期刊
ASTRONOMY & ASTROPHYSICS
卷 548, 期 -, 页码 -出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201220225
关键词
galaxies: jets; galaxies: Seyfert; gamma rays: galaxies; galaxies: individual: PMN J0948+0022
资金
- INSU/CNRS (France)
- MPG (Germany)
- IGN (Spain)
- International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne
- Academy of Finland [212656, 210338, 121148]
- NASA [NNX08AW31G, NNX11A043G, NAS5-00136]
- NSF [AST-0808050, AST-1109911, 1066293]
- NASA-Fermi grant [NNX08AV67G]
- Russian Foundation for Basic Research [11-02-00368]
- basic research program Active processes in galactic and extragalactic objects of the Physical Sciences Division of the Russian Academy of Sciences
- Dynasty Foundation
- KAKENHI [24540240]
- Japan Society for the Promotion of Science (JSPS) [24340042]
- ASI-INAF [I/009/10/0]
- Alfred P. Sloan Foundation
- National Science Foundation
- US Department of Energy
- National Aeronautics and Space Administration
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- American Museum of Natural History
- Astrophysical Institute Potsdam
- University of Basel
- University of Cambridge
- Case Western Reserve University
- University of Chicago
- Drexel University
- Fermilab
- Institute for Advanced Study
- Japan Participation Group
- Johns Hopkins University
- Joint Institute for Nuclear Astrophysics
- Kavli Institute for Particle Astrophysics and Cosmology
- Korean Scientist Group
- Chinese Academy of Sciences (LAMOST)
- Los Alamos National Laboratory
- Max Planck Institute for Astronomy (MPIA)
- Max Planck Institute for Astrophysics (MPA)
- New Mexico State University
- Ohio State University
- University of Pittsburgh
- University of Portsmouth
- Princeton University
- United States Naval Observatory
- University of Washington
- Grants-in-Aid for Scientific Research [24540240] Funding Source: KAKEN
- NASA [94461, NNX08AV67G] Funding Source: Federal RePORTER
We present more than three years of observations at different frequencies, from radio to high-energy gamma-rays, of the Narrow-Line Seyfert 1 (NLS1) Galaxy PMN J0948+0022 (z = 0.585). This source is the first NLS1 detected at energies above 100 MeV and therefore can be considered the prototype of this emerging new class of gamma-ray emitting active galactic nuclei (AGN). The observations performed from 2008 August 1 to 2011 December 31 confirmed that PMN J0948+0022 generates a powerful relativistic jet, which is able to develop an isotropic luminosity at gamma-rays of the order of 10(48) erg s(-1), at the level of powerful quasars. The evolution of the radiation emission of this source in 2009 and 2010 followed the canonical expectations of relativistic jets with correlated multiwave-length variability (gamma-rays followed by radio emission after a few months), but it was difficult to retrieve a similar pattern in the light curves of 2011. The comparison of gamma-ray spectra before and including 2011 data suggested that there was a softening of the high-energy spectral slope. We selected five specific epochs to be studied by modelling the broad-band spectrum, which are characterised by an outburst at gamma-rays or very low/high flux at other wavelengths. The observed variability can largely be explained by changes in the injected power, the bulk Lorentz factor of the jet, or the electron spectrum. The characteristic time scale of doubling/halving flux ranges from a few days to a few months, depending on the frequency and the sampling rate. The shortest doubling time scale at gamma-rays is 2.3 +/- 0.5 days. These small values underline the need of highly sampled multiwavelength campaigns to better understand the physics of these sources.
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