Properties of the Narrow Line Seyfert 1 Galaxies Revisited

Abstract

There is growing evidence to suggest that the black hole mass has been previously underestimated with the Hβ line width for certain active galactic nuclei (AGN). With the assumption of the flatter rather than isotropic velocity distribution of gases in the broad-line region of AGN, we investigated the properties of narrow line Seyfert 1 (NLS1) galaxies, like the black hole mass and the Eddington ratio, and compared with broad line Seyfert 1 (BLS1) galaxies. Since gamma-rays detected in a few NLS1s which favor a smaller viewing angle in NLS1s than BLS1s, with the projection effect we estimated the relative black hole mass and Eddington ratio for NLS1s and BLS1s. The result implies that the NLS1s and BLS1s have similar black hole masses and Eddington ratios, peaked at a larger black hole mass and lower Eddington ratio for the NLS1s than thought before. Furthermore, with applying the correction factor 6 of average black hole mass as derived from the modelling of both optical and UV data in radio-loud NLS1s by Calderone et al., to the Xu et al. sample, we find that the NLS1s and BLS1s also show similar black hole masses and Eddington ratios, peaked at 2.0 × 10 7 M ⊙ and 0.12 (Eddington ratio) for the NLS1s. The M BH − σ relation due to the enhanced black hole masses of NLS1s is discussed. In addition, there seems to show a linear correlation between jet power and disk luminosity for the flat spectrum radio-loud NLS1 sample, which implies an accretion dominated rather than black hole spin dominated jet.

A comparison of X-ray photon indices among the narrow and broad-line Seyfert 1 galaxies

“…To reconcile this discrepancy one possibility is that the higher R Edd in NLSy1s (compared to BLSy1s) can be due to the fact that the inclination angle of the NLSy1 is lower than that of the BLSy1. As a result, the observed FWHM (in km s −1 ) of Hβ line (FWHM×sin(θ)) of the BLR would have been underestimated more in the case of NLSy1 (due to smaller inclination) compared to the BLSy1 (e.g., see Baldi et al 2016;Liu et al 2016;). This will directly impact the underestimation of their M BH (being proportional to the observed FWHM in the common L-R BLR scaling relationship) and hence the over-estimation of the R Edd value (being inversely proportional to M BH ).…”

A Catalog of Narrow Line Seyfert 1 Galaxies from the Sloan Digital Sky Survey Data Release 12

“…Also, Calderone et al (2013), by modeling the optical and UV data for a sample of 23 radio-loud NLSy1 galaxies with a Shakura & Sunyaev disk, found M BH larger than 10 8 M , about six times larger than those obtained from single epoch viral black hole mass estimates. Furthermore, Decarli et al (2008) suggested that if the BLR has a disk-like geometry as opposed to a spherical geometry, the geometrical factor (f ) can fully account for the observed mass deficit in NLSy1 galaxies and ξ Edd turns out to be similar to BLSy1 galaxies (see also Liu et al 2016).…”

“…They are generally believed to have lower black hole masses (10 6 -10 8 M ) and higher Eddington ratios than BLSy1 galaxies (Zhou et al 2006, hereafter ZH06) since the former have narrower Balmer lines than the latter (see also Xu et al 2012). However, there are reports that the black hole masses of NLSy1 and BLSy1 galaxies are indifferent, and geometrical effects can fully account for the mass deficit in NLSy1 galaxies (Calderone et al 2013;Baldi et al 2016;Liu et al 2016). A majority of the population of NLSy1 galaxies are radio quiet with a minority of about 7% are known to be radio-loud (Pogge 2000).…”

Jetted Narrow-Line Seyfert 1 Galaxies & Co.: Where Do We Stand?

“…Other studies at infrared/optical wavelengths [18,[269][270][271][272][273][274][275][276][277][278][279] and at X-rays [254,280,281] have been done.…”