Simultaneous Radio and X-Ray Observations of the Wolf-Rayet Star WR 147

Details Simultaneous Radio and X-Ray Observations of the Wolf-Rayet Star WR 147 Simultaneous Radio and X-Ray Observations of the Wolf-Rayet Star WR 147

Oct 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999apj...524..394s&link_type=abstract

The Astrophysical Journal, Volume 524, Issue 1, pp. 394-405.

Astronomy and Astrophysics

Astronomy

26

Radio Continuum: Stars, Stars: Individual (Wr 147=As 431), Stars: Wolf-Rayet, X-Rays: Stars

Scientific paper

We present results of simultaneous ASCA/Very Large Array (VLA) observations of the Wolf-Rayet star WR 147 (AS 431). This WN 8 star is an optical double and may be a WR+OB colliding wind binary system. The new observations place tight constraints on the origin of its X-ray and radio emission. The X-ray emission is due to a multitemperature, optically thin thermal plasma, with the dominant contribution coming from plasma at kT~1 keV. The absorption column density derived from the X-ray spectrum is N_H=2x10^22 cm^-2, which agrees well with estimates based on the visual extinction but is too large to explain by wind absorption alone. The X-ray temperature structure is consistent with colliding wind shock emission, but the unabsorbed X-ray luminosity L_x=10^32.55 ergs s^-1 (0.5-10 keV) is several times smaller than that predicted from colliding wind shock models. The VLA data provide the most complete picture ever obtained of the radio spectral energy distribution of a WR star and consist of near-simultaneous observations at five different wavelengths (1.3, 2, 3.6, 6, and 21 cm). The radio emission consists of a thermal free-free component from the WR wind and a nonthermal component. If the nonthermal emission is due to relativistic particles accelerated by the Fermi mechanism in wind shocks, then the flux is expected to decline at high frequencies according to S_ν~ν^-0.5. However, the observed falloff is much steeper and cannot be reproduced by a simple power law or by synchrotron models that assume power-law electron energy distributions. A surprising result is that the nonthermal emission can be accurately modeled as synchrotron radiation from relativistic electrons that are nearly monoergetic.

Affiliated with

Also associated with

No associations

Rating

Simultaneous Radio and X-Ray Observations of the Wolf-Rayet Star WR 147 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Simultaneous Radio and X-Ray Observations of the Wolf-Rayet Star WR 147, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Simultaneous Radio and X-Ray Observations of the Wolf-Rayet Star WR 147 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1083877