Journal
ASTROPHYSICAL JOURNAL
Volume 778, Issue 2, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/778/2/163
Keywords
accretion, accretion disks; black hole physics; stars: black holes; X-rays: individual (NGC 1313 X-1, NGC 1313 X-2); X-rays: stars
Categories
Funding
- Centre National d'Etudes Spatiales (CNES)
- NASA [NNG08FD60C]
- National Aeronautics and Space Administration
- ESA Member States
- NASA
- Science and Technology Facilities Council [ST/K000985/1, ST/J001538/1] Funding Source: researchfish
- UK Space Agency [ST/L005611/1] Funding Source: researchfish
- STFC [ST/K000985/1, ST/J001538/1] Funding Source: UKRI
Ask authors/readers for more resources
We present the results of NuSTAR and XMM-Newton observations of the two ultraluminous X-ray sources: NGC 1313 X-1 and X-2. The combined spectral bandpass of the two satellites enables us to produce the first spectrum of X-1 between 0.3 and 30 keV, while X-2 is not significantly detected by NuSTAR above 10 keV. The NuSTAR data demonstrate that X-1 has a clear cutoff above 10 keV, whose presence was only marginally detectable with previous X-ray observations. This cutoff rules out the interpretation of X-1 as a black hole in a standard low/hard state, and it is deeper than predicted for the downturn of a broadened iron line in a reflection-dominated regime. The cutoff differs from the prediction of a single-temperature Comptonization model. Further, a cold disk-like blackbody component at similar to 0.3 keV is required by the data, confirming previous measurements by XMM-Newton only. We observe a spectral transition in X- 2, from a state with high luminosity and strong variability to a lower-luminosity state with no detectable variability, and we link this behavior to a transition from a super-Eddington to a sub-Eddington regime.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available