Journal article
Galaxy Properties at the Faint End of the HI Mass Function
The Astrophysical journal, Vol.918(1), 23
09/01/2021
DOI: 10.3847/1538-4357/ac03ae
Abstract
The Survey of H I in Extremely Low-mass Dwarfs (SHIELD) includes a volumetrically complete sample of 82 gasrich dwarfs with M-H I less than or similar to 10(7.2) M-circle dot selected from the ALFALFA survey. We are obtaining extensive follow-up observations of the SHIELD galaxies to study their gas, stellar, and chemical content, and to better understand galaxy evolution at the faint end of the H I mass function. Here, we investigate the properties of 30 SHIELD galaxies using Hubble Space Telescope imaging of their resolved stars and Westerbork Synthesis Radio Telescope observations of their neutral hydrogen. We measure tip of the red giant branch (TRGB) distances, star formation activity, and gas properties. The TRGB distances are up to 4 x greater than estimates from flow models, highlighting the importance of velocity-independent distance indicators in the nearby universe. The SHIELD galaxies are in underdense regions, with 23% located in voids; one galaxy appears paired with a more massive dwarf. We quantify galaxy properties at low masses including stellar and H I masses, star formation rate (SFRs), specific SFRs, star formation efficiencies, birth-rate parameters, and gas fractions. The lowest-mass systems lie below the mass thresholds where stellar mass assembly is predicted to be impacted by reionization. Even so, we find the star formation properties follow the same trends as higher-mass gas-rich systems, albeit with a different normalization. The H I disks are small (< r > < 0.7 kpc), making it difficult to measure the H I rotation using standard techniques; we develop a new methodology and report the velocity extent, and its associated spatial extent, with robust uncertainties.
Details
- Title: Subtitle
- Galaxy Properties at the Faint End of the HI Mass Function
- Creators
- Kristen B. W. McQuinn - Rutgers, The State University of New JerseyAnjana K. Telidevara - The University of Texas at AustinJackson Fuson - Macalester CollegeElizabeth A. K. Adams - Netherlands Institute for Radio AstronomyJohn M. Cannon - Macalester CollegeEvan D. Skillman - University of MinnesotaAndrew E. Dolphin - RTXMartha P. Haynes - Cornell UniversityKatherine L. Rhode - Indiana University BloomingtonJohn. J. Salzer - Indiana University BloomingtonRiccardo Giovanelli - Cornell UniversityAlex J. R. Gordon - Macalester Coll, Dept Phys & Astron, St Paul, MN 55105 USA
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.918(1), 23
- Publisher
- IOP Publishing Ltd
- DOI
- 10.3847/1538-4357/ac03ae
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Number of pages
- 36
- Grant note
- HST-GO-15243; NSF/AST-1714828 / Brinson Foundation NSF/AST-2009894 / Macalester College WISE research program - Netherlands Organisation for Scientific Research (NWO); Netherlands Organization for Scientific Research (NWO) NAS 5-26555 / NASA from the Space Telescope Science Institute by the Associations of Universities for Research in Astronomy, Incorporated, under NASA Netherlands Foundation for Scientific Research (NWO); Netherlands Organization for Scientific Research (NWO) COX grant from the University of Texas at Austin AST-1615483 / NSF; National Science Foundation (NSF)
- Language
- English
- Date published
- 09/01/2021
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627347902771
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