodade, P., additional, Kiehlmann, S., additional, King, O. G., additional, Kus, A., additional, Kylafis, N., additional, Mahabal, A., additional, Marecki, A., additional, Modi, D., additional, Myserlis, I., additional, Paleologou, E., additional, Papamastorakis, I., additional, Pazderska, B., additional, Pazderski, E., additional, Rajarshi, C., additional, Ramaprakash, A., additional, Readhead, A. C. S., additional, Reig, P., additional, Tassis, K., additional, and Zensus, J. A., additional

Published
2016
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30. Radio follow-up of the γ-ray flaring gravitational lens JVAS B0218+357

Author

Spingola, C., primary, Dallacasa, D., additional, Orienti, M., additional, Giroletti, M., additional, McKean, J. P., additional, Cheung, C. C., additional, Hovatta, T., additional, Ciprini, S., additional, D'Ammando, F., additional, Falco, E., additional, Larsson, S., additional, Max-Moerbeck, W., additional, Ojha, R., additional, Readhead, A. C. S., additional, Richards, J. L., additional, and Scargle, J., additional

Published
2016
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31. The high brightness temperature of B0529+483 revealed by RadioAstron and implications for interstellar scattering.

Author

Pilipenko, S. V., Kovalev, Y. Y., Andrianov, A. S., Bach, U., Buttaccio, S., Cassaro, P., Cim'o, G., Edwards, P. G., Gawrónski, M. P., Gurvits, L. I., Hovatta, T., Jauncey, D. L., Johnson, M. D., Kovalev, Yu. A., Kutkin, A. M., Lisakov, M. M., Melnikov, A. E., Orlati, A., Rudnitskiy, A. G., and Sokolovsky, K. V.

Subjects
BRIGHTNESS temperature, RADIO astronomy, INTERSTELLAR medium, SCATTERING (Physics), ACTIVE galactic nuclei
Abstract

The high brightness temperatures, Tb ≳ 1013 K, detected in several active galactic nuclei by RadioAstron space VLBI observations challenge theoretical limits. Refractive scattering by the interstellar medium may affect such measurements. We quantify the scattering properties and the sub-mas scale source parameters for the quasar B0529+483. Using RadioAstron correlated flux density measurements at 1.7, 4.8, and 22 GHz on projected baselines up to 240 000 km we find two characteristic angular scales in the quasar core, about 100 and 10 μas. Some indications of scattering substructure are found. Very high brightness temperatures, Tb ≥ 1013 K, are estimated at 4.8 and 22 GHz even taking into account the refractive scattering. Our findings suggest a clear dominance of the particle energy density over the magnetic field energy density in the core of this quasar. [ABSTRACT FROM AUTHOR]

Published
2018
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32. RoboPol: connection between optical polarization plane rotations and gamma-ray flares in blazars.

Author

Blinov, D., Pavlidou, V., Papadakis, I., Kiehlmann, S., Liodakis, I., Panopoulou, G. V., Angelakis, E., Baloković, M., Hovatta, T., King, O. G., Kus, A., Kylafis, N., Mahabal, A., Maharana, S., Myserlis, I., Paleologou, E., Papamastorakis, I., Pazderski, E., Pearson, T. J., and Ramaprakash, A.

Subjects
OPTICAL polarization, GAMMA ray astronomy, BL Lacertae objects, AMPLITUDE estimation, SOLAR flares
Abstract

We use results of our 3 yr polarimetric monitoring programme to investigate the previously suggested connection between rotations of the polarization plane in the optical emission of blazars and their gamma-ray flares in the GeV band. The homogeneous set of 40 rotation events in 24 sources detected by RoboPol is analysed together with the gamma-ray data provided by Fermi-LAT. We confirm that polarization plane rotations are indeed related to the closest gamma-ray flares in blazars and the time lags between these events are consistent with zero. Amplitudes of the rotations are anticorrelated with amplitudes of the gamma-ray flares. This is presumably caused by higher relativistic boosting (higher Doppler factors) in blazars that exhibit smaller amplitude polarization plane rotations. Moreover, the time-scales of rotations and flares are marginally correlated. [ABSTRACT FROM AUTHOR]

Published
2018
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34. RoboPol: first season rotations of optical polarization plane in blazars

Author

Blinov, D., primary, Pavlidou, V., additional, Papadakis, I., additional, Kiehlmann, S., additional, Panopoulou, G., additional, Liodakis, I., additional, King, O. G., additional, Angelakis, E., additional, Baloković, M., additional, Das, H., additional, Feiler, R., additional, Fuhrmann, L., additional, Hovatta, T., additional, Khodade, P., additional, Kus, A., additional, Kylafis, N., additional, Mahabal, A., additional, Myserlis, I., additional, Modi, D., additional, Pazderska, B., additional, Pazderski, E., additional, Papamastorakis, I., additional, Pearson, T. J., additional, Rajarshi, C., additional, Ramaprakash, A., additional, Reig, P., additional, Readhead, A. C. S., additional, Tassis, K., additional, and Zensus, J. A., additional

Published
2015
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35. High radio-frequency properties and variability of brightest cluster galaxies

Author

Hogan, M. T., primary, Edge, A. C., additional, Geach, J. E., additional, Grainge, K. J. B., additional, Hlavacek-Larrondo, J., additional, Hovatta, T., additional, Karim, A., additional, McNamara, B. R., additional, Rumsey, C., additional, Russell, H. R., additional, Salomé, P., additional, Aller, H. D., additional, Aller, M. F., additional, Benford, D. J., additional, Fabian, A. C., additional, Readhead, A. C. S., additional, Sadler, E. M., additional, and Saunders, R. D. E., additional

Published
2015
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37. Optical polarization map of the Polaris Flare with RoboPol

Author

Panopoulou, G., primary, Tassis, K., additional, Blinov, D., additional, Pavlidou, V., additional, King, O. G., additional, Paleologou, E., additional, Ramaprakash, A., additional, Angelakis, E., additional, Baloković, M., additional, Das, H. K., additional, Feiler, R., additional, Hovatta, T., additional, Khodade, P., additional, Kiehlmann, S., additional, Kus, A., additional, Kylafis, N., additional, Liodakis, I., additional, Mahabal, A., additional, Modi, D., additional, Myserlis, I., additional, Papadakis, I., additional, Papamastorakis, I., additional, Pazderska, B., additional, Pazderski, E., additional, Pearson, T. J., additional, Rajarshi, C., additional, Readhead, A. C. S., additional, Reig, P., additional, and Zensus, J. A., additional

Published
2015
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38. MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

Author

Aleksić, J., primary, Ansoldi, S., additional, Antonelli, L. A., additional, Antoranz, P., additional, Babic, A., additional, Bangale, P., additional, Barrio, J. A., additional, Becerra González, J., additional, Bednarek, W., additional, Bernardini, E., additional, Biasuzzi, B., additional, Biland, A., additional, Blanch, O., additional, Bonnefoy, S., additional, Bonnoli, G., additional, Borracci, F., additional, Bretz, T., additional, Carmona, E., additional, Carosi, A., additional, Colin, P., additional, Colombo, E., additional, Contreras, J. L., additional, Cortina, J., additional, Covino, S., additional, Da Vela, P., additional, Dazzi, F., additional, De Angelis, A., additional, De Caneva, G., additional, De Lotto, B., additional, de Oña Wilhelmi, E., additional, Delgado Mendez, C., additional, Di Pierro, F., additional, Dominis Prester, D., additional, Dorner, D., additional, Doro, M., additional, Einecke, S., additional, Eisenacher, D., additional, Elsaesser, D., additional, Fernández-Barral, A., additional, Fidalgo, D., additional, Fonseca, M. V., additional, Font, L., additional, Frantzen, K., additional, Fruck, C., additional, Galindo, D., additional, García López, R. J., additional, Garczarczyk, M., additional, Garrido Terrats, D., additional, Gaug, M., additional, Godinović, N., additional, González Muñoz, A., additional, Gozzini, S. R., additional, Hadasch, D., additional, Hanabata, Y., additional, Hayashida, M., additional, Herrera, J., additional, Hose, J., additional, Hrupec, D., additional, Idec, W., additional, Kadenius, V., additional, Kellermann, H., additional, Knoetig, M. L., additional, Kodani, K., additional, Konno, Y., additional, Krause, J., additional, Kubo, H., additional, Kushida, J., additional, La Barbera, A., additional, Lelas, D., additional, Lewandowska, N., additional, Lindfors, E., additional, Lombardi, S., additional, Longo, F., additional, López, M., additional, López-Coto, R., additional, López-Oramas, A., additional, Lorenz, E., additional, Lozano, I., additional, Makariev, M., additional, Mallot, K., additional, Maneva, G., additional, Mannheim, K., additional, Maraschi, L., additional, Marcote, B., additional, Mariotti, M., additional, Martínez, M., additional, Mazin, D., additional, Menzel, U., additional, Miranda, J. M., additional, Mirzoyan, R., additional, Moralejo, A., additional, Munar-Adrover, P., additional, Nakajima, D., additional, Neustroev, V., additional, Niedzwiecki, A., additional, Nievas Rosillo, M., additional, Nilsson, K., additional, Nishijima, K., additional, Noda, K., additional, Orito, R., additional, Overkemping, A., additional, Paiano, S., additional, Palatiello, M., additional, Paneque, D., additional, Paoletti, R., additional, Paredes, J. M., additional, Paredes-Fortuny, X., additional, Persic, M., additional, Poutanen, J., additional, Prada Moroni, P. G., additional, Prandini, E., additional, Puljak, I., additional, Reinthal, R., additional, Rhode, W., additional, Ribó, M., additional, Rico, J., additional, Rodriguez Garcia, J., additional, Saito, T., additional, Saito, K., additional, Satalecka, K., additional, Scalzotto, V., additional, Scapin, V., additional, Schultz, C., additional, Schweizer, T., additional, Shore, S. N., additional, Sillanpää, A., additional, Sitarek, J., additional, Snidaric, I., additional, Sobczynska, D., additional, Stamerra, A., additional, Steinbring, T., additional, Strzys, M., additional, Takalo, L., additional, Takami, H., additional, Tavecchio, F., additional, Temnikov, P., additional, Terzić, T., additional, Tescaro, D., additional, Teshima, M., additional, Thaele, J., additional, Torres, D. F., additional, Toyama, T., additional, Treves, A., additional, Vogler, P., additional, Will, M., additional, Zanin, R., additional, Berger, K., additional, Buson, S., additional, D'Ammando, F., additional, Gasparrini, D., additional, Hovatta, T., additional, Max-Moerbeck, W., additional, Readhead, A., additional, and Richards, J., additional

Published
2015
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41. Time correlation between the radio and gamma-ray activity in blazars and the production site of the gamma-ray emission

Author

Max-Moerbeck, W., primary, Hovatta, T., additional, Richards, J. L., additional, King, O. G., additional, Pearson, T. J., additional, Readhead, A. C. S., additional, Reeves, R., additional, Shepherd, M. C., additional, Stevenson, M. A., additional, Angelakis, E., additional, Fuhrmann, L., additional, Grainge, K. J. B., additional, Pavlidou, V., additional, Romani, R. W., additional, and Zensus, J. A., additional

Published
2014
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42. The RoboPol pipeline and control system

Author

King, O. G., primary, Blinov, D., additional, Ramaprakash, A. N., additional, Myserlis, I., additional, Angelakis, E., additional, Baloković, M., additional, Feiler, R., additional, Fuhrmann, L., additional, Hovatta, T., additional, Khodade, P., additional, Kougentakis, A., additional, Kylafis, N., additional, Kus, A., additional, Modi, D., additional, Paleologou, E., additional, Panopoulou, G., additional, Papadakis, I., additional, Papamastorakis, I., additional, Paterakis, G., additional, Pavlidou, V., additional, Pazderska, B., additional, Pazderski, E., additional, Pearson, T. J., additional, Rajarshi, C., additional, Readhead, A. C. S., additional, Reig, P., additional, Steiakaki, A., additional, Tassis, K., additional, and Zensus, J. A., additional

Published
2014
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43. The RoboPol optical polarization survey of gamma-ray-loud blazars

Author

Pavlidou, V., primary, Angelakis, E., additional, Myserlis, I., additional, Blinov, D., additional, King, O. G., additional, Papadakis, I., additional, Tassis, K., additional, Hovatta, T., additional, Pazderska, B., additional, Paleologou, E., additional, Baloković, M., additional, Feiler, R., additional, Fuhrmann, L., additional, Khodade, P., additional, Kus, A., additional, Kylafis, N., additional, Modi, D., additional, Panopoulou, G., additional, Papamastorakis, I., additional, Pazderski, E., additional, Pearson, T. J., additional, Rajarshi, C., additional, Ramaprakash, A., additional, Readhead, A. C. S., additional, Reig, P., additional, and Zensus, J. A., additional

Published
2014
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44. Connection between optical and γ-ray variability in blazars

Author

Hovatta, T., primary, Pavlidou, V., additional, King, O. G., additional, Mahabal, A., additional, Sesar, B., additional, Dancikova, R., additional, Djorgovski, S. G., additional, Drake, A., additional, Laher, R., additional, Levitan, D., additional, Max-Moerbeck, W., additional, Ofek, E. O., additional, Pearson, T. J., additional, Prince, T. A., additional, Readhead, A. C. S., additional, Richards, J. L., additional, and Surace, J., additional

Published
2014
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45. Multiwavelength observations of the γ-ray-emitting narrow-line Seyfert 1 PMN J0948+0022 in 2011

Author

D'Ammando, F., primary, Larsson, J., additional, Orienti, M., additional, Raiteri, C. M., additional, Angelakis, E., additional, Carramiñana, A., additional, Carrasco, L., additional, Drake, A. J., additional, Fuhrmann, L., additional, Giroletti, M., additional, Hovatta, T., additional, Max-Moerbeck, W., additional, Porras, A., additional, Readhead, A. C. S., additional, Recillas, E., additional, and Richards, J. L., additional

Published
2014
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48. Multifrequency studies of the narrow-line Seyfert 1 galaxy SBS 0846+513

Author

D'Ammando, F., primary, Orienti, M., additional, Finke, J., additional, Raiteri, C. M., additional, Angelakis, E., additional, Fuhrmann, L., additional, Giroletti, M., additional, Hovatta, T., additional, Karamanavis, V., additional, Max-Moerbeck, W., additional, Myserlis, I., additional, Readhead, A. C. S., additional, and Richards, J. L., additional

Published
2013
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50. Locating the γ -ray emission site in Fermi/LAT blazars - II. Multifrequency correlations.

Author

Ramakrishnan, V., Hovatta, T., Tornikoski, M., Nilsson, K., Lindfors, E., Baloković, M., Lähteenmaki, A., Reinthal, R., and Takalo, L.

Subjects
*GAMMA ray astronomy, *GAMMA ray bursts, *LARGE astronomical telescopes, *BL Lacertae objects, *LIGHT curves, *MILLIMETER astronomy
Abstract

In an attempt to constrain and understand the emission mechanism of γ-rays, we perform a cross-correlation analysis of 15 blazars using light curves in millimetre, optical and γ-rays. We use discrete correlation function and consider only correlations significant at the 99 per cent level. A strong correlation was found between 37 and 95 GHz with a near-zero time delay in most of the sources, and ~1 month or longer in the rest. A similar result was obtained between the optical and γ-ray bands. Of the 15 sources, less than 50 per cent showed a strong correlation between the millimetre and γ-ray or millimetre and optical bands. The primary reason for the lack of statistically significant correlation is the absence of a major outburst in the millimetre bands of most of the sources during the 2.5 yr time period investigated in our study. This may indicate that only the long-term variations or large flares are correlated between these bands. The variability of the sources at every waveband was also inspected using fractional rms variability (Fvar). The Fvar displays an increase with frequency reaching its maximum in the γ-rays. [ABSTRACT FROM AUTHOR]

Published
2016
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