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Published November 2020 | Version Published + Accepted Version
Journal Article Open

CO observations towards H I-rich Ultradiffuse Galaxies

Creators

  • 1. ROR icon Shanghai Astronomical Observatory
  • 2. ROR icon Chinese Academy of Sciences
  • 3. ROR icon University of Cologne
  • 4. ROR icon Nanjing University
  • 5. ROR icon California Institute of Technology
  • 6. ROR icon National Astronomical Observatories

Abstract

We present CO observations towards a sample of six H I-rich Ultradiffuse galaxies (UDGs) as well as one UDG (VLSB-A) in the Virgo Cluster with the Institut de RadioAstronomie Millimétrique (IRAM) 30-m telescope. CO J = 1–0 is marginally detected at 4σ level in AGC 122966, as the first detection of CO emission in UDGs. We estimate upper limits of molecular mass in other galaxies from the non-detection of CO lines. These upper limits and the marginal CO detection in AGC 122966 indicate low mass ratios between molecular and atomic gas masses. With the star formation efficiency derived from the molecular gas, we suggest that the inefficiency of star formation in such H I-rich UDGs is likely caused by the low efficiency in converting molecules from atomic gas, instead of low efficiency in forming stars from molecular gas.

Additional Information

© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2020 August 21. Received 2020 August 20; in original form 2020 May. Published: 27 August 2020. We thank the referee, Dr U. Lisenfeld, for helpful suggestions to improve the manuscript. This work is supported by National Key Basic Research and Development Program of China (grant no. 2017YFA0402704) and the National Natural Science Foundation of China grant 11590783 and U1731237. This study is based on observations carried out under project number 068-15 with the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). This work is also benefited from the International Space Science Institute (ISSI/ISSI-BJ) in Bern and Beijing, thanks to the funding of the team 'Chemical abundances in the ISM: the litmus test of stellar IMF variations in galaxies across cosmic time' (Principal Investigator DR and ZYZ). JW thanks Dr Yu Lu for helpful discussion about UDGs. Data Availability: The original CO data observed with IRAM 30-m telescope can be accessed by IRAM archive system at https://www.iram-institute.org/EN/content-page-386-7-386-0-0-0.html, while optical images can be obtained from PTF and ZTF archive systems. If anyone is interested in the reduced data presented in this paper, please contact Junzhi Wang at jzwang@shao.ac.cn.

Attached Files

Published - slaa150.pdf

Accepted Version - 2008.11890.pdf

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Additional details

Additional titles

Alternative title
CO observations toward HI-rich Ultra Diffuse Galaxies

Identifiers

Eprint ID
106844
Resolver ID
CaltechAUTHORS:20201130-105703382

Related works

Describes
https://arxiv.org/abs/2008.11890 (URL)
https://www.iram-institute.org/EN/content-page-386-7-386-0-0-0.html (URL)

Funding

National Key Basic Research and Development Program of China
2017YFA0402704
National Natural Science Foundation of China
11590783
National Natural Science Foundation of China
U1731237
Institut National des Sciences de l'Univers (INSU)
Centre National de la Recherche Scientifique (CNRS)
Max-Planck-Gesellschaft
Instituto Geográfico Naciona; (IGN)
International Space Science Institute (ISSI)

Dates

Created
2020-12-02
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Updated
2021-11-16
Created from EPrint's last_modified field