Chandra observations of the Cartwheel galaxy reveal a population of ultraluminous X-ray sources (ULXs) associated with a spreading wave of star formation which began a few hundred million years ago. The brightest source in the Cartwheel, with a luminosity L0.5-10keV ∼ 1.3 × 10 41erg s-1, was observed in this state for at least four years, and is probably the brightest long-lived off-nuclear source ever seen in external galaxies. A recent XMM-Newton follow up observation allowed us to witness a dimming of this source by at least a factor of 2 over a timescale of six months. This has provided the first evidence that the source is compact in nature and is not resulting from the superposition of fainter individual objects such as supernova remnants. In its current level of emission, this source fits the X-ray Luminosity Function consistent with an association to High Mass X-ray binaries, but we cannot exclude the possibility that the source harbours an intermediate-mass black hole. © 2007 American Institute of Physics.
Wolter, A., Trinchieri, G., Colpi, M. (2007). The Cartwheel ULXs peculiar behaviour. In The Multicolored Landscape of compact Objects and their Explosive Origins; Cefalu, Sicily; Italy; 11-24 June 2006 (pp. 747-750). AIP American Institute of Physics [10.1063/1.2774937].
The Cartwheel ULXs peculiar behaviour
COLPI, MONICAUltimo
2007
Abstract
Chandra observations of the Cartwheel galaxy reveal a population of ultraluminous X-ray sources (ULXs) associated with a spreading wave of star formation which began a few hundred million years ago. The brightest source in the Cartwheel, with a luminosity L0.5-10keV ∼ 1.3 × 10 41erg s-1, was observed in this state for at least four years, and is probably the brightest long-lived off-nuclear source ever seen in external galaxies. A recent XMM-Newton follow up observation allowed us to witness a dimming of this source by at least a factor of 2 over a timescale of six months. This has provided the first evidence that the source is compact in nature and is not resulting from the superposition of fainter individual objects such as supernova remnants. In its current level of emission, this source fits the X-ray Luminosity Function consistent with an association to High Mass X-ray binaries, but we cannot exclude the possibility that the source harbours an intermediate-mass black hole. © 2007 American Institute of Physics.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
