Hard X-Rays and Fluorescent Iron Emission from the Embedded Infrared Cluster in NGC 2071
Abstract
We present first results of XMM-Newton X-ray observations of the infrared cluster lying near the NGC 2071 reflection nebula in the Orion B region. This cluster is of interest because it is one of the closest regions known to harbor embedded high-mass stars. We report the discovery of hard X-ray emission from the dense central NGC 2071-IR subgroup, which contains at least three high-mass young stellar objects (NGC 2071 IRS 1, IRS 2, and IRS 3). A prominent X-ray source is detected within 1" of the infrared source IRS 1, which is thought to drive a powerful bipolar molecular outflow. The X-ray spectrum of this source is quite unusual compared to the optically thin plasma spectra normally observed in young stellar objects (YSOs). The spectrum is characterized by a hard broadband continuum plus an exceptionally broad emission line at ~6.4 keV from neutral or near-neutral iron. The fluorescent Fe line likely originates in cold material near the embedded star (i.e., a disk or envelope) that is irradiated by the hard, heavily absorbed X-ray source.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2007
- DOI:
- 10.1086/511815
- arXiv:
- arXiv:astro-ph/0612563
- Bibcode:
- 2007ApJ...658.1144S
- Keywords:
-
- Galaxy: Open Clusters and Associations: Individual: NGC Number: NGC 2071;
- Stars: Formation;
- X-Rays: Stars;
- Astrophysics
- E-Print:
- To appear in ApJ (8 pages, 7 figures)