XMM-Newton observations of the nitrogen-rich Wolf-Rayet star WR 1

Ignace, R., Oskinova, L.M. and Brown, J.C. (2003) XMM-Newton observations of the nitrogen-rich Wolf-Rayet star WR 1. Astronomy and Astrophysics, 408(1), 353 -361. (doi: 10.1051/0004-6361:20031024)

Abstract

We present XMM-Newton results for the X-ray spectrum from the N-richWolf-Rayet (WR) star WR1. The EPIC instrument was used to obtain a medium-resolution spectrum. The following features characterize this spectrum: ( a) significant emission "bumps" appear that are coincident with the wavelengths of typical strong lines, such as MgXI, SiXIII, and SXV; (b) little emission is detected above 4 keV, in contrast to recent reports of a hard component in the stars WR 6 and WR 110 which are of similar subtype; and ( c) evidence for sulfur K-edge absorption at about 2.6 keV, which could only arise from absorption of X- rays by the ambient stellar wind. The lack of hard emission in our dataset is suggestive that WR 1 may truly be a single star, thus representing the first detailed X-ray spectrum that isolates the WR wind alone ( in contrast to colliding wind zones). Although the properties of the S-edge are not well- constrained by our data, it does appear to be real, and its detection indicates that at least some of the hot gas in WR 1 must reside interior to the radius of optical depth unity for the total absorptive opacity at the energy of the edge.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Brown, Professor John and Oskinova, Dr Lidia
• Authors: Ignace, R., Oskinova, L.M., and Brown, J.C.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Astronomy and Astrophysics
• Publisher: EDP Sciences
• ISSN: 0004-6361
• ISSN (Online): 1432-0746
• Copyright Holders: Copyright © 2003 EDP Sciences
• First Published: First published in Astronomy and Astrophysics 408(1):353-361
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher