Point X-ray sources in elliptical galaxies

Natalia Ivanova*, Vicky Kalogera, Lipunov, Kim, Sivakoff

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We analyze the upper-end X-ray luminosity function (XLF) observed in elliptical galaxies for point sources. We propose that the observed XLF is dominated by transient BH systems in outburst and the XLF shape reflects the black hole (BH) mass spectrum among old X-ray transients. The BH mass spectrum - XLF connection depends on a weighting factor that is related to the transient duty cycle and depends on the host-galaxy age, the BH mass and the donor type (main sequence, red giant, or white dwarf). We argue that the assumption of a constant duty cycle for all systems leads to results inconsistent with current observations. The type of dominant donors in the upper-end XLF depends on what type of magnetic braking operates: in the case of "standard" magnetic braking, BH X-ray binaries with red-giant donors dominate, and in the case of weaker magnetic braking prescriptions main sequence donors dominate.

Original languageEnglish (US)
Pages (from-to)373-376
Number of pages4
JournalProceedings of the International Astronomical Union
Issue numberS230
StatePublished - 2005


  • Binaries:close
  • Galaxies:elliptical
  • Methods:statistical
  • X-rays:binaries

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science

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