This paper presents data from a 21 cm H I emission drift scan observation of a field partially covering the NGC 4636 galaxy group with the Five-hundred meter Aperture Radio Telescope (FAST). We construct a pipeline to reduce the data, and use SoFiA for source finding. When not contaminated by Radio Frequency Interference (RFI), the FAST observations are capable of detecting all of the galaxies previously detected by the Arecibo Legacy Fast ALFA (ALFALFA) survey in the same region. Comparing to ALFALFA for the detections in common, the FAST data show consistent integrated spectra when the H I disks are spatially unresolved, and capture more flux when the H I disks are resolved. The FAST data further reveal 10 new detections in the region mutually covered with ALFALFA, and 18 new detections beyond the footprint of ALFALFA. All of the new detections have the matching optical counterparts. For the member galaxies of the NGC 4636 group, the detection limit of FAST is deeper by 0.4 dex in H I mass than that of the ALFALFA data. After correcting for the incompleteness caused by RFI contamination, we show that the H I detection rate of galaxies rises steeply with radius out to the virial radius of the group, and flattens beyond that. We also examine four spatially resolved galaxy systems with potential tidal interaction features in detail. Considering that the data have been taken during the"shared-risk"period before a major source of local RFI was eliminated, the results highlight the power of FAST in detecting extragalactic H I.

Pei Zuo;Dong Yang;Jing Wang;Lister Staveley-Smith;Xuchen Lin;Bi-Qing For;Tobias Westmeier;Jie Wang;Kristine Spekkens;Virginia Kilborn;O.Ivy Wong;Di Li;Karen Lee-Waddell;Barbara Catinella;Luis C.Ho;Bärbel Koribalski;Bumhyun Lee;Ming Zhu

Kavli Institute for Astronomy and Astrophysics,Peking University,Beijing 100871,China;International Centre for Radio Astronomy Research(ICRAR),University of Western Australia,Crawley,WA 6009,Australia;Department of Astronomy,School of Physics,Peking University,Beijing 100871,China;ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions(ASTRO 3D),Australia;National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;Department of Physics and Space Science,Royal Military College of Canada,P.O.Box 17000,Station Forces,Kingston,Ontario,K7K 7B4,Canada;Centre for Astrophysics and Supercomputing,Swinburne University of Technology,John Street,Hawthorn,3122,Australia;CSIRO Space and Astronomy,Australia Telescope National Facility,P.O.Box 1130,Bentley,WA 6102,Australia;Research Center for Intelligent Computing Platforms,Zhejiang Laboratory,Hangzhou 311100,China;0 CSIRO Space and Astronomy,Australia Telescope National Facility,P.O.Box 76,NSW 1710,Australia;1 School of Science,Western Sydney University,Locked Bag 1797,Penrith,NSW 2751,Australia;2 Korea Astronomy and Space Science Institute,Daejeon 34055,Republic of Korea

天文和天体物理学研究

[1]Pei Zuo;Dong Yang;Jing Wang;Lister Staveley-Smith;Xuchen Lin;Bi-Qing For;Tobias Westmeier;Jie Wang;Kristine Spekkens;Virginia Kilborn;O.Ivy Wong;Di Li;Karen Lee-Waddell;Barbara Catinella;Luis C.Ho;Bärbel Koribalski;Bumhyun Lee;Ming Zhu-.Mapping H I in the NGC 4636 Galaxy Group with FAST)[J].天文和天体物理学研究,2022(09):202-222

SoFiA,Arecibo,ALFA,ALFALFA,flattens

Mapping,NGC,Galaxy,Group,FAST,This,paper,presents,data,from,emission,drift,scan,field,partially,covering,galaxy,group,Five,hundred,meter,Aperture,Radio,Telescope,We,construct,pipeline,reduce,source,finding,When,not,contaminated,by,Frequency,Interference,RFI,observations,capable,detecting,galaxies,previously,detected,Legacy,Fast,survey,same,region,Comparing,detections,common,show,consistent,integrated,spectra,when,disks,spatially,unresolved,capture,more,flux,further,reveal,new,mutually,covered,beyond,footprint,All,have,matching,optical,counterparts,For,member,limit,deeper,dex,mass,than,that,After,correcting,incompleteness,caused,contamination,rises,steeply,radius,out,virial,also,examine,four,systems,potential,tidal,interaction,features,detail,Considering,been,taken,during,shared,risk,period,before,major,local,was,eliminated,results,highlight,power,extragalactic

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