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The two ultraluminous X-ray sources in the galaxy NGC 925
- Source :
- Monthly Notices of the Royal Astronomical Society, 479(3), 4271-4277. Oxford University Press
- Publication Year :
- 2018
- Publisher :
- Oxford University Press, 2018.
-
Abstract
- NGC 925 ULX-1 and ULX-2 are two ultraluminous X-ray sources in the galaxy NGC 925, at a distance of 8.5 Mpc. For the first time, we analyzed high quality, simultaneous XMM-Newton and NuSTAR data of both sources. Although at a first glance ULX-1 resembles an intermediate mass black hole candidate (IMBH) because of its high X-ray luminosity ($(2$$-$$4)\times10^{40}$ erg s$^{-1}$) and its spectral/temporal features, a closer inspection shows that its properties are more similar to those of a typical super-Eddington accreting stellar black hole and we classify it as a `broadened disc' ultraluminous X-ray source. Based on the physical interpretation of this spectral state, we suggest that ULX-1 is seen at small inclination angles, possibly through the evacuated cone of a powerful wind originating in the accretion disc. The spectral classification of ULX-2 is less certain, but we disfavour an IMBH accreting at sub-Eddington rates as none of its spectral/temporal properties can be associated to either the soft or hard state of Galactic accreting black hole binaries.<br />Comment: Accepted on MNRAS with very minor comments, 7 pages, 5 figures, 1 table
- Subjects :
- Physics
High Energy Astrophysical Phenomena (astro-ph.HE)
Accretion (meteorology)
010308 nuclear & particles physics
Astrophysics::High Energy Astrophysical Phenomena
X-ray
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Stellar classification
01 natural sciences
Astrophysics - Astrophysics of Galaxies
Galaxy
Luminosity
Black hole
Space and Planetary Science
Intermediate-mass black hole
Astrophysics of Galaxies (astro-ph.GA)
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
Stellar black hole
Astrophysics - High Energy Astrophysical Phenomena
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Subjects
Details
- Language :
- English
- ISSN :
- 13652966 and 00358711
- Volume :
- 479
- Issue :
- 3
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Accession number :
- edsair.doi.dedup.....23e1544691d3072d3e38080deb162e23