SIMBAD references

2006ApJ...639L..35S - Astrophys. J., 639, L35-L38 (2006/March-1)

A rich population of X-ray-emitting Wolf-Rayet stars in the Galactic starburst cluster Westerlund 1.

SKINNER S.L., SIMMONS A.E., ZHEKOV S.A., TEODORO M., DAMINELI A. and PALLA F.

Abstract (from CDS):

Recent optical and infrared studies have revealed that the heavily reddened starburst cluster Westerlund 1 (Wd 1) contains at least 22 Wolf-Rayet (W-R) stars, constituting the richest W-R population of any Galactic cluster. We present results of a sensitive Chandra X-ray observation of Wd 1 that detected 12 of the 22 known W-R stars and the mysterious emission-line star W9. The fraction of detected WN stars is nearly identical to that of WC stars. The WN stars WR-A and WR-B, as well as W9, are exceptionally luminous in X-rays and have similar hard, heavily absorbed X-ray spectra with strong Si XIII and S XV emission lines. The luminous high-temperature X-ray emission of these three stars is characteristic of colliding-wind binary systems, but their binary status remains to be determined. Spectral fits of the X-ray-bright sources WR-A and W9 with isothermal plane-parallel shock models require high absorption column densities, log NH=22.56 (/cm2), and yield characteristic shock temperatures kTs~3 keV (Ts~35 MK).

Abstract Copyright:

Journal keyword(s): open clusters and associations: individual (Westerlund 1) - Stars: Formation - Stars: Wolf-Rayet - X-Rays: Stars

Nomenclature: Table 1: [SSZ2006] NN (Nos 1-13).

Status at CDS:  

Simbad objects: 20

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2020.05.28-15:25:30

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