FERMI/LARGE AREA TELESCOPE DISCOVERY OF GAMMA-RAY EMISSION FROM A RELATIVISTIC JET IN THE NARROW-LINE QUASAR PMN J0948+0022

By A. Abdo, M. Ackermann, M. Ajello, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B. Baughman and 161 more. 2009

164 citations recorded by the source corpus.

We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope of high-energy γ-ray emission from the peculiar quasar PMN J0948+0022 (z = 0.5846). The optical spectrum of this object exhibits rather narrow Hβ (FWHM(Hβ) ∼1500 km s−1), weak forbidden lines, and is therefore classified as a narrow-line type I quasar. This class of objects is thought to have relatively small black hole mass and to accrete at a high Eddington ratio. The radio loudness and variability of the compact radio core indicate the presence of a relativistic jet. Quasi-simultaneous radio/optical/X-ray and γ-ray observations are presented. Both radio and γ-ray emissions (observed over five months) are strongly variable. The simultaneous optical and X-ray data from Swift show a blue continuum attributed to the accretion disk and a hard X-ray spectrum attributed to the jet. The resulting broadband spectral energy distribution (SED) and, in particular, the γ-ray spectrum measured by Fermi are similar to those of more powerful Flat-Spectrum Radio Quasars (FSRQs). A comparison of the radio and γ-ray characteristics of PMN J0948+0022 with the other blazars detected by LAT shows that this source has a relatively low radio and γ-ray power with respect to other FSRQs. The physical parameters obtained from modeling the SED also fall at the low power end of the FSRQ parameter region discussed in Celotti & Ghisellini. We suggest that the similarity of the SED of PMN J0948+0022 to that of more massive and more powerful quasars can be understood in a scenario in which the SED properties depend on the Eddington ratio rather than on the absolute power.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/0c7e83d31707fd7fa2087c1c1c93260be53e0b76

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In Astronomy and Astrophysics

1. Bing Zhang
2. G. Ghisellini
3. F. Tavecchio
4. F. Ryde
5. E. Orlando
6. L. Maraschi
7. G. Ghirlanda
8. Luigi Foschini

In Nuclear and High Energy Physics

1. G. Ghisellini
2. F. Tavecchio
3. L. Maraschi
4. Luigi Foschini
5. E. Orlando
6. C. Dermer
7. G. Ghirlanda
8. A. Reimer

Citations in the corpus

• THE FIRST CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE (2010, background): “Abdo et al. (2009f) noted that, as the number of LAT detections increased, source confusion was likely to be more of a problem, and indeed, the 1LAC includes 35 LAT sources that are associated with more than one AGN (for a total of 73 such associations).”
• General physical properties of bright Fermi blazars (2009, background): “The Large Area Telescope (LAT) onboard theF rmi Satellite, in the first months of operation succeeded to double the number of know γ–ray emitting blazars (Abdo et al. 2009a, hereafter A09).”
• Properties of flat-spectrum radio-loud Narrow-Line Seyfert 1 Galaxies (2014, methodology): “However, since the optical spectrum of SDSS was observed in 2000 and the MW campaign used for the SED modelling were obtained in 2008–2011, it is also possible that the Eddington ratio really changed.”
• TeV BL Lac objects at the dawn of the Fermi era (2009, background): “Moreover, for three sources reported in Table 1 (0141+268, 2 Note that one of the sources classified as a FSRQ is a radio-loud narrowline Seyfert 1 galaxy (Abdo et al. 2009b; Foschini et al. 2009).”
• RADIO-LOUD NARROW-LINE SEYFERT 1 AS A NEW CLASS OF GAMMA-RAY ACTIVE GALACTIC NUCLEI (2009, methodology): “One of them is the already well-known PMN J0948+0022 (Abdo et al. 2009a).”
• BLAZARS IN THE FERMI ERA: THE OVRO 40 m TELESCOPE MONITORING PROGRAM (2010, methodology): “We also apply our observations in studies of the second mode through Fermi-LAT multiwavelength campaigns for flaring sources (e.g. Abdo et al. 2009; Fermi-LAT Collaboration et al. 2010)) and through collaboration with the F-GAMMA project, a complementary effort representing the second mode, focused…”