|
| | | | |
| | | |
| Stat |
Members: 3657
Articles: 2'599'751
Articles rated: 2609
06 October 2024 |
|
| | | | |
|
Article overview
| |
|
|
A Chandra Survey of Milky Way Globular Clusters. III. Searching for X-ray Signature of Intermediate-mass Black Holes | | Zhao Su
; Zhiyuan Li
; Meicun Hou
; Mengfei Zhang
; Zhongqun Cheng
; | | Date: |
1 Jun 2022 | | Abstract: | Globular clusters (GCs) are thought to harbor the long-sought population of
intermediate-mass black holes (IMBHs). We present a systematic search for a
putative IMBH in 81 Milky Way GCs, based on archival Chandra X-ray
observations. We find in only six GCs a significant X-ray source positionally
coincident with the cluster center, which have 0.5-8 keV luminosities between
$sim1 imes 10^{30}~{
m erg~s^{-1}}$ to $sim 4 imes10^{33}~{
m
erg~s^{-1}}$. However, the spectral and temporal properties of these six
sources can also be explained in terms of binary stars. The remaining 75 GCs do
not have a detectable central source, most with $3sigma$ upper limits ranging
between $10^{29-32}~{
m erg~s^{-1}}$ over 0.5-8 keV, which are significantly
lower than predicted for canonical Bondi accretion. To help understand the
feeble X-ray signature, we perform hydrodynamic simulations of stellar wind
accretion onto a $1000~{
m M_odot}$ IMBH from the most-bound orbiting star,
for stellar wind properties consistent with either a main-sequence (MS) star or
an asymptotic giant branch (AGB) star. We find that the synthetic X-ray
luminosity for the MS case ($sim 10^{19}
m~erg~s^{-1}$) is far below the
current X-ray limits. The predicted X-ray luminosity for the AGB case ($sim
10^{34}
m~erg~s^{-1}$), on the other hand, is compatible with the detected
central X-ray sources, in particular the ones in Terzan 5 and NGC 6652.
However, the probability of having an AGB star as the most-bound star around
the putative IMBH is very low. Our study strongly suggests that it is very
challenging to detect the accretion-induced X-ray emission from IMBHs, even if
they were prevalent in present-day GCs. | | Source: | arXiv, 2206.00284 | | 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.
|
| |
|
|
|
REGISTER