Fermi large area telescope observations of Markarian 421

The missing piece of its spectral energy distribution

A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler & 346 others S. Buson, G. A. Caliandro, R. A. Cameron, A. Cannon, P. A. Caraveo, S. Carrigan, J. M. Casandjian, E. Cavazzuti, C. Cecchi, Ö Çelik, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, A. De Angelis, F. De Palma, C. D. Dermer, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, L. Escande, C. Favuzzi, S. J. Fegan, J. Finke, W. B. Focke, P. Fortin, M. Frailis, L. Fuhrmann, Y. Fukazawa, T. Fukuyama, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, D. Horan, R. E. Hughes, G. Jóhannesson, A. S. Johnson, W. N. Johnson, M. Kadler, T. Kamae, H. Katagiri, Jun Kataoka, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, W. Max-Moerbeck, M. N. Mazziotta, J. E. Mcenery, J. Mehault, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, S. Nishino, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pavlidou, T. J. Pearson, V. Pelassa, M. Pepe, M. Pesce-Rollins, M. Pierbattista, F. Piron, T. A. Porter, S. Rainò, R. Rando, M. Razzano, A. Readhead, A. Reimer, O. Reimer, L. C. Reyes, J. L. Richards, S. Ritz, M. Roth, H. F W Sadrozinski, D. Sanchez, A. Sander, C. Sgrò, E. J. Siskind, P. D. Smith, G. Spandre, P. Spinelli, Stawarz, M. Stevenson, M. S. Strickman, D. J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, E. Troja, T. L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, A. E. Wehrle, B. L. Winer, K. S. Wood, Z. Yang, Y. Yatsu, T. Ylinen, J. A. Zensus, M. Ziegler, J. Aleksić, L. A. Antonelli, P. Antoranz, M. Backes, J. A. Barrio, J. Becerra González, W. Bednarek, A. Berdyugin, K. Berger, E. Bernardini, A. Biland, O. Blanch, R. K. Bock, A. Boller, G. Bonnoli, P. Bordas, D. Borla Tridon, V. Bosch-Ramon, D. Bose, I. Braun, T. Bretz, M. Camara, E. Carmona, A. Carosi, P. Colin, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, F. Dazzi, A. De Angelis, E. De Cea Del Pozo, C. Delgado Mendez, B. De Lotto, M. De Maria, F. De Sabata, A. Diago Ortega, M. Doert, A. Domínguez, D. Dominis Prester, D. Dorner, M. Doro, D. Elsaesser, D. Ferenc, M. V. Fonseca, L. Font, R. J García López, M. Garczarczyk, M. Gaug, G. Giavitto, N. Godinovi, D. Hadasch, A. Herrero, D. Hildebrand, D. Höhne-Mönch, J. Hose, D. Hrupec, T. Jogler, S. Klepser, T. Krähenbühl, D. Kranich, J. Krause, A. La Barbera, E. Leonardo, E. Lindfors, S. Lombardi, M. López, E. Lorenz, P. Majumdar, E. Makariev, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, M. Mariotti, M. Martínez, D. Mazin, M. Meucci, J. M. Miranda, R. Mirzoyan, H. Miyamoto, J. Moldón, A. Moralejo, D. Nieto, K. Nilsson, R. Orito, I. Oya, R. Paoletti, J. M. Paredes, S. Partini, M. Pasanen, F. Pauss, R. G. Pegna, M. A. Perez-Torres, M. Persic, J. Peruzzo, J. Pochon, F. Prada, P. G Prada Moroni, E. Prandini, N. Puchades, I. Puljak, T. Reichardt, W. Rhode, M. Ribó, J. Rico, M. Rissi, S. Rügamer, A. Saggion, K. Saito, T. Y. Saito, M. Salvati, M. Snchez-Conde, K. Satalecka, V. Scalzotto, V. Scapin, C. Schultz, T. Schweizer, M. Shayduk, S. N. Shore, A. Sierpowska-Bartosik, A. Sillanpää, J. Sitarek, D. Sobczynska, F. Spanier, S. Spiro, A. Stamerra, B. Steinke, J. Storz, N. Strah, J. C. Struebig, T. Suric, L. O. Takalo, F. Tavecchio, P. Temnikov, T. Terzić, D. Tescaro, M. Teshima, H. Vankov, R. M. Wagner, Q. Weitzel, V. Zabalza, F. Zandanel, R. Zanin, 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, R. Reinthal, E. Angelakis, M. Capalbi, A. Carramiñana, L. Carrasco, P. Cassaro, A. Cesarini, A. Falcone, M. A. Gurwell, T. Hovatta, Yu A. Kovalev, Y. Y. Kovalev, T. P. Krichbaum, H. A. Krimm, M. L. Lister, J. W. Moody, G. Maccaferri, Y. Mori, I. Nestoras, A. Orlati, C. Pace, C. Pagani, R. Pearson, M. Perri, B. G. Piner, E. Ros, A. C. Sadun, T. Sakamoto, J. Tammi, A. Zook

    Research output: Contribution to journalArticle

    163 Citations (Scopus)

    Abstract

    We report on the γ-ray activity of the high-synchrotron-peaked BL Lacertae object Markarian 421 (Mrk421) during the first 1.5years of Fermi operation, from 2008 August 5 to 2010 March 12. We find that the Large Area Telescope (LAT) γ-ray spectrum above 0.3GeV can be well described by a power-law function with photon index Γ = 1.78 0.02 and average photon flux F(> 0.3GeV) = (7.23 0.16) × 10-8phcm-2s -1. Over this time period, the Fermi-LAT spectrum above 0.3GeV was evaluated on seven-day-long time intervals, showing significant variations in the photon flux (up to a factor 3 from the minimum to the maximum flux) but mild spectral variations. The variability amplitude at X-ray frequencies measured by RXTE/ASM and Swift/BAT is substantially larger than that in γ-rays measured by Fermi-LAT, and these two energy ranges are not significantly correlated. We also present the first results from the 4.5 month long multifrequency campaign on Mrk421, which included the VLBA, Swift, RXTE, MAGIC, the F-GAMMA, GASP-WEBT, and other collaborations and instruments that provided excellent temporal and energy coverage of the source throughout the entire campaign (2009 January 19 to 2009 June 1). During this campaign, Mrk421 showed a low activity at all wavebands. The extensive multi-instrument (radio toTeV) data set provides an unprecedented, complete look at the quiescent spectral energy distribution (SED) for this source. The broadband SED was reproduced with a leptonic (one-zone synchrotron self-Compton) and a hadronic model (synchrotron proton blazar). Both frameworks are able to describe the average SED reasonably well, implying comparable jet powers but very different characteristics for the blazar emission site.

    Original languageEnglish
    Article number131
    JournalAstrophysical Journal
    Volume736
    Issue number2
    DOIs
    Publication statusPublished - 2011 Aug 1

    Fingerprint

    spectral energy distribution
    rays
    synchrotrons
    X Ray Timing Explorer
    telescopes
    photons
    Global Air Sampling Program
    BL Lacertae objects
    energy
    broadband
    intervals
    protons
    power law
    distribution
    radio
    x rays

    Keywords

    • acceleration of particles
    • BL Lacertae objects: general
    • BL Lacertae objects: individual (Mrk 421)
    • galaxies: active
    • gamma rays: general
    • radiation mechanisms: non-thermal

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Abdo, A. A., Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., ... Zook, A. (2011). Fermi large area telescope observations of Markarian 421: The missing piece of its spectral energy distribution. Astrophysical Journal, 736(2), [131]. https://doi.org/10.1088/0004-637X/736/2/131

    Fermi large area telescope observations of Markarian 421 : The missing piece of its spectral energy distribution. / Abdo, A. A.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Cannon, A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Çelik, Ö; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; De Angelis, A.; De Palma, F.; Dermer, C. D.; Do Couto E Silva, E.; Drell, P. S.; Dubois, R.; Dumora, D.; Escande, L.; Favuzzi, C.; Fegan, S. J.; Finke, J.; Focke, W. B.; Fortin, P.; Frailis, M.; Fuhrmann, L.; Fukazawa, Y.; Fukuyama, T.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Georganopoulos, M.; Germani, S.; Giebels, B.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Guiriec, S.; Hadasch, D.; Hayashida, M.; Hays, E.; Horan, D.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Johnson, W. N.; Kadler, M.; Kamae, T.; Katagiri, H.; Kataoka, Jun; Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lee, S. H.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Makeev, A.; Max-Moerbeck, W.; Mazziotta, M. N.; Mcenery, J. E.; Mehault, J.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Naumann-Godo, M.; Nishino, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Parent, D.; Pavlidou, V.; Pearson, T. J.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Readhead, A.; Reimer, A.; Reimer, O.; Reyes, L. C.; Richards, J. L.; Ritz, S.; Roth, M.; Sadrozinski, H. F W; Sanchez, D.; Sander, A.; Sgrò, C.; Siskind, E. J.; Smith, P. D.; Spandre, G.; Spinelli, P.; Stawarz; Stevenson, M.; Strickman, M. S.; Suson, D. J.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Troja, E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wang, P.; Wehrle, A. E.; Winer, B. L.; Wood, K. S.; Yang, Z.; Yatsu, Y.; Ylinen, T.; Zensus, J. A.; Ziegler, M.; Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Barrio, J. A.; González, J. Becerra; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Bordas, P.; Tridon, D. Borla; Bosch-Ramon, V.; Bose, D.; Braun, I.; Bretz, T.; Camara, M.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Dazzi, F.; De Angelis, A.; De Cea Del Pozo, E.; Mendez, C. Delgado; De Lotto, B.; De Maria, M.; De Sabata, F.; Ortega, A. Diago; Doert, M.; Domínguez, A.; Prester, D. Dominis; Dorner, D.; Doro, M.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; López, R. J García; Garczarczyk, M.; Gaug, M.; Giavitto, G.; Godinovi, N.; Hadasch, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Jogler, T.; Klepser, S.; Krähenbühl, T.; Kranich, D.; Krause, J.; Barbera, A. La; Leonardo, E.; Lindfors, E.; Lombardi, S.; López, M.; Lorenz, E.; Majumdar, P.; Makariev, E.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moralejo, A.; Nieto, D.; Nilsson, K.; Orito, R.; Oya, I.; Paoletti, R.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pauss, F.; Pegna, R. G.; Perez-Torres, M. A.; Persic, M.; Peruzzo, J.; Pochon, J.; Prada, F.; Moroni, P. G Prada; Prandini, E.; Puchades, N.; Puljak, I.; Reichardt, T.; Rhode, W.; Ribó, M.; Rico, J.; Rissi, M.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Snchez-Conde, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sierpowska-Bartosik, A.; Sillanpää, A.; Sitarek, J.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Struebig, J. C.; Suric, T.; Takalo, L. O.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Vankov, H.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; Villata, M.; Raiteri, C.; Aller, H. D.; Aller, M. F.; Chen, W. P.; Jordan, B.; Koptelova, E.; Kurtanidze, O. M.; Lähteenmäki, A.; Mcbreen, B.; Larionov, V. M.; Lin, C. S.; Nikolashvili, M. G.; Reinthal, R.; Angelakis, E.; Capalbi, M.; Carramiñana, A.; Carrasco, L.; Cassaro, P.; Cesarini, A.; Falcone, A.; Gurwell, M. A.; Hovatta, T.; Kovalev, Yu A.; Kovalev, Y. Y.; Krichbaum, T. P.; Krimm, H. A.; Lister, M. L.; Moody, J. W.; Maccaferri, G.; Mori, Y.; Nestoras, I.; Orlati, A.; Pace, C.; Pagani, C.; Pearson, R.; Perri, M.; Piner, B. G.; Ros, E.; Sadun, A. C.; Sakamoto, T.; Tammi, J.; Zook, A.

    In: Astrophysical Journal, Vol. 736, No. 2, 131, 01.08.2011.

    Research output: Contribution to journalArticle

    Abdo, AA, Ackermann, M, Ajello, M, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Blandford, RD, Bloom, ED, Bonamente, E, Borgland, AW, Bouvier, A, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Cannon, A, Caraveo, PA, Carrigan, S, Casandjian, JM, Cavazzuti, E, Cecchi, C, Çelik, Ö, Charles, E, Chekhtman, A, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cutini, S, De Angelis, A, De Palma, F, Dermer, CD, Do Couto E Silva, E, Drell, PS, Dubois, R, Dumora, D, Escande, L, Favuzzi, C, Fegan, SJ, Finke, J, Focke, WB, Fortin, P, Frailis, M, Fuhrmann, L, Fukazawa, Y, Fukuyama, T, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Georganopoulos, M, Germani, S, Giebels, B, Giglietto, N, Giommi, P, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, IA, Guiriec, S, Hadasch, D, Hayashida, M, Hays, E, Horan, D, Hughes, RE, Jóhannesson, G, Johnson, AS, Johnson, WN, Kadler, M, Kamae, T, Katagiri, H, Kataoka, J, Knödlseder, J, Kuss, M, Lande, J, Latronico, L, Lee, SH, Longo, F, Loparco, F, Lott, B, Lovellette, MN, Lubrano, P, Madejski, GM, Makeev, A, Max-Moerbeck, W, Mazziotta, MN, Mcenery, JE, Mehault, J, Michelson, PF, Mitthumsiri, W, Mizuno, T, Monte, C, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nakamori, T, Naumann-Godo, M, Nishino, S, Nolan, PL, Norris, JP, Nuss, E, Ohsugi, T, Okumura, A, Omodei, N, Orlando, E, Ormes, JF, Ozaki, M, Paneque, D, Panetta, JH, Parent, D, Pavlidou, V, Pearson, TJ, Pelassa, V, Pepe, M, Pesce-Rollins, M, Pierbattista, M, Piron, F, Porter, TA, Rainò, S, Rando, R, Razzano, M, Readhead, A, Reimer, A, Reimer, O, Reyes, LC, Richards, JL, Ritz, S, Roth, M, Sadrozinski, HFW, Sanchez, D, Sander, A, Sgrò, C, Siskind, EJ, Smith, PD, Spandre, G, Spinelli, P, Stawarz, Stevenson, M, Strickman, MS, Suson, DJ, Takahashi, H, Takahashi, T, Tanaka, T, Thayer, JG, Thayer, JB, Thompson, DJ, Tibaldo, L, Torres, DF, Tosti, G, Tramacere, A, Troja, E, Usher, TL, Vandenbroucke, J, Vasileiou, V, Vianello, G, Vilchez, N, Vitale, V, Waite, AP, Wang, P, Wehrle, AE, Winer, BL, Wood, KS, Yang, Z, Yatsu, Y, Ylinen, T, Zensus, JA, Ziegler, M, Aleksić, J, Antonelli, LA, Antoranz, P, Backes, M, Barrio, JA, González, JB, Bednarek, W, Berdyugin, A, Berger, K, Bernardini, E, Biland, A, Blanch, O, Bock, RK, Boller, A, Bonnoli, G, Bordas, P, Tridon, DB, Bosch-Ramon, V, Bose, D, Braun, I, Bretz, T, Camara, M, Carmona, E, Carosi, A, Colin, P, Colombo, E, Contreras, JL, Cortina, J, Covino, S, Dazzi, F, De Angelis, A, De Cea Del Pozo, E, Mendez, CD, De Lotto, B, De Maria, M, De Sabata, F, Ortega, AD, Doert, M, Domínguez, A, Prester, DD, Dorner, D, Doro, M, Elsaesser, D, Ferenc, D, Fonseca, MV, Font, L, López, RJG, Garczarczyk, M, Gaug, M, Giavitto, G, Godinovi, N, Hadasch, D, Herrero, A, Hildebrand, D, Höhne-Mönch, D, Hose, J, Hrupec, D, Jogler, T, Klepser, S, Krähenbühl, T, Kranich, D, Krause, J, Barbera, AL, Leonardo, E, Lindfors, E, Lombardi, S, López, M, Lorenz, E, Majumdar, P, Makariev, E, Maneva, G, Mankuzhiyil, N, Mannheim, K, Maraschi, L, Mariotti, M, Martínez, M, Mazin, D, Meucci, M, Miranda, JM, Mirzoyan, R, Miyamoto, H, Moldón, J, Moralejo, A, Nieto, D, Nilsson, K, Orito, R, Oya, I, Paoletti, R, Paredes, JM, Partini, S, Pasanen, M, Pauss, F, Pegna, RG, Perez-Torres, MA, Persic, M, Peruzzo, J, Pochon, J, Prada, F, Moroni, PGP, Prandini, E, Puchades, N, Puljak, I, Reichardt, T, Rhode, W, Ribó, M, Rico, J, Rissi, M, Rügamer, S, Saggion, A, Saito, K, Saito, TY, Salvati, M, Snchez-Conde, M, Satalecka, K, Scalzotto, V, Scapin, V, Schultz, C, Schweizer, T, Shayduk, M, Shore, SN, Sierpowska-Bartosik, A, Sillanpää, A, Sitarek, J, Sobczynska, D, Spanier, F, Spiro, S, Stamerra, A, Steinke, B, Storz, J, Strah, N, Struebig, JC, Suric, T, Takalo, LO, Tavecchio, F, Temnikov, P, Terzić, T, Tescaro, D, Teshima, M, Vankov, H, Wagner, RM, Weitzel, Q, Zabalza, V, Zandanel, F, Zanin, R, Villata, M, Raiteri, C, Aller, HD, Aller, MF, Chen, WP, Jordan, B, Koptelova, E, Kurtanidze, OM, Lähteenmäki, A, Mcbreen, B, Larionov, VM, Lin, CS, Nikolashvili, MG, Reinthal, R, Angelakis, E, Capalbi, M, Carramiñana, A, Carrasco, L, Cassaro, P, Cesarini, A, Falcone, A, Gurwell, MA, Hovatta, T, Kovalev, YA, Kovalev, YY, Krichbaum, TP, Krimm, HA, Lister, ML, Moody, JW, Maccaferri, G, Mori, Y, Nestoras, I, Orlati, A, Pace, C, Pagani, C, Pearson, R, Perri, M, Piner, BG, Ros, E, Sadun, AC, Sakamoto, T, Tammi, J & Zook, A 2011, 'Fermi large area telescope observations of Markarian 421: The missing piece of its spectral energy distribution', Astrophysical Journal, vol. 736, no. 2, 131. https://doi.org/10.1088/0004-637X/736/2/131
    Abdo, A. A. ; Ackermann, M. ; Ajello, M. ; Baldini, L. ; Ballet, J. ; Barbiellini, G. ; Bastieri, D. ; Bechtol, K. ; Bellazzini, R. ; Berenji, B. ; Blandford, R. D. ; Bloom, E. D. ; Bonamente, E. ; Borgland, A. W. ; Bouvier, A. ; Bregeon, J. ; Brez, A. ; Brigida, M. ; Bruel, P. ; Buehler, R. ; Buson, S. ; Caliandro, G. A. ; Cameron, R. A. ; Cannon, A. ; Caraveo, P. A. ; Carrigan, S. ; Casandjian, J. M. ; Cavazzuti, E. ; Cecchi, C. ; Çelik, Ö ; Charles, E. ; Chekhtman, A. ; Chiang, J. ; Ciprini, S. ; Claus, R. ; Cohen-Tanugi, J. ; Conrad, J. ; Cutini, S. ; De Angelis, A. ; De Palma, F. ; Dermer, C. D. ; Do Couto E Silva, E. ; Drell, P. S. ; Dubois, R. ; Dumora, D. ; Escande, L. ; Favuzzi, C. ; Fegan, S. J. ; Finke, J. ; Focke, W. B. ; Fortin, P. ; Frailis, M. ; Fuhrmann, L. ; Fukazawa, Y. ; Fukuyama, T. ; Funk, S. ; Fusco, P. ; Gargano, F. ; Gasparrini, D. ; Gehrels, N. ; Georganopoulos, M. ; Germani, S. ; Giebels, B. ; Giglietto, N. ; Giommi, P. ; Giordano, F. ; Giroletti, M. ; Glanzman, T. ; Godfrey, G. ; Grenier, I. A. ; Guiriec, S. ; Hadasch, D. ; Hayashida, M. ; Hays, E. ; Horan, D. ; Hughes, R. E. ; Jóhannesson, G. ; Johnson, A. S. ; Johnson, W. N. ; Kadler, M. ; Kamae, T. ; Katagiri, H. ; Kataoka, Jun ; Knödlseder, J. ; Kuss, M. ; Lande, J. ; Latronico, L. ; Lee, S. H. ; Longo, F. ; Loparco, F. ; Lott, B. ; Lovellette, M. N. ; Lubrano, P. ; Madejski, G. M. ; Makeev, A. ; Max-Moerbeck, W. ; Mazziotta, M. N. ; Mcenery, J. E. ; Mehault, J. ; Michelson, P. F. ; Mitthumsiri, W. ; Mizuno, T. ; Monte, C. ; Monzani, M. E. ; Morselli, A. ; Moskalenko, I. V. ; Murgia, S. ; Nakamori, T. ; Naumann-Godo, M. ; Nishino, S. ; Nolan, P. L. ; Norris, J. P. ; Nuss, E. ; Ohsugi, T. ; Okumura, A. ; Omodei, N. ; Orlando, E. ; Ormes, J. F. ; Ozaki, M. ; Paneque, D. ; Panetta, J. H. ; Parent, D. ; Pavlidou, V. ; Pearson, T. J. ; Pelassa, V. ; Pepe, M. ; Pesce-Rollins, M. ; Pierbattista, M. ; Piron, F. ; Porter, T. A. ; Rainò, S. ; Rando, R. ; Razzano, M. ; Readhead, A. ; Reimer, A. ; Reimer, O. ; Reyes, L. C. ; Richards, J. L. ; Ritz, S. ; Roth, M. ; Sadrozinski, H. F W ; Sanchez, D. ; Sander, A. ; Sgrò, C. ; Siskind, E. J. ; Smith, P. D. ; Spandre, G. ; Spinelli, P. ; Stawarz ; Stevenson, M. ; Strickman, M. S. ; Suson, D. J. ; Takahashi, H. ; Takahashi, T. ; Tanaka, T. ; Thayer, J. G. ; Thayer, J. B. ; Thompson, D. J. ; Tibaldo, L. ; Torres, D. F. ; Tosti, G. ; Tramacere, A. ; Troja, E. ; Usher, T. L. ; Vandenbroucke, J. ; Vasileiou, V. ; Vianello, G. ; Vilchez, N. ; Vitale, V. ; Waite, A. P. ; Wang, P. ; Wehrle, A. E. ; Winer, B. L. ; Wood, K. S. ; Yang, Z. ; Yatsu, Y. ; Ylinen, T. ; Zensus, J. A. ; Ziegler, M. ; Aleksić, J. ; Antonelli, L. A. ; Antoranz, P. ; Backes, M. ; Barrio, J. A. ; González, J. Becerra ; Bednarek, W. ; Berdyugin, A. ; Berger, K. ; Bernardini, E. ; Biland, A. ; Blanch, O. ; Bock, R. K. ; Boller, A. ; Bonnoli, G. ; Bordas, P. ; Tridon, D. Borla ; Bosch-Ramon, V. ; Bose, D. ; Braun, I. ; Bretz, T. ; Camara, M. ; Carmona, E. ; Carosi, A. ; Colin, P. ; Colombo, E. ; Contreras, J. L. ; Cortina, J. ; Covino, S. ; Dazzi, F. ; De Angelis, A. ; De Cea Del Pozo, E. ; Mendez, C. Delgado ; De Lotto, B. ; De Maria, M. ; De Sabata, F. ; Ortega, A. Diago ; Doert, M. ; Domínguez, A. ; Prester, D. Dominis ; Dorner, D. ; Doro, M. ; Elsaesser, D. ; Ferenc, D. ; Fonseca, M. V. ; Font, L. ; López, R. J García ; Garczarczyk, M. ; Gaug, M. ; Giavitto, G. ; Godinovi, N. ; Hadasch, D. ; Herrero, A. ; Hildebrand, D. ; Höhne-Mönch, D. ; Hose, J. ; Hrupec, D. ; Jogler, T. ; Klepser, S. ; Krähenbühl, T. ; Kranich, D. ; Krause, J. ; Barbera, A. La ; Leonardo, E. ; Lindfors, E. ; Lombardi, S. ; López, M. ; Lorenz, E. ; Majumdar, P. ; Makariev, E. ; Maneva, G. ; Mankuzhiyil, N. ; Mannheim, K. ; Maraschi, L. ; Mariotti, M. ; Martínez, M. ; Mazin, D. ; Meucci, M. ; Miranda, J. M. ; Mirzoyan, R. ; Miyamoto, H. ; Moldón, J. ; Moralejo, A. ; Nieto, D. ; Nilsson, K. ; Orito, R. ; Oya, I. ; Paoletti, R. ; Paredes, J. M. ; Partini, S. ; Pasanen, M. ; Pauss, F. ; Pegna, R. G. ; Perez-Torres, M. A. ; Persic, M. ; Peruzzo, J. ; Pochon, J. ; Prada, F. ; Moroni, P. G Prada ; Prandini, E. ; Puchades, N. ; Puljak, I. ; Reichardt, T. ; Rhode, W. ; Ribó, M. ; Rico, J. ; Rissi, M. ; Rügamer, S. ; Saggion, A. ; Saito, K. ; Saito, T. Y. ; Salvati, M. ; Snchez-Conde, M. ; Satalecka, K. ; Scalzotto, V. ; Scapin, V. ; Schultz, C. ; Schweizer, T. ; Shayduk, M. ; Shore, S. N. ; Sierpowska-Bartosik, A. ; Sillanpää, A. ; Sitarek, J. ; Sobczynska, D. ; Spanier, F. ; Spiro, S. ; Stamerra, A. ; Steinke, B. ; Storz, J. ; Strah, N. ; Struebig, J. C. ; Suric, T. ; Takalo, L. O. ; Tavecchio, F. ; Temnikov, P. ; Terzić, T. ; Tescaro, D. ; Teshima, M. ; Vankov, H. ; Wagner, R. M. ; Weitzel, Q. ; Zabalza, V. ; Zandanel, F. ; Zanin, R. ; Villata, M. ; Raiteri, C. ; Aller, H. D. ; Aller, M. F. ; Chen, W. P. ; Jordan, B. ; Koptelova, E. ; Kurtanidze, O. M. ; Lähteenmäki, A. ; Mcbreen, B. ; Larionov, V. M. ; Lin, C. S. ; Nikolashvili, M. G. ; Reinthal, R. ; Angelakis, E. ; Capalbi, M. ; Carramiñana, A. ; Carrasco, L. ; Cassaro, P. ; Cesarini, A. ; Falcone, A. ; Gurwell, M. A. ; Hovatta, T. ; Kovalev, Yu A. ; Kovalev, Y. Y. ; Krichbaum, T. P. ; Krimm, H. A. ; Lister, M. L. ; Moody, J. W. ; Maccaferri, G. ; Mori, Y. ; Nestoras, I. ; Orlati, A. ; Pace, C. ; Pagani, C. ; Pearson, R. ; Perri, M. ; Piner, B. G. ; Ros, E. ; Sadun, A. C. ; Sakamoto, T. ; Tammi, J. ; Zook, A. / Fermi large area telescope observations of Markarian 421 : The missing piece of its spectral energy distribution. In: Astrophysical Journal. 2011 ; Vol. 736, No. 2.
    @article{f9935dcb6afe4400998315d76c920ffa,
    title = "Fermi large area telescope observations of Markarian 421: The missing piece of its spectral energy distribution",
    abstract = "We report on the γ-ray activity of the high-synchrotron-peaked BL Lacertae object Markarian 421 (Mrk421) during the first 1.5years of Fermi operation, from 2008 August 5 to 2010 March 12. We find that the Large Area Telescope (LAT) γ-ray spectrum above 0.3GeV can be well described by a power-law function with photon index Γ = 1.78 0.02 and average photon flux F(> 0.3GeV) = (7.23 0.16) × 10-8phcm-2s -1. Over this time period, the Fermi-LAT spectrum above 0.3GeV was evaluated on seven-day-long time intervals, showing significant variations in the photon flux (up to a factor 3 from the minimum to the maximum flux) but mild spectral variations. The variability amplitude at X-ray frequencies measured by RXTE/ASM and Swift/BAT is substantially larger than that in γ-rays measured by Fermi-LAT, and these two energy ranges are not significantly correlated. We also present the first results from the 4.5 month long multifrequency campaign on Mrk421, which included the VLBA, Swift, RXTE, MAGIC, the F-GAMMA, GASP-WEBT, and other collaborations and instruments that provided excellent temporal and energy coverage of the source throughout the entire campaign (2009 January 19 to 2009 June 1). During this campaign, Mrk421 showed a low activity at all wavebands. The extensive multi-instrument (radio toTeV) data set provides an unprecedented, complete look at the quiescent spectral energy distribution (SED) for this source. The broadband SED was reproduced with a leptonic (one-zone synchrotron self-Compton) and a hadronic model (synchrotron proton blazar). Both frameworks are able to describe the average SED reasonably well, implying comparable jet powers but very different characteristics for the blazar emission site.",
    keywords = "acceleration of particles, BL Lacertae objects: general, BL Lacertae objects: individual (Mrk 421), galaxies: active, gamma rays: general, radiation mechanisms: non-thermal",
    author = "Abdo, {A. A.} and M. Ackermann and M. Ajello and L. Baldini and J. Ballet and G. Barbiellini and D. Bastieri and K. Bechtol and R. Bellazzini and B. Berenji and Blandford, {R. D.} and Bloom, {E. D.} and E. Bonamente and Borgland, {A. W.} and A. Bouvier and J. Bregeon and A. Brez and M. Brigida and P. Bruel and R. Buehler and S. Buson and Caliandro, {G. A.} and Cameron, {R. A.} and A. Cannon and Caraveo, {P. A.} and S. Carrigan and Casandjian, {J. M.} and E. Cavazzuti and C. Cecchi and {\"O} {\cC}elik and E. Charles and A. Chekhtman and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and J. Conrad and S. Cutini and {De Angelis}, A. and {De Palma}, F. and Dermer, {C. D.} and {Do Couto E Silva}, E. and Drell, {P. S.} and R. Dubois and D. Dumora and L. Escande and C. Favuzzi and Fegan, {S. J.} and J. Finke and Focke, {W. B.} and P. Fortin and M. Frailis and L. Fuhrmann and Y. Fukazawa and T. Fukuyama and S. Funk and P. Fusco and F. Gargano and D. Gasparrini and N. Gehrels and M. Georganopoulos and S. Germani and B. Giebels and N. Giglietto and P. Giommi and F. Giordano and M. Giroletti and T. Glanzman and G. Godfrey and Grenier, {I. A.} and S. Guiriec and D. Hadasch and M. Hayashida and E. Hays and D. Horan and Hughes, {R. E.} and G. J{\'o}hannesson and Johnson, {A. S.} and Johnson, {W. N.} and M. Kadler and T. Kamae and H. Katagiri and Jun Kataoka and J. Kn{\"o}dlseder and M. Kuss and J. Lande and L. Latronico and Lee, {S. H.} and F. Longo and F. Loparco and B. Lott and Lovellette, {M. N.} and P. Lubrano and Madejski, {G. M.} and A. Makeev and W. Max-Moerbeck and Mazziotta, {M. N.} and Mcenery, {J. E.} and J. Mehault and Michelson, {P. F.} and W. Mitthumsiri and T. Mizuno and C. Monte and Monzani, {M. E.} and A. Morselli and Moskalenko, {I. V.} and S. Murgia and T. Nakamori and M. Naumann-Godo and S. Nishino and Nolan, {P. L.} and Norris, {J. P.} and E. Nuss and T. Ohsugi and A. Okumura and N. Omodei and E. Orlando and Ormes, {J. F.} and M. Ozaki and D. Paneque and Panetta, {J. H.} and D. Parent and V. Pavlidou and Pearson, {T. J.} and V. Pelassa and M. Pepe and M. Pesce-Rollins and M. Pierbattista and F. Piron and Porter, {T. A.} and S. Rain{\`o} and R. Rando and M. Razzano and A. Readhead and A. Reimer and O. Reimer and Reyes, {L. C.} and Richards, {J. L.} and S. Ritz and M. Roth and Sadrozinski, {H. F W} and D. Sanchez and A. Sander and C. Sgr{\`o} and Siskind, {E. J.} and Smith, {P. D.} and G. Spandre and P. Spinelli and Stawarz and M. Stevenson and Strickman, {M. S.} and Suson, {D. J.} and H. Takahashi and T. Takahashi and T. Tanaka and Thayer, {J. G.} and Thayer, {J. B.} and Thompson, {D. J.} and L. Tibaldo and Torres, {D. F.} and G. Tosti and A. Tramacere and E. Troja and Usher, {T. L.} and J. Vandenbroucke and V. Vasileiou and G. Vianello and N. Vilchez and V. Vitale and Waite, {A. P.} and P. Wang and Wehrle, {A. E.} and Winer, {B. L.} and Wood, {K. S.} and Z. Yang and Y. Yatsu and T. Ylinen and Zensus, {J. A.} and M. Ziegler and J. Aleksić and Antonelli, {L. A.} and P. Antoranz and M. Backes and Barrio, {J. A.} and Gonz{\'a}lez, {J. Becerra} and W. Bednarek and A. Berdyugin and K. Berger and E. Bernardini and A. Biland and O. Blanch and Bock, {R. K.} and A. Boller and G. Bonnoli and P. Bordas and Tridon, {D. Borla} and V. Bosch-Ramon and D. Bose and I. Braun and T. Bretz and M. Camara and E. Carmona and A. Carosi and P. Colin and E. Colombo and Contreras, {J. L.} and J. Cortina and S. Covino and F. Dazzi and {De Angelis}, A. and {De Cea Del Pozo}, E. and Mendez, {C. Delgado} and {De Lotto}, B. and {De Maria}, M. and {De Sabata}, F. and Ortega, {A. Diago} and M. Doert and A. Dom{\'i}nguez and Prester, {D. Dominis} and D. Dorner and M. Doro and D. Elsaesser and D. Ferenc and Fonseca, {M. V.} and L. Font and L{\'o}pez, {R. J Garc{\'i}a} and M. Garczarczyk and M. Gaug and G. Giavitto and N. Godinovi and D. Hadasch and A. Herrero and D. Hildebrand and D. H{\"o}hne-M{\"o}nch and J. Hose and D. Hrupec and T. Jogler and S. Klepser and T. Kr{\"a}henb{\"u}hl and D. Kranich and J. Krause and Barbera, {A. La} and E. Leonardo and E. Lindfors and S. Lombardi and M. L{\'o}pez and E. Lorenz and P. Majumdar and E. Makariev and G. Maneva and N. Mankuzhiyil and K. Mannheim and L. Maraschi and M. Mariotti and M. Mart{\'i}nez and D. Mazin and M. Meucci and Miranda, {J. M.} and R. Mirzoyan and H. Miyamoto and J. Mold{\'o}n and A. Moralejo and D. Nieto and K. Nilsson and R. Orito and I. Oya and R. Paoletti and Paredes, {J. M.} and S. Partini and M. Pasanen and F. Pauss and Pegna, {R. G.} and Perez-Torres, {M. A.} and M. Persic and J. Peruzzo and J. Pochon and F. Prada and Moroni, {P. G Prada} and E. Prandini and N. Puchades and I. Puljak and T. Reichardt and W. Rhode and M. Rib{\'o} and J. Rico and M. Rissi and S. R{\"u}gamer and A. Saggion and K. Saito and Saito, {T. Y.} and M. Salvati and M. Snchez-Conde and K. Satalecka and V. Scalzotto and V. Scapin and C. Schultz and T. Schweizer and M. Shayduk and Shore, {S. N.} and A. Sierpowska-Bartosik and A. Sillanp{\"a}{\"a} and J. Sitarek and D. Sobczynska and F. Spanier and S. Spiro and A. Stamerra and B. Steinke and J. Storz and N. Strah and Struebig, {J. C.} and T. Suric and Takalo, {L. O.} and F. Tavecchio and P. Temnikov and T. Terzić and D. Tescaro and M. Teshima and H. Vankov and Wagner, {R. M.} and Q. Weitzel and V. Zabalza and F. Zandanel and R. Zanin and M. Villata and C. Raiteri and Aller, {H. D.} and Aller, {M. F.} and Chen, {W. P.} and B. Jordan and E. Koptelova and Kurtanidze, {O. M.} and A. L{\"a}hteenm{\"a}ki and B. Mcbreen and Larionov, {V. M.} and Lin, {C. S.} and Nikolashvili, {M. G.} and R. Reinthal and E. Angelakis and M. Capalbi and A. Carrami{\~n}ana and L. Carrasco and P. Cassaro and A. Cesarini and A. Falcone and Gurwell, {M. A.} and T. Hovatta and Kovalev, {Yu A.} and Kovalev, {Y. Y.} and Krichbaum, {T. P.} and Krimm, {H. A.} and Lister, {M. L.} and Moody, {J. W.} and G. Maccaferri and Y. Mori and I. Nestoras and A. Orlati and C. Pace and C. Pagani and R. Pearson and M. Perri and Piner, {B. G.} and E. Ros and Sadun, {A. C.} and T. Sakamoto and J. Tammi and A. Zook",
    year = "2011",
    month = "8",
    day = "1",
    doi = "10.1088/0004-637X/736/2/131",
    language = "English",
    volume = "736",
    journal = "Astrophysical Journal",
    issn = "0004-637X",
    publisher = "IOP Publishing Ltd.",
    number = "2",

    }

    TY - JOUR

    T1 - Fermi large area telescope observations of Markarian 421

    T2 - The missing piece of its spectral energy distribution

    AU - Abdo, A. A.

    AU - Ackermann, M.

    AU - Ajello, M.

    AU - Baldini, L.

    AU - Ballet, J.

    AU - Barbiellini, G.

    AU - Bastieri, D.

    AU - Bechtol, K.

    AU - Bellazzini, R.

    AU - Berenji, B.

    AU - Blandford, R. D.

    AU - Bloom, E. D.

    AU - Bonamente, E.

    AU - Borgland, A. W.

    AU - Bouvier, A.

    AU - Bregeon, J.

    AU - Brez, A.

    AU - Brigida, M.

    AU - Bruel, P.

    AU - Buehler, R.

    AU - Buson, S.

    AU - Caliandro, G. A.

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    PY - 2011/8/1

    Y1 - 2011/8/1

    N2 - We report on the γ-ray activity of the high-synchrotron-peaked BL Lacertae object Markarian 421 (Mrk421) during the first 1.5years of Fermi operation, from 2008 August 5 to 2010 March 12. We find that the Large Area Telescope (LAT) γ-ray spectrum above 0.3GeV can be well described by a power-law function with photon index Γ = 1.78 0.02 and average photon flux F(> 0.3GeV) = (7.23 0.16) × 10-8phcm-2s -1. Over this time period, the Fermi-LAT spectrum above 0.3GeV was evaluated on seven-day-long time intervals, showing significant variations in the photon flux (up to a factor 3 from the minimum to the maximum flux) but mild spectral variations. The variability amplitude at X-ray frequencies measured by RXTE/ASM and Swift/BAT is substantially larger than that in γ-rays measured by Fermi-LAT, and these two energy ranges are not significantly correlated. We also present the first results from the 4.5 month long multifrequency campaign on Mrk421, which included the VLBA, Swift, RXTE, MAGIC, the F-GAMMA, GASP-WEBT, and other collaborations and instruments that provided excellent temporal and energy coverage of the source throughout the entire campaign (2009 January 19 to 2009 June 1). During this campaign, Mrk421 showed a low activity at all wavebands. The extensive multi-instrument (radio toTeV) data set provides an unprecedented, complete look at the quiescent spectral energy distribution (SED) for this source. The broadband SED was reproduced with a leptonic (one-zone synchrotron self-Compton) and a hadronic model (synchrotron proton blazar). Both frameworks are able to describe the average SED reasonably well, implying comparable jet powers but very different characteristics for the blazar emission site.

    AB - We report on the γ-ray activity of the high-synchrotron-peaked BL Lacertae object Markarian 421 (Mrk421) during the first 1.5years of Fermi operation, from 2008 August 5 to 2010 March 12. We find that the Large Area Telescope (LAT) γ-ray spectrum above 0.3GeV can be well described by a power-law function with photon index Γ = 1.78 0.02 and average photon flux F(> 0.3GeV) = (7.23 0.16) × 10-8phcm-2s -1. Over this time period, the Fermi-LAT spectrum above 0.3GeV was evaluated on seven-day-long time intervals, showing significant variations in the photon flux (up to a factor 3 from the minimum to the maximum flux) but mild spectral variations. The variability amplitude at X-ray frequencies measured by RXTE/ASM and Swift/BAT is substantially larger than that in γ-rays measured by Fermi-LAT, and these two energy ranges are not significantly correlated. We also present the first results from the 4.5 month long multifrequency campaign on Mrk421, which included the VLBA, Swift, RXTE, MAGIC, the F-GAMMA, GASP-WEBT, and other collaborations and instruments that provided excellent temporal and energy coverage of the source throughout the entire campaign (2009 January 19 to 2009 June 1). During this campaign, Mrk421 showed a low activity at all wavebands. The extensive multi-instrument (radio toTeV) data set provides an unprecedented, complete look at the quiescent spectral energy distribution (SED) for this source. The broadband SED was reproduced with a leptonic (one-zone synchrotron self-Compton) and a hadronic model (synchrotron proton blazar). Both frameworks are able to describe the average SED reasonably well, implying comparable jet powers but very different characteristics for the blazar emission site.

    KW - acceleration of particles

    KW - BL Lacertae objects: general

    KW - BL Lacertae objects: individual (Mrk 421)

    KW - galaxies: active

    KW - gamma rays: general

    KW - radiation mechanisms: non-thermal

    UR - http://www.scopus.com/inward/record.url?scp=80051535196&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=80051535196&partnerID=8YFLogxK

    U2 - 10.1088/0004-637X/736/2/131

    DO - 10.1088/0004-637X/736/2/131

    M3 - Article

    VL - 736

    JO - Astrophysical Journal

    JF - Astrophysical Journal

    SN - 0004-637X

    IS - 2

    M1 - 131

    ER -