ALMA Imaging of the CO (7-6) Line Emission in the Submillimeter Galaxy LESS 073 at z = 4.755 The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc

• Published in: The Astrophysical journal Vol. 892; no. 2
• Main Authors: Zhao (赵应和), Yinghe, Lu, Nanyao, Díaz-Santos, Tanio, Gao, Yu, Xu, C. Kevin, Charmandaris, Vassilis, Inami, Hanae, Rigopoulou, Dimitra, Sanders, David B., Huang, Jiasheng, Wang, Zhong
• Format: Journal Article
• Language: English
• Published: The American Astronomical Society 07.04.2020
• Subjects: Galaxy evolution; High-redshift galaxies; Interstellar medium; Starburst galaxies
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ab75eb

In this paper we present our imaging observations on the CO (7−6) line and its underlying continuum emission of the young submillimeter galaxy LESS 073 at redshift 4.755, using the Atacama Large Millimeter/submillimeter Array. At the achieved resolution of ∼ (8 × 6 kpc2), the CO (7−6) emission is largely unresolved (with a deconvolved size of ), and the continuum emission is totally unresolved. The CO (7−6) line emission has an integrated flux of 0.86 0.08 Jy km s−1, and a line width of 343 40 km s−1. The continuum emission has a flux density of 0.51 mJy. By fitting the observed far-infrared spectral energy distribution (SED) of LESS 073 with a single-temperature modified blackbody function, we obtained a dust temperature K, 60-100 m flux density ratio , and total infrared luminosity . The SED-fit-based is consistent with those estimated from various line ratios as advocated by our earlier work, indicating that the proposed line-ratio-based method can be used to practically derive for high-z sources. The total molecular gas mass of LESS 073 is , and the inferred gas depletion time is about 43 Myr.