SIMBAD references

2011ApJ...728...10M - Astrophys. J., 728, 10 (2011/February-2)

Long-term X-ray variability study of IC342 from XMM-Newton observations.

MAK D.S.Y., PUN C.S.J. and KONG A.K.H.

Abstract (from CDS):

We presented the results of an analysis of four XMM-Newton observations of the starburst galaxy IC342 taken over a four-year span from 2001 to 2005, with an emphasis on investigating the long-term flux and spectral variability of the X-ray point sources. We detected a total of 61 X-ray sources within 35'x30' of the galaxy down to a luminosity of (1-2)x1037 erg/s depending on the local background. We found that 39 of the 61 detected sources showed long-term variability, in which 26 of them were classified as X-ray transients. We also found 19 sources exhibiting variations in hardness ratios or undergoing spectral transitions among observations, and were identified as spectral variables. In particular, eight of the identified X-ray transients showed spectral variability in addition to flux variability. The diverse patterns of variability observed are indicative of a population of X-ray binaries. We used X-ray colors, flux and spectral variability, and in some cases the optical or radio counterparts to classify the detected X-ray sources into several stellar populations. We identified a total of 11 foreground stars, 1 supersoft source (SSS), 3 quasisoft sources (QSSs), and 2 supernova remnants (SNRs). The identified SSS/QSSs are located near or on the spiral arms, associated with young stellar populations; the 2 SNRs are very close to the starburst nucleus where current star formation activities are dominated. We also discovered a spectral change in the nuclear source of IC342 for the first time by a series of X-ray spectrum analysis.

Abstract Copyright:

Journal keyword(s): galaxies: individual: IC342 - galaxies: starburst - X-rays: galaxies

Nomenclature: Table 2: [MPK2011] NN (Nos 1-61).

Simbad objects: 80

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