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The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies

Aleksić, J. and Hovatta, T. and Max-Moerbeck, W. and Readhead, A. C. S. (2015) The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies. Astronomy and Astrophysics, 576 . Art. No. A126. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:20150811-130323212

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Abstract

Aims. We perform an extensive characterization of the broadband emission of Mrk 421, as well as its temporal evolution, during the non-flaring (low) state. The high brightness and nearby location (z = 0.031) of Mrk 421 make it an excellent laboratory to study blazar emission. The goal is to learn about the physical processes responsible for the typical emission of Mrk 421, which might also be extended to other blazars that are located farther away and hence are more difficult to study. Methods. We performed a 4.5-month multi-instrument campaign on Mrk 421 between January 2009 and June 2009, which included VLBA, F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other instruments and collaborations. This extensive radio to very-high-energy (VHE; E> 100 GeV) γ-ray dataset provides excellent temporal and energy coverage, which allows detailed studies of the evolution of the broadband spectral energy distribution. Results. Mrk421 was found in its typical (non-flaring) activity state, with a VHE flux of about half that of the Crab Nebula, yet the light curves show significant variability at all wavelengths, the highest variability being in the X-rays. We determined the power spectral densities (PSD) at most wavelengths and found that all PSDs can be described by power-laws without a break, and with indices consistent with pink/red-noise behavior. We observed a harder-when-brighter behavior in the X-ray spectra and measured a positive correlation between VHE and X-ray fluxes with zero time lag. Such characteristics have been reported many times during flaring activity, but here they are reported for the first time in the non-flaring state. We also observed an overall anti-correlation between optical/UV and X-rays extending over the duration of the campaign. Conclusions. The harder-when-brighter behavior in the X-ray spectra and the measured positive X-ray/VHE correlation during the 2009 multi-wavelength campaign suggests that the physical processes dominating the emission during non-flaring states have similarities with those occurring during flaring activity. In particular, this observation supports leptonic scenarios as being responsible for the emission of Mrk 421 during non-flaring activity. Such a temporally extended X-ray/VHE correlation is not driven by any single flaring event, and hence is difficult to explain within the standard hadronic scenarios. The highest variability is observed in the X-ray band, which, within the one-zone synchrotron self-Compton scenario, indicates that the electron energy distribution is most variable at the highest energies.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1051/0004-6361/201424216DOIArticle
http://www.aanda.org/articles/aa/abs/2015/04/aa24216-14/aa24216-14.htmlPublisherArticle
http://arxiv.org/abs/1502.02650arXivDiscussion Paper
Additional Information:© 2015 ESO. Article published by EDP Sciences. Received 15 May 2014; Accepted 16 January 2015; Published online 17 April 2015. We would like to thank the referee for the useful comments that helped to improve the manuscript. We also thank Patricia Arévalo for helpful contributions and suggestions. 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, and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Centro de Excelencia Severo Ochoa SEV-2012-0234, CPAN CSD2007-00042, and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant 268740 of the Academy of Finland, by the Croatian Science Foundation (HrZZ) Project 09/176 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0. The VERITAS collaboration acknowledges support from the US Department of Energy, the US National Science Foundation and the Smithsonian Institution, by NSERC in Canada, by Science Foundation Ireland, and by STCF in the UK. We acknowledge the excellent work of the technical support at the FLWO and the collaboration institutions in the construction and operation of the instrument. The Fermi-LAT Collaboration acknowledges support from a number of agencies and institutes for both development and the operation of the LAT as well as scientific data analysis. These include NASA and DOE in the United States, CEA/Irfu and IN2P3/CNRS in France, ASI and INFN in Italy, MEXT, KEK, and JAXA in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the National Space Board in Sweden. Additional support from INAF in Italy and CNES in France for science analysis during the operations phase is also gratefully acknowledged. We acknowledge the use of public data from the Swift and RXTE data archives. The OVRO 40 m monitoring program is supported in part by NASA grants NNX08AW31G and NNX11A043G, and NSF grants AST-0808050 and AST-1109911. The Metsähovi team acknowledges the support from the Academy of Finland to our observing projects (numbers 212656, 210338, 121148, and others). The Abastumani Observatory team acknowledges financial support by the Shota Rustaveli National Science Foundation through project FR/577/6-320/13. The St. Petersburg University team acknowledges support from the Russian RFBR foundation via grant 09-02-00092. AZT-24 observations are made within an agreement between Pulkovo, Rome and Teramo observatories. This research is partly based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut fuer Radioastronomie) at Effelsberg, as well as with the Medicina and Noto telescopes operated by INAF–Istituto di Radioastronomia. M. Villata organized the optical-to-radio observations by GASP-WEBT as the president of the collaboration.
Funders:
Funding AgencyGrant Number
Bundesministerium für Bildung und Forschung (BMBF)UNSPECIFIED
Max-Planck-Gesellschaft (MPG)UNSPECIFIED
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Swiss National Fund (SNF)UNSPECIFIED
European Regional Development Fund (ERDF)UNSPECIFIED
Ministerio de Economía y Competitividad (MINECO)UNSPECIFIED
Japan Society for the Promotion of Science (JSPS)UNSPECIFIED
Ministry of Education, Culture, Sports, Science and Technology (MEXT)UNSPECIFIED
Centro de Excelencia Severo OchoaSEV-2012-0234
Consolider-Ingenio 2010 ProgrammeCPAN CSD2007-00042
MultiDarkCSD2009-00064
Academy of Finland268740
Croatian Science Foundation (HrZZ)09/176
University of Rijeka13.12.1.3.02
Deutsche Forschungsgemeinschaft (DFG)SFB823/C4
Deutsche Forschungsgemeinschaft (DFG)SFB876/C3
MNiSzW745/N-HESS-MAGIC/2010/0
Department of Energy (DOE)UNSPECIFIED
Smithsonian InstitutionUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Science Foundation, IrelandUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
NASAUNSPECIFIED
Commissariat à l’Energie Atomique (CEA)UNSPECIFIED
IN2P3/CNRS (France)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)UNSPECIFIED
KEK (Japan)UNSPECIFIED
Japan Aerospace Exploration Agency (JAXA) UNSPECIFIED
K. A. Wallenberg FoundationUNSPECIFIED
Swedish Research CouncilUNSPECIFIED
National Space Board (Sweden)UNSPECIFIED
NASA NNX08AW31G
NASANNX11A043G
NSFAST-0808050
NSFAST-1109911
Academy of Finland212656
Academy of Finland210338
Academy of Finland121148
Shota Rustaveli National Science FoundationFR/577/6-320/13
Russian Foundation for Basic Research (RFBR)09-02-00092
Subject Keywords:BL Lacertae objects: individual: Mrk 421
Record Number:CaltechAUTHORS:20150811-130323212
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150811-130323212
Official Citation:J. Aleksić, S. Ansoldi, L. A. Antonelli, P. Antoranz, A. Babic, P. Bangale, U. Barres de Almeida, J. A. Barrio, J. Becerra González, W. Bednarek, K. Berger, E. Bernardini, A. Biland, O. Blanch, R. K. Bock, S. Bonnefoy, G. Bonnoli, F. Borracci, T. Bretz, E. Carmona, A. Carosi, D. Carreto Fidalgo, P. Colin, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, P. Da Vela, F. Dazzi, A. De Angelis, G. De Caneva, B. De Lotto, C. Delgado Mendez, M. Doert, A. Domínguez, D. Dominis Prester, D. Dorner, M. Doro, S. Einecke, D. Eisenacher, D. Elsaesser, E. Farina, D. Ferenc, M. V. Fonseca, L. Font, K. Frantzen, C. Fruck, R. J. García López, M. Garczarczyk, D. Garrido Terrats, M. Gaug, G. Giavitto, N. Godinović, A. González Muñoz, S. R. Gozzini, A. Hadamek, D. Hadasch, A. Herrero, D. Hildebrand, J. Hose, D. Hrupec, W. Idec, V. Kadenius, H. Kellermann, M. L. Knoetig, J. Krause, J. Kushida, A. La Barbera, D. Lelas, N. Lewandowska, E. Lindfors, F. Longo, S. Lombardi, M. López, R. López-Coto, A. López-Oramas, E. Lorenz, I. Lozano, M. Makariev, K. Mallot, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, B. Marcote, M. Mariotti, M. Martínez, D. Mazin, U. Menzel, M. Meucci, J. M. Miranda, R. Mirzoyan, A. Moralejo, P. Munar-Adrover, D. Nakajima, A. Niedzwiecki, K. Nilsson, N. Nowak, R. Orito, A. Overkemping, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, X. Paredes-Fortuny, S. Partini, M. Persic, F. Prada, P. G. Prada Moroni, E. Prandini, S. Preziuso, I. Puljak, R. Reinthal, W. Rhode, M. Ribó, J. Rico, J. RodriguezGarcia, S. Rügamer, A. Saggion, K. Saito, M. Salvati, K. Satalecka, V. Scalzotto, V. Scapin, C. Schultz, T. Schweizer, S. N. Shore, A. Sillanpää, J. Sitarek, I. Snidaric, D. Sobczynska, F. Spanier, V. Stamatescu, A. Stamerra, T. Steinbring, J. Storz, S. Sun, T. Surić, L. Takalo, F. Tavecchio, P. Temnikov, T. Terzić, D. Tescaro, M. Teshima, J. Thaele, O. Tibolla, D. F. Torres, T. Toyama, A. Treves, M. Uellenbeck, P. Vogler, R. M. Wagner, F. Zandanel, R. Zanin, The MAGIC collaboration, S. Archambault, B. Behera, M. Beilicke, W. Benbow, R. Bird, J. H. Buckley, V. Bugaev, M. Cerruti, X. Chen, L. Ciupik, E. Collins-Hughes, W. Cui, J. Dumm, J. D. Eisch, A. Falcone, S. Federici, Q. Feng, J. P. Finley, H. Fleischhack, P. Fortin, L. Fortson, A. Furniss, S. Griffin, S. T. Griffiths, J. Grube, G. Gyuk, D. Hanna, J. Holder, G. Hughes, T. B. Humensky, C. A. Johnson, P. Kaaret, M. Kertzman, Y. Khassen, D. Kieda, H. Krawczynski, F. Krennrich, S. Kumar, M. J. Lang, G. Maier, S. McArthur, K. Meagher, P. Moriarty, R. Mukherjee, R. A. Ong, A. N. Otte, N. Park, A. Pichel, M. Pohl, A. Popkow, H. Prokoph, J. Quinn, K. Ragan, J. Rajotte, P. T. Reynolds, G. T. Richards, E. Roache, A. C. Rovero, G. H. Sembroski, K. Shahinyan, D. Staszak, I. Telezhinsky, M. Theiling, J. V. Tucci, J. Tyler, A. Varlotta, S. P. Wakely, T. C. Weekes, A. Weinstein, R. Welsing, A. Wilhelm, D. A. Williams, B. Zitzer, The VERITAS collaboration, M. Villata, C. Raiteri, H. D. Aller, M. F. Aller, W. P. Chen, B. Jordan, E. Koptelova, O. M. Kurtanidze, A. Lähteenmäki, B. McBreen, V. M. Larionov, C. S. Lin, M. G. Nikolashvili, E. Angelakis, M. Capalbi, A. Carramiñana, L. Carrasco, P. Cassaro, A. Cesarini, L. Fuhrmann, M. Giroletti, T. Hovatta, T. P. Krichbaum, H. A. Krimm, W. Max-Moerbeck, J. W. Moody, G. Maccaferri, Y. Mori, I. Nestoras, A. Orlati, C. Pace, R. Pearson, M. Perri, A. C. S. Readhead, J. L. Richards, A. C. Sadun, T. Sakamoto, J. Tammi, M. Tornikoski, Y. Yatsu and A. Zook A&A 576 A126 (2015) DOI: http://dx.doi.org/10.1051/0004-6361/201424216
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ID Code:59422
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:11 Aug 2015 20:32
Last Modified:03 Oct 2019 08:46

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