|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'506'133
Articles rated: 2609
26 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
No X-ray Bright Type II Quasars Among the Lyman-alpha Emitters | | S. Malhotra
; J. X. Wang
; J. E. Rhoads
; T. M. Heckman
; C.Norman
; | | Date: |
30 Dec 2002 | | Journal: | Astrophys.J. 585 (2003) L25-L28 | | Subject: | astro-ph | | Affiliation: | STScI), J. X. Wang (JHU), J. E. Rhoads (STScI), T. M. Heckman (JHU), C.Norman (STScI | | Abstract: | The Lyman-alpha emitters found at z=4.5 and 5.7 by the Large Area Lyman Alpha (LALA) survey have high equivalent widths in the Lyman-alpha line. Such lines can be produced by narrow-lined active galactic nuclei (AGNs) or by stellar populations with a very high proportion of young, massive stars. To check for Type-II (i.e., narrow-lined) quasars, we obtained a deep X-ray image of 49 Lyman-alpha sources in a single field of the ACIS instrument on the Chandra X-ray Observatory. None of these sources were detected with a 3-sigma limiting X-ray luminosity of 2.9x10^{43} ergs/s. For comparison, the two known high redshift type-II quasars have luminosities of 4x10^{43} ergs/s before extinction correction. The sources remain undetected in stacked images of the 49 lyman-alpha sources (with 6.5 Mega-seconds effective Chandra on-axis exposure) at 3-sigma limits of 4.9x10^{42} ergs/s. The resulting X-ray to lyman-alpha ratio is about 4-24 times lower than the ratio for known type-II quasars, while the average Lyman-alpha luminosity of the LALA sample is in between the two type-II’s. The cumulative X-ray to Lyman-alpha ratio limit is also below that of 90% of low-redshift Seyfert galaxies. | | Source: | arXiv, astro-ph/0301622 | | 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