Physical characterization of an unlensed, dusty star-forming galaxy at z=5.85
OA Location
Author(s)
Type
Journal Article
Abstract
We present a physical characterization of MM J100026.36+021527.9 (a.k.a. "Mambo-9"), a dusty star-forming galaxy (DSFG) at z = 5.850 ± 0.001. This is the highest-redshift unlensed DSFG (and fourth most distant overall) found to date and is the first source identified in a new 2 mm blank-field map in the COSMOS field. Though identified in prior samples of DSFGs at 850 μm to 1.2 mm with unknown redshift, the detection at 2 mm prompted further follow-up as it indicated a much higher probability that the source was likely to sit at z > 4. Deep observations from the Atacama Large Millimeter and submillimeter Array (ALMA) presented here confirm the redshift through the secure detection of 12CO(J = 6→5) and p-H2O (21,1 → 20,2). Mambo-9 is composed of a pair of galaxies separated by 6 kpc with corresponding star formation rates of 590 M ⊙ yr−1 and 220 M ⊙ yr−1, total molecular hydrogen gas mass of (1.7 ± 0.4) × 1011 M ⊙, dust mass of (1.3 ± 0.3) × 109 M ⊙, and stellar mass of (${3.2}_{-1.5}^{+1.0}$) × 109 M ⊙. The total halo mass, (3.3 ± 0.8) × 1012 M ⊙, is predicted to exceed 1015 M ⊙ by z = 0. The system is undergoing a merger-driven starburst that will increase the stellar mass of the system tenfold in τ depl = 40−80 Myr, converting its large molecular gas reservoir (gas fraction of ${96}_{-2}^{+1} \% $) into stars. Mambo-9 evaded firm spectroscopic identification for a decade, following a pattern that has emerged for some of the highest-redshift DSFGs found. And yet, the systematic identification of unlensed DSFGs like Mambo-9 is key to measuring the global contribution of obscured star formation to the star formation rate density at z gsim 4, the formation of the first massive galaxies, and the formation of interstellar dust at early times (lesssim1 Gyr).
Date Issued
2019-12-10
Date Acceptance
2019-10-29
Citation
The Astrophysical Journal: an international review of astronomy and astronomical physics, 2019, 887 (1), pp.1-18
ISSN
0004-637X
Publisher
American Astronomical Society
Start Page
1
End Page
18
Journal / Book Title
The Astrophysical Journal: an international review of astronomy and astronomical physics
Volume
887
Issue
1
Copyright Statement
© 2019. The American Astronomical Society. All rights reserved.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000506001500055&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
LARGE-MAGELLANIC-CLOUD
FORMATION RATE DENSITY
SUBMILLIMETER GALAXIES
MU-M
LUMINOSITY FUNCTION
INFRARED-EMISSION
INTERSTELLAR DUST
SOURCE CATALOG
MILKY-WAY
COSMOS
Publication Status
Published
Article Number
ARTN 55
Date Publish Online
2019-12-11