Hard X-rays from Ultra-Compact HII Regions in W49A

Details Hard X-rays from Ultra-Compact HII Regions in W49A Hard X-rays from Ultra-Compact HII Regions in W49A

2006-11-03

arxiv.org/abs/astro-ph/0611103v1

Astrophys.J.653:409-415,2006

Astronomy and Astrophysics

Astrophysics

12 pages, 7 figures, ApJ in press. See http://agyo.rikkyo.ac.jp/~tsujimot/ms.pdf for a higher quality version

Scientific paper

10.1086/507439

We report the Chandra detection of hard X-ray emission from the Welch ring in W49A, an organized structure of ultra-compact (UC) HII regions containing a dozen nascent early-type stars. Two UC HII regions are associated with hard X-ray emission in a deep Advanced CCD Imaging Spectrometer image exposed for 96.7 ks. One of the two X-ray sources has no near-infrared counterpart and is extended by ~5 arcsec, or ~0.3 pc, at a distance of ~11.4 kpc, which is spatially aligned with the cometary radio continuum emission associated with the UC HII region. The X-ray spectrum of the emission, when fit with a thermal model, indicates a heavily absorbed plasma with extinction of \~5x10^{23}/cm^{2}, temperature of ~7 keV, and X-ray luminosity in the 3.0-8.0 keV band of ~3x10^{33} ergs/s. Both the luminosity and the size of the emission resemble the extended hard emission found in UC HII regions in Sagittarius B2, yet they are smaller by an order of magnitude than the emission found in massive star clusters such as NGC 3603. Three possibilities are discussed for the cause of the hard extended emission in the Welch ring: an ensemble of unresolved point sources, shocked interacting winds of the young O stars, and a wind-blown bubble interacting with ambient cold matter.

Affiliated with

Also associated with

No associations

Rating

Hard X-rays from Ultra-Compact HII Regions in W49A 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 Hard X-rays from Ultra-Compact HII Regions in W49A, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hard X-rays from Ultra-Compact HII Regions in W49A will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-163217