SIMULTANEOUS OBSERVATIONS OF PKS 2155-304 WITH HESS, FERMI, RXTE, AND ATOM: SPECTRAL ENERGY DISTRIBUTIONS AND VARIABILITY IN A LOW STATE

被引：122

作者：

Aharonian, F. ^{[1
,2
]}

Akhperjanian, A. G. ^{[3
]}

Anton, G. ^{[4
]}

de Almeida, U. Barres ^{[5
]}

Bazer-Bachi, A. R. ^{[6
]}

Becherini, Y. ^{[7
,8
]}

Behera, B. ^{[9
]}

Bernloehr, K. ^{[1
,10
]}

Boisson, C. ^{[11
]}

Bochow, A. ^{[1
]}

Borrel, V. ^{[6
]}

Brion, E. ^{[12
]}

Brucker, J. ^{[4
]}

Brun, P. ^{[12
]}

Buehler, R. ^{[1
]}

Bulik, T. ^{[13
]}

Buesching, I. ^{[14
]}

Boutelier, T. ^{[15
]}

Chadwick, P. M. ^{[5
]}

Charbonnier, A. ^{[16
]}

Chaves, R. C. G. ^{[1
]}

Cheesebrough, A. ^{[5
]}

Chounet, L. M. ^{[17
]}

Clapson, A. C. ^{[1
]}

Coignet, G. ^{[18
]}

Dalton, M. ^{[10
]}

Daniel, M. K. ^{[5
]}

Davids, I. D. ^{[14
,19
]}

Degrange, B. ^{[17
]}

Deil, C. ^{[1
]}

Dickinson, H. J. ^{[5
]}

Djannati-Atai, A. ^{[7
,8
]}

Domainko, W. ^{[1
]}

Drury, L. O. C. ^{[2
]}

Dubois, F. ^{[18
]}

Dubus, G. ^{[15
]}

Dyks, J. ^{[13
]}

Dyrda, M. ^{[20
]}

Egberts, K. ^{[1
]}

Emmanoulopoulos, D. ^{[9
]}

Espigat, P. ^{[7
,8
]}

Farnier, C. ^{[21
]}

Feinstein, F. ^{[21
]}

Fiasson, F. ^{[21
]}

Foerster, A. ^{[1
]}

Fontaine, G. ^{[17
]}

Fuessling, M. ^{[10
]}

Gabici, S. ^{[2
]}

Gallant, Y. A. ^{[21
]}

Gerard, L. ^{[7
,8
]}

机构：

[1] Max Planck Inst Kernphys, D-69029 Heidelberg, Germany

[2] Dublin Inst Adv Studies, Dublin 2, Ireland

[3] Yerevan Phys Inst, Yerevan 375036, Armenia

[4] Univ Erlangen Nurnberg, Phys Inst, D-91058 Erlangen, Germany

[5] Univ Durham, Dept Phys, Durham DH1 3LE, England

[6] CNRS UPS, Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France

[7] Univ Paris 07, Astroparticule & Cosmol APC, CNRS, F-75205 Paris 13, France

[8] Univ Paris 07, CNRS, CEA, Observ Paris,UMR 7164, Paris, France

[9] Heidelberg Univ, Landessternwarte, D-69117 Heidelberg, Germany

[10] Humboldt Univ, Inst Phys, D-12489 Berlin, Germany

[11] Univ Paris Diderot, CNRS, Observ Paris, LUTH, F-92190 Meudon, France

[12] CE Saclay, IRFU DSM CEA, F-91191 Gif Sur Yvette, France

[13] Nicolaus Copernicus Astron Ctr, PL-00716 Warsaw, Poland

[14] Northwest Univ, Unit Space Phys, ZA-2520 Potchefstroom, South Africa

[15] Univ Grenoble 1, INSU CNRS, Lab Astrophys Grenoble, F-38041 Grenoble 9, France

[16] Univ Paris 07, Univ Paris 06, LPNHE, CNRS IN2P3, F-75252 Paris 5, France

[17] Ecole Polytech, CNRS IN2P3, Lab Leprince Ringuet, Palaiseau, France

[18] CNRS IN2P3, Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France

[19] Univ Namibia, Windhoek, Namibia

[20] Inst Fizyki Jadrowej PAN, PL-31342 Krakow, Poland

[21] Univ Montpellier 2, CNRS IN2P3, Lab Phys Theor & Astroparticules, Montpellier, France

[22] Univ Hamburg, Inst Expt Phys, D-22761 Hamburg, Germany

[23] Univ Leeds, Sch Phys & Astron, Leeds LS2 9JT, W Yorkshire, England

[24] Univ Tubingen, Inst Astron & Astrophys, D-72076 Tubingen, Germany

[25] Nicolaus Copernicus Univ, Torun Ctr Astron, PL-87100 Torun, Poland

[26] Charles Univ Prague, Inst Particle & Nucl Phys, Prague 18000 8, Czech Republic

[27] Uniwersytet Jagiellonski, Obserwatorium Astron, PL-30244 Krakow, Poland

[28] Univ Adelaide, Sch Chem & Phys, Adelaide, SA 5005, Australia

[29] Ruhr Univ Bochum, Lehrstuhl Weltraum & Astrophys 4, Inst Theoret Phys, D-44780 Bochum, Germany

[30] USN, Div Space Sci, Res Lab, Washington, DC 20375 USA

[31] Stanford Univ, WW Hansen Expt Phys Lab, Kavli Inst Particle Astrophys & Cosmol, Dept Phys, Stanford, CA 94305 USA

[32] Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA

[33] Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Dept Physics, Santa Cruz, CA 95064 USA

[34] Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA

[35] AlbaNova, Oskar Klein Ctr Cosmo Particle Phys, SE-10691 Stockholm, Sweden

[36] Albanova, Stockholm Observ, SE-10691 Stockholm, Sweden

[37] Ist Nazl Fis Nucl, Sez Pisa, I-56127 Pisa, Italy

[38] CEA IRFU CNRS Univ Paris Diderot, Serv Astrophys, Lab AIM, CEA Saclay, F-91191 Gif Sur Yvette, France

[39] Ist Nazl Fis Nucl, Sez Trieste, I-34127 Trieste, Italy

[40] Univ Trieste, Dipartimento Fis, I-34127 Trieste, Italy

[41] Rice Univ, Dept Phys & Astron, Houston, TX 77251 USA

[42] Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy

[43] Univ Padua, Dipartimento Fis G Galilei, I-35131 Padua, Italy

[44] AlbaNova, Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden

[45] Ohio State Univ, Ctr Cosmol & Astroparticle Phys, Dept Phys, Columbus, OH 43210 USA

[46] Ist Nazl Fis Nucl, Sez Perugia, I-06123 Perugia, Italy

[47] Univ Perugia, Dipartimento Fis, I-06123 Perugia, Italy

[48] Univ Politecn Bari, Dipartimento Fis M Merlin, I-70126 Bari, Italy

[49] Ist Nazl Fis Nucl, Sez Bari, I-70126 Bari, Italy

[50] INAF Ist Astrofis Spaziale & Fis Cosm, I-20133 Milan, Italy

来源：

ASTROPHYSICAL JOURNAL LETTERS | 2009年 / 696卷 / 02期

关键词：

BL Lacertae objects: individual (PKS 2155-304); galaxies: active; gamma rays: observations; MULTIWAVELENGTH OBSERVATIONS; RAY SOURCES; GAMMA-RAYS; EGRET DATA; TELESCOPE; ASTRONOMY; GALAXIES; FLARE;

D O I：

10.1088/0004-637X/696/2/L150

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report on the first simultaneous observations that cover the optical, X-ray, and high-energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 2008 August 25 and 2008 September 6 (MJD 54704-54715), jointly with the Fermi Gamma-ray Space Telescope and the HESS atmospheric Cherenkov array, providing the first simultaneous MeV-TeV spectral energy distribution (SED) with the new generation of gamma-ray telescopes. The ATOM telescope and the RXTE and Swift observatories provided optical and X-ray coverage of the low-energy component over the same time period. The object was close to the lowest archival X-ray and very high energy (VHE; > 100 GeV) state, whereas the optical flux was much higher. The light curves show relatively little (similar to 30%) variability overall when compared to past flaring episodes, but we find a clear optical/VHE correlation and evidence for a correlation of the X-rays with the high-energy spectral index. Contrary to previous observations in the flaring state, we do not find any correlation between the X-ray and VHE components. Although synchrotron self-Compton models are often invoked to explain the SEDs of BL Lac objects, the most common versions of these models are at odds with the correlated variability we find in the various bands for PKS 2155-304.

引用

页码：L150 / L155

页数：6

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