University of Texas Rio Grande Valley ScholarWorks @ UTRGV Physics and Astronomy Faculty Publications and Presentations College of Sciences 8-9-2021 WALLABY Pre-Pilot Survey: H I Content of the Eridanus Supergroup B. Q. For University of Western Australia J. Wang Tobias Westmeier O. I. Wong C. Murugeshan See next page for additional authors Follow this and additional works at: https://scholarworks.utrgv.edu/pa_fac Part of the Astrophysics and Astronomy Commons, and the Physics Commons Recommended Citation B-Q For, J Wang, T Westmeier, O I Wong, C Murugeshan, L Staveley-Smith, H M Courtois, D Pomarede, K Spekkens, B Catinella, K B W McQuinn, A Elagali, B S Koribalski, K Lee-Waddell, J P Madrid, A Popping, T N Reynolds, J Rhee, K Bekki, H Denes, P Kamphuis, L Verdes-Montenegro, WALLABY Pre-Pilot Survey: H I Content of the Eridanus Supergroup, Monthly Notices of the Royal Astronomical Society, 2021;, stab2257, https://doi.org/10.1093/mnras/stab2257 This Article is brought to you for free and open access by the College of Sciences at ScholarWorks @ UTRGV. It has been accepted for inclusion in Physics and Astronomy Faculty Publications and Presentations by an authorized administrator of ScholarWorks @ UTRGV. For more information, please contact [email protected], [email protected]. Authors B. Q. For, J. Wang, Tobias Westmeier, O. I. Wong, C. Murugeshan, L. Staveley-Smith, H. M. Courtois, D. Pomarede, and Juan P. Madrid This article is available at ScholarWorks @ UTRGV: https://scholarworks.utrgv.edu/pa_fac/476 1 Downloaded from https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stab2257/6346561 by The University of Texas Rio Grande Valley user on 12 August 2021 WALLABY Pre-Pilot Survey: H i Content of the Eridanus Supergroup B.-Q. For,1;2? J. Wang,3 T. Westmeier,1;2 O.I. Wong,4;1;2 C. Murugeshan,4;2 L. Staveley-Smith,1;2 H.M. Courtois,5 D. Pomare`de,6 K. Spekkens,7 B. Catinella,1;2 K.B.W. McQuinn,8 A. Elagali,9 B.S. Koribalski,10;11;2 K. Lee-Waddell,1;4 J.P. Madrid,12 A. Popping,1 T.N. Reynolds,1;2 J. Rhee,1;2 K. Bekki,1 H. De`nes,13 P. Kamphuis,14 & L. Verdes-Montenegro15 1International Centre for Radio Astronomy Research, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia 2ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) 3Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China 4CSIRO Space & Astronomy, PO Box 1130, Bentley, WA 6102, Australia 5Univ Claude Bernard Lyon 1, IP2I Lyon, IUF, F-69622, Villeurbanne, France 6Institut de Recherche sur les Lois Fondamentales de l^aA˘ZUnivers,´ CEA Universit Paris-Saclay, France 7Royal Military College of Canada, PO Box 17000, Station Forces, Kingston, ON K7K7B4, Canada 8Rutgers University, Department of Physics and Astronomy, 136 Frelinghuysen Road, Piscataway, NJ 08854, USA 9Telethon Kids Institute, Perth Children^aA˘Zs´ Hospital, Perth, Australia 10CSIRO Space & Astronomy, PO Box 76, Epping, NSW 1710, Australia 11School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia 12The University of Texas Rio Grande Valley, One West University Blvd, Brownsville, TX 78520, USA 13ASTRON, The Netherlands Institute for Radio Astronomy, Oude Hoogeveensedijk 4, 7991 PD, Dwingeloo, the Netherlands 14Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute, 44780 Bochum, Germany 15Instituto de Astrofi´sica de Andaluci´a, CSIC, Glorieta de la Astronomi´a, E-18080, Granada, Spain Accepted XXX. Received YYY; in original form ZZZ ABSTRACT We present observations of the Eridanus supergroup obtained with the Australian Square Kilometre Array Pathfinder (ASKAP) as part of the pre-pilot survey for the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). The total number of detected H i sources is 55, of which 12 are background galaxies not associated with the Eridanus supergroup. Two massive H i clouds are identified and large H i debris fields are seen in the NGC 1359 interacting galaxy pair, and the face-on spiral galaxy NGC 1385. We describe the data products from the source finding algorithm and present the basic parameters. The presence of distorted H i morphology in all detected galaxies suggests ongoing tidal interactions within the subgroups. The Eridanus group has a large fraction of H i deficient galaxies as compared to previously studied galaxy groups. These H i deficient galaxies are not found at the centre of the group. We find that galaxies in the Eridanus supergroup do not follow the general trend of the atomic gas fraction versus stellar mass scaling relation, which indicates that the scaling relation changes with environmental density. In general, the majority of these galaxies are actively forming stars. Key words: galaxies: star formation { galaxies: ISM { galaxies: groups: general 1 INTRODUCTION tions show that the star formation is suppressed in cluster environments (G´omez et al. 2003; Cortese et al. 2019) and The star formation-density and morphology-density rela- the fraction of early-type (elliptical and lenticular) galax- tions highlight the dependence of galaxy evolution on en- ies increases in denser cluster environments as compared vironment. A galaxy cluster is the most striking place to to the fraction of late-type (spiral and irregular) galaxies look for environmental effects on galaxy evolution. Observa- (Dressler 1980; Postman et al. 2005). Recent studies of clus- ORIGINAL UNEDITEDters in the local MANUSCRIPT Universe have shown conflicting results. While a morphology-density relation remains within each ? E-mail: [email protected] © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society 2 ◦ ◦ halo, the total fraction of early-type galaxies is nearly con- 3π steradian of the sky (−90 < δ < +30 ). The estimated Downloaded from https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stab2257/6346561 by The University of Texas Rio Grande Valley user on 12 August 2021 stant across three orders of magnitude in cluster halo mass root-mean-square (RMS) noise level is anticipated to be 1.6 −1 (13 ≤ log Mh/(h M ) ≤ 15.8) (Hoyle et al. 2012). The mJy per beam per 18.5 kHz channel. The survey is ex- study of Simard et al.(2009) also shows no clear trend of pected to detect 500,000 galaxies (Koribalski et al. 2020). the early-type fractions in clusters as a function of cluster The main advantage of ASKAP over traditional radio in- velocity dispersion. These results suggest that most mor- terferometers is the use of a state-of-the-art phased array phological transformation is happening in groups prior to feed (PAF), which allows the formation of multiple beams merging into massive clusters. The small velocity dispersion on the sky simutaneously to achieve a fast survey speed. of galaxy groups also results in more galaxy mergers than For WALLABY, the targeted angular and spectral resolu- in clusters (e.g., Hickson 1997). A combination of nature tion of 3000 and 4 km s−1 at z = 0 are two to thirty times and nurture must be at play to drive such differences. The better than some of the single-dish surveys, most notably evolutionary effects imposed by different environments are the H i Parkes All-Sky Survey (HIPASS; Barnes et al. 2001) important to understand. and the Arecibo Legacy Fast ALFA survey (ALFALFA; In order to gain a full picture of galaxy evolution, it is Giovanelli et al. 2005). WALLABY will revolutionize the H i crucial to investigate the gas and stellar content of galaxies. extragalactic field by providing a large statistical sample of Hydrogen gas makes up the baryonic matter that is channel- galaxies at high resolution across a wide range of environ- ing through large-scale structure filaments to haloes, cool- ments from voids to groups and clusters. ing to neutral form in galaxy disks and then to molecular To verify the observational feasibility of ASKAP and gas to form stars. Observations of H i are a direct way to to improve the efficiency of the ASKAP data reduction trace recent and ongoing interaction between galaxies and pipeline, a WALLABY early science program was carried their environment due to its large extent beyond the stellar out in 2018 using 12 to 16 ASKAP antennas. Studies of the disk (Hibbard & van Gorkom 1996). Interactions can occur NGC 7162 group (Reynolds et al. 2019) and the LGG 351 via a number of physical processes, such as cold gas accre- group of Galaxies 351 (For et al. 2019) show that the ma- tion with fresh gas channeling from the intergalactic medium jority of galaxies in these groups are actively forming stars (IGM) directly into the galaxies, hot mode gas accretion indicating inefficiency of gas removal processes in the loose with gas being shock-heated to high halo virial temperatures group environment. H i debris due to tidal interaction has and falling back to the galaxy centre as it cools (Katz et al. also been identified in the NGC 7232 galaxy group, with 2003; Kereˇset al. 2005), tidal stripping due to gravitational one gas cloud postulated to be the progenitor of a long-lived interaction (Chung et al. 2009; For et al. 2014) and ram- tidal dwarf galaxy (Lee-Waddell et al. 2019). Detailed stud- pressure stripping when galaxies pass through a dense IGM ies of individual galaxies, NGC 1566 (Elagali et al. 2019) and (Kenney et al. 2004; Abramson et al. 2011). These processes IC 5201 (Kleiner et al. 2019), have also highlighted the im- largely contribute to gas removal and accretion in galax- portance of high resolution imaging. The resolved H i kine- ies, which in turn, affect their star formation efficiency matics allowed them to recover the dark matter fractions by (Cortese et al.