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تسجيل مستخدم جديدObservations of the gamma-ray emitting narrow-line Seyfert 1, SBS 0846+513, and its host galaxy
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The gamma-ray emitting galaxy SBS 0846+513 has been classified as a Narrow-Line Seyfert 1 from its spectroscopy, and on that basis it was thought likely to have a small central black hole hosted in a spiral galaxy. But very few of the gamma-ray Narrow-Line Seyfert 1s have high-resolution imaging of their hosts, so it is unknown how those expectations hold up for the gamma-emitting class. We have observed this galaxy in the J-band with the Large Binocular Telescopes LUCI1 camera and the ARGOS adaptive optics system. We estimate its black hole mass to lie between $7.70 leq log frac{text{M}}{text{M}_odot} leq 8.19$, using the correlation with bulge luminosity, or $7.96 leq log frac{text{M}}{text{M}_odot} leq 8.16$ using the correlation with S{e}rsic index, putting its mass at the high end of the Narrow Line Seyfert 1 range. These estimates are independent of the Broad Line Region viewing geometry and avoid underestimates due to looking down the jet axis. Its host shows evidence of a bulge + disc structure, both from two-dimensional modeling and isophote shape, in keeping with the expectations. Mergers and interactions appear to be common among the gamma-ray Narrow-Line Seyfert 1s, and we see some circumstantial evidence for companion galaxies or disturbed features in the host.
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We report Fermi-LAT observations of the radio-loud AGN SBS 0846+513 (z=0.5835), optically classified as a Narrow-Line Seyfert 1 galaxy, together with new and archival radio-to-X-ray data. The source was not active at gamma-ray energies during the fir
st two years of Fermi operation. A significant increase in activity was observed during 2010 October-2011 August. In particular a strong gamma-ray flare was observed in 2011 June reaching an isotropic gamma-ray luminosity (0.1-300 GeV) of 1.0x10^48 erg/s, comparable to that of the brightest flat spectrum radio quasars, and showing spectral evolution in gamma rays. An apparent superluminal velocity of (8.2+/-1.5)c in the jet was inferred from 2011-2012 VLBA images, suggesting the presence of a highly relativistic jet. Both the power released by this object during the flaring activity and the apparent superluminal velocity are strong indications of the presence of a relativistic jet as powerful as those of blazars. In addition, variability and spectral properties in radio and gamma-ray bands indicate blazar-like behaviour, suggesting that, except for some distinct optical characteristics, SBS 0846+513 could be considered as a young blazar at the low end of the blazars black hole mass distribution.
The narrow-line Seyfert 1 galaxy SBS 0846+513 was first detected by the Large Area Telescope (LAT) on-board Fermi in 2011 June-July when it underwent a period of flaring activity. Since then, as Fermi continues to accumulate data on this source, its
flux has been monitored on a daily basis. Two further gamma-ray flaring episodes from SBS 0846+513 were observed in 2012 May and August, reaching a daily peak flux integrated above 100 MeV of (50+/-12)x10^-8 ph/cm^2/s, and (73+/-14)x10^-8 ph/cm^2/s on May 24 and August 7, respectively. Three outbursts were detected at 15 GHz by the Owens Valley Radio Observatory 40-m telescope in 2012 May, 2012 October, and 2013 January, suggesting a complex connection with the gamma-ray activity. The most likely scenario suggests that the 2012 May gamma-ray flare may not be directly related to the radio activity observed over the same period, while the two gamma-ray flaring episodes may be related to the radio activity observed at 15 GHz in 2012 October and 2013 January. The gamma-ray flare in 2012 May triggered Swift observations that confirmed that SBS 0846+513 was also exhibiting high activity in the optical, UV and X-ray bands, thus providing a firm identification between the gamma-ray source and the lower-energy counterpart. We compared the spectral energy distribution (SED) of the flaring state in 2012 May with that of a quiescent state. The two SEDs, modelled as an external Compton component of seed photons from a dust torus, could be fitted by changing the electron distribution parameters as well as the magnetic field. No significant evidence of thermal emission from the accretion disc has been observed. Interestingly, in the 5 GHz radio luminosity vs. synchrotron peak frequency plot SBS 0846+513 seems to lie in the flat spectrum radio quasar part of the so-called `blazar sequence.
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Filippo DAmmando
, Jose A.n Acosta-Pulido (Instituto de Astrofisica de Canarias
, Departamento den Astrofisica
2018
The detection of gamma-ray emission from narrow-line Seyfert 1 galaxies (NLSy1) has challenged the idea that large black hole (BH) masses ($ge$10$^8$ M$_{odot}$) are needed to launch relativistic jets. We present near-infrared imaging data of the gam
ma-ray-emitting NLSy1 PKS 1502+036 obtained with the Very Large Telescope. Its surface brightness profile, extending to $sim$ 20 kpc, is well described by the combination of a nuclear component and a bulge with a Sersic index $n$ = 3.5, which is indicative of an elliptical galaxy. A circumnuclear structure observed near PKS 1502+036 may be the result of galaxy interactions. A BH mass of about $sim 7 times 10^{8}$ M$_{odot}$ has been estimated by the bulge luminosity. The presence of an additional faint disc component cannot be ruled out with the present data, but this would reduce the BH mass estimate by only $sim$ 30%. These results, together with analogous findings obtained for FBQS J1644+2619, indicate that the relativistic jets in gamma-ray-emitting NLSy1 are likely produced by massive black holes at the center of elliptical galaxies.
The discovery of $gamma$-ray emission from radio-loud narrow-line Seyfert 1 (NLSy1) galaxies has questioned the need for large black hole masses (> 10$^8$ M$_{odot}$) to launch relativistic jets. We present near-infrared data of the $gamma$-ray-emitt
ing NLSy1 FBQS J1644+2619 that were collected using the camera CIRCE (Canarias InfraRed Camera Experiment) at the 10.4-m Gran Telescopio Canarias to investigate the structural properties of its host galaxy and to infer the black hole mass. The 2D surface brightness profile is modelled by the combination of a nuclear and a bulge component with a Sersic profile with index $n$ = 3.7, indicative of an elliptical galaxy. The structural parameters of the host are consistent with the correlations of effective radius and surface brightness against absolute magnitude measured for elliptical galaxies. From the bulge luminosity, we estimated a black hole mass of (2.1$pm$0.2) $times$10$^8$ M$_{odot}$, consistent with the values characterizing radio-loud active galactic nuclei.
We present a multi-frequency study of PKS J1222$+$0413 (4C$+$04.42), currently the highest redshift $gamma$-ray emitting narrow-line Seyfert 1 ($gamma$-NLS1). We assemble a broad spectral energy distribution (SED) including previously unpublished dat
asets: X-ray data obtained with the NuSTAR and Neil Gehrels Swift observatories; near-infrared, optical and UV spectroscopy obtained with VLT X-shooter; and multiband radio data from the Effelsberg telescope. These new observations are supplemented by archival data from the literature. We apply physical models to the broadband SED, parameterising the accretion flow and jet emission to investigate the disc-jet connection. PKS J1222$+$0413 has a much greater black hole mass than most other NLS1s, $M_mathrm{BH}approx2times10^{8}$ M$_odot$, similar to those found in flat spectrum radio quasars (FSRQs). Therefore this source provides insight into how the jets of $gamma$-NLS1s relate to those of FSRQs.
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