|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'501'711
Articles rated: 2609
19 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Why X-ray--Selected AGN Appear Optically Dull | | J. R. Rigby
; G. H. Rieke
; J. L. Donley
; A. Alonso-Herrero
; P. G. Pérez-González
; | | Date: |
13 Mar 2006 | | Abstract: | We investigate why half of X-ray--selected active galactic nuclei (AGN) in deep surveys lack signs of accretion in their optical spectra. The majority of these ``optically--dull’’ AGN are no more than 6 times fainter than their host galaxies in rest-frame R-band; as such, AGN lines are unlikely to be overwhelmed by stellar continuum in at least half the sample. We find that optically--dull AGN have the mid--infrared emission and L(x)/L(IR) ratios characteristic of local Seyferts, suggesting that the cause of optical dullness is not missing UV--optical continua. We compare the morphologies of 22 optically--dull and 9 optically--active AGN at 0.5<z<0.8, and find that optically--dull AGN show a wide range of axis ratio, but optically--active AGN have only very round axis ratios. We conclude that hard X-rays select AGN in host galaxies with a wide range of inclination angle, but only those AGN in the most face-on or spheroidal host galaxies show optical emission lines. Thus, extranuclear dust in the host galaxy plays an important role in hiding the emission lines of optically--dull AGN. | | Source: | arXiv, astro-ph/0603313 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER