The Brightest Cluster X-ray Sources

Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

ApJ Letters, in press

Scientific paper

There have been several recent claims of black hole binaries in globular clusters. I show that these candidate systems could instead be ultracompact X-ray binaries (UCXBs) in which a neutron star accretes from a white dwarf. They would represent a slightly earlier evolutionary stage of known globular cluster UCXBs such as 4U 1820--30, with white dwarf masses $\sim 0.2\msun$, and orbital periods below 5 minutes. Accretion is slightly super--Eddington, and makes these systems ultraluminous sources (ULXs) with rather mild beaming factors $b \sim 0.3$. Their theoretical luminosity function flattens slightly just above $\le$ and then steepens at $\sim 3\le$. It predicts of order 2 detections in elliptical galaxies such as NGC 4472, as observed. The very bright X-ray source HLX--1 lies off the plane of its host S0a galaxy. If this is an indication of globular cluster membership, it could conceivably be a more extreme example of a UCXB with white dwarf mass $M_2 \simeq 0.34\msun$. The beaming here is tighter ($b \sim 2.5 - 9 \times 10^{-3}$), but the system's distance of 95 Mpc easily eliminates any need to invoke improbable alignment of the beam for detection. If its position instead indicates membership of a satellite dwarf galaxy, HLX-1 could have a much higher accretor mass $\sim 1000\msun$

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

The Brightest Cluster X-ray Sources does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Brightest Cluster X-ray Sources, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Brightest Cluster X-ray Sources will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-320900

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.