Multiwavelength Characterization of an ACT-selected, Lensed Dusty Star-forming Galaxy at z = 2.64
AuthorRoberts-Borsani, G. W.
Jiménez-Donaire, M. J.
Baker, A. J.
Gallardo, P. A.
Hughes, J. P.
Marriage, T. A.
Wilson, G. W.
Wollack, E. J.
AffiliationUniv Arizona, Steward Observ
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationMultiwavelength Characterization of an ACT-selected, Lensed Dusty Star-forming Galaxy at z = 2.64 2017, 844 (2):110 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2017. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWe present CI(2-1) and multi-transition (CO)-C-12 observations of a dusty star-forming galaxy, ACT J2029+0120, which we spectroscopically confirm to lie at z = 2.64. We detect CO(3-2), CO(5-4), CO(7-6), CO(8-7), and CI (2-1) at high significance, tentatively detect HCO+(4-3), and place strong upper limits on the integrated strength of dense gas tracers (HCN(4-3) and CS(7-6)). Multi-transition CO observations and dense gas tracers can provide valuable constraints on the molecular gas content and excitation conditions in high-redshift galaxies. We therefore use this unique data set to construct a CO spectral line energy distribution (SLED) of the source, which is most consistent with that of a ULIRG/Seyfert or QSO host object in the taxonomy of the Herschel Comprehensive ULIRG Emission Survey. We employ RADEX models to fit the peak of the CO SLED, inferring a temperature of T similar to 117 K and n(H2) similar to 10(5) cm(-3), most consistent with a ULIRG/QSO object and the presence of high-density tracers. We also find that the velocity width of the C I line is potentially larger than seen in all CO transitions for this object, and that the L'(Ci(2-1))/L'(CO(3-2)) ratio is also larger than seen in other lensed and unlensed submillimeter galaxies and QSO hosts; if confirmed, this anomaly could be an effect of differential lensing of a shocked molecular outflow.
VersionFinal published version
SponsorsSpace Telescope Science Institute [HST-HF2-51352.001]; Association of Universities for Research in Astronomy, Inc. [NAS5-26555]; U.S. National Science Foundation [AST-0955810, AST-0408698, AST-0965625, PHY-0855887, PHY-1214379]; Princeton University; University of Pennsylvania; Canada Foundation for Innovation (CFI); Comision Nacional de Investigacion Cientifica y Tecnologica de Chile (CONICYT); CFI under Compute Canada; Government of Ontario; Ontario Research FundResearch Excellence; University of Toronto