Bulletin de la Société Royale des Sciences de Liège

0037-9565 1783-5720

 

sinds 05 februari 2011 :
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Yasuharu Sugawara, Yoshitomo Maeda, Yohko Tsuboi, Kenji Hamaguchi, Michael Corcoran, Andy Pollock, Anthony Moffat, Peredur Williams, Sean Dougherty & Julian Pittard

The variable X-ray spectrum of theWolf-Rayet binary WR140 with Suzaku

(Volume 80 - Année 2011)
Article
Open Access

Abstract

We report the preliminary results of the Suzaku observations of the W-R binaryWR140 (WC7+O5I). We executed the observations at four different epochs around periastron passage in Jan. 2009 to understand the W-R stellar wind as well as the wind-wind collision shocks. The total exposure was 210 ks. We detected hard X-ray excess in the HXD band (> 10 keV) for the first time from a W-R binary. Another notable discovery was a soft component which is less absorbed even by the dense wind. The spectra can be fitted by three different components; one is for the cool component with kT=0.1–0.6 keV, one for a dominant high-temperature component with kT ~3 keV, and one for the hardest power-law component with the photon index of ~2. As periastron approached, the column density of the high-temperature component increased, which can be explained as self-absorption by the W-R wind. The emission measure of the dominant, high-temperature component is not inversely proportional to the distance between the two stars.

Om dit artikel te citeren:

Yasuharu Sugawara, Yoshitomo Maeda, Yohko Tsuboi, Kenji Hamaguchi, Michael Corcoran, Andy Pollock, Anthony Moffat, Peredur Williams, Sean Dougherty & Julian Pittard, «The variable X-ray spectrum of theWolf-Rayet binary WR140 with Suzaku», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 80 - Année 2011, 724 - 728 URL : http://popups.ulg.be/0037-9565/index.php?id=3199.

Over : Yasuharu Sugawara

Department of Physics, Chuo University, Japan

Over : Yoshitomo Maeda

Department of High Energy Astrophysics, ISAS/JAXA

Over : Yohko Tsuboi

Department of Physics, Chuo University, Japan

Over : Kenji Hamaguchi

CRESST and X-ray Astrophysics Laboratory NASA/GSFC, and

Over : Michael Corcoran

Department of Physics, University of Maryland

Over : Andy Pollock

CRESST and X-ray Astrophysics Laboratory NASA/GSFC, and

Over : Anthony Moffat

Universities Space Research Association

Over : Peredur Williams

European Space Agency, XMM-Newton Science Operations Centre

Over : Sean Dougherty

Département de Physique, Université de Montréal

Over : Julian Pittard

Institute for Astronomy, Royal Observatory Edinburgh