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TOPIC: PMN J0948+0022
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RE: PMN J0948+0022
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Title: The Variable Optical Polarisation of J0948+0022
Authors: H. R. Miller, J. R. Eggen, J. D. Maune

The results of monitoring the optical polarisation and the gamma-ray flux for the radio-loud narrow-line Seyfert 1 galaxy is reported. We have detected a weak correlation between the gamma-ray variability and the optical variability. However, these observations do not provide conclusive evidence that the emissions are due to a relativistic jet oriented close to the line-of-sight to the observer.

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Blobrana


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Title: The XMM-Newton view of the radio loud narrow line Seyfert1 galaxy PMN J0948+0022
Authors: Subir Bhattacharyya (BARC), Himali Bhatt (BARC), Nilay Bhatt (BARC), Krishna Kumar Singh (BARC)

We analysed the archival XMM-Newton data of radio loud narrow line Seyfert1 galaxy PMN J0948+0022 in the energy range 0.3--10.0 keV. The X-ray data revealed the spectrum in 0.3--10.0 keV energy band is not a simple power-law as described in literature. Instead it consisted of a power-law with soft excess below 2.5 keV. The X-ray spectrum was fitted with four different models and it was shown the soft excess component of the spectrum in 0.3--2.5 keV energy range could be described reasonably well within the framework of the thermal Comptonisation model as well as relativistically blurred reflection model. The power-law component required to fit the spectrum beyond 2.5 keV was found to be rather hard compared to the ones observed in other obscured active galactic nuclei. It is also shown that the Swift/XRT spectrum from the source could not reveal the soft excess component due to poor statistics. The fractional variability estimated from XMM-Newton data indicates the presence of independently varying components in the spectrum above 1 keV.

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Blobrana


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Posts: 131433
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Seyfert 1 galaxy J0948+0022
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Title: The Extreme Optical Variability of J0948+0022
Authors: Jeremy D. Maune, H. Richard Miller, Joesph R. Eggen

We report on observations of the optical variability of the radio-loud, narrow-line Seyfert 1 galaxy J0948+0022 on time scales ranging from minutes to years. Implications regarding recent suggestions that the object may constitute a prototype for an emerging class of blazar-like objects similar to FSRQs are discussed. The optical microvariability observed for J0948+0022 is found to be similar to that found for a typical LBL blazar. Based on observations of J0948+0022 in a flaring state and a significantly lower state, one can demonstrate that these rapid variations are most likely originating in the relativistic jet and not in the accretion disk

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Blobrana


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PMN J0948+0022
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Title: Fermi/LAT discovery of gamma-ray emission from a relativistic jet in the narrow-line quasar PMN J0948+0022
Authors: The Fermi/LAT Collaboration: A.A. Abdo, et al., G. Ghisellini, L. Maraschi, F. Tavecchio, E. Angelakis

We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope of high-energy gamma-ray emission from the peculiar quasar PMN J0948+0022 (z=0.5846). The optical spectrum of this object exhibits rather narrow Hbeta (FWHM(Hbeta) ~ 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 high Eddington ratio. The radio loudness and variability of the compact radio core indicates the presence of a relativistic jet. Quasi simultaneous radio-optical-X-ray and gamma-ray observations are presented. Both radio and gamma-ray emission (observed over 5-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 broad band spectral energy distribution (SED) and, in particular, the gamma-ray spectrum measured by Fermi are similar to those of more powerful FSRQ. A comparison of the radio and gamma-ray characteristics of PMN J0948+0022 with the other blazars detected by LAT shows that this source has a relatively low radio and gamma-ray power, with respect to other FSRQ. The physical parameters obtained from modelling the SED also fall at the low power end of the FSRQ parameter region discussed in Celotti & Ghisellini (2008). 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.

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