The dwarf galaxy population as revealed by ALFALFA

Elizabeth A. K. Adams, Catherine Ball, John M. Cannon, Martha P. Haynes, Alec Hirschauer, Riccardo Giovanelli, William Janesh, Steven Janowiecki, Luke Leisman, Kristen B. W. McQuinn, Katherine L. Rhode, John J. Salzer

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The combination of sensitivity and large sky coverage of the ALFALFA HI survey has enabled the detection of difficult to observe low mass galaxies in large numbers, including dwarf galaxies overlooked in optical surveys. Three different, but connected, studies of dwarf galaxies from the ALFALFA survey are of particular interest: SHIELD (Survey of HI in Extremely Low-mass Dwarfs), candidate gas-rich ultra- faint dwarf galaxies, and the (Almost) Dark population. SHIELD is a systematic multiwavelength study of all dwarf galaxies from ALFALFA with MHI < 107.2 M and clear optical counterparts. Candidate gas-rich ultra-faint dwarf galaxies extend the dwarf galaxy population to even lower masses. These galaxies are identified as isolated HI clouds with no discernible optical counterpart but subsequent observations reveal that some are extremely faint, gas- dominated galaxies. Leo P, discovered first as an HI detection, and then found to be an actively star-forming galaxy, bridges the gap between these candidate galaxies and the SHIELD sample. The (Almost) Dark sample consists of galaxies whose optical counterparts are overlooked in current optical surveys but which are clear detections in ALFALFA. This sample includes field gas-rich ultra-diffuse galaxies. Coma P, with a peak surface brightness of only ~26.4 mag arcsec-2 in g', demonstrates the sort of extreme low surface brightness galaxy that can be discovered in an HI survey.
Originele taal-2English
TitelDwarf Galaxies
SubtitelFrom the deep Universe to the present. Proceedings IAU Symposium N. 344, 2019
RedacteurenK.B.W. McQuinn, S. Stierwalt
Uitgeverij International Astronomical Union
Aantal pagina's4
UitgaveSymposium S344
StatusPublished - 1-okt.-2019
EvenementIAUS 344: Dwarf Galaxies: From the Deep Universe to the Present - Vienna , Austria
Duur: 20-aug.-201924-aug.-2019


ConferenceIAUS 344

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