A Hard X-Ray Study of Ultraluminous X-ray Source NGC 5204 X-1 with NuSTAR and XMM-Newton

Autor: Mukherjee, E. S., Walton, D. J., Bachetti, M., Harrison, F. A., Barret, D., Bellm, E., Boggs, S. E., Christensen, F. E., Craig, W. W., Fabian, A. C., Fuerst, F., Grefenstette, B. W., Hailey, C. J., Madsen, K. K., Middleton, M. J., Miller, J. M., Rana, V., Stern, D., Zhang, W.
Rok vydání: 2015
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1088/0004-637X/808/1/64
Popis: We present the results from coordinated X-ray observations of the ultraluminous X-ray source NGC 5204 X-1 performed by NuSTAR and XMM-Newton in early 2013. These observations provide the first detection of NGC 5204 X-1 above 10 keV, extending the broadband coverage to 0.3-20 keV. The observations were carried out in two epochs separated by approximately 10 days, and showed little spectral variation, with an observed luminosity of Lx = (4.95+/-0.11)e39 erg/s. The broadband spectrum confirms the presence of a clear spectral downturn above 10 keV seen in some previous observations. This cutoff is inconsistent with the standard low/hard state seen in Galactic black hole binaries, as would be expected from an intermediate mass black hole accreting at significantly sub-Eddington rates given the observed luminosity. The continuum is apparently dominated by two optically thick thermal-like components, potentially accompanied by a faint high energy tail. The broadband spectrum is likely associated with an accretion disk that differs from a standard Shakura & Sunyaev thin disk.
Comment: 7 pages, 5 figures. Accepted for publication in ApJ
Databáze: arXiv