|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'501'711
Articles rated: 2609
20 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
A Chandra X-ray study of the interacting binaries in the old open cluster NGC6791 | | Maureen van den Berg
; Frank Verbunt
; Gianpiero Tagliaferri
; Tomaso Belloni
; Luigi R. Bedin
; Imants Platais
; | | Date: |
10 Jan 2013 | | Abstract: | We present the first X-ray study of NGC6791, one of the oldest open clusters
known (8 Gyr). Our Chandra observation is aimed at uncovering the population of
close interacting binaries down to Lx ~ 1e30 erg/s (0.3-7 keV). We detect 86
sources within 8 arcmin of the cluster center, including 59 inside the
half-mass radius. We identify twenty sources with proper-motion cluster
members, which are a mix of cataclysmic variables (CVs), active binaries (ABs),
and binaries containing sub-subgiants. With follow-up optical spectroscopy we
confirm the nature of one CV. We discover one new, X-ray variable candidate CV
with Balmer and HeII emission lines in its optical spectrum; this is the first
X-ray--selected CV confirmed in an open cluster. The number of CVs per unit
mass is consistent with the field, suggesting that the 3-4 CVs observed in
NGC6791 are primordial. We compare the X-ray properties of NGC6791 with those
of a few old open (NGC6819, M67) and globular clusters (47Tuc, NGC6397). It is
puzzling that the number of ABs brighter than 1e30 erg/s normalized by cluster
mass is lower in NGC6791 than in M67 by a factor ~3 to 7. CVs, ABs, and
sub-subgiants brighter than 1e30 erg/s are under-represented per unit mass in
the globular clusters compared to the oldest open clusters, and this accounts
for the lower total X-ray luminosity per unit mass of the former. This
indicates that the net effect of dynamical encounters may be the destruction of
even some of the hardest (i.e. X-ray--emitting) binaries. | | Source: | arXiv, 1301.2331 | | 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