THE GOULD's BELT VERY LARGE ARRAY SURVEY. I. THE OPHIUCHUS COMPLEX
- Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México Apartado Postal 3-72, 58090 Morelia, Michoacán (Mexico)
- National Radio Astronomy Observatory, Domenici Science Operations Center, 1003 Lopezville Road, Socorro, NM 87801 (United States)
- Paul Harris 9065, Las Condes, Santiago (Chile)
- Division of Physics, Math, and Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
- Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States)
- Department of Astronomy, The University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712 (United States)
- Centro de Investigaciones de Astronomía, Mérida 5101-A (Venezuela, Bolivarian Republic of)
- National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
We present large-scale (∼2000 arcmin{sup 2}), deep (∼20 μJy), high-resolution (∼1'') radio observations of the Ophiuchus star-forming complex obtained with the Karl G. Jansky Very Large Array at λ = 4 and 6 cm. In total, 189 sources were detected, 56 of them associated with known young stellar sources, and 4 with known extragalactic objects; the other 129 remain unclassified, but most of them are most probably background quasars. The vast majority of the young stars detected at radio wavelengths have spectral types K or M, although we also detect four objects of A/F/B types and two brown dwarf candidates. At least half of these young stars are non-thermal (gyrosynchrotron) sources, with active coronas characterized by high levels of variability, negative spectral indices, and (in some cases) significant circular polarization. As expected, there is a clear tendency for the fraction of non-thermal sources to increase from the younger (Class 0/I or flat spectrum) to the more evolved (Class III or weak line T Tauri) stars. The young stars detected both in X-rays and at radio wavelengths broadly follow a Güdel-Benz relation, but with a different normalization than the most radioactive types of stars. Finally, we detect a ∼70 mJy compact extragalactic source near the center of the Ophiuchus core, which should be used as gain calibrator for any future radio observations of this region.
- OSTI ID:
- 22270950
- Journal Information:
- Astrophysical Journal, Vol. 775, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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