CHANDRA AND SPITZER IMAGING OF THE INFRARED CLUSTER IN NGC 2071
- CASA, University of Colorado, Boulder, CO 80309-0389 (United States)
- Ritter Observatory, Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States)
- Institute of Astronomy, ETH Zuerich, Wolfgang-Pauli-Str. 27, 8093 Zuerich (Switzerland)
- Integral Science Data Centre, Ch. d'Ecogia 16, CH-1290 Versoix (Switzerland)
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States)
- Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, 05508-900 Sao Paulo, SP (Brazil)
We present results of a sensitive Chandra X-ray observation and Spitzer mid-infrared (mid-IR) observations of the IR cluster lying north of the NGC 2071 reflection nebula in the Orion B molecular cloud. We focus on the dense cluster core known as NGC 2071-IR, which contains at least nine IR sources within a 40'' x 40'' region. This region shows clear signs of active star formation including powerful molecular outflows, Herbig-Haro objects, and both OH and H{sub 2}O masers. We use Spitzer Infrared Array Camera (IRAC) images to aid in X-ray source identification and to determine young stellar object (YSO) classes using mid-IR colors. Spitzer IRAC colors show that the luminous source IRS 1 is a class I protostar. IRS 1 is believed to be driving a powerful bipolar molecular outflow and may be an embedded B-type star or its progenitor. Its X-ray spectrum reveals a fluorescent Fe emission line at 6.4 keV, arising in cold material near the protostar. The line is present even in the absence of large flares, raising questions about the nature of the ionizing mechanism responsible for producing the 6.4 keV fluorescent line. Chandra also detects X-ray sources at or near the positions of IRS 2, IRS 3, IRS 4, and IRS 6 and a variable X-ray source coincident with the radio source VLA 1, located just 2'' north of IRS 1. No IR data are yet available to determine a YSO classification for VLA 1, but its high X-ray absorption shows that it is even more deeply embedded than IRS 1, suggesting that it could be an even younger, less-evolved protostar.
- OSTI ID:
- 21313645
- Journal Information:
- Astrophysical Journal, Vol. 701, Issue 1; Other Information: DOI: 10.1088/0004-637X/701/1/710; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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