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1. The Great Markarian 421 Flare of 2010 February: Multiwavelength Variability and Correlation Studies

Author

Abeysekara, A. U., Benbow, W., Bird, R., Brill, A., Brose, R., Buchovecky, M., Buckley, J. H., Christiansen, J. L., Chromey, A. J., Daniel, M. K., Dumm, J., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Galante, N., Gent, A., Gillanders, G. H., Giuri, C., Gueta, O., Hassan, T., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kar, P., Kelley-Hoskins, N., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Kumar, S., Lang, M. J., Moriarty, P., Mukherjee, R., Nelson, T., Nieto, D., Nievas-Rosillo, M., O’Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pichel, A., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rovero, A. C., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Stevenson, B., Sushch, I., Tyler, J., Vassiliev, V. V., Wakely, S. P., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Zitzer, B., Acciari, V. A., 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, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D’Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Do Souto Espiñera, E., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernández-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., Gallozzi, S., García López, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Godinović, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Inoue, S., Ishio, K., Iwamura, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Nöthe, M., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Peñil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Sun, S., Surić, T., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tsujimoto, S., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vovk, I., Will, M., Zarić, D., Aller, H. D., Aller, M. F., Carini, M. T., Horan, D., Jordan, B., Jorstad, S. G., Kurtanidze, O. M., Kurtanidze, S. O., Lähteenmäki, A., Larionov, V. M., Larionova, E. G., Madejski, G., Marscher, A. P., Max-Moerbeck, W., Moody, J. Ward, Morozova, D. A., Nikolashvili, M. G., Raiteri, C. M., Readhead, A. C. S., Richards, J. L., Sadun, A. C., Sakamoto, T., Sigua, L. A., Smith, P. S., Talvikki, H., Tammi, J., Tornikoski, M., Troitsky, I. S., Villata, M., (VERITAS Collaboration), (MAGIC Collaboration), (Multiwavelength Partners), Department of Energy (US), Smithsonian Institution, National Science Foundation (US), National Energy Research Scientific Computing Center (US), German Research Foundation, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Ministerio de Economía y Competitividad (España), Department of Atomic Energy (India), Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), Croatian Science Foundation, University of Rijeka, Polish National Agency for Academic Exchange, National Aeronautics and Space Administration (US), Shota Rustaveli National Science Foundation, Boston University, University of Utah, Harvard University, University of California Los Angeles, Columbia University, University of Potsdam, Washington University St. Louis, California Polytechnic State University, San Luis Obispo, Iowa State University, University of Minnesota Twin Cities, Pennsylvania State University, Purdue University, California State University, East Bay, Georgia Institute of Technology, National University of Ireland, Galway, German Electron Synchrotron, University of California Santa Cruz, University of Delaware, University of Iowa, DePauw University, McGill University, Complutense University, University College Dublin, University of Wisconsin-Madison, Universidad de Buenos Aires, Cork Institute of Technology, University of Alabama, University of Chicago, Instituto de Astrofísica de Canarias, University of Udine, INAF, Osservatorio Astronomico di Roma, Swiss Federal Institute of Technology Zurich, Dortmund University, Saha Institute of Nuclear Physics, Centro Brasileiro de Pesquisas Físicas, University of Łódź, University of Siena, National Institute for Nuclear Physics, Max Planck Institute for Physics, Institute for High Energy Physics, University of Padova, University of Pisa, University of Würzburg, University of Turku, Autonomous University of Barcelona, University of Barcelona, National Academy of Sciences of the Republic of Armenia, The University of Tokyo, Bulgarian Academy of Sciences, Fudan University, University of Michigan, Ann Arbor, Western Kentucky University, CNRS, Dublin Institute for Advanced Studies, Ilia State University, Department of Electronics and Nanoengineering, St. Petersburg State University, United States Department of Energy, Universidad de Chile, Brigham Young University, California Institute of Technology, University of Colorado Denver, Aoyama Gakuin University, University of Arizona, Metsähovi Radio Observatory, Aalto-yliopisto, Aalto University, Abeysekara, A. U., Benbow, W., Bird, R., Brill, A., Brose, R., Buchovecky, M., Buckley, J. H., Christiansen, J. L., Chromey, A. J., Daniel, M. K., Dumm, J., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Galante, N., Gent, A., Gillanders, G. H., Giuri, C., Gueta, O., Hassan, T., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kar, P., Kelley-Hoskins, N., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Kumar, S., Lang, M. J., Moriarty, P., Mukherjee, R., Nelson, T., Nieto, D., Nievas-Rosillo, M., O'Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pichel, A., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rovero, A. C., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Stevenson, B., Sushch, I., Tyler, J., Vassiliev, V. V., Wakely, S. P., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Zitzer, B., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Do Souto Espiñera, E., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernandez-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., Gallozzi, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Godinovic, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Inoue, S., Ishio, K., Iwamura, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Machado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Masuda, S., Mazin, D., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nothe, M., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Peñil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Sun, S., Suric, T., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tsujimoto, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vovk, I., Will, M., Zaric, D., Aller, H. D., Aller, M. F., Carini, M. T., Horan, D., Jordan, B., Jorstad, S. G., Kurtanidze, O. M., Kurtanidze, S. O., Lahteenmaki, A., Larionov, V. M., Larionova, E. G., Madejski, G., Marscher, A. P., Max-Moerbeck, W., Moody, J. W., Morozova, D. A., Nikolashvili, M. G., Raiteri, C. M., Readhead, A. C. S., Richards, J. L., Sadun, A. C., Sakamoto, T., Sigua, L. A., Smith, P. S., Talvikki, H., Tammi, J., Tornikoski, M., Troitsky, I. S., and Villata, M.

Subjects
Multiple days, Gamma-ray astronomY, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Flux, Markarian galaxies, Astrophysics, Blazar, 01 natural sciences, 7. Clean energy, BL Lacertae object, High energy astrophysic, law.invention, law, Observatory, BL Lacertae objects, Blazars, High energy astrophysics, Relativistic jets, Gamma-ray astronomy, Time domain astronomy, Relativistic jet, 0103 physical sciences, MAGIC (telescope), BL lacertae objects, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Astronomy and Astrophysics, Light curve, Space and Planetary Science, Markarian galaxie, Electrónica, Electricidad, Flare
Abstract

We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of 2010 February, when an extraordinary flare reaching a level of ∼27 Crab Units above 1 TeV was measured in very high energy (VHE) γ-rays with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory. This is the highest flux state for Mrk 421 ever observed in VHE γ-rays. Data are analyzed from a coordinated campaign across multiple instruments, including VHE γ-ray (VERITAS, Major Atmospheric Gamma-ray Imaging Cherenkov), high-energy γ-ray (Fermi-LAT), X-ray (Swift, Rossi X-ray Timing Experiment, MAXI), optical (including the GASP-WEBT collaboration and polarization data), and radio (Metsahovi, Owens Valley Radio Observatory, University of Michigan Radio Astronomy Observatory). Light curves are produced spanning multiple days before and after the peak of the VHE flare, including over several flare "decline" epochs. The main flare statistics allow 2 minute time bins to be constructed in both the VHE and optical bands enabling a cross-correlation analysis that shows evidence for an optical lag of ∼25-55 minutes, the first time-lagged correlation between these bands reported on such short timescales. Limits on the Doppler factor (δ ⪆ 33) and the size of the emission region (δR≲ 3.8 × 10cm) are obtained from the fast variability observed by VERITAS during the main flare. Analysis of 10 minute binned VHE and X-ray data over the decline epochs shows an extraordinary range of behavior in the flux-flux relationship, from linear to quadratic to lack of correlation to anticorrelation. Taken together, these detailed observations of an unprecedented flare seen in Mrk 421 are difficult to explain with the classic single-zone synchrotron self-Compton model., This research is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, the Smithsonian Institution, and NSERC in Canada. This research used resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy’s Office of Science, and the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under contract No. DE-AC02- 05CH11231. We acknowledge the excellent work of the technical support staff at the Fred Lawrence Whipple Observatory and the collaborating institutions in the construction and operation of the instrument. The MAGIC collaboration would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish MINECO (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2- R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015- 71662-C2-2-P, FPA201790566REDC), the Indian Department of Atomic Energy, the Japanese JSPS and MEXT, and the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588 and SEV2015-0548 and Unidad de Excelencia “María de Maeztu” MDM-2014-0369, the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782, the University of Rijeka Project 13.12.1.3.02, the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382, and the Brazilian MCTIC, CNPq, and FAPERJ. This publication makes use of data obtained at Metsähovi Radio Observatory, operated by Aalto University, Finland, and the OVRO 40 m monitoring program, which is supported in part by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G and NSF grants AST-0808050 and AST1109911. The UMRAO data were obtained through NSF grant AST 0607523 and NASA Fermi GI award NNX09AU16G. The St. Petersburg University team acknowledges support from Russian RFBR foundation, grant 12-02-00452. The Abastumani Observatory team acknowledges financial support by the Shota Rustaveli National Science Foundation through project FR/577/6-320/13. The Steward Observatory data were obtained under Fermi Guest Investigator Program grant NNX09AU10G. The research at Boston University is supported by NASA grant 80NSSC17K0649 and NSF grant AST-1615796. Software. VEGAS (Cogan 2008), Event Display (Daniel 2008), MARS (Moralejo et al. 2009), Fermi Science Tools81, HEASoft (FTOOLS+XANADU; HEASARC 2014), REX,85 Xspec (Arnaud 1996), emcee (Foreman-Mackey et al. 2013).

Published
2020

2. The Great Markarian 421 Flare of February 2010: Multiwavelength variability and correlation studies

Author

Abeysekara, A. U., Benbow, W., Bird, R., Brill, A., Brose, R., Buchovecky, M., Buckley, J. H., Christiansen, J. L., Chromey, A. J., Daniel, M. K., Dumm, J., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Galante, N., Gent, A., Gillanders, G. H., Giuri, C., Gueta, O., Hassan, T., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kar, P., Kelley-Hoskins, N., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Kumar, S., Lang, M. J., Moriarty, P., Mukherjee, R., Nelson, T., Nieto, D., Nievas-Rosillo, M., O'Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pichel, A., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rovero, A. C., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Stevenson, B., Sushch, I., Tyler, J., Vassiliev, V. V., Wakely, S. P., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Zitzer, B., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Baack, D., Babi��, A., Banerjee, B., de Almeida, U. Barres, Barrio, J. A., Gonz��lez, J. Becerra, Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Espi��era, E. Do Souto, Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Ramazani, V. Fallah, Fattorini, A., Fern��ndez-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., Gallozzi, S., L��pez, R. J. Garc��a, Garczarczyk, M., Gasparyan, S., Gaug, M., Godinovi��, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Inoue, S., Ishio, K., Iwamura, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., L��pez, M., L��pez-Coto, R., L��pez-Oramas, A., Fraga, B. Machado de Oliveira, Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Mart��nez, M., Masuda, S., Mazin, D., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogu��s, L., N��the, M., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pe��il, P., Peresano, M., Persic, M., Moroni, P. G. Prada, Prandini, E., Puljak, I., Rhode, W., Rib��, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., ��nidari��, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Sun, S., Suri��, T., Tavecchio, F., Temnikov, P., Terzi��, T., Teshima, M., Torres-Alb��, N., Tsujimoto, S., van Scherpenberg, J., Vanzo, G., Acosta, M. Vazquez, Vovk, I., Will, M., Zari��, D., Aller, H. D., Aller, M. F., Carini, M. T., Horan, D., Jordan, B., Jorstad, Svetlana G., Kurtanidze, O. M., Kurtanidze, S. O., L��hteenm��ki, A., Larionov, V. M., Larionova, E. G., Madejski, G., Marscher, Alan P., Max-Moerbeck, W., Moody, J. Ward, Morozova, D. A., Nikolashvili, M. G., Raiteri, C. M., Readhead, A. C. S., Richards, J. L., Sadun, Alberto C., Sakamoto, T., Sigua, L. A., Smith, P. S., Talvikki, H., Tammi, J., Tornikoski, M., Troitsky, I. S., Villata, M., Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), VERITAS, and MAGIC

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of February, 2010 when an extraordinary flare reaching a level of $\sim$27~Crab Units above 1~TeV was measured in very-high-energy (VHE) $\gamma$-rays with the VERITAS observatory. This is the highest flux state for Mrk 421 ever observed in VHE $\gamma$-rays. Data are analyzed from a coordinated campaign across multiple instruments including VHE $\gamma$-ray (VERITAS, MAGIC), high-energy (HE) $\gamma$-ray (Fermi-LAT), X-ray (Swift}, RXTE, MAXI), optical (including the GASP-WEBT collaboration and polarization data) and radio (Mets\"ahovi, OVRO, UMRAO). Light curves are produced spanning multiple days before and after the peak of the VHE flare, including over several flare `decline' epochs. The main flare statistics allow 2-minute time bins to be constructed in both the VHE and optical bands enabling a cross-correlation analysis that shows evidence for an optical lag of $\sim$25-55 minutes, the first time-lagged correlation between these bands reported on such short timescales. Limits on the Doppler factor ($\delta \gtrsim 33$) and the size of the emission region ($ \delta^{-1}R_B \lesssim 3.8\times 10^{13}\,\,\mbox{cm}$) are obtained from the fast variability observed by VERITAS during the main flare. Analysis of 10-minute-binned VHE and X-ray data over the decline epochs shows an extraordinary range of behavior in the flux-flux relationship: from linear to quadratic to lack of correlation to anti-correlation. Taken together, these detailed observations of an unprecedented flare seen in Mrk 421 are difficult to explain by the classic single-zone synchrotron self-Compton model., Comment: 41 pages including 3 appendices, 13 figures; version accepted to Astrophysical Journal

Published
2020
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3. The Great Markarian 421 flare of 2010 February:multiwavelength variability and correlation studies

Author

Abeysekara, A. U. (A. U.), Benbow, W. (W.), Bird, R. (R.), Brill, A. (A.), Brose, R. (R.), Buchovecky, M. (M.), Buckley, J. H. (J. H.), Christiansen, J. L. (J. L.), Chromey, A. J. (A. J.), Daniel, M. K. (M. K.), Dumm, J. (J.), Falcone, A. (A.), Feng, Q. (Q.), Finley, J. P. (J. P.), Fortson, L. (L.), Furniss, A. (A.), Galante, N. (N.), Gent, A. (A.), Gillanders, G. H. (G. H.), Giuri, C. (C.), Gueta, O. (O.), Hassan, T. (T.), Hervet, O. (O.), Holder, J. (J.), Hughes, G. (G.), Humensky, T. B. (T. B.), Johnson, C. A. (C. A.), Kaaret, P. (P.), Kar, P. (P.), Kelley-Hoskins, N. (N.), Kertzman, M. (M.), Kieda, D. (D.), Krause, M. (M.), Krennrich, F. (F.), Kumar, S. (S.), Lang, M. J. (M. J.), Moriarty, P. (P.), Mukherjee, R. (R.), Nelson, T. (T.), Nieto, D. (D.), Nievas-Rosillo, M. (M.), O'Brien, S. (S.), Ong, R. A. (R. A.), Otte, A. N. (A. N.), Park, N. (N.), Petrashyk, A. (A.), Pichel, A. (A.), Pohl, M. (M.), Prado, R. R. (R. R.), Pueschel, E. (E.), Quinn, J. (J.), Ragan, K. (K.), Reynolds, P. T. (P. T.), Richards, G. T. (G. T.), Roache, E. (E.), Rovero, A. C. (A. C.), Rulten, C. (C.), Sadeh, I. (I), Santander, M. (M.), Sembroski, G. H. (G. H.), Shahinyan, K. (K.), Stevenson, B. (B.), Sushch, I. (I), Tyler, J. (J.), Vassiliev, V. V. (V. V.), Wakely, S. P. (S. P.), Weinstein, A. (A.), Wells, R. M. (R. M.), Wilcox, P. (P.), Wilhelm, A. (A.), Williams, D. A. (D. A.), Zitzer, B. (B.), 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. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Chai, Y. (Y.), 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), Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Souto Espinera, E. (E.), Prester, D. D. (D. Dominis), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Godinovic, N. (N.), Green, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, 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.), 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.), Masuda, S. (S.), Mazin, D. (D.), Miceli, D. (D.), 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), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Noethe, M. (M.), Paiano, S. (S.), Palacio, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), 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.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Sun, S. (S.), Suric, T. (T.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Aller, H. D. (H. D.), Aller, M. F. (M. F.), Carini, M. T. (M. T.), Horan, D. (D.), Jordan, B. (B.), Jorstad, S. G. (S. G.), Kurtanidze, O. M. (O. M.), Kurtanidze, S. O. (S. O.), Lahteenmaki, A. (A.), Larionov, V. M. (V. M.), Larionova, E. G. (E. G.), Madejski, G. (G.), Marscher, A. P. (A. P.), Max-Moerbeck, W. (W.), Moody, J. W. (J. Ward), Morozova, D. A. (D. A.), Nikolashvili, M. G. (M. G.), Raiteri, C. M. (C. M.), Readhead, A. C. (A. C. S.), Richards, J. L. (J. L.), Sadun, A. C. (A. C.), Sakamoto, T. (T.), Sigua, L. A. (L. A.), Smith, P. S. (P. S.), Talvikki, H. (H.), Tammi, J. (J.), Tornikoski, M. (M.), Troitsky, I. S. (I. S.), and Villata, M. (M.)

Subjects
Gamma-ray astronomy, Astrophysics::High Energy Astrophysical Phenomena, Time domain astronomy, BL Lacertae objects, Markarian galaxies, Relativistic jets, High energy astrophysics, Blazars
Abstract

We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of 2010 February, when an extraordinary flare reaching a level of ~27 Crab Units above 1 TeV was measured in very high energy (VHE) γ-rays with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory. This is the highest flux state for Mrk 421 ever observed in VHE γ-rays. Data are analyzed from a coordinated campaign across multiple instruments, including VHE γ-ray (VERITAS, Major Atmospheric Gamma-ray Imaging Cherenkov), high-energy γ-ray (Fermi-LAT), X-ray (Swift, Rossi X-ray Timing Experiment, MAXI), optical (including the GASP-WEBT collaboration and polarization data), and radio (Metsähovi, Owens Valley Radio Observatory, University of Michigan Radio Astronomy Observatory). Light curves are produced spanning multiple days before and after the peak of the VHE flare, including over several flare “decline“ epochs. The main flare statistics allow 2 minute time bins to be constructed in both the VHE and optical bands enabling a cross-correlation analysis that shows evidence for an optical lag of ~25–55 minutes, the first time-lagged correlation between these bands reported on such short timescales. Limits on the Doppler factor (δ ≳ 33) and the size of the emission region (δ⁻¹ RB ≲ × 10¹³ cm) are obtained from the fast variability observed by VERITAS during the main flare. Analysis of 10 minute binned VHE and X-ray data over the decline epochs shows an extraordinary range of behavior in the flux–flux relationship, from linear to quadratic to lack of correlation to anticorrelation. Taken together, these detailed observations of an unprecedented flare seen in Mrk 421 are difficult to explain with the classic single-zone synchrotron self-Compton model.

Published
2020

4. Multi-Wavelength Observations of the Blazar 1ES 1011+496 in Spring 2008

Author

Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., De Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. De O Na, Mendez, C. Delgado, Pierro, F. Di, Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Fernández-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Giammaria, P., Godinović, N., Muñoz, A. González, Guberman, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Nakajima, D., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saito, T., Satalecka, K., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., Lucarelli, F., Pittori, C., Vercellone, S., Berdyugin, A., Carini, M. T., Lähteenmäki, A., Pasanen, M., Pease, A., Sainio, J., Tornikoski, M., and Walters, R.

Abstract

Monthly notices of the Royal Astronomical Society 459, 2286 - 2298 (2016). doi:10.1093/mnras/stw710, The BL Lac object 1ES 1011+496 was discovered at very high energy (VHE, E > 100GeV) γ-rays by Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) in Spring 2007. Before that the source was little studied in different wavelengths. Therefore, a multiwavelength (MWL) campaign was organized in Spring 2008. Along MAGIC, the MWL campaign included the Metsähovi Radio Observatory, Bell and Kungliga Vetenskapsakademien (KVA) optical telescopes and the Swift and AGILE satellites. MAGIC observations span from 2008 March to May for a total of 27.9 h, of which 19.4 h remained after quality cuts. The light curve showed no significant variability yielding an integral flux above 200 GeV of (1.3 ± 0.3) × 10$^{−11}$ photons cm$^{−2}$ s$^{−1}$. The differential VHE spectrum could be described with a power-law function with a spectral index of 3.3 ± 0.4. Both results were similar to those obtained during the discovery. Swift X-ray Telescope observations revealed an X-ray flare, characterized by a harder-when-brighter trend, as is typical for high synchrotron peak BL Lac objects (HBL). Strong optical variability was found during the campaign, but no conclusion on the connection between the optical and VHE γ-ray bands could be drawn. The contemporaneous spectral energy distribution shows a synchrotron-dominated source, unlike concluded in previous work based on non-simultaneous data, and is well described by a standard one-zone synchrotron self-Compton model. We also performed a study on the source classification. While the optical and X-ray data taken during our campaign show typical characteristics of an HBL, we suggest, based on archival data, that 1ES 1011+496 is actually a borderline case between intermediate and high synchrotron peak frequency BL Lac objects., Published by Oxford Univ. Press, Oxford

Published
2016
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5. Space Telescope and Optical Reverberation Mapping Project. IV. Anomalous Behavior of the Broad Ultraviolet Emission Lines in NGC 5548

Author

Goad, M. R., Korista, K. T., De Rosa, G., Kriss, G. A., Edelson, R., Barth, A. J., Ferland, G. J., Kochanek, C. S., Netzer, H., Peterson, B. M., Bentz, M. C., Bisogni, S., Crenshaw, D. M., Denney, K. D., Ely, J., Fausnaugh, M. M., Grier, C. J., Gupta, A., Horne, K. D., Kaastra, J., Pancoast, A., Pei, L., Pogge, R. W., Skielboe, A., Starkey, D., Vestergaard, M., Zu, Y., Anderson, M. D., Arevalo, P., Bazhaw, C., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Brewer, B. J., Cackett, E. M., Carini, M. T., Croxall, K. V., Bonta, E. Dalla, de Lorenzo-Caceres, A., Dietrich, M., Efimova, N. V., Evans, P. A., Filippenko, A. V., Flatland, K., Gehrels, N., Geier, S., Gelbord, G. M., Gonzalez, L., Gorjian, V., Grupe, D., Hall, P. B., Hicks, S., Horenstein, D., Hutchison, T., Im, M., Jensen, J. J., Joner, M. D., Jones, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, M., Kim, S. C., Klimanov, S. A., Larionov, V. M., Lee, J. C., Leonard, D. C., Lira, P., MacInnis, F., Manne-Nicholas, E. R., Mathur, S., McHardy, I. M., Montouri, C., Musso, R., Nazarov, S. V., Norris, R. P., Nousek, J. A., Okhmat, D. N., Papadakis, I., Parks, J. R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Saylor, D. A., Schimoia, J. S., Schnulle, K., Sergeev, S. G., Siegel, M., Spencer, M., Sung, H. -I., Teems, K. G., Treu, T., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., Zheng, W. -K., High Energy Astrophys. & Astropart. Phys (API, FNWI), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, ITA, USA, and GBR

Subjects
Active galactic nucleus, 010504 meteorology & atmospheric sciences, Cosmic Origins Spectrograph, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, galaxies: individual (NGC-5548), galaxies: nuclei, galaxies: Seyfert Supporting material: animation, Continuum (design consultancy), Doubly ionized oxygen, NDAS, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, QB Astronomy, Emission spectrum, Seyfert Supporting material: animation [Galaxies], 010303 astronomy & astrophysics, QC, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, QB, Galáxia NGC 5548, Physics, individual (NGC – 5548) [Galaxies], active, galaxies: individual (NGC, 5548), galaxies: nuclei, galaxies: Seyfert [galaxies], Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxias seyfert, Galaxy, Galáxias ativas, QC Physics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), nuclei [Galaxies], individual (NGC-5548) [Galaxies], Reverberation mapping, Equivalent width, Nucleo galatico
Abstract

During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert~1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far-UV continuum and broad emission-line variations decorrelated for ~60 to 70 days, starting ~75 days after the first HST/COS observation. Following this anomalous state, the flux and variability of the broad emission lines returned to a more normal state. This transient behavior, characterised by significant deficits in flux and equivalent width of the strong broad UV emission lines, is the first of its kind to be unambiguously identified in an active galactic nucleus reverberation mapping campaign. The largest corresponding emission-line flux deficits occurred for the high-ionization collisionally excited lines, C IV and Si IV(+O IV]), and also He II(+O III]), while the anomaly in Ly-alpha was substantially smaller. This pattern of behavior indicates a depletion in the flux of photons with E_{\rm ph} > 54 eV, relative to those near 13.6 eV. We suggest two plausible mechanisms for the observed behavior: (i) temporary obscuration of the ionizing continuum incident upon BLR clouds by a moving veil of material lying between the inner accretion disk and inner BLR, perhaps resulting from an episodic ejection of material from the disk, or (ii) a temporary change in the intrinsic ionizing continuum spectral energy distribution resulting in a deficit of ionizing photons with energies > 54 eV, possibly due to a transient restructuring of the Comptonizing atmosphere above the disk. Current evidence appears to favor the latter explanation., 12 pages, 2 figures, accepted for publication in ApJ, Friday 25th March 2016. A movie of the anomalous emission-line behavior can be found in the ancilliary documents

Published
2016
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6. Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy

Author

Mathur, S., Gupta, A., Page, K., Pogge, R. W., Krongold, Y., Goad, M. R., Adams, S. M., Anderson, M. D., Arã©valo, P., Barth, A. J., Bazhaw, C., Beatty, T. G., Bentz, M. C., Bigley, A., Bisogni, S., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Brown, J. E., Brown, J. S., Cackett, E. M., Canalizo, G., Carini, M. T., Clubb, K. I., Comerford, J. M., Coker, C. T., Corsini, E. M., Crenshaw, D. M., Croft, S., Croxall, K. V., Dalla Bontã , E., Deason, A. J., Denney, K. D., De Lorenzo-cã¡ceres, A., De Rosa, G., Dietrich, M., Edelson, R., Ely, J., Eracleous, M., Evans, P. A., Fausnaugh, M. M., Ferland, G. J., Filippenko, A. V., Flatland, K., Fox, O. D., Gates, E. L., Gehrels, N., Geier, S., Gelbord, J. M., Gorjian, V., Greene, J. E., Grier, C. J., Grupe, D., Hall, P. B., Henderson, C. B., Hicks, S., Holmbeck, E., Holoien, T. W. -. S., Horenstein, D., Horne, Keith, Hutchison, T., Im, M., Jensen, J. J., Johnson, C. A., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kelly, P. L., Kennea, J. A., Kim, M., Kim, S., Kim, S. C., King, A., Klimanov, S. A., Kochanek, C. S., Korista, K. T., Kriss, G. A., Lau, M. W., Lee, J. C., Leonard, D. C., Li, M., Lira, P., Ma, Z., Macinnis, F., Manne-nicholas, E. R., Malkan, M. A., Mauerhan, J. C., Mcgurk, R., Mchardy, I. M., Montouri, C., Morelli, L., Mosquera, A., Mudd, D., Muller-sanchez, F., Musso, R., Nazarov, S. V., Netzer, H., Nguyen, M. L., Norris, R. P., Nousek, J. A., Ochner, P., Okhmat, D. N., Ou-yang, B., Pancoast, A., Papadakis, I., Parks, J. R., Pei, L., Peterson, B. M., Pizzella, A., Poleski, R., Pott, J. -. U., Rafter, S. E., Rix, H. -. W., Runnoe, J., Saylor, D. A., Schimoia, J. S., Schnã¼lle, K., Sergeev, S. G., Shappee, B. J., Shivvers, I., Siegel, M., Simonian, G. V., Siviero, A., Skielboe, A., Somers, G., Spencer, M., Starkey, D., Stevens, D. J., Sung, H. -. I., Tayar, J., Tejos, N., Turner, C. S., Uttley, P., Van Saders, J., Vestergaard, M., Vican, L., Villanueva, S., Villforth, C., Weiss, Y., Woo, J. -. H., Yan, H., Young, S., Yuk, H., Zheng, W., Zhu, W., Zu, Y., Corsini, ENRICO MARIA, USA, High Energy Astrophys. & Astropart. Phys (API, FNWI), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
active [Galaxies], individual (NGC 5548) [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, Continuum (design consultancy), FOS: Physical sciences, Flux, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Spectral line, individual (NGC 5548) [X-rays], galaxies: individual (NGC 5548), X-rays: galaxies, X-rays: individual (NGC 5548), Astronomy and Astrophysics, Space and Planetary Science, Spitzer Space Telescope, 0103 physical sciences, QB Astronomy, Emission spectrum, 010303 astronomy & astrophysics, QC, Optical depth, QB, Physics, 010308 nuclear & particles physics, 3rd-DAS, Astrophysics - Astrophysics of Galaxies, galaxies [X-rays], QC Physics, 13. Climate action, Astrophysics of Galaxies (astro-ph.GA), Reverberation mapping, Anomaly (physics)
Abstract

During the Space Telescope and Optical Reverberation Mapping Project (STORM) observations of NGC 5548, the continuum and emission-line variability became de-correlated during the second half of the 6-month long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as a part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than being due to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all the three observations: the UV emission line flux decrease, the soft-excess increase, and the emission line anomaly., ApJ in press. Replaced with the accepted version

Published
2017
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7. Results from the Blazar Monitoring Campaign at the Whipple 10m Gamma-ray Telescope

Author

Steele, David, Collaboration, For The VERITAS, Carini, M. T., Charlot, P., Kurtanidze, O., Lahteenmaki, A., Montaruli, T., Sadun, A. C., Villata, M., Institute of Space and Atmospheric Studies [Saskatoon] (ISAS), Department of Physics and Engineering Physics [Saskatoon], University of Saskatchewan [Saskatoon] (U of S)-University of Saskatchewan [Saskatoon] (U of S), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Torino (OATo), and Istituto Nazionale di Astrofisica (INAF)

Subjects
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics (astro-ph), [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics
Abstract

In September 2005, the observing program of the Whipple 10 m gamma-ray telescope was redefined to be dedicated almost exclusively to AGN monitoring. Since then the five Northern Hemisphere blazars that had already been detected at Whipple are monitored routinely each night that they are visible. Thanks to the efforts of a large number of multiwavelength collaborators, the first year of this program has been very successful. We report here on the analysis of Markarian 421 observations taken from November, 2005 to May, 2006 in the gamma-ray, X-ray, optical and radio bands., 4 pages; contribution to the 30th International Cosmic Ray Conference, Merida, Mexico, July 2007

Published
2008

8. Large-scale wind structures in OB supergiants: a search for rotationally modulated H��variability

Author

Morel, T., Marchenko, S. V., Pati, A. K., Kuppuswamy, K., Carini, M. T., Wood, E., and Zimmerman, R.

Subjects
Astrophysics (astro-ph), FOS: Physical sciences
Abstract

We present the results of a long-term monitoring campaign of the H��line in a sample of bright OB-supergiants (O7.5-B9) that aims at detecting rotationally modulated changes potentially related to the existence of large-scale wind structures. A total of 22 objects were monitor ed during 36 nights spread over 6 months in 2001-2002. Coordinated broad-band photometric observations were also obtained for some targets. Conspicuous evidence for variability in H��is found for the stars displaying a feature contaminated by wind emission. Most changes take place on a daily time-scale, although hourly variations are also occasionally detected. Convincing evidence for a cyclical pattern of variability in H��has been found in 2 stars: HD 14134 and HD 42087 (periodic signals are also detected in other stars, but independent confirmation is required). Rotational modulation is suggested from the similarity between the observed recurrence time-scales (in the range 13-25 days) and estimated periods of stellar rotation. We call attention to the atypical case of HD 14134 which exhibits a clear 12.8-d periodicity both in the photometric and in the spectroscopic data sets. This places this object among a handful of early-type stars where one may observe a clear link between extended wind structures and photospheric disturbances. Further modelling may test the hypothesis that azimuthally-extended wind streams are responsible for the patterns of spectral variability in our target stars., 18 pages, accepted for publication in MNRAS

Published
2004
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9. Coordinated Multiwavelength Observations of BL Lacertae in 2000

Author

Böttcher, M., Marscher, A. P., Ravasio, M., Villata, M., Raiteri, C. M., Aller, H. D., Aller, M. F., Teräsranta, H., Mang, O., Tagliaferri, G., Aharonian, F., Krawczynski, H., Kurtanidze, O. M., Nikolashvili, M. G., Ibrahimov, M. A., Papadakis, I. E., Tsinganos, K., Sadakane, K., Okada, N., Takalo, L. O., Sillanpää, A., Tosti, Gino, Ciprini, S., Frasca, A., Marilli, E., Robb, R., Noble, J. C., Jorstad, S. G., Hagen Thorn, V. A., Larionov, V. M., Nesci, R., Maesano, M., Schwartz, R. D., Basler, J., Gorham, P. W., Iwamatsu, H., Kato, T., Pullen, C., Benítez, E., J. A., De, Moilanen, M., Oksanen, A., Rodriguez, D., Sadun, A. C., Kelly, M., Carini, M. T., Miller, H. R., Catalano, S., Dultzin Hacyan, D., Fan, J. H., Ghisellini, G., Ishioka, R., Karttunen, H., Keinänen, P., Kudryavtseva, N. A., Lainela, M., Lanteri, L., Larionova, E. G., Matsumoto, K., Mattox, J. R., Mchardy, I., Montagni, F., Nucciarelli, Giuliano, Ostorero, L., Papamastorakis, J., Pasanen, M., Sobrito, G., and Uemura, M.

Subjects
Physics, Electron energy, Astrophysics (astro-ph), Galaxies: BL Lacertae Objects: Individual: Name: BL Lacertae, Galaxies: Active- Gamma Rays: Theory, Radiation Mechanisms: Nonthermal, FOS: Physical sciences, Flux, Quiescent state, HEGRA, Astronomy and Astrophysics, Astrophysics, Light curve, Synchrotron, law.invention, Space and Planetary Science, law
Abstract

BL Lacertae was the target of an extensive multiwavelength monitoring campaign in the second half of 2000. Simultaneous or quasi-simultaneous observations were taken at radio (UMRAO and Metsaehovi) and optical(WEBT collaboration) frequencies, in X-rays (BeppoSAX and RXTE), and at VHE gamma-rays (HEGRA). The WEBT optical campaign achieved an unprecedented time coverage, virtually continuous over several 10 - 20 hour segments. It revealed intraday variability on time scales of ~ 1.5 hours and evidence for spectral hardening associated with increasing optical flux. During the campaign, BL Lacertae underwent a major transition from a rather quiescent state prior to September 2000, to a flaring state for the rest of the year. This was also evident in the X-ray activity of the source. BeppoSAX observations on July 26/27 revealed a rather low X-ray flux and a hard spectrum, while a BeppoSAX pointing on Oct. 31 - Nov. 2, 2000, indicated significant variability on time scales of < a few hours, and provided evidence for the synchrotron spectrum extending out to ~ 10 keV during that time. During the July 26/27 observation, there is a tantalizing, though not statistically significant, indication of a time delay of ~ 4 - 5 hr between the BeppoSAX and the R-band light curve. Also, a low-significance detection of a time delay of 15 d between the 14.5 GHz and the 22 GHz radio light curves is reported. Several independent methods to estimate the co-moving magnetic field in the source are presented, suggesting a value of ~ 2 e_B^{2/7} G, where e_B is the magnetic-field equipartition factor w.r.t. the electron energy density in the jet., Accepted for publication in ApJ

Published
2003

10. The Whole Earth Blazar telescope on BL Lacertae

Author

Villata, M., Raiteri, C. M., Kurtanidze, O. M., Nikolashvili, M. G., Ibrahimov, M. A., Papadakis, I. E., Tsinganos, K., Sadakane, K., Okada, N., Takalo, L. O., Sillanpää, A., Tosti, G., Ciprini, S., Frasca, A., Marilli, E., Robb, R. M., Noble, J. C., Jorstad, S. G., Hagen Thorn, V. A., Larionov, V. M., Nesci, R., Maesano, M., Schwartz, R. D., Basler, J., Gorham, P. W., Iwamatsu, H., Kato, T., Pullen, C., Benítez, E., de Diego, J. A., Moilanen, M., Oksanen, A., Rodriguez, D., Sadun, A. C., Kelly, M., Carini, M. T., Miller, H. R., Catalano, S., Dultzin Hacyan, D., Fan, J. H., Ishioka, R., Karttunen, H., Keinínen, P., Kudryavtseva, N. A., Lainela, M., Lanteri, L., Larionova, E. G., Matsumoto, K., Mattox, J. R., Montagni, F., Nucciarelli, G., Ostorero, Luisa, Papamastorakis, J., Pasanen, M., Sobrito, G., and Uemura, M.

Published
2003

11. The Whole Earth Blazar Telescope and the BL Lac Campaign 2000

Author

Raiteri, C. M., Massimo Villata, Kurtanidze, O. M., Nikolashvili, M. G., Ibrahimov, M. A., Papadakis, I. E., Tsinganos, K., Sadakane, K., Okada, N., Takalo, L. O., Sillanpaa, A., Tosti, G., Ciprini, S., Frasca, A., Marilli, E., Robb, R. M., Noble, J. C., Jorstad, S. G., Hagen-Thorn, V. A., Larionov, V. M., Sclavi, S., Nesci, R., Schwartz, R. D., Basler, J., Gorham, P. W., Iwamatsu, H., Kato, T., Pullen, C., Benitez, E., Diego, J. A., Moilanen, M., Oksanen, A., Rodriguez, D., Sadun, A. C., Kelly, M., Carini, M. T., Miller, H. R., Catalano, S., Dultzin-Hacyan, D., Fan, J. H., Ishioka, R., Karttunen, H., Keinanen, P., Kudryavtseva, N. A., Lainela, M., Lanteri, L., Larionova, E. G., Maesano, M., Matsumoto, K., Mattox, J. R., Montagni, F., Nucciarelli, G., Ostorero, L., Papamastorakis, J., Pasanen, M., Sobrito, G., Uemura, M., and D Alessio, F.

Published
2002

12. The Whole Year Blazar Telescope (WYBT)

Author

Tosti, G., Massimo Villata, Carini, M. T., Carosati, D., Coloma, J. M., Hroch, F., Ibrahimov, M. A., Kurtanidze, O. M., Nesci, R., Oksanen, A., Pullen, C., Sillanpaa, A., and Takalo, L. O.

Published
2002

13. A possible optical/gamma-ray short-term correlation in 3C 279

Author

Hartman, R. C., Thompson, D. J., Villata, M., Claudia Maria Raiteri, Sobrito, G., Ostorero, L., Francesco, G., Tosti, G., Kurtanidze, O., Nikolashvili, M., Takalo, L., Sillanpää, A., Koskimies, M., Pursimo, T., Rekola, R., Heidt, J., Wagner, S., Carini, M. T., Noble, J. C., Balonek, T. J., Miller, H. R., Ferrara, E. C., Mcfarland, J. P., and Wilson, J. W.

Published
2001

14. Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. II. An intensive study of NGC 5548 at optical wavelengths

Author

Peterson, B. M., Balonek, T. J., Barker, E. S., Bechtold, J., Bertram, R., Bochkarev, N. G., Bolte, M. J., Bond, D., Boroson, T. A., Carini, M. T., Carone, T. E., Christensen, J. A., Clements, S. D., Cochran, A. L., Cohen, R. D., Crampton, D., Dietrich, M., Elvis, M., Ferguson, A., Filippenko, A. V., Fricke, K. J., C Gaskell, Halpern, J. P., Huchra, J. P., Hutchings, J. B., Kollatschny, W., Koratkar, A. P., Korista, K. T., Krolik, J. H., Lame, N. J., Laor, A., Leacock, R. J., Macalpine, G. M., Malkan, M. A., Maoz, D., Miller, H. R., Morris, S. L., Netzer, H., Oliveira, C. L. M., Penfold, J., Penston, M. V., Pérez, E., Pogge, R. W., Richmond, M. W., Romanishin, W., Rosenblatt, E. I., Saddlemyer, L., Sadun, A., Sawyer, S. R., Shields, J. C., Shapovalova, A. I., Smith, A. G., Smith, H. A., Smith, P. S., Sun, W. -H, Thiele, U., Turner, T. J., Veilleux, S., Wagner, R. M., Weymann, R. J., Willkes, B. J., Wills, B. J., Wills, D., and Younger, P. F.

15. The Whole Earth Blazar telescope on BL Lacertae (Poster)

Author

Villata, M., Claudia Maria Raiteri, Kurtanidze, O. M., Nikolashvili, M. G., Ibrahimov, M. A., Papadakis, I. E., Tsinganos, K., Sadakane, K., Okada, N., Takalo, L. O., Sillanpää, A., Tosti, G., Ciprini, S., Frasca, A., Marilli, E., Robb, R. M., Noble, J. C., Jorstad, S. G., Hagen-Thorn, V. A., Larionov, V. M., Nesci, R., Maesano, M., Schwartz, R. D., Basler, J., Gorham, P. W., Iwamatsu, H., Kato, T., Pullen, C., Benítez, E., Diego, J. A., Moilanen, M., Oksanen, A., Rodriguez, D., Sadun, A. C., Kelly, M., Carini, M. T., Miller, H. R., Catalano, S., Dultzin-Hacyan, D., Fan, J. H., Ishioka, R., Karttunen, H., Keinínen, P., Kudryavtseva, N. A., Lainela, M., Lanteri, L., Larionova, E. G., Matsumoto, K., Mattox, J. R., Montagni, F., Nucciarelli, G., Ostorero, L., Papamastorakis, J., Pasanen, M., Sobrito, G., and Uemura, M.

16. The WEBT BL Lacertae campaign 2000

Author

Villata, M, Raiteri, C. M., Kurtanizde, O. M., Nikolashvili, M. G., Ibrahimov, M. A., Papadakis, I. E., Tsinganos, K, Sadakane, K, Okada, N, Takalo, L. O., Sillanpaeae, A, Tosti, G, Ciprini, S, Frasca, A, Marilli, E, Robb, R. M., Noble, J. C., Jorstad, S. G., HAGEN THORN, V. A., Larionov, V. M., Massaro, E, Nesci, R, Schwartz, R. D., Basler, J, Gorham, P. W., Iwamatsu, H, Kato, T, Pullen, C, Benitez, E, DE DIEGO, J. A., Moilanen, M, Oksanen, A, Rodriguez, D, Sadun, A. C., Kelly, M, Carini, M. T., Miller, H. R., Catalano, S, DULTZIN HACYAN, D, Fan, J. H., Ishioka, R, Karttunen, H, Keinaenen, P, Kudryavtseva, N. A., Lainela, M, Lanteri, L, Larionova, E. G., Maesano, M, Matsumoto, K, Mattox, J. R., Montagni, F, Nucciarelli, G, Ostorero, Luisa, Papamastorakis, J, Pasanen, M, Sobrito, G, and Uemura, M.

Subjects
jets, Physics, Brightness, active galaxies, BL Lacertae objects, BL Lacertae, quasars, Astronomy and Astrophysics, Astrophysics, Correlation function (astronomy), Viewing angle, Light curve, Galaxy, law.invention, Telescope, symbols.namesake, Space and Planetary Science, law, symbols, Blazar, Doppler effect
Abstract

We present UBVRI light curves of BL Lacertae from May 2000 to January 2001, obtained by 24 telescopes in 11 countries. More than 15000 observations were performed in that period, which was the extension of the Whole Earth Blazar Telescope (WEBT) campaign originally planned for July-August 2000. Rapid flux oscillations are present all the time, involving variations up to a few tenths of mag on hour time scales, and witnessing an intense intraday activity of this source. Colour indexes have been derived by coupling the highest precision B and R data taken by the same instrument within 20 min and after subtracting the host galaxy contribution from the fluxes. The 620 indexes obtained show that the optical spectrum is weakly sensitive to the long-term trend, while it strictly follows the short-term flux behaviour, becoming bluer when the brightness increases. Thus, spectral changes are not related to the host galaxy contribution, but they are an intrinsic feature of fast flares. We suggest that the achromatic mechanism causing the long-term flux base-level modulation can be envisaged in a variation of the relativistic Doppler beaming factor, and that this variation is likely due to a change of the viewing angle. Discrete correlation function (DCF) analysis reveals the existence of a characteristic time scale of variability of about 7 h in the light curve of the core WEBT campaign, while no measurable time delay between variations in the B and R bands is found.

17. VizieR Online Data Catalog: Space telescope RM project. III. NGC 5548 LCs (Fausnaugh+, 2016)

Author

Fausnaugh, M. M., Denney, K. D., Barth, A. J., Bentz, M. C., Bottorff, M. C., Carini, M. T., Croxall, K. V., Rosa, G., Goad, M. R., Horne, K., Joner, M. D., Kaspi, S., Kim, M., Klimanov, S. A., Kochanek, C. S., Leonard, D. C., Netzer, H., Peterson, B. M., Schnulle, K., Sergeev, S. G., Marianne Vestergaard, Zheng, W., Zu, Y., Anderson, M. D., Arevalo, P., Bazhaw, C., Borman, G. A., Boroson, T. A., Brandt, W. N., Breeveld, A. A., Brewer, B. J., Cackett, E. M., Crenshaw, D. M., Dalla Bonta, E., Lorenzo-Caceres, A., Dietrich, M., Edelson, R., Efimova, N. V., Ely, J., Evans, P. A., Filippenko, A. V., Flatland, K., Gehrels, N., Geier, S., Gelbord, J. M., Gonzalez, L., Gorjian, V., Grier, C. J., Grupe, D., Hall, P. B., Hicks, S., Horenstein, D., Hutchison, T., Im, M., Jensen, J. J., Jones, J., Kaastra, J., Kelly, B. C., Kennea, J. A., Kim, S. C., Korista, K. T., Kriss, G. A., Lee, J. C., Lira, P., Macinnis, F., Manne-Nicholas, E. R., Mathur, S., Mchardy, I. M., Montouri, C., Musso, R., Nazarov, S. V., Norris, R. P., Nousek, J. A., Okhmat, D. N., Pancoast, A., Papadakis, I., Parks, J. R., Pei, L., Pogge, R. W., Pott, J. -U, Rafter, S. E., Rix, H., Saylor, D. A., Schimoia, J. S., Siegel, M., Spencer, M., Starkey, D., Sung, H., Teems, K. G., Treu, T., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J., Yan, H., and Young, S.

18. Simultaneous Optical and X-Ray Observations of BL Lacertae

Author

Nesci, R., Massaro, E., Montagni, F., Sclavi, S., Balonek, T., Caler, M., Tremonti, C., D Alessio, F., Catalano, S., Frasca, A., Marilli, E., Tagliaferri, G., Ghisellini, G., Ravasio, M., Giommi, P., Lucio Chiappetti, Kato, T., Uemura, M., Kurtanidze, O. M., Nikolashvili, M. G., Carini, M. T., Noble, J. C., Tosti, G., Nucciarelli, G., and Mattox, J.

19. Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum

Author

Andrew J. King, K. G. Teems, Gabriele Ponti, J. S. Schimoia, Calen B. Henderson, Michael S. Brotherton, S. Paltani, Nahum Arav, Alessandro Siviero, Radosław Poleski, P. Lira, Sang Chul Kim, Thomas W.-S. Holoien, Wei Zhu, A. de Lorenzo-Cáceres, M. C. Bottorff, Dirk Grupe, Gabriela Canalizo, M. Eracleous, S. G. Sergeev, F. MacInnis, Massimo Cappi, M. Dietrich, Alis J. Deason, Haojing Yan, Giorgio Matt, Ciro Pinto, Michael T. Carini, Minjin Kim, Brandon C. Kelly, I. M. McHardy, Scott M. Adams, L. Gonzalez, J. J. Jensen, Julia M. Comerford, Yair Krongold, Tim Waters, B. Scott, C. S. Turner, G. A. Borman, R. McGurk, Nicolas Tejos, J. R. Parks, K. Flatland, Michael D. Joner, Kirk T. Korista, L. Di Gesu, Emma Gardner, Jon C. Mauerhan, Jessie C. Runnoe, Douglas C. Leonard, Kelsey I. Clubb, M. H. Siegel, C. A. Johnson, D. A. Starkey, H. Yuk, M. A. Malkan, Justin Ely, Ying Zu, Aaron J. Barth, Cassandra Lochhaas, Patrick L. Kelly, E. Holmbeck, Hyun-Il Sung, Patrick B. Hall, C. Montuori, Christopher S. Kochanek, Bradley M. Peterson, Tommaso Treu, Missagh Mehdipour, Marie Wingyee Lau, A. Skielboe, Catherine J. Grier, J. A. Kennea, Thomas G. Beatty, R. W. Pogge, J. van Saders, A. Bigley, S. Hicks, Catia Silva, H. W. Rix, Vardha N. Bennert, D. M. Crenshaw, E. Dalla Bontà, Miao Li, A. A. Breeveld, Dom Walton, D. N. Okhmat, Elisa Costantini, P. Ochner, Y. Weiss, M. L. Nguyen, Ryan Norris, Susanna Bisogni, Ehud Behar, Jacobo Ebrero, Garrett Somers, Phil Uttley, S. Rafter, Kelly D. Denney, K. Schnülle, Carolin Villforth, Keith Horne, Smita Mathur, G. V. Simonian, R. Boissay-Malaquin, Gary J. Ferland, J. S. Brown, Jelle Kaastra, Ana M. Mosquera, Stefano Bianchi, Misty C. Bentz, A. Pancoast, Alessandro Pizzella, WeiKang Zheng, N. Gehrels, Daniel J. Stevens, M. Dehghanian, Kevin V. Croxall, Isaac Shivvers, A. Gupta, Chris Done, J. E. Brown, B. De Marco, Gerard A. Kriss, Steve Croft, S. V. Nazarov, J. A. Nousek, Jae-Ok Lee, P. Arévalo, G. De Rosa, Michael Fausnaugh, Rick Edelson, Phil Evans, Lorenzo Morelli, S. Geier, Enrico Maria Corsini, M. R. Goad, V. Gorjian, W. N. Brandt, Elinor L. Gates, Shai Kaspi, D. A. Saylor, Jong-Hak Woo, Edward M. Cackett, Liuyi Pei, T. Hutchison, Jamie Tayar, E. R. Manne-Nicholas, Laura Vican, Daniel Proga, Steven Villanueva, D. Mudd, J.-U. Pott, F. Müller-Sánchez, Alexei V. Filippenko, Hagai Netzer, S. A. Klimanov, B. J. Shappee, J. M. Gelbord, Marianne Vestergaard, M. Spencer, Zhiyuan Ma, Carl T. Coker, S. Y. Kim, Myungshin Im, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, High Energy Astrophys. & Astropart. Phys (API, FNWI), Kriss, G. A., De Rosa, G., Ely, J., Peterson, B. M., Kaastra, J., Mehdipour, M., Ferland, G. J., Dehghanian, M., Mathur, S., Edelson, R., Korista, K. T., Arav, N., Barth, A. J., Bentz, M. C., Brandt, W. N., Crenshaw, D. M., Bontà, E. Dalla, Denney, K. D., Done, C., Eracleous, M., Fausnaugh, M. M., Gardner, E., Goad, M. R., Grier, C. J., Horne, Keith, Kochanek, C. S., Mchardy, I. M., Netzer, H., Pancoast, A., Pei, L., Pogge, R. W., Proga, D., Silva, C., Tejos, N., Vestergaard, M., Adams, S. M., Anderson, M. D., Arévalo, P., Beatty, T G., Behar, E., Bennert, V. N., Bianchi, S., Bigley, A., Bisogni, S., Boissay-Malaquin, R., Borman, G. A., Bottorff, M. C., Breeveld, A. A., Brotherton, M., Brown, J. E., Brown, J. S., Cackett, E. M., Canalizo, G., Cappi, M., Carini, M. T., Clubb, K. I., Comerford, J. M., Coker, C. T., Corsini, E. M., Costantini, E., Croft, S., Croxall, K. V., Deason, A. J., De Lorenzo-Cáceres, A., De Marco, B., Dietrich, M., Di Gesu, L., Ebrero, J., Evans, P. A., Filippenko, A. V., Flatland, K., Gates, E. L., Gehrels, N., Geier, S., Gelbord, J. M., Gonzalez, L., Gorjian, V., Grupe, D., Gupta, A., Hall, P. B., Henderson, C. B., Hicks, S., Holmbeck, E., Holoien, T. W. -S., Hutchison, T. A., Im, M., Jensen, J. J., Johnson, C. A., Joner, M. D., Kaspi, S., Kelly, B. C., Kelly, P. L., Kennea, J. A., Kim, M., Kim, S. C., Kim, S. Y., King, A., Klimanov, S. A., Krongold, Y., Lau, M. W., Lee, J. C., Leonard, D. C., Li, Miao, Lira, P., Lochhaas, C., Ma, Zhiyuan, Macinnis, F., Malkan, M. A., Manne-Nicholas, E. R., Matt, G., Mauerhan, J. C., Mcgurk, R., Montuori, C., Morelli, L., Mosquera, A., Mudd, D., Müller-Sánchez, F., Nazarov, S. V., Norris, R. P., Nousek, J. A., Nguyen, M. L., Ochner, P., Okhmat, D. N., Paltani, S., Parks, J. R., Pinto, C., Pizzella, A., Poleski, R., Ponti, G., Pott, J. -U., Rafter, S. E., Rix, H. -W., Runnoe, J., Saylor, D. A., Schimoia, J. S., Schnülle, K., Scott, B., Sergeev, S. G., Shappee, B. J., Shivvers, I., Siegel, M., Simonian, G. V., Siviero, A., Skielboe, A., Somers, G., Spencer, M., Starkey, D., Stevens, D. J., Sung, H. -I., Tayar, J., Teems, K. G., Treu, T., Turner, C. S., Uttley, P., Van Saders, J ., Vican, L., Villforth, C., Villanueva Jr., S., Walton, D. J., Waters, T., Weiss, Y., Woo, J. -H., Yan, H., Yuk, H., Zheng, W., Zhu, W., Zu, Y., and USA

Subjects
Seyfert [Galaxies], galaxies: active, galaxies: individual (NGC 5548), galaxies: nuclei, galaxies: Seyfert, 010504 meteorology & atmospheric sciences, Absorption spectroscopy, active [Galaxies], individual (NGC 5548) [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Continuum (design consultancy), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Luminosity, 0103 physical sciences, QB Astronomy, Emission spectrum, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, QC, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, QB, Physics, Astronomy and Astrophysics, DAS, Astrophysics - Astrophysics of Galaxies, Galaxy, QC Physics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), nuclei [Galaxies], Reverberation mapping
Abstract

We model the ultraviolet spectra of the Seyfert 1 galaxy NGC~5548 obtained with the Hubble Space Telescope during the 6-month reverberation-mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Ly$\alpha$ and C IV, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data. The velocity-binned lag profiles of Ly$\alpha$ and C IV have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show delayed response to continuum variations corresponding to recombination in gas with a density of $\sim 10^5~\rm cm^{-3}$. The high-ionization narrow absorption lines decorrelate from continuum variations during the same period as the broad emission lines. Analyzing the response of these absorption lines during this period shows that the ionizing flux is diminished in strength relative to the far-ultraviolet continuum. The broad absorption lines associated with the X-ray obscurer decrease in strength during this same time interval. The appearance of X-ray obscuration in $\sim\,2012$ corresponds with an increase in the luminosity of NGC 5548 following an extended low state. We suggest that the obscurer is a disk wind triggered by the brightening of NGC 5548 following the decrease in size of the broad-line region during the preceding low-luminosity state., Comment: 50 pages, 30 figures, uses aastex62.cls. Accepted for publication in ApJ, 07/06/2019. High-level products page in MAST will go live after 7/15/2019. Replaced Figure 4 on 7/12/2019 to be more red/green color-blind friendly

Published
2019
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20. Multiwavelength observations of the blazar 1ES 1011+496 in Spring 2008

Author

Pierre Colin, E. de Oña Wilhelmi, Kari Nilsson, L. Maraschi, M. Will, Francesco Longo, Tomislav Terzić, Daniela Dorner, C. Pittori, Michael T. Carini, R. Clavero, Louis Antonelli, E. Prandini, Pratik Majumdar, M. V. Fonseca, Mosè Mariotti, K. Kodani, J. Becerra González, W. Bednarek, M. Makariev, M. Palatiello, Ievgen Vovk, Fabrizio Tavecchio, S. N. Shore, M. Gaug, J. Herrera, J. Palacio, J. M. Paredes, Koji Noda, F. Di Pierro, Antonio Stamerra, Thomas Bretz, Elisa Bernardini, Stefano Covino, T. Schweizer, R. Zanin, D. Dominis Prester, A.-K. Overkemping, Adrian Biland, B. Biasuzzi, R. López-Coto, Juri Poutanen, Nikola Godinovic, R. Reinthal, Benito Marcote, Jose Luis Contreras, Saverio Lombardi, S. Rügamer, Marcel Strzys, R. Walters, Junko Kushida, D. Nakajima, Francesco Dazzi, Juan Abel Barrio, A. Niedzwiecki, P. Da Vela, Juan Cortina, Y. Hanabata, S. Bonnefoy, J. Rico, A. González Muñoz, Razmik Mirzoyan, Oscar Blanch, U. Barres de Almeida, P. Antoranz, Tomoki Saito, D. Tescaro, K. Frantzen, P. Temnikov, E. Colombo, Damir Lelas, K. Mallot, David Paneque, J. Sainio, Arka Chatterjee, M. Hayashida, R. J. García López, L. O. Takalo, Kyoshi Nishijima, Wolfgang Rhode, M. H. Wu, D. Guberman, Dorota Sobczyńska, D. Fidalgo, Gareth Hughes, E. Carmona, Markus Garczarczyk, P. G. Prada Moroni, Anne Lähteenmäki, A. De Angelis, Andrei Berdyugin, A. Pease, S. Paiano, Masahiro Teshima, A. Treves, Vitaly Neustroev, D. Garrido Terrats, G. De Caneva, Alba Fernández-Barral, Stefano Ansoldi, Karl Mannheim, Elina Lindfors, M. I. Martínez, Julian Sitarek, Julia Thaele, Riccardo Paoletti, W. Idec, Massimo Persic, C. Schultz, V. Scapin, Yusuke Konno, F. Lucarelli, Daniel Mazin, Marina Manganaro, Marc Ribó, G. Maneva, T. Toyama, S. Vercellone, D. Galindo, Merja Tornikoski, J. E. Ward, Alicia López-Oramas, Ana Babić, Sabrina Einecke, P. Bangale, Reiko Orito, J. Rodriguez Garcia, Christian Fruck, Hidetoshi Kubo, B. De Lotto, A. La Barbera, Konstancja Satalecka, Michele Doro, X. Paredes-Fortuny, J. Hose, D. Elsaesser, M. Nievas Rosillo, H. Takami, B. Banerjee, D. Glawion, Vassil Verguilov, U. Menzel, Diego F. Torres, M. Pasanen, Abelardo Moralejo, A. Sillanpää, T. Steinbring, Ll. Font, I. Snidaric, E. Lorenz, Max Ludwig Ahnen, P. Giammaria, G. Bonnoli, Dario Hrupec, M. A. Lopez, F. Borracci, C. Delgado Mendez, Alessandro Carosi, Jose Miguel Miranda, Ivica Puljak, Glawion, D., Universitat de Barcelona, Ahnen, M. L, Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., De Oña Wilhelmi, E., Delgado Mendez, C., Di Pierro, F., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinović, N., González Muñoz, A., Guberman, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., López Oramas, A., Lorenz, E., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Rügamer, S., Saito, T., Satalecka, K., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., Lucarelli, F., Pittori, C., Vercellone, S., Berdyugin, A., Carini, M. T., Lähteenmäki, A., Pasanen, M., Pease, A., Sainio, J., Tornikoski, M., Walters, R., Department of Radio Science and Engineering, Aalto-yliopisto, and Aalto University

Subjects
galaxie [X-rays], galaxie [Gamma-rays], Radiation mechanisms: non-thermal, radiation mechanisms: non-thermal, galaxies: active, gamma-rays, galaxies, X-rays: galaxies, BL-LACERTAE OBJECTS, ACTIVE GALACTIC NUCLEI, LARGE-AREA TELESCOPE, GAMMA-RAY EMISSION, SPECTRAL ENERGY-DISTRIBUTIONS, ALL-SKY SURVEY, LAC, OBJECTS, X-RAY, MAGIC TELESCOPES, SOURCE CATALOG, Astrophysics, Galaxies: active, Gamma-rays: galaxies, Astronomy and Astrophysics, Space and Planetary Science, 01 natural sciences, Radiació, law.invention, law, MAGIC (telescope), 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Spectral index, Radiation, Gamma ray, galaxies [Gamma-rays], galaxies [X-rays], Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Flare, BL Lac object, Active galactic nucleus, radiation mechanisms, non-thermal galaxies, active gamma-rays, galaxies X-rays, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, 0103 physical sciences, Blazar, ta115, non-thermal [Radiation mechanisms], 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysic, Light curve, Galàxies actives, Active galaxies, ddc:520
Abstract

The BL Lac object 1ES 1011+496 was discovered at Very High Energy gamma-rays by MAGIC in spring 2007. Before that the source was little studied in different wavelengths. Therefore a multi-wavelength (MWL) campaign was organized in spring 2008. Along MAGIC, the MWL campaign included the Metsahovi radio observatory, Bell and KVA optical telescopes and the Swift and AGILE satellites. MAGIC observations span from March to May, 2008 for a total of 27.9 hours, of which 19.4 hours remained after quality cuts. The light curve showed no significant variability. The differential VHE spectrum could be described with a power-law function. Both results were similar to those obtained during the discovery. Swift XRT observations revealed an X-ray flare, characterized by a harder when brighter trend, as is typical for high synchrotron peak BL Lac objects (HBL). Strong optical variability was found during the campaign, but no conclusion on the connection between the optical and VHE gamma-ray bands could be drawn. The contemporaneous SED shows a synchrotron dominated source, unlike concluded in previous work based on nonsimultaneous data, and is well described by a standard one zone synchrotron self Compton model. We also performed a study on the source classification. While the optical and X-ray data taken during our campaign show typical characteristics of an HBL, we suggest, based on archival data, that 1ES 1011+496 is actually a borderline case between intermediate and high synchrotron peak frequency BL Lac objects., 13 pages, accepted for publication in MNRAS

Published
2016
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