Abstract
The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. We model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus.
| Original language | English |
|---|---|
| Article number | 159 |
| Journal | Astrophysical Journal |
| Volume | 751 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2012 Jun 1 |
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
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Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state. / Ackermann, M.; Ajello, M.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cutini, S.; D'Ammando, F.; De Palma, F.; Dermer, C. D.; Do Couto, E.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Fuhrmann, L.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Guiriec, S.; Hadasch, D.; Hayashida, M.; Hughes, R. E.; Itoh, R.; Jóhannesson, G.; Johnson, A. S.; Katagiri, H.; Kataoka, J.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Lee, S. H.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; 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.; Naumann-Godo, M.; Nishino, S.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Pelassa, V.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Rastawicki, D.; Razzano, M.; Readhead, A.; Reimer, A.; Reimer, O.; Reyes, L. C.; Richards, J. L.; Sbarra, C.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Szostek, A.; Takahashi, H.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Zimmer, S.; Moderski, R.; Nalewajko, K.; Sikora, M.; Villata, M.; Raiteri, C. M.; Aller, H. D.; Aller, M. F.; Arkharov, A. A.; Benítez, E.; Berdyugin, A.; Blinov, D. A.; Boettcher, M.; Bravo Calle, O. J.A.; Buemi, C. S.; Carosati, D.; Chen, W. P.; Diltz, C.; Dipaola, A.; Dolci, M.; Efimova, N. V.; Forné, E.; Gurwell, M. A.; Heidt, J.; Hiriart, D.; Jordan, B.; Kimeridze, G.; Konstantinova, T. S.; Kopatskaya, E. N.; Koptelova, E.; Kurtanidze, O. M.; Lähteenmäki, A.; Larionova, E. G.; Larionova, L. V.; Larionov, V. M.; Leto, P.; Lindfors, E.; Lin, H. C.; Morozova, D. A.; Nikolashvili, M. G.; Nilsson, K.; Oksman, M.; Roustazadeh, P.; Sievers, A.; Sigua, L. A.; Sillanpää, A.; Takahashi, T.; Takalo, L. O.; Tornikoski, M.; Trigilio, C.; Troitsky, I. S.; Umana, G.; Angelakis, E.; Krichbaum, T. P.; Nestoras, I.; Riquelme, D.; Krips, M.; Trippe, S.; Arai, A.; Kawabata, K. S.; Sakimoto, K.; Sasada, M.; Sato, S.; Uemura, M.; Yamanaka, M.; Yoshida, M.; Belloni, T.; Tagliaferri, G.; Bonning, E. W.; Isler, J.; Urry, C. M.; Hoversten, E.; Falcone, A.; Pagani, C.; Stroh, M.
In: Astrophysical Journal, Vol. 751, No. 2, 159, 01.06.2012.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state
AU - Ackermann, M.
AU - Ajello, M.
AU - Ballet, J.
AU - Barbiellini, G.
AU - Bastieri, D.
AU - Bellazzini, R.
AU - Blandford, R. D.
AU - Bloom, E. D.
AU - Bonamente, E.
AU - Borgland, A. W.
AU - Bottacini, E.
AU - Bregeon, J.
AU - Brigida, M.
AU - Bruel, P.
AU - Buehler, R.
AU - Buson, S.
AU - Caliandro, G. A.
AU - Cameron, R. A.
AU - Caraveo, P. A.
AU - Casandjian, J. M.
AU - Cavazzuti, E.
AU - Cecchi, C.
AU - Charles, E.
AU - Chekhtman, A.
AU - Chiang, J.
AU - Ciprini, S.
AU - Claus, R.
AU - Cohen-Tanugi, J.
AU - Cutini, S.
AU - D'Ammando, F.
AU - De Palma, F.
AU - Dermer, C. D.
AU - Do Couto, E.
AU - Drell, P. S.
AU - Drlica-Wagner, A.
AU - Dubois, R.
AU - Favuzzi, C.
AU - Fegan, S. J.
AU - Ferrara, E. C.
AU - Focke, W. B.
AU - Fortin, P.
AU - Fuhrmann, L.
AU - Fukazawa, Y.
AU - Fusco, P.
AU - Gargano, F.
AU - Gasparrini, D.
AU - Gehrels, N.
AU - Germani, S.
AU - Giglietto, N.
AU - Giommi, P.
AU - Giordano, F.
AU - Giroletti, M.
AU - Glanzman, T.
AU - Godfrey, G.
AU - Grenier, I. A.
AU - Guiriec, S.
AU - Hadasch, D.
AU - Hayashida, M.
AU - Hughes, R. E.
AU - Itoh, R.
AU - Jóhannesson, G.
AU - Johnson, A. S.
AU - Katagiri, H.
AU - Kataoka, J.
AU - Knödlseder, J.
AU - Kuss, M.
AU - Lande, J.
AU - Larsson, S.
AU - Lee, S. H.
AU - Longo, F.
AU - Loparco, F.
AU - Lott, B.
AU - Lovellette, M. N.
AU - Lubrano, P.
AU - Madejski, G. M.
AU - Mazziotta, M. N.
AU - McEnery, J. E.
AU - Mehault, J.
AU - Michelson, P. F.
AU - Mitthumsiri, W.
AU - Mizuno, T.
AU - Monte, C.
AU - Monzani, M. E.
AU - Morselli, A.
AU - Moskalenko, I. V.
AU - Murgia, S.
AU - Naumann-Godo, M.
AU - Nishino, S.
AU - Norris, J. P.
AU - Nuss, E.
AU - Ohsugi, T.
AU - Okumura, A.
AU - Omodei, N.
AU - Orlando, E.
AU - Ozaki, M.
AU - Paneque, D.
AU - Panetta, J. H.
AU - Pelassa, V.
AU - Pesce-Rollins, M.
AU - Pierbattista, M.
AU - Piron, F.
AU - Pivato, G.
AU - Porter, T. A.
AU - Rainò, S.
AU - Rando, R.
AU - Rastawicki, D.
AU - Razzano, M.
AU - Readhead, A.
AU - Reimer, A.
AU - Reimer, O.
AU - Reyes, L. C.
AU - Richards, J. L.
AU - Sbarra, C.
AU - Sgrò, C.
AU - Siskind, E. J.
AU - Spandre, G.
AU - Spinelli, P.
AU - Szostek, A.
AU - Takahashi, H.
AU - Tanaka, T.
AU - Thayer, J. G.
AU - Thayer, J. B.
AU - Thompson, D. J.
AU - Tinivella, M.
AU - Torres, D. F.
AU - Tosti, G.
AU - Troja, E.
AU - Usher, T. L.
AU - Vandenbroucke, J.
AU - Vasileiou, V.
AU - Vianello, G.
AU - Vitale, V.
AU - Waite, A. P.
AU - Winer, B. L.
AU - Wood, K. S.
AU - Yang, Z.
AU - Zimmer, S.
AU - Moderski, R.
AU - Nalewajko, K.
AU - Sikora, M.
AU - Villata, M.
AU - Raiteri, C. M.
AU - Aller, H. D.
AU - Aller, M. F.
AU - Arkharov, A. A.
AU - Benítez, E.
AU - Berdyugin, A.
AU - Blinov, D. A.
AU - Boettcher, M.
AU - Bravo Calle, O. J.A.
AU - Buemi, C. S.
AU - Carosati, D.
AU - Chen, W. P.
AU - Diltz, C.
AU - Dipaola, A.
AU - Dolci, M.
AU - Efimova, N. V.
AU - Forné, E.
AU - Gurwell, M. A.
AU - Heidt, J.
AU - Hiriart, D.
AU - Jordan, B.
AU - Kimeridze, G.
AU - Konstantinova, T. S.
AU - Kopatskaya, E. N.
AU - Koptelova, E.
AU - Kurtanidze, O. M.
AU - Lähteenmäki, A.
AU - Larionova, E. G.
AU - Larionova, L. V.
AU - Larionov, V. M.
AU - Leto, P.
AU - Lindfors, E.
AU - Lin, H. C.
AU - Morozova, D. A.
AU - Nikolashvili, M. G.
AU - Nilsson, K.
AU - Oksman, M.
AU - Roustazadeh, P.
AU - Sievers, A.
AU - Sigua, L. A.
AU - Sillanpää, A.
AU - Takahashi, T.
AU - Takalo, L. O.
AU - Tornikoski, M.
AU - Trigilio, C.
AU - Troitsky, I. S.
AU - Umana, G.
AU - Angelakis, E.
AU - Krichbaum, T. P.
AU - Nestoras, I.
AU - Riquelme, D.
AU - Krips, M.
AU - Trippe, S.
AU - Arai, A.
AU - Kawabata, K. S.
AU - Sakimoto, K.
AU - Sasada, M.
AU - Sato, S.
AU - Uemura, M.
AU - Yamanaka, M.
AU - Yoshida, M.
AU - Belloni, T.
AU - Tagliaferri, G.
AU - Bonning, E. W.
AU - Isler, J.
AU - Urry, C. M.
AU - Hoversten, E.
AU - Falcone, A.
AU - Pagani, C.
AU - Stroh, M.
PY - 2012/6/1
Y1 - 2012/6/1
N2 - The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. We model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus.
AB - The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. We model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus.
UR - http://www.scopus.com/inward/record.url?scp=84861396505&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84861396505&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/751/2/159
DO - 10.1088/0004-637X/751/2/159
M3 - Article
AN - SCOPUS:84861396505
VL - 751
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 159
ER -