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IMAGING THE MOLECULAR GAS IN A SUBMILLIMETER GALAXY ATz= 4.05: COLD MODE ACCRETION OR A MAJOR MERGER?
- Source :
- The Astrophysical Journal. 714:1407-1417
- Publication Year :
- 2010
- Publisher :
- American Astronomical Society, 2010.
-
Abstract
- We present a high resolution (down to 0.18"), multi-transition imaging study of the molecular gas in the z = 4.05 submillimeter galaxy GN20. GN20 is one of the most luminous starburst galaxy known at z > 4, and is a member of a rich proto-cluster of galaxies at z = 4.05 in GOODS-North. We have observed the CO 1-0 and 2-1 emission with the VLA, the CO 6-5 emission with the PdBI Interferometer, and the 5-4 emission with CARMA. The H_2 mass derived from the CO 1-0 emission is 1.3 \times 10^{11} (\alpha/0.8) Mo. High resolution imaging of CO 2-1 shows emission distributed over a large area, appearing as partial ring, or disk, of ~ 10kpc diameter. The integrated CO excitation is higher than found in the inner disk of the Milky Way, but lower than that seen in high redshift quasar host galaxies and low redshift starburst nuclei. The VLA CO 2-1 image at 0.2" resolution shows resolved, clumpy structure, with a few brighter clumps with intrinsic sizes ~ 2 kpc. The velocity field determined from the CO 6-5 emission is consistent with a rotating disk with a rotation velocity of ~ 570 km s^{-1} (using an inclination angle of 45^o), from which we derive a dynamical mass of 3 \times 10^{11} \msun within about 4 kpc radius. The star formation distribution, as derived from imaging of the radio synchrotron and dust continuum, is on a similar scale as the molecular gas distribution. The molecular gas and star formation are offset by ~ 1" from the HST I-band emission, implying that the regions of most intense star formation are highly dust-obscured on a scale of ~ 10 kpc. The large spatial extent and ordered rotation of this object suggests that this is not a major merger, but rather a clumpy disk accreting gas rapidly in minor mergers or smoothly from the proto-intracluster medium. ABSTRACT TRUNCATED<br />Comment: 33 pages, 8 figures, submitted to the ApJ, aas latex format
- Subjects :
- Physics
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
010308 nuclear & particles physics
Star formation
Astrophysics::High Energy Astrophysical Phenomena
Milky Way
FOS: Physical sciences
Astronomy and Astrophysics
Quasar
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
01 natural sciences
Galaxy
Synchrotron
Accretion (astrophysics)
Redshift
law.invention
13. Climate action
Space and Planetary Science
law
0103 physical sciences
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Excitation
Astrophysics - Cosmology and Nongalactic Astrophysics
Subjects
Details
- ISSN :
- 15384357 and 0004637X
- Volume :
- 714
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....7f228e52ddb7b8756ac8234379706fcd