SDSS J094857.3+002225: A Very Radio Loud, Narrow‐Line Quasar with Relativistic Jets?

Zhou, Hongyan; Wang, Tinggui; Dong, Xiao-Bo; Zhou, Yong; Li, Cheng

doi:10.1086/345523

Cited by 95 publications

(182 citation statements)

References 30 publications

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“…Thus, the first discoveries of RLNLS1s (e.g. Remillard et al 1986, Oshlack et al 2001, Zhou et al 2003 seemed to be exceptions, rather than the tip of an iceberg. The early surveys revealed only a handful of objects: 11 by Zhou & Wang (2002) and Komossa et al (2006a), and 16 by Whalen et al (2006).…”

Section: Introductionmentioning

confidence: 99%

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Properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

Foschini

Berton

Caccianiga

et al. 2015

A&A

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We have conducted a multiwavelength survey of 42 radio loud narrow-1ine Seyfert 1 galaxies (RLNLS1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. We analyse data from radio frequencies to X-rays, and supplement these with information available from online catalogues and the literature in order to cover the full electromagnetic spectrum. This is the largest known multiwavelength survey for this type of source. We detected 90% of the sources in X-rays and found 17% at γ rays. Extreme variability at high energies was also found, down to timescales as short as hours. In some sources, dramatic spectral and flux changes suggest interplay between a relativistic jet and the accretion disk. The estimated masses of the central black holes are in the range ∼ 10 6−8 M ⊙ , lower than those of blazars, while the accretion luminosities span a range from ∼ 0.01 to ∼ 0.49 times the Eddington limit, with an outlier at 0.003, similar to those of quasars. The distribution of the calculated jet power spans a range from ∼ 10 42.6 to ∼ 10 45.6 erg s −1 , generally lower than quasars and BL Lac objects, but partially overlapping with the latter. Once normalised by the mass of the central black holes, the jet power of the three types of active galactic nuclei are consistent with each other, indicating that the jets are similar and the observational differences are due to scaling factors. Despite the observational differences, the central engine of RLNLS1s is apparently quite similar to that of blazars. The historical difficulties in finding radio-loud narrow-line Seyfert 1 galaxies might be due to their low power and to intermittent jet activity.

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Section: Introductionmentioning

confidence: 99%

“…with the ratio between radio and optical flux densities greater than 10. One source is also in the present sample (J0948 + 0022, Zhou et al 2003), while we have discarded the other (J1722 + 5654, Komossa et al 2006b) because of its steep radio index (see Sect. 2).…”

Section: Introductionmentioning

confidence: 99%

Properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

Foschini

Berton

Caccianiga

et al. 2015

A&A

188

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“…The optical spectrum of PMN J0948+0022 exhibits the usual characteristics of NLS1s (cf. Osterbrock & Pogge 1985;Goodrich 1989): FWHM(Hβ) = 1500 ± 55 km s −1 , [OIII]/Hβ < 3, strong optical FeII emission (Zhou et al 2003). Such types of AGN are generally radio quiet (Ulvestadt et al 1995;Komossa et al 2006), so it was a surprise to detect strong radio emission.…”

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confidence: 99%

“…Zhou et al (2003) first reported the unexpected connection of its NLS1 character with strong and flat-spectrum radio emission. The optical spectrum of PMN J0948+0022 exhibits the usual characteristics of NLS1s (cf.…”

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confidence: 99%

“…Such types of AGN are generally radio quiet (Ulvestadt et al 1995;Komossa et al 2006), so it was a surprise to detect strong radio emission. The radio power at 5 GHz was measured to be ∼10 43 erg s −1 , a relatively small value for a blazar, but very high for a NLS1, resulting in a radio loudness RL = f 5 GHz / f 440 nm > ∼ 10 3 (Zhou et al 2003). This value is among the highest for a NLS1, although not the highest (cf.…”

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confidence: 99%

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Radio-to-γ-ray monitoring of the narrow-line Seyfert 1 galaxy PMN J0948 + 0022 from 2008 to 2011

Foschini

Angelakis

Fuhrmann

et al. 2012

A&A

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We present more than three years of observations at different frequencies, from radio to high-energy γ-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 γ-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 γ-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 multiwavelength variability (γ-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 γ-ray spectra before and including 2011 data suggested that there was a softening of the highenergy spectral slope. We selected five specific epochs to be studied by modelling the broad-band spectrum, which are characterised by an outburst at γ-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 γ-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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