HIGH-SENSITIVITY ARRAY OBSERVATIONS OF THE z = 1.87 SUBMILLIMETER GALAXY GOODS 850-3
- National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)
- Argelander-Institut fuer Astronomie, Auf dem Huegel 71, D-53121 Bonn (Germany)
We present sensitive phase-referenced Very Long Baseline Interferometry (VLBI) results on the radio continuum emission from the z = 1.87 luminous submillimeter galaxy (SMG) GOODS 850-3. The observations were carried out at 1.4 GHz using the High-Sensitivity Array (HSA). Our sensitive tapered VLBI image of GOODS 850-3 at 0.''47 x 0.''34 (3.9 x 2.9 kpc) resolution shows a marginally resolved continuum structure with a peak flux density of 148 {+-} 38 {mu}Jy beam{sup -1}, and a total flux density of 168 {+-} 73 {mu}Jy, consistent with previous Very Large Array and MERLIN measurements. The deconvolved size of the source is 0.''27({+-}0.''12) x <0.''23, or 2.3({+-}1.0) x <1.9 kpc, and the derived intrinsic brightness temperature is >(5 {+-} 2) x 10{sup 3} K. The radio continuum position of this galaxy coincides with a bright and extended near-infrared source that nearly disappears in the deep Hubble Space Telescope optical image, indicating a dusty source of nearly 9 kpc in diameter. No continuum emission is detected at the full VLBI resolution (13.2 x 7.2 mas, 111 x 61 pc), with a 4{sigma} point source upper limit of 26 {mu}Jy beam{sup -1}, or an upper limit to the intrinsic brightness temperature of 4.7 x 10{sup 5} K. The extent of the observed continuum source at 1.4 GHz and the derived brightness temperature limits are consistent with the radio emission (and thus presumably the far-infrared emission) being powered by a major starburst in GOODS 850-3, with a star formation rate of {approx}2500 M {sub sun} yr{sup -1}. Moreover, the absence of any continuum emission at the full resolution of the VLBI observations indicates the lack of a compact radio-loud active galactic nucleus in this z = 1.87 SMG.
- OSTI ID:
- 21301194
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 139, Issue 4; Other Information: DOI: 10.1088/0004-6256/139/4/1622; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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