THE DIFFERENT NATURE OF SEYFERT 2 GALAXIES WITH AND WITHOUT HIDDEN BROAD-LINE REGIONS

Journal Article · Fri Apr 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/730/2/121· OSTI ID:21574826

Yuzhong, Wu; Enpeng, Zhang; Yanchun, Liang; Chengmin, Zhang

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] {lambda}14.32/[Ne II] {lambda}12.81 and [O IV] {lambda}25.89/[Ne II] {lambda}12.81 line ratios than non-HBLR Sy2s; and (3) HBLR Sy2s have smaller IRAS f{sub 60}/f{sub 25} flux ratios, which show the relative strength of the host galaxy and nuclear emission, than non-HBLR Sy2s. Consequently, we suggest that HBLR Sy2s and non-HBLR Sy2s are AGN dominated and starburst dominated, respectively. In addition, non-HBLR Sy2s can be classified into luminous (L{sub [OIII]}>10{sup 41} erg s{sup -1}) and less luminous (L{sub [OIII]} < 10{sup 41} erg s{sup -1}) samples, when considering only their obscuration. We suggest that (1) the invisibility of polarized broad lines (PBLs) in the luminous non-HBLR Sy2s depends on the obscuration and (2) the invisibility of PBLs in the less luminous non-HBLR Sy2s depends on the very low Eddington ratio rather than the obscuration.

• OSTI ID: 21574826
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 730; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
GALAXIES
GALAXY NUCLEI
MATHEMATICS
SEYFERT GALAXIES
STATISTICS