Identification of Two Bright z > 3 Submillimeter Galaxy Candidates in the COSMOS Field
Abstract
We present high-resolution interferometric Submillimeter Array imaging at 890 μm (~2'' resolution) of two millimeter selected galaxies—MMJ100015+021549 and MMJ100047+021021—discovered with the Max-Planck Millimeter Bolometer (MAMBO) on the IRAM 30 m telescope and also detected with Bolocam on the CSO, in the COSMOS field. The first source is significantly detected at the ~11σ level, while the second source is tentatively detected at the ~4σ level, leading to a positional accuracy of ~0farcs2-0farcs3. MM100015+021549 is identified with a faint radio and K-band source. MMJ100047+021021 shows no radio emission and is tentatively identified with a very faint K-band peak which lies at ~1farcs2 from a clumpy optical source. The submillimeter-to-radio flux ratio for MM100015+021549 yields a redshift of ~4.8, consistent with the redshift implied by the UV-to-submillimeter photometry, z ~ 3.0-5.0. We find evidence for warm dust in this source with an infrared luminosity in the range ~(0.9-2.5) × 1013 L sun, supporting the increasing evidence for a population of luminous submillimeter galaxies at z > 3. Finally, the lack of photometric data for MMJ100047+021021 does not allow us to investigate its properties in detail; however, its submillimeter-to-radio flux ratio implies z > 3.5.
Based on observations obtained with the SMA, which is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. Also based on observations obtained, within the COSMOS Legacy Survey, with the Institut de Radioastronomie Millimetrique (IRAM) 30 m telescope, the Caltech Submillimeter Observatory (CSO), the APEX telescope, the Hubble Space Telescope (HST), the Spitzer Space Telescope, the Subaru telescope, the Kitt Peak National Observatory (KPNO), the Cerro Tololo Inter-American Observatory (CTIO), the National Optical Astronomy Observatory (NOAO), the United Kingdom IR telescope (UKIRT), and the Canada-France-Hawaii telescope (CFHT). The National Radio Astronomy Observatory (NRAO) is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.- Publication:
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The Astrophysical Journal
- Pub Date:
- August 2010
- DOI:
- 10.1088/2041-8205/719/1/L15
- arXiv:
- arXiv:1007.0200
- Bibcode:
- 2010ApJ...719L..15A
- Keywords:
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- galaxies: evolution;
- galaxies: high-redshift;
- galaxies: starburst;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Accepted for publication in ApJ letters