An Observational Diagnostic for Ultraluminous X-Ray Sources
نویسندگان
چکیده
منابع مشابه
An Observational Diagnostic for Ultraluminous X-ray Sources
We consider observational tests for the nature of Ultraluminous X-ray sources (ULXs). These must distinguish between thermal–timescale mass transfer on to stellar–mass black holes leading to anisotropic X-ray emission, and accretion on to intermediate–mass black holes. We suggest that long–term transient behavior via the thermal–viscous disk instability could discriminate between these two poss...
متن کاملUltraluminous X-ray Sources
The Chandra X-Ray Observatory was used to image the collisional ring galaxy Arp 147 for 42 ks. We detect nine X-ray sources with luminosities in the range of (1.4–7) × 1039 erg s−1 (assuming that the sources emit isotropically) in or near the blue knots of star formation associated with the ring. A source with an X-ray luminosity of 1.4 × 1040 erg s−1 is detected in the nuclear region of the in...
متن کاملMultiwavelength Observations of Ultraluminous X-Ray Sources
Multiwavelength observations may help us understand the physical nature of the ultraluminous X-ray sources (ULXs) found in external galaxies. Enabled by the arcsecond X-ray source positions now available from Chandra, there has been significant recent progress in the identification of optical and radio counterparts to ULXs. Recent results are reviewed on the identification of optical stellar co...
متن کاملOptical Counterparts of Ultraluminous X-ray Sources
Despite much observational and theoretical effort little is presently known about the nature of the luminous nonnuclear X-ray sources which appear to largely surpass the Eddington limit of a few solar masses. Here we present first results of our OHP/ESO/CFHT optical survey of the environments of variable ultraluminous X-ray sources (ULX) in nearby galaxies. At the position of several ULX we fin...
متن کاملX-ray Monitoring of Ultraluminous X-ray Sources
X-ray monitoring observations were performed with the Swift observatory of the ultraluminous Xray sources Holmberg IX X-1, NGC 5408 X-1, and NGC 4395 X-2 and also of the nuclear X-ray source in NGC 4395. Holmberg IX X-1 remains in the hard X-ray spectral state as its flux varies by a factor of 7 up to an (isotropic) luminosity of 2.8 × 10 erg s. This behavior may suggest an unusually massive co...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2004
ISSN: 0004-637X,1538-4357
DOI: 10.1086/382953