Massive metal-poor stars might end their life by directly collapsing into massive (approximate to 25-80 solar masses) 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
Mapelli, M., Ripamonti, E., Zampieri, L., Colpi, M. (2011). Remnants of massive metal-poor stars: Viable engines for ultra-luminous X-ray sources. ASTRONOMISCHE NACHRICHTEN, 332(4), 414-417 [10.1002/asna.201011511].
Remnants of massive metal-poor stars: Viable engines for ultra-luminous X-ray sources
RIPAMONTI, EMANUELE;COLPI, MONICA
2011
Abstract
Massive metal-poor stars might end their life by directly collapsing into massive (approximate to 25-80 solar masses) 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
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