Remnants of massive metal-poor stars: Viable engines for ultra-luminous X-ray sources
Abstract
Massive metal-poor stars might end their life by directly collapsing into massive (≈25-80 M_⊙) black holes (BHs). We derive the number of massive BHs (N_BH) that are expected to form per galaxy via this mechanism. We select a sample of 66 galaxies with X-ray coverage, measurements of the star formation rate (SFR) and of the metallicity. We find that N_BH correlates with the number of observed ultra-luminous X-ray sources (ULXs) per galaxy (N_ULX) in this sample. We discuss the dependence of N_ULX and of N_BH on the SFR and on the metallicity.
- Publication:
-
Astronomische Nachrichten
- Pub Date:
- May 2011
- DOI:
- arXiv:
- arXiv:1009.5706
- Bibcode:
- 2011AN....332..414M
- Keywords:
-
- black hole physics;
- galaxies: starburst;
- X-rays: binaries;
- X-rays: galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 4 pages, 3 figures, accepted for publication in the Astronomische Nachrichten, to appear in the proceedings of the conference "Ultra-luminous X-ray sources and Middle Weight Black Holes" (Madrid, May 24-26, 2010)