The Different Nature of Seyfert 2 Galaxies With and Without Hidden Broad-line Regions

  title={The Different Nature of Seyfert 2 Galaxies With and Without Hidden Broad-line Regions},
  author={Yu-Zhong Wu and En-peng Zhang and Yan-chun Liang and Cheng-min Zhang and Yongheng Zhao},
  journal={The Astrophysical Journal},
We compile a large sample of 120 Seyfert 2 galaxies (Sy2s) which contains 49 hidden broad-line region (HBLR) Sy2s and 71 non-HBLR Sy2s. From the difference in the power sources between two groups, we test whether HBLR Sy2s are dominated by active galactic nuclei (AGNs) and whether non-HBLR Sy2s are dominated by starbursts. We show that (1) HBLR Sy2s have larger accretion rates than non-HBLR Sy2s; (2) HBLR Sy2s have larger [Ne V] λ14.32/[Ne II] λ12.81 and [O IV] λ25.89/[Ne II] λ12.81 line ratios… 

Figures and Tables from this paper

We present a large sample which contains 45 Seyfert 1 galaxies (Sy1s), 46 hidden broad-line region (HBLR) Seyfert 2 galaxies (Sy2s), 57 non-HBLR Sy2s, and 22 starburst galaxies to distinguish their
The dichotomy of Seyfert 2 galaxies: intrinsic differences and evolution
We present a study of the local environment (≤200 h −1 kpc) of 31 hidden broad line region (HBLR) and 43 non-HBLR Seyfert 2 (Sy2) galaxies in the nearby universe (z ≤ 0.04). To compare our findings,
Upholding the unified model for active galactic nuclei: VLT/FORS2 spectropolarimetry of Seyfert 2 galaxies
The origin of the unification model for Active Galactic Nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068.
We compare the 4000 A break (Dn (4000)) strength in the central kpc of hidden broad-line region (HBLR) and non-HBLR Seyfert 2 galaxies to investigate the origin of these galaxies. Our results show
Simultaneous X-ray and optical observations of true type 2 Seyfert galaxies
We present the results of a campaign of simultaneous X-ray and optical observations of ‘true’ type 2 Seyfert galaxies candidates, i.e. active galactic nuclei without a broad-line region (BLR). Out of
The link between the Hidden Broad Line Region and the accretion rate in Seyfert 2 galaxies
In the past few years, more and more pieces of evidence have been presented for a revision of the widely accepted unified model of active galactic nuclei. A model based solely on orientation cannot
Large-scale environments of narrow-line Seyfert 1 galaxies
Studying large-scale environments of narrow-line Seyfert 1 (NLS1) galaxies gives a new perspective on their properties, particularly their radio loudness. The large-scale environment is believed to
The Evolution Sequence in Narrow-Line and Broad-Line SEYFERT 1 Galaxies
  • Y. Z. Wu, S. Zhang
  • Physics
    Proceedings of the International Astronomical Union
  • 2012
Abstract Collecting a sample of 50 narrow-line Seyfert 1 galaxies (NLS1s) and 44 broad-line Seyfert 1 galaxies (BLS1s), we show that the theoretical maximum starburst line derived by Kewley et al.
A high Eddington-ratio, true Seyfert 2 galaxy candidate: implications for broad-line region models
A bright, soft X-ray source was detected on 2010 July 14 during an XMM–Newton slew at a position consistent with the galaxy GSN 069 ( z = 0.018). Previous ROSAT observations failed to detect the
Statistical multifrequency study of narrow-line Seyfert 1 galaxies
High-energy {\gamma}-rays, which are produced by powerful relativistic jets, are usually associated with blazars and radio galaxies. In the current active galactic nuclei (AGN) paradigm, such jets


The Eddington Ratios in Seyfert 2 Galaxies with and without Hidden Broad-Line Regions
Using a large sample of 90 Seyfert 2 galaxies (Sy2s) with spectropolarimetric observations, we test the suggestion that the presence of hidden broad-line regions (HBLRs) in Sy2s depends upon the
Seyfert 2 Galaxies with Spectropolarimetric Observations
We present a compilation of radio, infrared, optical, and hard X-ray (2-10 keV) data for a sample of 90 Seyfert 2 galaxies (Sy2s) with spectropolarimetric observations (41 Sy2s with detection of
The Unified Model of Active Galactic Nuclei. I. Non-Hidden Broad-Line Region Seyfert 2 and Narrow-Line Seyfert 1 Galaxies
The unified model of Seyfert galaxies suggests that there are hidden broad-line regions (HBLRs) in Seyfert 2 galaxies (S2s). However, there is increasing evidence for the appearance of a subclass of
The Unified Model of Active Galactic Nuclei. II. Evolutionary Connection
We assemble a sample composed of 243 nearby Seyfert galaxies with redshifts z ≤ 0.05 to test the unification scheme. The sample contains 94 broad emission line Seyfert 1 galaxies (BLS1s), 44 narrow
The Unified Model and Evolution of Active Galaxies: Implications from a Spectropolarimetric Study
We extend the analysis presented in Paper I of a spectropolarimetric survey of the CfA and 12 lm samples of Seyfert 2 galaxies (S2s). We confirm that polarized (hidden) broad-line region (HBLR) S2s
Investigating the Nuclear Obscuration in Two Types of Seyfert 2 Galaxies
We build a large sample of Seyfert 2 galaxies (Sy2s) with both optical spectropolarimetric and X-ray data available, in which 29 of the Sy2s have a detection of polarized broad emission lines (PBLs)
Dust Morphology of Hidden Broad-Line Region and Non-Hidden Broad-Line Region Seyfert 2 Galaxies
We investigate the nuclear dust properties of hidden broad-line region (HBLR) and non-HBLR Seyfert 2 galaxies. Optical images obtained from the Hubble Space Telescope for a selected sample of HBLR
Nuclear obscuration and scattering in Seyfert 2 galaxies
We study the relation between gaseous absorbing column density (N$_{\rm H}$), infrared colors and detectability of the broad lines in a large sample of Seyfert 2 galaxies(Sy2s). We confirm that Sy2s
VISIR / VLT mid-infrared imaging of Seyfert nuclei: nuclear dust emission and the Seyfert-2 dichotomy
Aims. Half of the Seyfert-2 galaxies escaped detection of broad lines in their polarised spectra observed so far. Some authors have suspected that these non-HBLRs contain real Sy2 nuclei without
Unabsorbed Seyfert 2 galaxies
We present a sample of 17 type 2 Seyfert galaxies which have an X-ray column density lower than 10 22 cm 2 .T he Compton thin nature of these sources is strongly suggested by isotropic indicators. We