Study of correlation between ultraluminous X-ray sources and their host galaxies

[摘要] Ultraluminous X-ray sources (ULXs) are defined as non-nuclear point-source objects with apparent X-ray luminosities, Lx> 2×1039erg s-1, in the 0.3-8 keV band. ULXs are often explained using two different scenarios, (1) ULXs as intermediate mass black hole (IMBH) with sub-Eddington accretion and (2) ULXs as stellar mass black hole with super-Eddington accretion. There are two methods that commonly used to study the characteristics of ULXs. One method is to study the X-ray spectra of ULXs, to determine the characteristics of their accretion flows from fitting their spectra using available spectral models. The other method is to investigate how population of ULXs correlate with their environment, in this case their host galaxies. Our goal is to find correlation between ULXs and the properties of its host galaxies, for example with Star Formation Rate (SFR), mass and morphology. From this study we found a positive correlation between ULXs number and SFR. From X-ray luminosity function, we found upper limit of black holes mass that power ULXs is about 100 Mo.

[发布机构] Bandung Institute of Technology, Bandung, Indonesia^1

[效力级别] 天文学

[关键词] Accretion flow;Intermediate mass black holes;Positive correlations;Spectral models;Star formation rates;Stellar-mass black holes;Ultraluminous x-ray sources;X-ray luminosity