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158 results on '"Chilingarian, A"'

1. Overestimation of Astrophysical Gamma-Ray Energies during Thunderstorms: Synergy of Galactic and Atmospheric Accelerators

Author: A. Chilingarian and M. Zazyan
Subjects: Galactic cosmic rays, Astrophysics, QB460-466
Abstract: Particle accelerators abound in space plasmas, saturating the cosmos with fully stripped nuclei and gamma rays, with energies surpassing the capabilities of human-made accelerators by orders of magnitude. Upon reaching Earth’s atmosphere, these particles trigger extensive air showers (EASs), generating millions of secondary cosmic rays of lower energies. Free electrons from EASs developing in the atmosphere are seeds for atmospheric electron accelerators. Strong atmospheric electric fields (AEFs) evolving during thunderstorms act as accelerators, amplifying the intensity of electrons many times, significantly enlarging the EAS size (number of electrons). Thus, the energy of the primary cosmic ray recovered by EAS size can be significantly overestimated. Recently discovered by high-altitude EAS arrays, PeVatron candidates (ultra–high-energy (UHE) astrophysical gamma-ray sources) must be carefully examined according to the atmospheric conditions during EAS detection. Large High Altitude Air Shower Observatory and High-Altitude Water Cherenkov Observatory arrays are located in regions of frequent thunderstorms, and an AEF’s strength can reach and surpass the critical strength to start relativistic runaway electron avalanches. A few registered UHE gamma rays from stellar sources can be registered at just this time when the AEF highly enhances the EAS size. Thunderstorm ground enhancements are copiously registered at mountain peaks of Eastern Europe, Germany, and Armenia, with energies well above the threshold energy of EAS array scintillators. Thus, the overestimation of the energy of primary particles is not an exotic process but a consequence of already well-established physical phenomena. Consequently, a report on each registered UHE gamma ray should include the recorded time and corresponding weather conditions.
Published: 2024
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2. A Closer Look at the Extended Edge-on Low-surface Brightness Galaxies

Author: Anna S. Saburova, Damir Gasymov, Evgenii V. Rubtsov, Igor V. Chilingarian, Sviatoslav Borisov, Ivan Gerasimov, Fedor Kolganov, Anastasia V. Kasparova, Roman I. Uklein, Michal Bílek, Kirill A. Grishin, Anatoly Zasov, Mariia Demianenko, Ivan Yu. Katkov, Ana Lalović, and Srdjan Samurović
Subjects: Galaxy evolution, Galaxy rotation, Galaxy formation, Galaxy physics, Astrophysics, QB460-466
Abstract: To understand the origin of extended disks of low-surface brightness (LSB) galaxies, we studied in detail four such systems with large disks seen edge on. Two of them are edge-on giant LSB galaxies (gLSBGs) recently identified by our team. The edge-on orientation of these systems boosts their surface brightnesses that provided an opportunity to characterize stellar populations spectroscopically and yielded the first such measurements for edge-on gLSBGs. We collected deep images of one galaxy using the 1.4 m Milanković Telescope, which we combined with the archival Subaru Hyper Suprime-Cam and DESI Legacy Surveys data available for the three other systems, and measured the structural parameters of the disks. We acquired deep long-slit spectra with the Russian 6 m telescope and the 10 m Keck II telescope and estimated stellar population properties in the high-surface brightness and LSB regions as well as the gas-phase metallicity distribution. The gas metallicity gradients are shallow to flat in the range between 0 and −0.03 dex per exponential disk scale length, which is consistent with the extrapolation of the gradient–scale length relation for smaller disk galaxies. Our estimates of stellar velocity dispersion in the LSB disks as well as the relative thickness of the disks indicate the dynamical overheating. Our observations favor mergers as the essential stage in the formation scenario for massive LSB galaxies.
Published: 2024
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3. Probing the History of the Galaxy Assembly of the Counterrotating Disk Galaxy PGC 66551

Author: Ivan Yu. Katkov, Damir Gasymov, Alexei Yu. Kniazev, Joseph D. Gelfand, Evgenii V. Rubtsov, Igor V. Chilingarian, and Olga K. Sil’chenko
Subjects: Disk galaxies, Galaxy kinematics, Galaxy stellar content, Galaxy accretion, Astrophysics, QB460-466
Abstract: Stellar counterrotation in disk galaxies directly relates to the complex phenomenon of the disk mass assembly believed to be driven by external processes, such as accretion and mergers. The study of such systems makes it possible to reveal the source of external accretion and establish the details of this process. In this paper, we investigate the galaxy PGC 66551 (MaNGA ID 1-179561), which hosts two large-scale counterrotating (CR) stellar disks identified in the Sloan Digital Sky Survey MaNGA data and then confirmed using deep follow-up spectroscopy with the 10 m Southern African Large Telescope. We measured the properties of ionized gas and stellar populations of both CR disks in PGC 66551. We found that the CR disk is compact, contains young stars with subsolar metallicity, and has a stellar mass of 5 × 10 ^9 M _⊙ , which amounts to ≈20% of the galaxy’s total. Surprisingly, the main 8 Gyr old disk has a significantly lower metallicity of −0.8 dex than other CR galaxies. We developed a simple analytic model of the history of the metal enrichment, which we applied to PGC 66551 and constrained the parameters of the galactic outflow wind, and estimated the metallicity of the infalling gas that formed the CR disk to be −0.9... −0.5 dex. Our interpretation prefers a merger with a gas-rich satellite over cold accretion from a cosmic filament as a source of gas, which then formed the CR disk in PGC 66551.
Published: 2024
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4. The Cygnus Loop: Shock Precursors and Electron–Ion Equilibration

Author: John C. Raymond, Ji Yeon Seok, Bon-Chul Koo, Igor V. Chilingarian, Kirill Grishin, Nelson Caldwell, Min Xie, and Robert Fesen
Subjects: Supernova remnants, Interstellar plasma, Astrophysics, QB460-466
Abstract: The outermost edges of some supernova remnants are marked by filaments of pure Balmer line emission produced by nonradiative shock fronts. The H α profiles of these filaments provide the shock speed and electron–proton temperature ratio in the shock. We have used the Hectochelle multiobject spectrograph on the MMT telescope to observe nine positions along the eastern nonradiative filaments of the Cygnus Loop, thereby extending the studies of Medina et al. to lower shock speeds. We complement the spectra with images from 1993 to 2020 to measure proper motions to further constrain the parameters. We also present observations of the photoionization precursor to show that the gas is strongly heated, and that the H α emission from the precursor is dominated by collisional excitation rather than recombination.
Published: 2023
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5. Multimessenger Characterization of Markarian 501 during Historically Low X-Ray and γ-Ray Activity

Author: H. Abe, S. Abe, V. A. Acciari, I. Agudo, T. Aniello, S. Ansoldi, L. A. Antonelli, A. Arbet-Engels, C. Arcaro, M. Artero, K. Asano, D. Baack, A. Babić, A. Baquero, U. Barres de Almeida, J. A. Barrio, I. Batković, J. Baxter, J. Becerra González, W. Bednarek, E. Bernardini, M. Bernardos, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, A. Biland, O. Blanch, G. Bonnoli, Ž. Bošnjak, I. Burelli, G. Busetto, R. Carosi, M. Carretero-Castrillo, A. J. Castro-Tirado, G. Ceribella, Y. Chai, A. Chilingarian, S. Cikota, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, G. D’Amico, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, A. Del Popolo, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, F. Di Pierro, L. Di Venere, E. Do Souto Espiñeira, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsaesser, G. Emery, J. Escudero, V. Fallah Ramazani, L. Fariña, A. Fattorini, L. Foffano, L. Font, C. Fruck, S. Fukami, Y. Fukazawa, R. J. García López, M. Garczarczyk, S. Gasparyan, M. Gaug, J. G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinović, R. Grau, D. Green, J. G. Green, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, J. Herrera, D. Hrupec, M. Hütten, R. Imazawa, T. Inada, R. Iotov, K. Ishio, I. Jiménez Martínez, J. Jormanainen, D. Kerszberg, Y. Kobayashi, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, L. Linhoff, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, A. Lorini, E. Lyard, B. Machado de Oliveira Fraga, P. Majumdar, M. Makariev, G. Maneva, N. Mang, M. Manganaro, S. Mangano, K. Mannheim, M. Mariotti, M. Martínez, A. Mas-Aguilar, D. Mazin, S. Menchiari, S. Mender, S. Mićanović, D. Miceli, T. Miener, J. M. Miranda, R. Mirzoyan, E. Molina, H. A. Mondal, A. Moralejo, D. Morcuende, V. Moreno, T. Nakamori, C. Nanci, L. Nava, V. Neustroev, M. Nievas Rosillo, C. Nigro, K. Nilsson, K. Nishijima, T. Njoh Ekoume, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, A. Okumura, J. Otero-Santos, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, L. Pavletić, M. Persic, M. Pihet, G. Pirola, F. Podobnik, P. G. Prada Moroni, E. Prandini, G. Principe, C. Priyadarshi, W. Rhode, M. Ribó, J. Rico, C. Righi, A. Rugliancich, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, F. G. Saturni, B. Schleicher, K. Schmidt, F. Schmuckermaier, J. L. Schubert, T. Schweizer, J. Sitarek, V. Sliusar, D. Sobczynska, A. Spolon, A. Stamerra, J. Strišković, D. Strom, M. Strzys, Y. Suda, T. Surić, H. Tajima, M. Takahashi, R. Takeishi, F. Tavecchio, P. Temnikov, K. Terauchi, T. Terzić, M. Teshima, L. Tosti, S. Truzzi, A. Tutone, S. Ubach, J. van Scherpenberg, M. Vazquez Acosta, S. Ventura, V. Verguilov, I. Viale, C. F. Vigorito, V. Vitale, I. Vovk, R. Walter, M. Will, C. Wunderlich, T. Yamamoto, D. Zarić, The MAGIC Collaboration, M. Cerruti, J. A. Acosta-Pulido, G. Apolonio, R. Bachev, M. Baloković, E. Benítez, I. Björklund, V. Bozhilov, L. F. Brown, A. Bugg, W. Carbonell, M. I. Carnerero, D. Carosati, C. Casadio, W. Chamani, W. P. Chen, R. A. Chigladze, G. Damljanovic, K. Epps, A. Erkenov, M. Feige, J. Finke, A. Fuentes, K. Gazeas, M. Giroletti, T. S. Grishina, A. C. Gupta, M. A. Gurwell,, E. Heidemann, D. Hiriart, W. J. Hou, T. Hovatta, S. Ibryamov, M. D. Joner, S. G. Jorstad, J. Kania, S. Kiehlmann, G. N. Kimeridze, E. N. Kopatskaya, M. Kopp, M. Korte, B. Kotas, S. Koyama, J. A. Kramer, L. Kunkel, S. O. Kurtanidze, O. M. Kurtanidze, A. Lähteenmäki, J. M. López, V. M. Larionov, E. G. Larionova, L. V. Larionova, C. Leto, C. Lorey, R. Mújica, G. M. Madejski, N. Marchili, A. P. Marscher, M. Minev, A. Modaressi, D. A. Morozova, T. Mufakharov, I. Myserlis, A. A. Nikiforova, M. G. Nikolashvili, E. Ovcharov, M. Perri, C. M. Raiteri, A. C. S. Readhead, A. Reimer, D. Reinhart, S. Righini, K. Rosenlehner, A. C. Sadun, S. S. Savchenko, A. Scherbantin, L. Schneider, K. Schoch, D. Seifert, E. Semkov, L. A. Sigua, C. Singh, P. Sola, Y. Sotnikova, M. Spencer, R. Steineke, M. Stojanovic, A. Strigachev, M. Tornikoski, E. Traianou, A. Tramacere, Yu. V. Troitskaya, I. S. Troitskiy, J. B. Trump, A. Tsai, A. Valcheva, A. A. Vasilyev, F. Verrecchia, M. Villata, O. Vince, K. Vrontaki, Z. R. Weaver, E. Zaharieva, and N. Zottmann
Subjects: Active galaxies, BL Lacertae objects, Markarian galaxies, Active galactic nuclei, Blazars, Astrophysics, QB460-466
Abstract: We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and very-high-energy (VHE) γ -rays. A significant correlation (>3 σ ) between X-rays and VHE γ -rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between the Swift X-Ray Telescope and Fermi-LAT. We additionally find correlations between high-energy γ -rays and radio, with the radio lagging by more than 100 days, placing the γ -ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE γ -rays from mid-2017 to mid-2019 with a stable VHE flux (>0.2 TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2 yr long low state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED toward the low state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock.
Published: 2023
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6. New Generation Stellar Spectral Libraries in the Optical and Near-infrared. I. The Recalibrated UVES-POP Library for Stellar Population Synthesis

Author: Sviatoslav B. Borisov, Igor V. Chilingarian, Evgenii V. Rubtsov, Cédric Ledoux, Claudio Melo, Kirill A. Grishin, Ivan Yu. Katkov, Vladimir S. Goradzhanov, Anton V. Afanasiev, Anastasia V. Kasparova, and Anna S. Saburova
Subjects: Stellar atmospheres, Stellar abundances, Stellar effective temperatures, Stellar populations, Astronomy databases, Star atlases, Astrophysics, QB460-466
Abstract: We present reprocessed flux-calibrated spectra of 406 stars from the UVES-POP stellar library in the wavelength range 320–1025 nm, which can be used for stellar population synthesis. The spectra are provided in the two versions having spectral resolving power R = 20,000 and R = 80,000. Raw spectra from the ESO data archive were re-reduced using the latest version of the UVES data reduction pipeline with some additional algorithms that we developed. The most significant improvements in comparison with the original UVES-POP release are (i) an updated echelle order merging, which eliminates “ripples” present in the published spectra; (ii) a full telluric correction; (iii) merging of nonoverlapping UVES spectral setups taking into account the global continuum shape; (iv) a spectrophotometric correction and absolute flux calibration; and (v) estimates of the interstellar extinction. For 364 stars from our sample, we computed atmospheric parameters T _eff , surface gravity log g , metallicity [Fe/H], and α -element enhancement [ α /Fe] by using a full-spectrum fitting technique based on a grid of synthetic stellar atmospheres and a novel minimization algorithm. We also provide projected rotational velocity $v\sin i$ and radial velocity v _rad estimates. The overall absolute flux uncertainty in the reprocessed data set is better than 2%, with subpercent accuracy for about half of the stars. A comparison of the recalibrated UVES-POP spectra with other spectral libraries shows a very good agreement in flux; at the same time, Gaia DR3 BP/RP spectra are often discrepant with our data, which we attribute to spectrophotometric calibration issues in Gaia DR3.
Published: 2023
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7. Increase in the count rates of ground-based cosmic-ray detectors caused by the heliomagnetic disturbance on 5 November 2023.

Author: Chilingarian, A., Karapetyan, T., Sargsyan, B., Zazyan, M., Knapp, J., Walter, M., and Rehm, T.
Abstract: This letter presents a rare physical phenomenon associated with solar activity, manifesting in anomalies within neutron, electron, and gamma-ray fluxes in the atmosphere. Conventionally, the Earth's magnetic-field disturbances reduce cosmic-ray intensity reaching the surface. However, a temporary surge in cosmic-ray flux occurs intermittently known as the magnetospheric effect (ME). Our observations reveal that this effect predominantly induces a count rate increase in particle detectors positioned at middle latitudes on mountaintops. On November 5, 2023, a 2–3% increase in neutron monitors at mountain altitudes and up to 5% increase in thin plastic scintillators registering electrons and gamma rays was observed. This flux escalation coincided with a southward orientation of the interplanetary magnetic field. Importantly, we present, for the first time, the energy spectrum of the Magnetospheric Effect observed at two mountaintops: Aragats and Zugspitze. Simulations of low-energy proton interactions in the terrestrial atmosphere affirm the augmentation of low-energy cosmic rays. Protons, typically restricted by the geomagnetic cutoff, reached the Earth's atmosphere, generating detectable particle showers on the Earth's surface. To sum up, 1) we measure an increase in the count rate of magnetospheric origin using particle detectors located at mountain altitudes and middle latitudes; 2) for the first time, we measured the energy spectra of the particle fluxes during the magnetospheric effect with spectrometers located on Mount Aragats and Zugspitze; 3) particle flux enhancement coincides with the depletion of the horizontal component of the geomagnetic field; 4) we explain why the magnetospheric effect was observed at mountain altitudes and not at sea level. [ABSTRACT FROM AUTHOR]
Published: 2024
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8. Thunderstorm ground enhancements observed on Aragats mountain in Armenia in the wintertime

Author: Chilingarian, Ashot, primary, Hovsepyan, Gagik, additional, Aslanyan, Davit, additional, Karapetyan, T., additional, Sargsyan, B., additional, and Svechnikova, Ekaterina, additional
Published: 2023
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9. Color Transformations of Photometric Measurements of Galaxies in Optical and Near-infrared Wide-field Imaging Surveys*

Author: Toptun, Victoria A., primary, Chilingarian, Igor V., additional, Grishin, Kirill A., additional, and Katkov, Ivan Yu., additional
Published: 2023
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10. Sinergy of extra-terrestrial particle accelerators and accelerators operated in the terrestrial atmosphere

Author: Chilingarian, A, primary, Hovsepyan, G, additional, and Zazyan, M, additional
Published: 2022
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11. On the vertical and horizontal profiles of the atmospheric electric field during thunderstorms

Author: Chilingarian, A, primary, Hovsepyan, G, additional, Karapetyan, T, additional, Sargsyan, B, additional, and Zazyan, M, additional
Published: 2022
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12. The horizontal profile of the atmospheric electric fields as measured during thunderstorms by the network of NaI spectrometers located on the slopes of Mt. Aragats

Author: Chilingarian, A., primary, Hovsepyan, G., additional, Karapetyan, T., additional, Kozliner, L., additional, Chilingaryan, S., additional, Pokhsraryan, D., additional, and Sargsyan, B., additional
Published: 2022
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13. Development of the relativistic runaway avalanches in the lower atmosphere above mountain altitudes

Author: Chilingarian, A., primary, Hovsepyan, G., additional, Karapetyan, T., additional, Sargsyan, B., additional, and Zazyan, M., additional
Published: 2022
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14. Multi-messenger observations of thunderstorm-related bursts of cosmic rays

Author: Chilingarian, A., primary, Hovsepyan, G., additional, Karapetyan, T., additional, Khanykyanc, Y., additional, Pokhsraryan, D., additional, Sargsyan, B., additional, Chilingaryan, S., additional, and Soghomonyan, S., additional
Published: 2022
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15. New Generation Stellar Spectral Libraries in the Optical and Near-infrared. I. The Recalibrated UVES-POP Library for Stellar Population Synthesis.

Author: Borisov, Sviatoslav B., Chilingarian, Igor V., Rubtsov, Evgenii V., Ledoux, Cédric, Melo, Claudio, Grishin, Kirill A., Katkov, Ivan Yu., Goradzhanov, Vladimir S., Afanasiev, Anton V., Kasparova, Anastasia V., and Saburova, Anna S.
Published: 2023
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16. Measurements of energy spectra of relativistic electrons and gamma-rays from avalanches developed in the thunderous atmosphere with Aragats Solar Neutron Telescope

Author: Chilingarian, A., primary, Hovsepyan, G., additional, Karapetyan, T., additional, Sargsyan, B., additional, and Chilingaryan, S., additional
Published: 2022
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17. Investigating the Blazar TXS 0506+056 through Sharp Multiwavelength Eyes During 2017-2019

Author: MAGIC Collaboration, Acciari, V. A., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, 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., 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., Espiñeira, E. Do Souto, Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., 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., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Hassan, T., Heckmann, L., Herrera, J., Hoang, 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., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Fraga, B. Machado de Oliveira, 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., 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., Rosillo, M. Nievas, 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., Persic, M., Pihet, M., Moroni, P. G. Prada, 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., 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., 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., Will, M., Wunderlich, C., Yamamoto, T., Zarić, D., Collaboration, OVRO, Hodges, M., Hovatta, T., Kiehlmann, S., Liodakis, I., Max-Moerbeck, W., Pearson, T. J., Readhead, A. C. S., Reeves, R. A., Collaboration, Metsähovi, Lähteenmaäki, A., Tornikoski, M., Tammi, J., D'Ammando, F., Marchini, A., Metsähovi Radio Observatory, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Ministerio de Ciencia e Innovación (España), European Commission, Federal Ministry of Education and Research (Germany), Istituto Nazionale di Astrofisica, Istituto Nazionale di Fisica Nucleare, Swiss National Science Foundation, Department of Atomic Energy (India), Ministry of Education, Culture, Sports, Science and Technology (Japan), Ministry of Education and Science (Bulgaria), Academy of Finland, Generalitat de Catalunya, Croatian Science Foundation, and German Research Foundation
Subjects: High energy astrophysics, Jets, Blazars, Gamma-rays, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::High Energy Astrophysical Phenomena, gamma ray, VHE, FOS: Physical sciences, Bethe-Heitler, blazar, IceCube, X-ray, optical, High Energy Astrophysical Phenomena (astro-ph.HE), Astronomy and Astrophysics, neutrino, current, MAGIC, cascade, flux, Space and Planetary Science, ddc:520, spectral, Física nuclear, photon neutrino
Abstract: This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.--Full list of authors: Acciari, V. A.; Aniello, T.; 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.; Bernardini, E.; Bernardos, M.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Biland, A.; Blanch, O.; Bökenkamp, H.; Bonnoli, G.; Bošnjak, Ž.; 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.; Vela, P. Da; 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.; 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.; Hassan, T.; Heckmann, L.; Herrera, J.; Hoang, J.; Hrupec, D.; Hütten, M.; Inada, T.; Iotov, R.; Ishio, K.; Iwamura, Y.; Jiménez Martínez, I.; Jormanainen, J.; Jouvin, L.; 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 de Oliveira Fraga, B.; Maggio, C.; Majumdar, P.; Makariev, M.; Mallamaci, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Mariotti, M.; Martínez, M.; Mas Aguilar, A.; 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.; 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.; Pavletić, 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.; 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.; Terzić, 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.; Zarić, D.; Hodges, M.; Hovatta, T.; Kiehlmann, S.; Liodakis, I.; Max-Moerbeck, W.; Pearson, T. J.; Readhead, A. C. S.; Reeves, R. A.; Lähteenmäki, A.; Tornikoski, M.; Tammi, J.; D'Ammando, F.; Marchini, A.; MAGIC Collaboration; OVRO Collaboration; Metsahovi Collaboration., The blazar TXS 0506+056 got into the spotlight of the astrophysical community in 2017 September, when a high-energy neutrino detected by IceCube (IceCube-170922A) was associated at the 3σ level with a γ-ray flare from this source. This multi-messenger photon-neutrino association remains, as per today, the most significant association ever observed. TXS 0506+056 was a poorly studied object before the IceCube-170922A event. To better characterize its broadband emission, we organized a multiwavelength campaign lasting 16 months (2017 November to 2019 February), covering the radio band (Metsähovi, OVRO), the optical/UV (ASAS-SN, KVA, REM, Swift/UVOT), the X-rays (Swift/XRT, NuSTAR), the high-energy γ rays (Fermi/LAT), and the very high-energy (VHE) γ rays (MAGIC). In γ rays, the behavior of the source was significantly different from the behavior in 2017: MAGIC observations show the presence of flaring activity during 2018 December, while the source only shows an excess at the 4σ level during the rest of the campaign (74 hr of accumulated exposure); Fermi/LAT observations show several short (on a timescale of days to a week) flares, different from the long-term brightening of 2017. No significant flares are detected at lower energies. The radio light curve shows an increasing flux trend that is not seen in other wavelengths. We model the multiwavelength spectral energy distributions in a lepto-hadronic scenario, in which the hadronic emission emerges as Bethe-Heitler and pion-decay cascade in the X-rays and VHE γ rays. According to the model presented here, the 2018 December γ-ray flare was connected to a neutrino emission that was too brief and not bright enough to be detected by current neutrino instruments. © 2022. The Author(s). Published by the American 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 Innovación (MICINN) (PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-104114RB-C33, 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 DO1-400/18.12.2020 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, CEX2019-000920-S), the Unidad de Excelencia "María de Maeztu" (CEX2019-000918-M, MDM-2015-0509-18-2) 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. E.P. acknowledges funding from the Italian Ministry of Education, University and Research (MIUR) through the "Dipartimenti di eccellenza" project Science of the universe. M.C. has received financial support through the Postdoctoral Junior Leader Fellowship Programme from la Caixa Banking Foundation, grant No. LCF/BQ/LI18/11630012. This research has made use of data from the OVRO 40 m monitoring program, which was supported in part by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G, and NSF grants AST-0808050 and AST-1109911, and private funding from Caltech and the MPIfR. This publication makes use of data obtained at Metsähovi Radio Observatory, operated by Aalto University in Finland.
Published: 2022
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18. On the vertical and horizontal profiles of the atmospheric electric field during thunderstorms

Author: A Chilingarian, G Hovsepyan, T Karapetyan, B Sargsyan, and M Zazyan
Subjects: History, Computer Science Applications, Education
Abstract: We present the first results of a new experiment on Mt. Aragats for measuring the horizontal profile of atmospheric electric fields during thunderstorms. Networks of advanced particle spectrometers operated on the slopes of Mt. Aragats continuously measure fluxes of charged and neutral particles, periodically registering impulsive enhancements, so-called Thunderstorm Ground Enhancements (TGEs). This gives the possibility to estimate the strength of the electric field in the lower atmosphere. Relativistic Runaway Electron Avalanches (RREAs) are registered by the particle detectors located on the Earth's surface as TGEs sometimes exceeding the fair-weather fluxes up to a hundred times. The strong accelerating electric field can reach 1.7-2.2 kV/cm at altitudes 3-6 km, and extend down to 50-150 m above the Earth's surface. The horizontal extent of the electric field can reach 10 km and more.
Published: 2022
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19. Development of the relativistic runaway avalanches in the lower atmosphere above mountain altitudes

Author: A. Chilingarian, G. Hovsepyan, T. Karapetyan, B. Sargsyan, and M. Zazyan
Subjects: General Physics and Astronomy
Abstract: The comparative analysis of three thunderstorms on Aragats in May 2021 demonstrates that relativistic runaway electron avalanches (RREAs) can reach very low altitudes above the Earth’s surface on mountain altitudes. RREAs which reach the Earth’s surface are registered by the particle detectors as thunderstorm ground enhancements (TGEs) —large enhancements of electron and gamma ray fluxes, sometimes exceeding the fair-weather background fluxes up to a hundred times. By comparing the energy spectra of electrons and gamma rays it is possible to estimate the height above the ground where an RREA terminates and avalanche particles exit the accelerating field. For the several TGEs registered on Aragats, this estimate varied between 50 and 150 meters. The threshold electric field can reach on heights of . When a lightning’s active zone is above particle detectors RREAs last tens of seconds to a few minutes, until lightning flashes terminate electron acceleration. If the lightning activity is far from the detector site, TGEs are extended for a few tens of minutes and smoothly decay and TGE has a more or less symmetrical shape.
Published: 2022
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20. Measurement of TGE particle energy spectra: An insight in the cloud charge structure

Author: Chilingarian, A., primary, Hovsepyan, G., additional, and Zazyan, M., additional
Published: 2021
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21. Unraveling the complex behavior of Mrk 421 with simultaneous X-Ray and VHE observations during an extreme flaring activity in 2013 April

Author: Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. K. (L. K.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cerruti, M. (M.), Chai, Y. (Y.), Chilingarian, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Del Puppo, F. (F.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Ferrara, G. (G.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Gliwny, P. (P.), Godinovic, N. (N.), Green, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Huetten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kajiwara, Y. (Y.), Kerszberg, D. (D.), Kobayashi, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Machado de Oliveira Fraga, B. (B.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Mender, S. (S.), Micanovic, S. (S.), Miceli, D. (D.), Miener, T. (T.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nozaki, S. (S.), Ohtani, Y. (Y.), Oka, T. (T.), Otero-Santos, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pavletic, L. (L.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schleicher, B. (B.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Spolon, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Ventura, S. (S.), Verguilov, V. (V.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Petropoulou, M. (M.), Finke, J. (J.), D'Ammando, F. (F.), Balokovi, M. (M.), Madejskic, G. (G.), Mori, K. (K.), Puccetti, S. (Simonetta), Leto, C. (C.), Perri, M. (M.), Verrecchia, F. (F.), Villata, M. (M.), Raiteri, C. M. (C. M.), Agudo, I. (I), Bachev, R. (R.), Berdyugin, A. (A.), Blinov, D. A. (D. A.), Chanishvili, R. (R.), Chen, W. P. (W. P.), Chigladze, R. (R.), Damljanovic, G. (G.), Eswaraiah, C. (C.), Grishina, T. S. (T. S.), Ibryamov, S. (S.), Jordan, B. (B.), Jorstad, S. G. (S. G.), Joshi, M. (M.), Kopatskaya, E. N. (E. N.), Kurtanidze, O. M. (O. M.), Kurtanidze, S. O. (S. O.), Larionova, E. G. (E. G.), Larionova, L. V. (L., V), Larionov, V. M. (V. M.), Latev, G. (G.), Lin, H. C. (H. C.), Marscher, A. P. (A. P.), Mokrushina, A. A. (A. A.), Morozova, D. A. (D. A.), Nikolashvili, M. G. (M. G.), Semkov, E. (E.), Smith, P. S. (P. S.), Strigachev, A. (A.), Troitskaya, Y. V. (Yu, V), Troitsky, I. S. (I. S.), Vince, O. (O.), Barnes, J. (J.), Guver, T. (T.), Moody, J. W. (J. W.), Sadun, A. C. (A. C.), Hovatta, T. (T.), Richards, J. L. (J. L.), Max-Moerbeck, W. (W.), Readhead, A. C. (A. C. S.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Tammi, J. (J.), Ramakrishnan, V. (V), Reinthal, R. (R.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. K. (L. K.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cerruti, M. (M.), Chai, Y. (Y.), Chilingarian, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Del Puppo, F. (F.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Ferrara, G. (G.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Gliwny, P. (P.), Godinovic, N. (N.), Green, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Huetten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kajiwara, Y. (Y.), Kerszberg, D. (D.), Kobayashi, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Machado de Oliveira Fraga, B. (B.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Mender, S. (S.), Micanovic, S. (S.), Miceli, D. (D.), Miener, T. (T.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nozaki, S. (S.), Ohtani, Y. (Y.), Oka, T. (T.), Otero-Santos, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pavletic, L. (L.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schleicher, B. (B.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Spolon, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Ventura, S. (S.), Verguilov, V. (V.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Petropoulou, M. (M.), Finke, J. (J.), D'Ammando, F. (F.), Balokovi, M. (M.), Madejskic, G. (G.), Mori, K. (K.), Puccetti, S. (Simonetta), Leto, C. (C.), Perri, M. (M.), Verrecchia, F. (F.), Villata, M. (M.), Raiteri, C. M. (C. M.), Agudo, I. (I), Bachev, R. (R.), Berdyugin, A. (A.), Blinov, D. A. (D. A.), Chanishvili, R. (R.), Chen, W. P. (W. P.), Chigladze, R. (R.), Damljanovic, G. (G.), Eswaraiah, C. (C.), Grishina, T. S. (T. S.), Ibryamov, S. (S.), Jordan, B. (B.), Jorstad, S. G. (S. G.), Joshi, M. (M.), Kopatskaya, E. N. (E. N.), Kurtanidze, O. M. (O. M.), Kurtanidze, S. O. (S. O.), Larionova, E. G. (E. G.), Larionova, L. V. (L., V), Larionov, V. M. (V. M.), Latev, G. (G.), Lin, H. C. (H. C.), Marscher, A. P. (A. P.), Mokrushina, A. A. (A. A.), Morozova, D. A. (D. A.), Nikolashvili, M. G. (M. G.), Semkov, E. (E.), Smith, P. S. (P. S.), Strigachev, A. (A.), Troitskaya, Y. V. (Yu, V), Troitsky, I. S. (I. S.), Vince, O. (O.), Barnes, J. (J.), Guver, T. (T.), Moody, J. W. (J. W.), Sadun, A. C. (A. C.), Hovatta, T. (T.), Richards, J. L. (J. L.), Max-Moerbeck, W. (W.), Readhead, A. C. (A. C. S.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Tammi, J. (J.), Ramakrishnan, V. (V), and Reinthal, R. (R.)
Abstract: We report on a multiband variability and correlation study of the TeV blazar Mrk 421 during an exceptional flaring activity observed from 2013 April 11 to 19. The study uses, among others, data from GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), Swift, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Large Area Telescope, Very Energetic Radiation Imaging Telescope Array System (VERITAS), and Major Atmospheric Gamma Imaging Cherenkov (MAGIC). The large blazar activity and the 43 hr of simultaneous NuSTAR and MAGIC/VERITAS observations permitted variability studies on 15 minute time bins over three X-ray bands (3–7 keV, 7–30 keV, and 30–80 keV) and three very-high-energy (VHE; >0.1 TeV) gamma-ray bands (0.2–0.4 TeV, 0.4–0.8 TeV, and >0.8 TeV). We detected substantial flux variations on multi-hour and sub-hour timescales in all of the X-ray and VHE gamma-ray bands. The characteristics of the sub-hour flux variations are essentially energy independent, while the multi-hour flux variations can have a strong dependence on the energy of the X-rays and the VHE gamma-rays. The three VHE bands and the three X-ray bands are positively correlated with no time lag, but the strength and characteristics of the correlation change substantially over time and across energy bands. Our findings favor multi-zone scenarios for explaining the achromatic/chromatic variability of the fast/slow components of the light curves, as well as the changes in the flux–flux correlation on day-long timescales. We interpret these results within a magnetic reconnection scenario, where the multi-hour flux variations are dominated by the combined emission from various plasmoids of different sizes and velocities, while the sub-hour flux variations are dominated by the emission from a single small plasmoid moving across the magnetic reconnection layer.
Published: 2020

22. Unraveling the Complex Behavior of Mrk 421 with Simultaneous X-Ray and VHE Observations during an Extreme Flaring Activity in 2013 April

Author: Federal Ministry of Education and Research (Germany), Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Istituto Nazionale di Fisica Nucleare, Ministerio de Economía y Competitividad (España), European Commission, Department of Atomic Energy (India), Ministry of Education, Culture, Sports, Science and Technology (Japan), Japan Society for the Promotion of Science, Ministry of Education, Youth and Science (Bulgaria), Academy of Finland, Croatian Science Foundation, University of Rijeka, German Research Foundation, National Centre for Research and Development (Poland), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, National Aeronautics and Space Administration (US), Department of Energy (US), Centre National de la Recherche Scientifique (France), Russian Science Foundation, Gordon and Betty Moore Foundation, John Templeton Foundation, Shota Rustaveli National Science Foundation, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Acciari, Victor, Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babić, A., Banerjee, B., Barres de Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, Wlodek, Palatiello, M., Max-Moerbeck, W., MAGIC Collaboration, Readhead, A. C. S., Lähteenmäki, Anne, Tornikoski, Merja, Tammi, J., Martínez, M., Ramakrishnan, V., Ishio, K., Do Souto Espiñeira, E., Reinthal, R., Cerruti, Matteo, Paneque, D., Chai, Y., Chilingarian, A., Fattorini, A., Cikota, S., Colak, S.M., Colin, U., Colombo, E., Sitarek, J., Peresano, M., Contreras, J.L., Mazin, D., Cortina, J., Paoletti, R., Covino, Stefano, D'Elia, V., Da Vela, Paolo, Ferrara, G., Dazzi, F., Maneva, G., de Angelis, A., Mannheim, K., de Lotto, B., Del Puppo, F., Delfino, M., Delgado, J., Paredes, Josep M., Mender, S., Depaoli, D., Foffano, L., Šnidarić, I., Fonseca, M.V., Font, L., Iwamura, Y., Fruck, Christian, Fukami, S., García López, R. J., Garczarczyk, M., Gasparyan, S., Pavletić, L., Finke, J., Sobczynska, D., Miceli, D., Gaug, Markus, Giglietto, N., Jouvin, L., Giordano, F., Gliwny, P., Godinović, N., Green, D., Hadasch, D., Hahn, A., Spolon, A., Peñil, P., Hassan, T., Baloković, M., Kajiwara, Y., Kerszberg, Daniel, Miener, T., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Stamerra, A., Kurtanidze, S.O., Perri, M., Lelas, D., Leone, F., Lindfors, E., Madejski, G., Lombardi, S., Longo, F., López, M., Minev, M., Bigongiari, C., López-Coto, R., Busetto, G., López-Oramas, A., di Pierro, F., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Mori, K., Makariev, M., Strom, D., Mallamaci, M., Miranda, J. M., Larionova, Elena G., Mirzoyan, R., Molina, E., Persic, M., Moralejo, A., Morcuende, D., Moreno, Vicente, Moretti, E., Marscher, Alan P., Munar-Adrover, P., Puccetti, Simonetta, Bernardini, E., Larionova, Liyudmila V., Neustroev, V., Nigro, C., Nilsson, Kari, Moroni, P. G. Prada, Ninci, D., Nishijima, K., D'Ammando, F., Noda, K., Nogués, L., Nozaki, S., Ohtani, Y., Larionov, Valeri M., Leto, C., Oka, T., Besenrieder, J., Prandini, E., Puljak, I., Strzys, M., Rhode, W., Ribó, Marc, Rico, J., Righi, C., Rugliancich, A., Latev, G., di Venere, L., Bonnoli, G., Saha, L., Sahakyan, N., Suda, Y., Saito, T., Bhattacharyya, W., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Lin, H. C., Schweizer, T., Prester, D. Dominis, Surić, T., Takahashi, M., Verrecchia, F., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Herrera, J., Ramazani, V. Fallah, Torres-Albà, N., Biland, A., Tosti, L., Donini, A., van Scherpenberg, J., Vanzo, G., Vázquez Acosta, M., Villata, M., Ventura, S., Bellizzi, L. K., Verguilov, V., Berti, A., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Dorner, D., Blanch, O., Zarić, D., Raiteri, C.M., Hoang, J., Agudo, Iván, Bachev, R., Mokrushina, A. A., Berdyugin, A., Blinov, D.A., Chanishvili, R., Chen, W. P., Chigladze, R., Doro, M., Manganaro, M., Hrupec, D., Bošnjak, Ž., Damljanovic, G., Eswaraiah, C., Morozova, D.A., Grishina, T.S., Ibryamov, S., Jordan, B., Jorstad, S.G., Joshi, M., Kopatskaya, Evgenia N., Hütten, M., Elsaesser, D., Kurtanidze, O.M., Maraschi, L., Nikolashvili, M.G., Semkov, E., Carosi, R., Smith, P. S., Strigachev, A., Troitskaya, Yu. V., Troitsky, I. S., Inada, T., Otero-Santos, J., Mićanović, S., Vince, O., Barnes, J., Güver, T., Mariotti, M., Moody, J.W., Sadun, A. C., Hovatta, T., Ceribella, G., Inoue, S., Richards, J. L., Federal Ministry of Education and Research (Germany), Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Istituto Nazionale di Fisica Nucleare, Ministerio de Economía y Competitividad (España), European Commission, Department of Atomic Energy (India), Ministry of Education, Culture, Sports, Science and Technology (Japan), Japan Society for the Promotion of Science, Ministry of Education, Youth and Science (Bulgaria), Academy of Finland, Croatian Science Foundation, University of Rijeka, German Research Foundation, National Centre for Research and Development (Poland), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, National Aeronautics and Space Administration (US), Department of Energy (US), Centre National de la Recherche Scientifique (France), Russian Science Foundation, Gordon and Betty Moore Foundation, John Templeton Foundation, Shota Rustaveli National Science Foundation, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Acciari, Victor, Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babić, A., Banerjee, B., Barres de Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, Wlodek, Palatiello, M., Max-Moerbeck, W., MAGIC Collaboration, Readhead, A. C. S., Lähteenmäki, Anne, Tornikoski, Merja, Tammi, J., Martínez, M., Ramakrishnan, V., Ishio, K., Do Souto Espiñeira, E., Reinthal, R., Cerruti, Matteo, Paneque, D., Chai, Y., Chilingarian, A., Fattorini, A., Cikota, S., Colak, S.M., Colin, U., Colombo, E., Sitarek, J., Peresano, M., Contreras, J.L., Mazin, D., Cortina, J., Paoletti, R., Covino, Stefano, D'Elia, V., Da Vela, Paolo, Ferrara, G., Dazzi, F., Maneva, G., de Angelis, A., Mannheim, K., de Lotto, B., Del Puppo, F., Delfino, M., Delgado, J., Paredes, Josep M., Mender, S., Depaoli, D., Foffano, L., Šnidarić, I., Fonseca, M.V., Font, L., Iwamura, Y., Fruck, Christian, Fukami, S., García López, R. J., Garczarczyk, M., Gasparyan, S., Pavletić, L., Finke, J., Sobczynska, D., Miceli, D., Gaug, Markus, Giglietto, N., Jouvin, L., Giordano, F., Gliwny, P., Godinović, N., Green, D., Hadasch, D., Hahn, A., Spolon, A., Peñil, P., Hassan, T., Baloković, M., Kajiwara, Y., Kerszberg, Daniel, Miener, T., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Stamerra, A., Kurtanidze, S.O., Perri, M., Lelas, D., Leone, F., Lindfors, E., Madejski, G., Lombardi, S., Longo, F., López, M., Minev, M., Bigongiari, C., López-Coto, R., Busetto, G., López-Oramas, A., di Pierro, F., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Mori, K., Makariev, M., Strom, D., Mallamaci, M., Miranda, J. M., Larionova, Elena G., Mirzoyan, R., Molina, E., Persic, M., Moralejo, A., Morcuende, D., Moreno, Vicente, Moretti, E., Marscher, Alan P., Munar-Adrover, P., Puccetti, Simonetta, Bernardini, E., Larionova, Liyudmila V., Neustroev, V., Nigro, C., Nilsson, Kari, Moroni, P. G. Prada, Ninci, D., Nishijima, K., D'Ammando, F., Noda, K., Nogués, L., Nozaki, S., Ohtani, Y., Larionov, Valeri M., Leto, C., Oka, T., Besenrieder, J., Prandini, E., Puljak, I., Strzys, M., Rhode, W., Ribó, Marc, Rico, J., Righi, C., Rugliancich, A., Latev, G., di Venere, L., Bonnoli, G., Saha, L., Sahakyan, N., Suda, Y., Saito, T., Bhattacharyya, W., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Lin, H. C., Schweizer, T., Prester, D. Dominis, Surić, T., Takahashi, M., Verrecchia, F., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Herrera, J., Ramazani, V. Fallah, Torres-Albà, N., Biland, A., Tosti, L., Donini, A., van Scherpenberg, J., Vanzo, G., Vázquez Acosta, M., Villata, M., Ventura, S., Bellizzi, L. K., Verguilov, V., Berti, A., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Dorner, D., Blanch, O., Zarić, D., Raiteri, C.M., Hoang, J., Agudo, Iván, Bachev, R., Mokrushina, A. A., Berdyugin, A., Blinov, D.A., Chanishvili, R., Chen, W. P., Chigladze, R., Doro, M., Manganaro, M., Hrupec, D., Bošnjak, Ž., Damljanovic, G., Eswaraiah, C., Morozova, D.A., Grishina, T.S., Ibryamov, S., Jordan, B., Jorstad, S.G., Joshi, M., Kopatskaya, Evgenia N., Hütten, M., Elsaesser, D., Kurtanidze, O.M., Maraschi, L., Nikolashvili, M.G., Semkov, E., Carosi, R., Smith, P. S., Strigachev, A., Troitskaya, Yu. V., Troitsky, I. S., Inada, T., Otero-Santos, J., Mićanović, S., Vince, O., Barnes, J., Güver, T., Mariotti, M., Moody, J.W., Sadun, A. C., Hovatta, T., Ceribella, G., Inoue, S., and Richards, J. L.
Abstract: We report on a multiband variability and correlation study of the TeV blazar Mrk 421 during an exceptional flaring activity observed from 2013 April 11 to 19. The study uses, among others, data from GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), Swift, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Large Area Telescope, Very Energetic Radiation Imaging Telescope Array System (VERITAS), and Major Atmospheric Gamma Imaging Cherenkov (MAGIC). The large blazar activity and the 43 hr of simultaneous NuSTAR and MAGIC/VERITAS observations permitted variability studies on 15 minute time bins over three X-ray bands (3-7 keV, 7-30 keV, and 30-80 keV) and three very-high-energy (VHE; >0.1 TeV) gamma-ray bands (0.2-0.4 TeV, 0.4-0.8 TeV, and >0.8 TeV). We detected substantial flux variations on multi-hour and sub-hour timescales in all of the X-ray and VHE gamma-ray bands. The characteristics of the sub-hour flux variations are essentially energy independent, while the multi-hour flux variations can have a strong dependence on the energy of the X-rays and the VHE gamma-rays. The three VHE bands and the three X-ray bands are positively correlated with no time lag, but the strength and characteristics of the correlation change substantially over time and across energy bands. Our findings favor multi-zone scenarios for explaining the achromatic/chromatic variability of the fast/slow components of the light curves, as well as the changes in the flux-flux correlation on day-long timescales. We interpret these results within a magnetic reconnection scenario, where the multi-hour flux variations are dominated by the combined emission from various plasmoids of different sizes and velocities, while the sub-hour flux variations are dominated by the emission from a single small plasmoid moving across the magnetic reconnection layer. © 2020. The American Astronomical Society. All rights reserved.
Published: 2020

23. Lightning observations using broadband VHF interferometer and electric field measurements

Author: Chilingarian, A., primary, Dolgonosov, M., additional, Kiselyov, A., additional, Khanikyants, Y., additional, and Soghomonyan, S., additional
Published: 2020
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24. Estimating Statistical Uncertainties of Internal Kinematics of Galaxies and Star Clusters Derived Using Full Spectrum Fitting

Author: Chilingarian, Igor V., primary and Grishin, Kirill A., additional
Published: 2020
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25. Measurement of TGE particle energy spectra: An insight in the cloud charge structure

Author: M. Zazyan, G. Hovsepyan, and Ashot Chilingarian
Subjects: Physics, Range (particle radiation), Spectrometer, Astrophysics::High Energy Astrophysical Phenomena, Electric field, Thunderstorm, Gamma ray, General Physics and Astronomy, Charge (physics), Electron, Spectral line, Computational physics
Abstract: In this letter, we present for the first time the method to get insight into the charge structure of the thundercloud using simultaneously measured electron and gamma ray spectra of thunderstorm ground enhancement (TGE). We discuss and compare two main scenarios that can support the initiation of the relativistic runaway electron avalanches (RREA) in the thundercloud. One of the scenarios includes the emergence of the lower positive charged layer (LPCR). The LPCR is a shortliving charge structure sitting on hydrometeors, which exhibit accidental charge reversals depending on temperature changes. LPCR can sustain a positive (downwards directed) near-surface electric field for several minutes, before falling down with precipitation. Recently, we launched on Aragats full-scale operation of a large spectrometer, which is capable measuring the energy spectra of electrons and gamma rays in the energy range from 4 to 100 MeV. Comparison of energy spectra of electrons and gamma rays makes it possible to scrutinize the LPCR emergence and estimate the height where the strong electric field that originates the RREA terminates.
Published: 2021
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26. Fresh Insights on the Kinematics of M49's Globular Cluster System with MMT/Hectospec Spectroscopy.

Author: Taylor, Matthew A., Ko, Youkyung, Côté, Patrick, Ferrarese, Laura, Peng, Eric W., Zabludoff, Ann, Roediger, Joel, Sánchez-Janssen, Rubén, Hendel, David, Chilingarian, Igor, Liu, Chengze, Spengler, Chelsea, and Zhang, Hongxin
Subjects: GLOBULAR clusters, KINEMATICS, VIRGO Cluster, DWARF galaxies, SPECTROMETRY
Abstract: We present the first results of an MMT/Hectospec campaign to measure the kinematics of globular clusters (GCs) around M49—the brightest galaxy in the Virgo galaxy cluster, which dominates the Virgo B subcluster. The data include kinematic tracers beyond 95 kpc (∼5.2 effective radii) for M49 for the first time, enabling us to achieve three key insights reported here. First, beyond ∼20′–30′ (∼100–150 kpc), the GC kinematics sampled along the minor photometric axis of M49 become increasingly hotter, indicating a transition from GCs related to M49 to those representing the Virgo B intra-cluster medium. Second, there is an anomaly in the line-of-sight radial velocity dispersion (σr,los) profile in an annulus ∼10–15′ (∼50–90 kpc) from M49 in which the kinematics cool by Δσr,los ≈ 150 km s−1 relative to those in- or outward. The kinematic fingerprint of a previous accretion event is hinted at in projected phase-space, and we isolate GCs that both give rise to this feature, and are spatially co-located with two prominent stellar shells in the halo of M49. Third, we find a subsample of GCs with velocities representative of the dwarf galaxy VCC 1249 that is currently interacting with M49. The spatial distribution of these GCs closely resembles the morphology of VCC 1249's isophotes, indicating that several of these GCs are likely in the act of being stripped from the dwarf during its passage through M49's halo. Taken together, these results point toward the opportunity of witnessing ongoing giant halo assembly in the depths of a cluster environment. [ABSTRACT FROM AUTHOR]
Published: 2021
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27. Lightning observations using broadband VHF interferometer and electric field measurements

Author: M. S. Dolgonosov, A. A. Kiselyov, S. Soghomonyan, Ashot Chilingarian, and Y. Khanikyants
Subjects: Physics, Interferometry, Optics, business.industry, Electric field, Broadband, business, Instrumentation, Lightning, Mathematical Physics
Published: 2020
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28. Binospec: A Wide-field Imaging Spectrograph for the MMT

Author: Fabricant, Daniel, primary, Fata, Robert, additional, Epps, Harland, additional, Gauron, Thomas, additional, Mueller, Mark, additional, Zajac, Joseph, additional, Amato, Stephen, additional, Barberis, Jack, additional, Bergner, Henry, additional, Brennan, Patricia, additional, Brown, Warren, additional, Chilingarian, Igor, additional, Geary, John, additional, Kradinov, Vladimir, additional, McLeod, Brian, additional, Smith, Matthew, additional, and Woods, Deborah, additional
Published: 2019
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29. Binospec Software System

Author: Kansky, Jan, primary, Chilingarian, Igor, additional, Fabricant, Daniel, additional, Matthews, Anne, additional, Moran, Sean, additional, Paegert, Martin, additional, Gibson, J. Duane, additional, Porter, Dallan, additional, and Roll, John, additional
Published: 2019
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30. Data Reduction Pipeline for the MMT and Magellan Infrared Spectrograph

Author: Yuri Beletsky, Igor Chilingarian, Sean Moran, Brian A. McLeod, Daniel G. Fabricant, and Warren R. Brown
Subjects: Computer science, Pipeline (computing), media_common.quotation_subject, Astrophysics::Instrumentation and Methods for Astrophysics, Subtraction, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Reduction (complexity), Transmission (telecommunications), Space and Planetary Science, Sky, Data quality, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Spectrograph, Astrophysics::Galaxy Astrophysics, Data reduction, media_common, Remote sensing
Abstract: We describe the new spectroscopic data reduction pipeline for the multi-object MMT/Magellan Infrared Spectrograph. The pipeline is implemented in idl as a stand-alone package and is publicly available in both stable and development versions. We describe novel algorithms for sky subtraction and correction for telluric absorption. We demonstrate that our sky subtraction technique reaches the Poisson limit set by the photon statistics. Our telluric correction uses a hybrid approach by first computing a correction function from an observed stellar spectrum, and then differentially correcting it using a grid of atmosphere transmission models for the target airmass value. The pipeline provides a sufficient level of performance for real time reduction and thus enables data quality control during observations. We reduce an example dataset to demonstrate the high data reduction quality., Comment: PASP in press, 14 pages, 6 figures
Published: 2015
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31. Center for Astrophysics Optical Infrared Science Archive. I. FAST Spectrograph.

Author: Mink, Jessica, Brown, Warren R., Chilingarian, Igor V., Fabricant, Daniel, Kurtz, Michael J., Moran, Sean, Rhee, Jaehyon, Tokarz, Susan, and Wyatt, William F.
Published: 2021
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32. Binospec Software System

Author: Daniel G. Fabricant, Anne Matthews, Jan Kansky, Martin Paegert, J. Duane Gibson, Dallan Porter, John Roll, Igor Chilingarian, and Sean Moran
Subjects: Focus (computing), Instrument control, 010504 meteorology & atmospheric sciences, business.industry, Computer science, Interface (computing), Real-time computing, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Automation, Software, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Control system, 0103 physical sciences, Software system, Astrophysics - Instrumentation and Methods for Astrophysics, business, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Spectrograph, 0105 earth and related environmental sciences
Abstract: Binospec is a high-throughput, 370 to 1000 nm, imaging spectrograph that addresses two adjacent 8' by 15' fields of view. Binospec was commissioned in late 2017 at the f/5 focus of the 6.5m MMT and is now available to all MMT observers. Here we describe the Binospec software used for observation planning, instrument control, and data reduction. The software and control systems incorporate a high level of automation to minimize observer workload. Instrument configuration and observation sequencing is implemented using a database-driven approach to maximize observatory efficiency. A web-based interface allows users to define observations, monitor status, and retrieve data products., PASP in press; 22 pages; 12 figures
Published: 2019
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33. Turbulence and Energetic Particles in Radiative Shock Waves in the Cygnus Loop. II. Development of Postshock Turbulence.

Author: Raymond, John C., Slavin, Jonathan D., Blair, William P., Chilingarian, Igor V., Burkhart, Blakesley, and Sankrit, Ravi
Subjects: SHOCK waves, TURBULENCE, MAGNETIC flux density, HOUGH transforms
Abstract: Radiative shock waves in the Cygnus Loop and other supernova remnants show different morphologies in [O iii ] and Hα emission. We use HST spectra and narrowband images to study the development of turbulence in the cooling region behind a shock on the west limb of the Cygnus Loop. We refine our earlier estimates of shock parameters that were based upon ground-based spectra, including ram pressure, vorticity, and magnetic field strength. We apply several techniques, including Fourier power spectra and the Rolling Hough Transform, to quantify the shape of the rippled shock front as viewed in different emission lines. We assess the relative importance of thermal instabilities, the thin shell instability, upstream density variations, and upstream magnetic field variations in producing the observed structure. [ABSTRACT FROM AUTHOR]
Published: 2020
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34. Turbulence and Energetic Particles in Radiative Shock Waves in the Cygnus Loop. I. Shock Properties.

Author: Raymond, John C., Chilingarian, Igor V., Blair, William P., Sankrit, Ravi, Slavin, Johnathan D., and Burkhart, Blakesley
Subjects: *SHOCK waves, *MAGNETIC flux density, *SYNCHROTRON radiation, *COSMIC rays, *ADIABATIC compression, *CYGNUS (Constellation)
Abstract: We have obtained a contiguous set of long-slit spectra of a shock wave in the Cygnus Loop to investigate its structure, which is far from the morphology predicted by 1D models. Proper motions from Hubble Space Telescope images combined with the known distance to the Cygnus Loop provide an accurate shock speed. Earlier analyses of shock spectra estimated the shock speed, postshock density, temperature, and elemental abundances. In this paper we determine several more shock parameters: a more accurate shock speed, ram pressure, density, compression ratio, dust destruction efficiency, magnetic field strength, and vorticity in the cooling region. From the derived shock properties we estimate the emissivities of synchrotron emission in the radio and pion decay emission in the gamma-rays. Both are consistent with the observations if we assume simple adiabatic compression of ambient cosmic-rays as in the van der Laan mechanism. We also find that, although the morphology is far from that predicted by 1D models and the line ratios vary dramatically from point to point, the average spectrum is matched reasonably well by 1D shock models with the shock speed derived from the measured proper motion. A subsequent paper will analyze the development of turbulence in the cooling zone behind the shock. [ABSTRACT FROM AUTHOR]
Published: 2020
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35. Aragats space-environmental centre: status and SEP forecasting possibilities

Author: V. Babayan, K. Avakyan, S. Ghazaryan, G. Gharagyozyan, A. Hovhanissyan, A Yeremian, A.P. Garyaka, R. M. Martirosov, S. Tserunyan, M. Zazyan, H. Martirosian, G. S. Karapetyan, A. Vardanyan, S. Chilingarian, N. Bostanjyan, H. E. Sogoyan, V. A. Ivanov, L. Melkumyan, Ashot Chilingarian, S. Sokhoyan, N. Gevorgyan, and V. S. Eganov
Subjects: Physics, Proton (rocket family), Nuclear and High Energy Physics, COSMIC cancer database, Muon, Meteorology, Physics::Space Physics, Detector, Satellite, Neutron, Space (mathematics), Space environment, Remote sensing
Abstract: The Aragats Space Environment Center in Armenia provides real-time monitoring of cosmic particle fluxes. Neutron monitors operating at altitudes of 2000 m and 3200 m on Mt Aragats continuously gather data to detect possible abrupt enhancement of the count rates. Additional high precision detectors, measuring muon and electron fluxes, along with directional information have been put in operation on Mt Aragats in the summer of 2002. We plan to use this information to establish an early warning system against extreme solar energetic particle (SEP) events which pose danger to the satellite electronics and the space station crew. Solar ion and proton fluxes as measured by space-borne sensors on ACE and GOES satellites are used to derive expected arrival times of highest energy ions at 1 AU. The peaks in the time series detected by Aragats neutron monitors, coincided with these times, demonstrate the possibility of early detection of SEP events using the ground-based detectors.
Published: 2003
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36. MMT and Magellan Infrared Spectrograph

Author: Maureen A. Conroy, John C. Geary, Henry Bergner, Michael Burke, Igor Chilingarian, Warren R. Brown, Joseph Zajac, Dylan Curley, Tim Norton, Anne Matthews, Gabor Furesz, Justin Holwell, Harland W. Epps, Paul Martini, George Nystrom, John Roll, Daniel G. Fabricant, Stephen Amato, Ken McCracken, Edward Hertz, Sang Park, and Brian McLeod
Subjects: Materials science, Infrared, Wavelength range, business.industry, Astronomy and Astrophysics, Field of view, Exoplanet, law.invention, Telescope, Optics, Space and Planetary Science, law, Spectroscopy, business, Spectrograph, Image resolution
Abstract: The MMT and Magellan infrared spectrograph (MMIRS) is a cryogenic multiple-slit spectrograph operating in the wavelength range 0.9-2.4 μm. The refractive optics of MMIRS offer a 6'.9 × 6'.9 field of view for imaging with a spatial resolution of 0.2 arcsec pixel-1 on a HAWAII-2 array. For spectroscopy, MMIRS can be used with long slits up to 6'.9 long, or with custom slit masks having slitlets distributed over a 4' × 6'.9 area. A range of dispersers offer spectral resolutions of 800-3000. MMIRS is designed to be used at the f/5 foci of the MMT or Magellan Clay 6.5 m telescopes. MMIRS was commissioned in 2009 at the MMT and has been in routine operation at the Magellan Clay Telescope since 2010. MMIRS is being used for a wide range of scientific investigations from exoplanet atmospheres to Lyα emitters.
Published: 2012
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37. EXPLAINING THE STELLAR INITIAL MASS FUNCTION WITH THE THEORY OF SPATIAL NETWORKS

Author: Massachusetts Institute of Technology. Department of Physics, Klishin, Andrei, Chilingarian, Igor, Massachusetts Institute of Technology. Department of Physics, Klishin, Andrei, and Chilingarian, Igor
Abstract: The distributions of stars and prestellar cores by mass (initial and dense core mass functions, IMF/DCMF) are among the key factors regulating star formation and are the subject of detailed theoretical and observational studies. Results from numerical simulations of star formation qualitatively resemble an observed mass function, a scale-free power law with a sharp decline at low masses. However, most analytic IMF theories critically depend on the empirically chosen input spectrum of mass fluctuations which evolve into dense cores and, subsequently, stars, and on the scaling relation between the amplitude and mass of a fluctuation. Here we propose a new approach exploiting techniques from the field of network science. We represent a system of dense cores accreting gas from the surrounding diffuse interstellar medium (ISM) as a spatial network growing by preferential attachment and assume that the ISM density has a self-similar fractal distribution following the Kolmogorov turbulence theory. We effectively combine gravoturbulent and competitive accretion approaches and predict the accretion rate to be proportional to the dense core mass: dM/dt ∝ M. Then we describe the dense core growth and demonstrate that the power-law core mass function emerges independently of the initial distribution of density fluctuations by mass. Our model yields a power law solely defined by the fractal dimensionalities of the ISM and accreting gas. With a proper choice of the low-mass cut-off, it reproduces observations over three decades in mass. We also rule out a low-mass star dominated "bottom-heavy" IMF in a single star-forming region., Smithsonian Astrophysical Observatory. Telescope Data Center, Russian Foundation for Basic Research (project 15-52-15050), Russian Foundation for Basic Research (project 15-32-21062), Russian Foundation for Basic Research (President of Russian Federation grant MD-7355-2015.2), Russian Fundamental Science Foundation (project 14-22-00041)
Published: 2016

38. Very high energy gamma-ray radiation from the stellar mass black hole binary Cygnus X-1

Author: Albert, J., Aliu, E., Anderhub, H., Antoranz, P., Armada, A., Baixeras, C., Barrio, J. A., Bartko, H., Bastieri, Denis, Becker, J. K., Bednarek, W., Berger, K., Bigongiari, Ciro, Biland, A., Bock, R. K., Bordas, P., Bosch Ramon, V., Bretz, T., Britvitch, I., Camara, M., Carmona, E., Chilingarian, A., Coarasa, J. A., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Curtef, V., Danielyan, V., Dazzi, Francesco, De Angelis, A., Delgado, C., de los Reyes, R., De Lotto, B., Domingo Santamaría, E., Dorner, D., Doro, Michele, Errando, M., Fagiolini, M., Ferenc, D., Fernández, E., Firpo, R., Flix, J., Fonseca, M. V., Font, L., Fuchs, M., Galante, N., García López, R. J., Garczarczyk, M., Gaug, M., Giller, M., Goebel, F., Hakobyan, D., Hayashida, M., Hengstebeck, T., Herrero, A., Höhne, D., Hose, J., Hsu, C. C., Jacon, P., Jogler, T., Kosyra, R., Kranich, D., Kritzer, R., Laille, A., Lindfors, E., Lombardi, Saverio, Longo, F., López, J., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mannheim, K., Mansutti, O., Mariotti, Mose', Martínez, M., Mazin, D., Merck, C., Meucci, M., Meyer, M., Miranda, J. M., Mirzoyan, R., Mizobuchi, S., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Oña Wilhelmi, E., Otte, N., Oya, I., Panniello, M., Paoletti, R., Paredes, J. M., Pasanen, M., Pascoli, Donatella, Pauss, F., Pegna, R., Persic, M., Peruzzo, Luigi, Piccioli, A., Prandini, Elisa, Puchades, N., Raymers, A., Rhode, W., Ribó, M., Rico, J., Rissi, M., Robert, A., Rügamer, S., Saggion, Antonio, Saito, T., Sánchez, A., Sartori, Paolo, Scalzotto, VILLI MARIO, Scapin, V., Schmitt, R., Schweizer, T., Shayduk, M., Shinozaki, K., Shore, S. N., Sidro, N., Sillanpää, A., Sobczynska, D., Stamerra, A., Stark, L. S., Takalo, L., Temnikov, P., Tescaro, D., Teshima, M., Torres, D. F., Turini, N., Vankov, H., Vitale, V., Wagner, R. M., Wibig, T., Wittek, W., Zandanel, F., Zanin, R., Zapatero, J., J., Albert, E., Aliu, H., Anderhub, P., Antoranz, A., Armada, C., Baixera, J. A., Barrio, H., Bartko, D., Bastieri, J. K., Becker, W., Bednarek, K., Berger, C., Bigongiari, A., Biland, R. K., Bock, P., Borda, V., Bosch Ramon, T., Bretz, I., Britvitch, M., Camara, E., Carmona, A., Chilingarian, J. A., Coarasa, S., Commichau, J. L., Contrera, J., Cortina, M. T., Costado, V., Curtef, V., Danielyan, F., Dazzi, A. D., Angeli, C., Delgado, R., Reye, B. D., Lotto, E., Domingo SantamariA, D., Dorner, M., Doro, M., Errando, M., Fagiolini, D., Ferenc, E., Fernandez, R., Firpo, J., Flix, M. V., Fonseca, L., Font, M., Fuch, N., Galante, R. J., Garcia Lopez, M., Garczarczyk, M., Gaug, M., Giller, F., Goebel, D., Hakobyan, M., Hayashida, T., Hengstebeck, A., Herrero, D., Hohne, J., Hose, C. C., Hsu, P., Jacon, T., Jogler, R., Kosyra, D., Kranich, R., Kritzer, A., Laille, E., Lindfor, S., Lombardi, Longo, Francesco, J., Lopez, M., Lopez, E., Lorenz, P., Majumdar, G., Maneva, K., Mannheim, O., Mansutti, M., Mariotti, M., Martinez, D., Mazin, C., Merck, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, S., Mizobuchi, A., Moralejo, D., Nieto, K., Nilsson, J., Ninkovic, E., Ona Wilhelmi, N., Otte, I., Oya, M., Panniello, R., Paoletti, J. M., Parede, M., Pasanen, D., Pascoli, F., Pau, R., Pegna, M., Persic, L., Peruzzo, A., Piccioli, E., Prandini, N., Puchade, A., Raymer, W., Rhode, M., Ribo, J., Rico, M., Rissi, A., Robert, S., Rugamer, A., Saggion, T., Saito, A., Sanchez, P., Sartori, V., Scalzotto, V., Scapin, R., Schmitt, T., Schweizer, M., Shayduk, K., Shinozaki, S. N., Shore, N., Sidro, A., Sillanpaa, D., Sobczynska, A., Stamerra, L. S., Stark, L., Takalo, P., Temnikov, D., Tescaro, M., Teshima, D. F., Torre, N., Turini, H., Vankov, V., Vitale, R. M., Wagner, T., Wibig, W., Wittek, F., Zandanel, R., Zanin, and J., Zapatero
Subjects: Black Holes, Stellar mass, Flux, FOS: Physical sciences, Astrophysics, law.invention, X-ray astronomy, law, Gamma ray astronomy, Astronomia de raigs gamma, Physics, Nebula, Acceleradors de partícules, Astrophysics (astro-ph), Gamma ray, Sigma, Astronomy and Astrophysics, Black Hole, Very High Energy Gamma-ray Astronomy, MAGIC telescope, Particle accelerators, Astronomia de raigs X, Black hole, Crab Nebula, Space and Planetary Science, Electrónica, Física nuclear, Electricidad, Flare
Abstract: We report on the results from the observations in very high energy band (VHE, E_gamma > 100 GeV) of the black hole X-ray binary (BHXB) Cygnus X-1. The observations were performed with the MAGIC telescope, for a total of 40 hours during 26 nights, spanning the period between June and November 2006. Searches for steady gamma-ray signals yielded no positive result and upper limits to the integral flux ranging between 1 and 2% of the Crab nebula flux, depending on the energy, have been established. We also analyzed each observation night independently, obtaining evidence of gamma-ray signals at the 4.0 standard deviations (sigma) significance level (3.2 sigma after trial correction) for 154 minutes effective on-time (EOT) on September 24 between 20h58 and 23h41 UTC, coinciding with an X-ray flare seen by RXTE, Swift and INTEGRAL. A search for faster-varying signals within a night resulted in an excess with a significance of 4.9 sigma (4.1 sigma after trial correction) for 79 minutes EOT between 22h17 and 23h41 UTC. The measured excess is compatible with a point-like source at the position of Cygnus X-1, and excludes the nearby radio nebula powered by its relativistic jet. The differential energy spectrum is well fitted by an unbroken power-law described by dN/(dA dt dE) = (2.3+- 0.6) x 10^{-12} (E/1 TeV)^{-3.2 +- 0.6}. This is the first experimental evidence of VHE emission from a stellar-mass black hole, and therefore from a confirmed accreting X-ray binary., 4 ApJL-formatted pages, 4 figures. Revised version accepted for publication at ApJL (26-06-2007)
Published: 2007

39. Observation of gamma rays from the galactic center with the MAGIC telescope

Author: Albert, J., Aliu, E., Anderhub, H., Antoranz, P., Armada, A., Asensio, M., Baixeras, C., Barrio, J. A., Bartelt, M., Bartko, H., Bastieri, D., Bavikadi, R., Bednarek, W., Berger, K., Bigongiari, C., Biland, A., Bisesi, E., Bock, R. K., Bretz, T., Britvitch, I., Camara, M., Chilingarian, A., Ciprini, S., Coarasa, J. A., Commichau, S., Contreras, J. L., Cortina, J., Curtef, V., Danielyan, V., Dazzi, F., De Angelis, A., de los Reyes, R., De Lotto, B., Domingo Santamaría, E., Dorner, D., Doro, M., Errando, M., Fagiolini, M., Ferenc, D., Fernández, E., Firpo, R., Flix, J., Fonseca, M. V., Font, L., Galante, N., Garczarczyk, M., Gaug, M., Giller, M., Goebel, F., Hakobyan, D., Hayashida, M., Hengstebeck, T., Höhne, D., Hose, J., Jacon, P., Kalekin, O., Kranich, D., Laille, A., Lenisa, T., Liebing, P., Lindfors, E., Longo, F., López, J., López, M., Lorenz, E., Lucarelli, F., Majumdar, P., Maneva, G., Mannheim, K., Mariotti, M., Martínez, M., Mase, K., Mazin, D., Merck, M., Meucci, M., Meyer, M., Miranda, J. M., Mirzoyan, R., Mizobuchi, S., Moralejo, A., Nilsson, K., Oña Wilhelmi, E., Orduña, R., Otte, N., Oya, I., Paneque, D., Paoletti, R., Pasanen, M., Pascoli, D., Pauss, F., Pavel, N., Pegna, R., Peruzzo, L., Piccioli, A., Prandini, E., Rico, J., Rhode, W., Riegel, B., Rissi, M., Robert, A., Rügamer, S., Saggion, A., Sánchez, A., Sartori, P., Scalzotto, V., Schmitt, R., Schweizer, T., Shayduk, M., Shinozaki, K., Shore, S. N., Sidro, N., Sillanpää, A., Sobczynska, D., Stamerra, Antonio, Stepanian, A., Stark, L. S., Takalo, L., Temnikov, P., Tescaro, D., Teshima, M., Tonello, N., Torres, A., Torres, D. F., Turini, Nicola, Vankov, H., Vardanyan, A., Vitale, V., Wagner, R. M., Wibig, T., Wittek, W., Zapatero, J., J., Albert, E., Aliu, H., Anderhub, P., Antoranz, A., Armada, M., Asensio, C., Baixera, J. A., Barrio, M., Bartelt, H., Bartko, D., Bastieri, R., Bavikadi, W., Bednarek, K., Berger, C., Bigongiari, A., Biland, E., Bisesi, R. K., Bock, T., Bretz, I., Britvitch, M., Camara, A., Chilingarian, S., Ciprini, J. A., Coarasa, S., Commichau, J. L., Contrera, J., Cortina, V., Curtef, V., Danielyan, F., Dazzi, Angelis, A., Los, R., Lotto, B., E., Domingo Santamar\ia, D., Dorner, M., Doro, M., Errando, M., Fagiolini, D., Ferenc, E., Fernandez, R., Firpo, J., Flix, M. V., Fonseca, L., Font, N., Galante, M., Garczarczyk, M., Gaug, M., Giller, F., Goebel, D., Hakobyan, M., Hayashida, T., Hengstebeck, D., H\ohne, J., Hose, P., Jacon, O., Kalekin, D., Kranich, A., Laille, T., Lenisa, P., Liebing, E., Lindfor, Longo, Francesco, J., Lopez, M., Lopez, E., Lorenz, F., Lucarelli, P., Majumdar, G., Maneva, K., Mannheim, M., Mariotti, M., Mart\inez, K., Mase, D., Mazin, M., Merck, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, S., Mizobuchi, A., Moralejo, K., Nilsson, E., O\~na Wilhelmi, R., Ordu\~na, N., Otte, I., Oya, D., Paneque, R., Paoletti, M., Pasanen, D., Pascoli, F., Pau, N., Pavel, R., Pegna, L., Peruzzo, A., Piccioli, E., Prandini, J., Rico, W., Rhode, B., Riegel, M., Rissi, A., Robert, S., R\ugamer, A., Saggion, A., Sanchez, P., Sartori, V., Scalzotto, R., Schmitt, T., Schweizer, M., Shayduk, K., Shinozaki, S. N., Shore, N., Sidro, A., Sillanp\a\a, D., Sobczynska, A., Stamerra, A., Stepanian, L. S., Stark, L., Takalo, P., Temnikov, D., Tescaro, M., Teshima, N., Tonello, A., Torre, D. F., Torre, N., Turini, H., Vankov, A., Vardanyan, V., Vitale, R. M., Wagner, T., Wibig, W., Wittek, and J., Zapatero
Subjects: Astrofísica, High energy, Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Astrophysics, Power law, Spectral line, Acceleration of Particles, Galaxy: Center, Gamma Rays: Observations, MAGIC (telescope), Physics, Center [Galaxy], Observations [Gamma Rays], Galactic Center, Astrophysics (astro-ph), Gamma ray, Astronomy and Astrophysics, Space and Planetary Science, Acceleration of Particle, Electrónica, Física nuclear, Electricidad, Energy (signal processing)
Abstract: Recently, the Galactic Center has been reported to be a source of very high energy (VHE) gamma-rays by the VERITAS, CANGAROO and HESS experiments. The energy spectra as measured by these experiments show substantial differences. In this Letter we present MAGIC observations of the Galactic Center, resulting in the detection of a differential gamma-ray flux consistent with a steady, hard-slope power law, described as dN/(dA dt dE) = (2.9+/-0.6)*10^{-12} (E/TeV)^{-2.2+/-0.2} cm^{-2}s^{-1}TeV^{-1}. The gamma-ray source is centered at (Ra, Dec)=(17h 45m 20s, -29deg 2'. This result confirms the previous measurements by the HESS experiment and indicates a steady source of TeV gamma-rays. We briefly describe the observational technique used, the procedure implemented for the data analysis, and discuss the results in the perspective of different models proposed for the acceleration of the VHE gamma-rays., ApJL submitted
Published: 2006

40. Discovery of very high energy gamma rays from 1ES 1218+30.4

Author: J. Albert, E. Aliu, H. Anderhub, P. Antoranz, A. Armada, M. Asensio, C. Baixeras, J. A. Barrio, M. Bartelt, H. Bartko, D. Bastieri, S. R. Bavikadi, W. Bednarek, K. Berger, C. Bigongiari, A. Biland, E. Bisesi, R. K. Bock, T. Bretz, I. Britvitch, M. Camara, A. Chilingarian, S. Ciprini, J. A. Coarasa, S. Commichau, J. L. Contreras, J. Cortina, V. Curtef, V. Danielyan, F. Dazzi, A. De Angelis, R. de los Reyes, B. De Lotto, E. Domingo-Santamaría, D. Dorner, M. Doro, M. Errando, M. Fagiolini, D. Ferenc, E. Fernández, R. Firpo, J. Flix, M. V. Fonseca, L. Font, N. Galante, M. Garczarczyk, M. Gaug, M. Giller, F. Goebel, D. Hakobyan, M. Hayashida, T. Hengstebeck, D. Höhne, J. Hose, P. Jacon, O. Kalekin, D. Kranich, A. Laille, T. Lenisa, P. Liebing, E. Lindfors, F. Longo, J. López, M. López, E. Lorenz, F. Lucarelli, P. Majumdar, G. Maneva, K. Mannheim, M. Mariotti, M. Martínez, K. Mase, D. Mazin, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, S. Mizobuchi, A. Moralejo, K. Nilsson, E. Oña-Wilhelmi, R. Orduña, N. Otte, I. Oya, D. Paneque, R. Paoletti, M. Pasanen, D. Pascoli, F. Pauss, N. Pavel, R. Pegna, M. Persic, L. Peruzzo, A. Piccioli, M. Poller, E. Prandini, W. Rhode, J. Rico, B. Riegel, M. Rissi, A. Robert, S. Rügamer, A. Saggion, A. Sánchez, P. Sartori, V. Scalzotto, R. Schmitt, T. Schweizer, M. Shayduk, K. Shinozaki, S. N. Shore, N. Sidro, A. Sillanpää, D. Sobczyńska, A. Stamerra, L. S. Stark, L. Takalo, P. Temnikov, D. Tescaro, M. Teshima, N. Tonello, A. Torres, D. F. Torres, N. Turini, H. Vankov, A. Vardanyan, V. Vitale, R. M. Wagner, T. Wibig, W. Wittek, J. Zapatero, J., Albert, E., Aliu, H., Anderhub, P., Antoranz, A., Armada, M., Asensio, C., Baixera, J. A., Barrio, M., Bartelt, H., Bartko, D., Bastieri, S. R., Bavikadi, W., Bednarek, K., Berger, C., Bigongiari, A., Biland, E., Bisesi, R. K., Bock, T., Bretz, I., Britvitch, M., Camara, A., Chilingarian, S., Ciprini, J. A., Coarasa, S., Commichau, J. L., Contrera, J., Cortina, V., Curtef, V., Danielyan, F., Dazzi, Angelis, A., Los, R., Lotto, B., E., Domingo Santamar\ia, D., Dorner, M., Doro, M., Errando, M., Fagiolini, D., Ferenc, E., Fernandez, R., Firpo, J., Flix, M. V., Fonseca, L., Font, N., Galante, M., Garczarczyk, M., Gaug, M., Giller, F., Goebel, D., Hakobyan, M., Hayashida, T., Hengstebeck, D., H\ohne, J., Hose, P., Jacon, O., Kalekin, D., Kranich, A., Laille, T., Lenisa, P., Liebing, E., Lindfor, Longo, Francesco, J., Lopez, M., Lopez, E., Lorenz, F., Lucarelli, P., Majumdar, G., Maneva, K., Mannheim, M., Mariotti, M., Mart\inez, K., Mase, D., Mazin, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, S., Mizobuchi, A., Moralejo, K., Nilsson, E., O\~na Wilhelmi, R., Ordu\~na, N., Otte, I., Oya, D., Paneque, R., Paoletti, M., Pasanen, D., Pascoli, F., Pau, N., Pavel, R., Pegna, M., Persic, L., Peruzzo, A., Piccioli, M., Poller, E., Prandini, W., Rhode, J., Rico, B., Riegel, M., Rissi, A., Robert, S., R\ugamer, A., Saggion, A., Sanchez, P., Sartori, V., Scalzotto, R., Schmitt, T., Schweizer, M., Shayduk, K., Shinozaki, S. N., Shore, N., Sidro, A., Sillanp\a\a, D., Sobczynska, A., Stamerra, L. S., Stark, L., Takalo, P., Temnikov, D., Tescaro, M., Teshima, N., Tonello, A., Torre, D. F., Torre, N., Turini, H., Vankov, A., Vardanyan, V., Vitale, R. M., Wagner, T., Wibig, W., Wittek, and J., Zapatero
Subjects: BL Lacertae objects: individual (1ES 1218+30.4), Gamma Rays: Observations, Astrophysics, 01 natural sciences, Power law, law.invention, Telescope, law, individual (1ES 1218+30.4) [BL Lacertae objects], 0103 physical sciences, Energy spectrum, 010303 astronomy & astrophysics, Cherenkov radiation, Gamma Rays: Observation, Physics, 010308 nuclear & particles physics, Observations [Gamma Rays], Gamma ray, Astronomy, Astronomy and Astrophysics, Redshift, Space and Planetary Science, Electrónica, Física nuclear, Electricidad
Abstract: The MAGIC collaboration has studied the high-frequency-peaked BL Lac object 1ES 1218 + 30.4, at a redshift z = 0.182, using the MAGIC imaging air Cerenkov telescope located on the Canary Island of La Palma. A gamma-ray signal was observed with 6.4 sigma significance. The differential energy spectrum for an energy threshold of 120 GeV can be fitted by a simple power law, yielding F-E = (8.1 +/- 2.1) x 10(-7)[E/(250 GeV)](-3.0 +/- 0.4) TeV-1 F (E) m(-2) s(-1). During the 6 days of observation in 2005 January, no time variability on timescales of days was found within the statistical errors. The observed integral flux above 350 GeV is nearly a factor of 2 below the upper limit reported by the Whipple collaboration in 2003.
Published: 2006

41. Observation of very high energy gamma-ray emission from the active galactic nucleus 1ES 1959+650 using the MAGIC telescope

Author: J. Albert, E. Aliu, H. Anderhub, P. Antoranz, A. Armada, M. Asensio, C. Baixeras, J. A. Barrio, H. Bartko, D. Bastieri, W. Bednarek, K. Berger, C. Bigongiari, A. Biland, E. Bisesi, R. K. Bock, T. Bretz, I. Britvitch, M. Camara, A. Chilingarian, S. Ciprini, J. A. Coarasa, S. Commichau, J. L. Contreras, J. Cortina, V. Danielyan, F. Dazzi, A. . Angelis, R. . los, B. . Lotto, E. Domingo Santamar\ia, D. Dorner, M. Doro, M. Errando, D. Ferenc, E. Fernandez, R. Firpo, J. Flix, M. V. Fonseca, L. Font, N. Galante, M. Garczarczyk, M. Gaug, J. Gebauer, R. Giannitrapani, M. Giller, F. Goebel, D. Hakobyan, M. Hayashida, T. Hengstebeck, D. H\ohne, J. Hose, P. Jacon, O. Kalekin, D. Kranich, A. Laille, T. Lenisa, P. Liebing, E. Lindfors, J. Lopez, M. Lopez, E. Lorenz, F. Lucarelli, P. Majumdar, G. Maneva, K. Mannheim, M. Mariotti, M. Mart\inez, K. Mase, D. Mazin, C. Merck, M. Merck, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, S. Mizobuchi, A. Moralejo, K. Nilsson, E. O\~na Wilhelmi, R. Ordu\~na, N. Otte, I. Oya, D. Paneque, R. Paoletti, M. Pasanen, D. Pascoli, F. Pauss, N. Pavel, R. Pegna, L. Peruzzo, A. Piccioli, M. Pin, E. Prandini, J. Rico, W. Rhode, B. Riegel, M. Rissi, A. Robert, G. Rossato, S. R\ugamer, A. Saggion, A. Sanchez, P. Sartori, V. Scalzotto, R. Schmitt, T. Schweizer, M. Shayduk, K. Shinozaki, N. Sidro, A. Sillanp\a\a, D. Sobczynska, A. Stamerra, L. Stark, L. Takalo, P. Temnikov, D. Tescaro, M. Teshima, N. Tonello, A. Torres, D. F. Torres, N. Turini, H. Vankov, V. Vitale, R. M. Wagner, T. Wibig, W. Wittek, J. Zapatero, LONGO, FRANCESCO, J., Albert, E., Aliu, H., Anderhub, P., Antoranz, A., Armada, M., Asensio, C., Baixera, J. A., Barrio, H., Bartko, D., Bastieri, W., Bednarek, K., Berger, C., Bigongiari, A., Biland, E., Bisesi, R. K., Bock, T., Bretz, I., Britvitch, M., Camara, A., Chilingarian, S., Ciprini, J. A., Coarasa, S., Commichau, J. L., Contrera, J., Cortina, V., Danielyan, F., Dazzi, Angelis, A., Los, R., Lotto, B., E., Domingo Santamar\ia, D., Dorner, M., Doro, M., Errando, D., Ferenc, E., Fernandez, R., Firpo, J., Flix, M. V., Fonseca, L., Font, N., Galante, M., Garczarczyk, M., Gaug, J., Gebauer, R., Giannitrapani, M., Giller, F., Goebel, D., Hakobyan, M., Hayashida, T., Hengstebeck, D., H\ohne, J., Hose, P., Jacon, O., Kalekin, D., Kranich, A., Laille, T., Lenisa, P., Liebing, E., Lindfor, Longo, Francesco, J., Lopez, M., Lopez, E., Lorenz, F., Lucarelli, P., Majumdar, G., Maneva, K., Mannheim, M., Mariotti, M., Mart\inez, K., Mase, D., Mazin, C., Merck, M., Merck, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, S., Mizobuchi, A., Moralejo, K., Nilsson, E., O\~na Wilhelmi, R., Ordu\~na, N., Otte, I., Oya, D., Paneque, R., Paoletti, M., Pasanen, D., Pascoli, F., Pau, N., Pavel, R., Pegna, L., Peruzzo, A., Piccioli, M., Pin, E., Prandini, J., Rico, W., Rhode, B., Riegel, M., Rissi, A., Robert, G., Rossato, S., R\ugamer, A., Saggion, A., Sanchez, P., Sartori, V., Scalzotto, R., Schmitt, T., Schweizer, M., Shayduk, K., Shinozaki, N., Sidro, A., Sillanp\a\a, D., Sobczynska, A., Stamerra, L., Stark, L., Takalo, P., Temnikov, D., Tescaro, M., Teshima, N., Tonello, A., Torre, D. F., Torre, N., Turini, H., Vankov, V., Vitale, R. M., Wagner, T., Wibig, W., Wittek, and J., Zapatero
Subjects: RADIO-SOURCES, Active galactic nucleus, gamma ray astronomy, IMAGING CHERENKOV DETECTOR, Astrophysics::High Energy Astrophysical Phenomena, galaxies: individual (1ES 1959+650), TEV BLAZAR 1ES-1959+650, ACCELERATION, SENSITIVITY, NEUTRINOS, SPECTRA, OBJECTS, Flux, Astrophysics, Galaxies: Active, Gamma Rays: Observations, MAGIC (telescope), Cherenkov radiation, Physics, Observations [Gamma Rays], Gamma ray, HEGRA, Astronomy and Astrophysics, Light curve, Active [Galaxies], Crab Nebula, Space and Planetary Science, Electrónica, Física nuclear, Electricidad, individual (1ES 1959+650) [galaxies]
Abstract: The MAGIC Cerenkov telescope has observed very high energy (VHE) gamma-ray emission from the active galactic nucleus 1ES 1959+650 during 6 hr in 2004 September and October. The observations were carried out alternating with observations of the Crab Nebula, whose data were used as a reference source for optimizing gamma -ray/hadron separation and for flux comparison. The data analysis shows VHE gamma-ray emission of 1ES 1959+650 with similar to 8 sigma significance, at a time of low activity in both optical and X-ray wavelengths. An integral flux above similar to 180 GeV of about 20% that of the Crab Nebula was obtained. The light curve, sampled over 7 days, shows no significant variations. The differential energy spectrum between 180 GeV and 2 TeV can be fitted with a power-law of index -2.72 +/- 0.14. The spectrum is consistent with the slightly steeper spectrum seen by HEGRA at higher energies, also during periods of low X-ray activity.
Published: 2006

42. MAGIC observations of very high energy gamma-rays from HESS J1813-178

Author: J. Albert, E. Aliu, H. Anderhub, P. Antoranz, A. Armada, M. Asensio, C. Baixeras, J. A. Barrio, M. Bartel, H. Bartko, D. Bastieri, R. Bavikadi, W. Bednarek, K. Berger, C. Bigongiari, A. Biland, E. Bisesi, O. Blanch, R. K. Bock, T. Bretz, I. Britvitch, M. Camara, A. Chilingarian, S. Ciprini, J. A. Coarasa, S. Commichau, J. L. Contreras, J. Cortina, V. Curtev, V. Danielyan, F. Dazzi, A. De Angelis, R. de los Reyes, B. De Lotto, E. Domingo-Santamaria, D. Dorner, M. Doro, M. Errando, M. Fagiolini, D. Ferenc, E. Fernández, R. Firpo, J. Flix, M. V. Fonseca, L. Font, N. Galante, M. Garczarczyk, M. Gaug, J. Gebauer, M. Giller, F. Goebel, D. Hakobyan, M. Hayashida, T. Hengstebeck, D. Höhne, J. Hose, P. Jacon, O. Kalekin, D. Kranich, A. Laille, T. Lenisa, P. Liebing, E. Lindfors, F. Longo, M. López, J. López, E. Lorenz, F. Lucarelli, P. Majumdar, G. Maneva, K. Mannheim, M. Mariotti, M. Martínez, K. Mase, D. Mazin, C. Merck, M. Merck, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, S. Mizobuchi, A. Moralejo, K. Nilsson, E. Oña-Wilhelmi, R. Orduña, N. Otte, I. Oya, D. Paneque, R. Paoletti, M. Pasanen, D. Pascoli, F. Pauss, N. Pavel, R. Pegna, L. Peruzzo, A. Piccioli, E. Prandini, J. Rico, W. Rhode, B. Riegel, M. Rissi, A. Robert, G. Rossato, S. Rügamer, A. Saggion, A. Sanchez, P. Sartori, V. Scalzotto, R. Schmitt, T. Schweizer, M. Shayduk, K. Shinozaki, S. Shore, N. Sidro, A. Sillanpää, D. Sobczynska, A. Stamerra, L. Stark, L. Takalo, P. Temnikov, D. Tescaro, M. Teshima, N. Tonello, A. Torres, D. F. Torres, N. Turini, H. Vankov, V. Vitale, R. Wagner, T. Wibig, W. Wittek, J. Zapatero, J., Albert, E., Aliu, H., Anderhub, P., Antoranz, A., Armada, M., Asensio, C., Baixera, J. A., Barrio, M., Bartel, H., Bartko, D., Bastieri, R., Bavikadi, W., Bednarek, K., Berger, C., Bigongiari, A., Biland, E., Bisesi, O., Blanch, R. K., Bock, T., Bretz, I., Britvitch, M., Camara, A., Chilingarian, S., Ciprini, J. A., Coarasa, S., Commichau, J. L., Contrera, J., Cortina, V., Curtev, V., Danielyan, F., Dazzi, Angelis, A., Los, R., Lotto, B., E., Domingo Santamaria, D., Dorner, M., Doro, M., Errando, M., Fagiolini, D., Ferenc, E., Fernandez, R., Firpo, J., Flix, M. V., Fonseca, L., Font, N., Galante, M., Garczarczyk, M., Gaug, J., Gebauer, M., Giller, F., Goebel, D., Hakobyan, M., Hayashida, T., Hengstebeck, D., H\ohne, J., Hose, P., Jacon, O., Kalekin, D., Kranich, A., Laille, T., Lenisa, P., Liebing, E., Lindfor, Longo, Francesco, M., Lopez, J., Lopez, E., Lorenz, F., Lucarelli, P., Majumdar, G., Maneva, K., Mannheim, M., Mariotti, M., Mart\inez, K., Mase, D., Mazin, C., Merck, M., Merck, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, S., Mizobuchi, A., Moralejo, K., Nilsson, E., O\~na Wilhelmi, R., Ordu\~na, N., Otte, I., Oya, D., Paneque, R., Paoletti, M., Pasanen, D., Pascoli, F., Pau, N., Pavel, R., Pegna, L., Peruzzo, A., Piccioli, E., Prandini, J., Rico, W., Rhode, B., Riegel, M., Rissi, A., Robert, G., Rossato, S., R\ugamer, A., Saggion, A., Sanchez, P., Sartori, V., Scalzotto, R., Schmitt, T., Schweizer, M., Shayduk, K., Shinozaki, S., Shore, N., Sidro, A., Sillanp\a\a, D., Sobczynska, A., Stamerra, L., Stark, L., Takalo, P., Temnikov, D., Tescaro, M., Teshima, N., Tonello, A., Torre, D. F., Torre, N., Turini, H., Vankov, V., Vitale, R., Wagner, T., Wibig, W., Wittek, and J., Zapatero
Subjects: Astrofísica, High energy, Observation [Gamma Rays], Acceleration of Particles, Gamma Rays: Observations, ISM: Supernova Remnants, FOS: Physical sciences, Astrophysics, Power law, Supernova Remnants [ISM], Coincident, Cosmic rays, Physics, gamma ray astronomy, IMAGING CHERENKOV DETECTOR, Astrophysics (astro-ph), Magic (programming), Gamma ray, Astronomy and Astrophysics, Galactic plane, Space and Planetary Science, Acceleration of Particle, Electrónica, Física nuclear, Electricidad, acceleration of particles
Abstract: Recently, the HESS collaboration has reported the detection of gamma-ray emission above a few hundred GeV from eight new sources located close to the Galactic Plane. The source HESS J1813-178 has sparked particular interest, as subsequent radio observations imply an association with SNR G12.82-0.02. Triggered by the detection in VHE gamma-rays, a positionally coincident source has also been found in INTEGRAL and ASCA data. In this Letter we present MAGIC observations of HESS J1813-178, resulting in the detection of a differential gamma-ray flux consistent with a hard-slope power law, described as dN/(dA dt dE) = (3.3+/-0.5)*10^{-12} (E/TeV)^{-2.1+/-0.2} cm^(-2)s^(-1)TeV^(-1). We briefly discuss the observational technique used, the procedure implemented for the data analysis, and put this detection in the perspective of multifrequency observations., Accepted by ApJ Letters
Published: 2006

43. Arrival time distributions of muons from extensive air showers as signature of the mass composition of cosmic rays

Author: M. Föller, G. Völker, H. Rebel, and Ashot Chilingarian
Subjects: Physics, Nuclear and High Energy Physics, Muon, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Nonparametric statistics, Cosmic ray, Signature (logic), Nuclear physics, Atmosphere, Shower, KASCADE
Abstract: The central detector of the KASCADE experiment which is intended to study the main components of EAS will be equipped with a trigger and fast timing facility which will enable measurements of the arrival time distributions of the muons. In particular, at larger distances from the shower axis the arrival time distributions are expected to map the longitudinal development of the showers in the atmosphere and may provide additional information about the nature of the primary particle through differences between the mean free paths and the interaction cross sections with air nuclei. We have investigated this aspect with respect to the KASCADE set-up on the basis of EAS simulations using the Monte Carlo code CORSIKA. The mean arrival time distributions of muons, observed at various distances from the shower core and for different primary energies and shower sizes, respectively, have been analysed with advanced statistical techniques, based on Bayes decision rules and nonparametric multivariate analysing methods, in order to specify the merits of the mean arrival time information of the muon component as a signature for the mass composition of cosmic rays. It turns out that muon arrival time distributions, observed with the KASCADE facility, exhibit promising features and mass discrimination effects for larger shower sizes, i.e. higher primary energies, around 1016 eV.
Published: 1995
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44. Lightning origination and thunderstorm ground enhancements terminated by the lightning flash

Author: Chilingarian, A., primary, Hovsepyan, G., additional, Khanikyanc, G., additional, Reymers, A., additional, and Soghomonyan, S., additional
Published: 2015
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45. Data Reduction Pipeline for the MMT and Magellan Infrared Spectrograph

Author: Chilingarian, Igor, primary, Beletsky, Yuri, additional, Moran, Sean, additional, Brown, Warren, additional, McLeod, Brian, additional, and Fabricant, Daniel, additional
Published: 2015
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46. Quantum states of the light for dynamic diffraction in the DFB system

Author: Yu S Chilingarian, Sergei M. Arakelian, and A. P. Alodjants
Subjects: Quantum optics, Diffraction, Physics, Optics, Quantum state, business.industry, Physics::Optics, General Physics and Astronomy, Acousto-optics, Diffraction topography, business, Quantum
Abstract: A new method of formation of quantum states of the light in a system with non-linear dynamic diffraction is discussed for the first time. The squeezed states of the light are obtained for two geometries (Bragg and Laue) of non-linear diffraction in a spatially periodic medium. The approach also gives new opportunities for the experimental verification of the quantum properties of the light.
Published: 1992
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47. Magic observations of the unidentified gamma-ray source TEV J2032+4130

Author: J. Albert, E. Aliu, H. Anderhub, P. Antoranz, C. Baixeras, J. A. Barrio, H. Bartko, D. Bastieri, J. K. Becker, W. Bednarek, K. Berger, C. Bigongiari, A. Biland, R. K. Bock, G. Bonnoli, P. Bordas, V. Bosch-Ramon, T. Bretz, I. Britvitch, M. Camara, E. Carmona, A. Chilingarian, S. Commichau, J. L. Contreras, J. Cortina, M. T. Costado, V. Curtef, F. Dazzi, A. De Angelis, C. Delgado, R. de los Reyes, E. Domingo-Santamaría, B. De Lotto, M. De Maria, F. De Sabata, D. Dorner, M. Doro, M. Errando, M. Fagiolini, D. Ferenc, E. Fernández, R. Firpo, M. V. Fonseca, L. Font, N. Galante, R. J. García-López, M. Garczarczyk, M. Gaug, F. Goebel, M. Hayashida, A. Herrero, D. Höhne, J. Hose, C. C. Hsu, S. Huber, T. Jogler, R. Kosyra, D. Kranich, A. Laille, E. Leonardo, E. Lindfors, S. Lombardi, F. Longo, M. López, E. Lorenz, P. Majumdar, G. Maneva, N. Mankuzhiyil, K. Mannheim, M. Mariotti, M. Martínez, D. Mazin, C. Merck, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, S. Mizobuchi, A. Moralejo, D. Nieto, K. Nilsson, J. Ninkovic, E. Oña-Wilhelmi, N. Otte, I. Oya, M. Panniello, R. Paoletti, J. M. Paredes, M. Pasanen, D. Pascoli, F. Pauss, R. Pegna, M. Persic, L. Peruzzo, A. Piccioli, E. Prandini, N. Puchades, A. Raymers, W. Rhode, M. Ribó, J. Rico, M. Rissi, A. Robert, S. Rügamer, A. Saggion, T. Y. Saito, A. Sánchez, P. Sartori, V. Scalzotto, V. Scapin, R. Schmitt, T. Schweizer, M. Shayduk, K. Shinozaki, S. N. Shore, N. Sidro, A. Sillanpää, D. Sobczynska, F. Spanier, A. Stamerra, L. S. Stark, L. Takalo, P. Temnikov, D. Tescaro, M. Teshima, D. F. Torres, N. Turini, H. Vankov, A. Venturini, V. Vitale, R. M. Wagner, W. Wittek, F. Zandanel, R. Zanin, J. Zapatero, APC - Astrophysique des Hautes Energies (APC - AHE), AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO), 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)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-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, and 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)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)
Subjects: [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Photon, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Astrophysics, gamma ray astronomy, Cosmic rays, IMAGING CHERENKOV DETECTOR, 01 natural sciences, Power law, law.invention, Telescope, law, Observacions astronòmiques, Gamma ray astronomy, 0103 physical sciences, Astronomia de raigs gamma, MAGIC (telescope), 010303 astronomy & astrophysics, Physics, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astrophysics (astro-ph), Gamma ray, HEGRA, Astronomy and Astrophysics, Space and Planetary Science, High Energy Physics::Experiment, Electrónica, Física nuclear, Electricidad, Energy (signal processing), gamma rays: observations, Astronomical observations
Abstract: We observed the first known very high energy (VHE) gamma-ray emitting unidentified source, TeV J2032+4130, for 94 hours with the MAGIC telescope. The source was detected with a significance of 5.6 sigma. The flux, position, and angular extension are compatible with the previous ones measured by the HEGRA telescope system five years ago. The integral flux amounts to (4.5+-0.3stat+-0.35sys)x10^{-13} ph cm$^{-2}$ s$^{-1}$ above 1 TeV. The source energy spectrum, obtained with the lowest energy threshold to date, is compatible with a single power law with a hard photon index of Gamma=-2.0+-0.3stat+-0.2sys., 4 pages, 3 figures, accepted for publication in The Astrophysical Journal Letters. Corrected typos
Published: 2008
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48. Lightning origination and thunderstorm ground enhancements terminated by the lightning flash

Author: S. Soghomonyan, Ashot Chilingarian, A. Reymers, G. Hovsepyan, and G. Khanikyanc
Subjects: Lightning detection, Meteorology, General Physics and Astronomy, Upper-atmospheric lightning, Lightning, law.invention, Lightning strike, Flash (photography), Air shower, law, Thunderstorm, Environmental science, Particle flux, Remote sensing
Abstract: Proceeding from the measurements of the lightning occurrences, slow and fast electric-field disturbances, particle flux enhancements and their abrupt terminations, we formulate a lightning origination model. Registration of the extensive air shower simultaneously with lightning detection allows us to propose a solution to the long-standing problem of its role in the lightning initiation. Our analysis is based on the numerous Thunderstorm Ground Enhancements detected in 2012–2014 at Mt. Aragats in Armenia.
Published: 2015
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49. On the origin of the particle fluxes from the thunderclouds: Energy spectra analysis

Author: Chilingarian, A., primary, Hovsepyan, G., additional, and Vanyan, L., additional
Published: 2014
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50. Aragats space-environmental centre: status and SEP forecasting possibilities

Author: Chilingarian, A, primary, Avakyan, K, additional, Babayan, V, additional, Bostanjyan, N, additional, Chilingarian, S, additional, Eganov, V, additional, Hovhanissyan, A, additional, Karapetyan, G, additional, Gevorgyan, N, additional, Gharagyozyan, G, additional, Ghazaryan, S, additional, Garyaka, A, additional, Ivanov, V, additional, Martirosian, H, additional, Martirosov, R, additional, Melkumyan, L, additional, Sogoyan, H, additional, Sokhoyan, S, additional, Tserunyan, S, additional, Vardanyan, A, additional, Yeremian, A, additional, and Zazyan, M, additional
Published: 2003
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