2003/05/19 by P. J. Humphrey, Philip J. Humphrey, G. Fabbiano +4 · 2 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Black hole (networking) #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Physics #Star formation #Stellar mass #X-ray Spectroscopy and Fluorescence Analysis #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2003.06802.x
published as Mon.Not.Roy.Astron.Soc.344:134,2003 · 16 pages including 7 figures, MNRAS accepted
arxiv created 2003/05/19 · openalex publication_date 2003/09/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present results of a Chandra survey of the ultraluminous X-ray sources (ULX) in 13 normal galaxies, in which we combine source detection with X-ray flux measurement. 22 ULX were detected, i.e. with Lx > 1 × 1039 erg s−1 (L10) and 39 other sources were detected with Lx > 5 × 1038 erg s−1 (L5). We also use radial intensity profiles to remove extended sources from the sample. The majority of sources are not extended, which for a typical distance constrains the emission region size to less than 50 pc. X-ray colour–colour diagrams and spectral fitting results were examined for indicators of the ULX nature. In the case of the brighter sources, spectral fitting generally requires two-component models. In only a few cases do colour–colour diagrams or spectral fitting provide evidence of a black hole nature. We find no evidence of a correlation with stellar mass, however, there is a strong correlation with star formation as indicated by the 60-μm flux as found in previous studies.