ALMA/ACA CO Survey of the IC 1459 and NGC 4636 Groups: Environmental Effects on the Molecular Gas of Group Galaxies

Bumhyun Lee, Jing Wang, Aeree Chung, Luis C. Ho, Ran Wang, Tomonari Michiyama, Juan Molina, Yongjung Kim, Li Shao, Virginia Kilborn, Shun Wang, Xuchen Lin, Dawoon E. Kim, Barbara Catinella, Luca Cortese, Nathan Deg, Helga Denes, Ahmed Elagali, Bi Qing For, Dane KleinerBärbel S. Koribalski, Karen Lee-Waddell, Jonghwan Rhee, Kristine Spekkens, Tobias Westmeier, O. Ivy Wong, Frank Bigiel, Albert Bosma, Benne W. Holwerda, Jan M. van der Hulst, Sambit Roychowdhury, Lourdes Verdes-Montenegro, Martin A. Zwaan

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3 Citations (Scopus)


We present new results of a 12CO(J = 1-0) imaging survey using the Atacama Compact Array (ACA) for 31 H i detected galaxies in the IC 1459 and NGC 4636 groups. This is the first CO imaging survey for loose galaxy groups. We obtained well-resolved CO data (∼0.7-1.5 kpc) for a total of 16 galaxies in two environments. By comparing our ACA CO data with the H i and UV data, we probe the impacts of the group environment on the cold gas components (CO and H i gas) and star formation activity. We find that CO and/or H i morphologies are disturbed in our group members, some of which show highly asymmetric CO distributions (e.g., IC 5264, NGC 7421, and NGC 7418). In comparison with isolated galaxies in the xCOLD GASS sample, our group galaxies tend to have low star formation rates and low H2 gas fractions. Our findings suggest that the group environment can change the distribution of cold gas components, including the molecular gas and star formation properties of galaxies. This is supporting evidence that preprocessing in the group-like environment can play an important role in galaxy evolution.

Original languageEnglish
Article number31
JournalAstrophysical Journal, Supplement Series
Issue number1
Publication statusPublished - 2022 Sept 1

Bibliographical note

Funding Information:
L.C.H. was supported by the National Science Foundation of China (11721303, 11991052, 12011540375) and the China Manned Space Project (CMS-CSST-2021-A04, CMS-CSST-2021-A06).

Funding Information:
J.M.vdH. acknowledges funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC grant Agreement No. 291531 (‘HIStoryNU’).

Funding Information:
This paper makes use of the following ALMA data: ADS/JAO.ALMA#2019.1.01804.S. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under a cooperative agreement by Associated Universities, Inc.

Funding Information:
A.B. acknowledges support from the Centre National d’Etudes Spatiales (CNES), France.

Funding Information:
L.V.M. acknowledges financial support from the State Agency for Research of the Spanish Ministry of Science, Innovation and Universities through the “Center of Excellence Severo Ochoa” awarded to the Instituto de Astrofisica de Andalucia (SEV-2017-0709), from grant RTI2018-096228-B-C31 (Ministry of Science, Innovation and Universities/State Agency for Research/European Regional Development Funds, European Union), and grant IAA4SKA (Ref. P18-RT-3082) from the Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades de la Junta de Andalucia and the European Regional Development Fund from the European Union.

Funding Information:
We thank the anonymous referee for helpful suggestions and comments. B.L. acknowledges support from the National Science Foundation of China (12073002, 11721303, 11991052) and the National Key R&D Program of China (2016YFA0400702). B.L. is supported by the Boya Fellowship at Peking University. B.L. gratefully thanks Hyein Yoon for useful discussions. This work was partly supported by the Korea Astronomy and Space Science Institute grant funded by the Korean government (MSIT) (Project No. 2022-1-840-05). Support for this work was also provided by the National Research Foundation of Korea by grant No. 2018R1D1A1B07048314.

Funding Information:
L.C. is the recipient of an Australian Research Council Future Fellowship (FT180100066) funded by the Australian Government.

Funding Information:
The Australian SKA Pathfinder is part of the Australia Telescope National Facility ( ) which is managed by CSIRO. The operation of ASKAP is funded by the Australian Government with support from the National Collaborative Research Infrastructure Strategy. ASKAP uses the resources of the Pawsey Supercomputing Centre. The establishment of ASKAP, the Murchison Radio-astronomy Observatory, and the Pawsey Supercomputing Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund. We acknowledge the Wajarri Yamatji people as the traditional owners of the Observatory site.

Funding Information:
Y.K. was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2021R1C1C2091550) and acknowledges the support from China Postdoc Science General (2020M670022), and Special (2020T130018) grants funded by the China Postdoctoral Science Foundation.

Funding Information:
F.B. acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 726384/Empire).

Funding Information:
K.S. acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC).

Funding Information:
This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 679627; project name FORNAX).

Funding Information:
Parts of this research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013.

Funding Information:
T.M. appreciates support from NAOJ ALMA Scientific Research grant No. 2021-17A. T.M. is supported by JSPS KAKENHI grant No. 22K14073.

Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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