X-ray emission from galaxies - Shedding light on the nature of ESO 243-49 HLX-1
Abstract
The point-like X-ray source HLX-1, hosted in the S0 galaxy ESO 243-49, is the brightest known ultraluminous X-ray source and likely the strongest intermediate-mass black hole candidate. In this talk, I discuss the hypothesis that ESO 243-49 is undergoing (or just underwent) a minor merger with a gas-rich low-mass late-type galaxy. I show the results of N-body/smoothed particle hydrodynamics simulations, suggesting that the observed star formation rate (SFR) in ESO 243-49 is a consequence of the interaction and that the companion galaxy already underwent the second pericentre passage. I propose that the counterpart of HLX-1 coincides with the nucleus (and possibly with the nuclear star cluster) of the secondary galaxy. I estimate that, if the minor merger scenario is correct, the number density of X-ray sources similar to HLX-1 is 10^{-6} Mpc^{-3}.
- Publication:
-
Half a Century of X-ray Astronomy
- Pub Date:
- September 2012
- Bibcode:
- 2012hcxa.confE.130M