X-ray spectral state is not correlated with luminosity in Holmberg II X-1Report as inadecuate



 X-ray spectral state is not correlated with luminosity in Holmberg II X-1


X-ray spectral state is not correlated with luminosity in Holmberg II X-1 - Download this document for free, or read online. Document in PDF available to download.

Download or read this book online for free in PDF: X-ray spectral state is not correlated with luminosity in Holmberg II X-1
The ultraluminous X-ray source ULX Holmberg II X-1 has been observed over 4 months in 2009-2010 by the Swift observatory. The source luminosity varied by a factor of up to 14, reaching a maximum 0.3-10 keV luminosity of ~3.0E40 erg-s. The spectral properties do not vary much over these 4 months, with only a slight monotonic increase of the hardness ratio with the count rate. This means that the erratic flaring activity of the source is not associated with spectral changes, as seen in other ULXs. Conversely, comparison with data obtained by Swift in 2006 shows a completely different picture: while at a luminosity also seen in the 2009-2010 data, the source appears with a hard spectrum. Thus, it appears that, as in Galactic black hole binaries, spectral states in this ULX are not determined only by the X-ray luminosity.



Author: Fabien Grisé; Philip Kaaret; Hua Feng; Jari Kajava; Sean Farrell

Source: https://archive.org/







Related documents