dc.contributor |
Universitat de Barcelona |
dc.contributor.author |
MAGIC Collaboration |
dc.contributor.author |
Marcote Martin, Benito |
dc.contributor.author |
Moldón Vara, Francisco Javier |
dc.contributor.author |
Munar i Adrover, Pere |
dc.contributor.author |
Paredes i Poy, Josep Maria |
dc.contributor.author |
Ribó Gomis, Marc |
dc.contributor.author |
Zanin, Roberta |
dc.date |
2014-10-14T08:20:19Z |
dc.date |
2014-10-14T08:20:19Z |
dc.date |
2014-03 |
dc.date |
2014-10-14T08:20:20Z |
dc.identifier.citation |
0004-6361 |
dc.identifier.citation |
644031 |
dc.identifier.uri |
http://hdl.handle.net/2445/58575 |
dc.format |
10 p. |
dc.format |
application/pdf |
dc.language.iso |
eng |
dc.publisher |
Springer Verlag |
dc.relation |
Versió postprint del document publicat a: http://dx.doi.org/10.1051/0004-6361/201321938 |
dc.relation |
Astronomy and Astrophysics, 2014, vol. 563, p. A91 |
dc.relation |
http://dx.doi.org/10.1051/0004-6361/201321938 |
dc.rights |
(c) Springer Verlag, 2014 |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.subject |
Galàxies actives |
dc.subject |
Astronomia de raigs X |
dc.subject |
Astronomia de raigs gamma |
dc.subject |
Raigs còsmics |
dc.subject |
Astrofísica |
dc.subject |
Active galaxies |
dc.subject |
X-ray astronomy |
dc.subject |
Gamma ray astronomy |
dc.subject |
Cosmic rays |
dc.subject |
Astrophysics |
dc.title |
Rapid and multiband variability of the TeV bright active nucleus of the galaxy IC 310 |
dc.type |
info:eu-repo/semantics/article |
dc.type |
info:eu-repo/semantics/acceptedVersion |
dc.description.abstract |
The radio galaxy IC 310 has recently been identified as a γ-ray emitter based on observations at GeV energies with Fermi-LAT and at very high energies (VHE, E > 100 GeV) with the MAGIC telescopes. Originally classified as a head-tail radio galaxy, the nature of this object is subject of controversy since its nucleus shows blazar-like behavior. Aims. To understand the nature of IC 310 and the origin of the VHE emission, we studied the spectral and flux variability of IC 310 from the X-ray band to the VHE γ-ray regime. Methods. The light curve of IC 310 above 300 GeV has been measured with the MAGIC telescopes from 2009 October to 2010 February. Contemporaneous Fermi-LAT data (2008−2011) in the 10−500 GeV energy range were also analyzed. In the X-ray regime, archival observations from 2003 to 2007 with XMM-Newton, Chandra, and Swift-XRT in the 0.5−10 keV band were studied. Results. The VHE light curve reveals several high-amplitude and short-duration flares. Day-to-day flux variability is clearly present (>5σ). The photon index between 120 GeV and 8 TeV remains at the value Γ ~ 2.0 during both low and high flux states. The VHE spectral shape does not show significant variability, whereas the flux at 1 TeV changes by a factor of ~7. Fermi-LAT detected only eight γ-ray events in the energy range 10 GeV 500 GeV in three years of observation. The measured photon index of Γ = 1.3 ± 0.5 in the Fermi-LAT range is very hard. The X-ray measurements show strong variability in both flux and photon index. The latter varied from 1.76 ± 0.07 to 2.55 ± 0.07. Conclusions. The rapid variability measured in γ-rays and X-rays confirms the blazar-like behavior of IC 310. The multi-TeV γ-ray emission seems to originate from scales of less than 80 Schwarzschild radii (for a black hole mass of 2 × 108 M⊙) within the compact core of its FR I radio jet with orientation angle 10°−38°. The spectral energy distribution resembles that of an extreme blazar, albeit the luminosity is more than two orders of magnitude lower. |