Measuring the black hole mass in Ultraluminous X-ray Sources with the X-ray Scaling Method

Abstract

In our recent work, we demonstrated that a novel X-ray scaling method, originally introduced for Galactic black holes, could be reliably extended to estimate the mass of supermassive black holes accreting at moderate to high level. Here, we apply this X-ray scaling method to ultraluminous X-ray sources (ULXs) to constrain their \mbh. Using 49 ULXs with multiple \xmm\ observations, we infer that ULXs host both stellar mass BHs and intermediate mass BHs. The majority of the sources of our sample seem to be consistent with the hypothesis of highly accreting massive stellar BHs with $M_{\mathrm{BH}}\sim 100M_{\odot }$. Our results are in general agreement with the \mbh\ values obtained with alternative methods, including model-independent variability methods. This suggests that the X-ray scaling method is an actual scale-independent method that can be applied to all BH systems accreting at moderate-high rate.

14 pages, 10 figures

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Cited by in corpus (4)

• On the contribution of ULXs to stellar feedback: an intermediate mass black hole candidate and the population of ULXs in the low-metallicity starburst galaxy ESO 338-4
• Estimating black hole masses in obscured AGN using X-rays
• Broadband X-ray spectral analysis of the ULX NGC 1313\,X-1 using JeTCAF: Origin of the ULX bubble
• Estimating the black hole mass of NGC1313 X-1 based on the spectral and timing properties