SIMBAD references

2010ApJ...724L.148G - Astrophys. J., 724, L148-L152 (2010/December-1)

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

GRISE F., KAARET P., FENG H., KAJAVA J.J.E. and FARRELL S.A.

Abstract (from CDS):

The ultraluminous X-ray source (ULX) Holmberg II X-1 has been observed over four 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 ∼3.0x1040 erg/s. The spectral properties do not vary much over these four 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.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - black hole physics - X-rays: binaries - X-rays: individual: Holmberg II X-1

Simbad objects: 10

goto Full paper

goto View the reference in ADS

To bookmark this query, right click on this link: simbad:2010ApJ...724L.148G and select 'bookmark this link' or equivalent in the popup menu


2020.10.23-03:27:03

© Université de Strasbourg/CNRS

    • Contact