2017/03/31 by E. Papastergis, E. A. K. Adams, A. J. Romanowsky · 84 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Field (mathematics) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Hydrogen #Hydrogen line #Line (geometry) #Sign (mathematics) #Star formation #Stellar mass #astro-ph.GA
paper · pdf · doi:10.1051/0004-6361/201730795
published in Astronomy and Astrophysics 601, L10 (EDP Sciences) · Accepted by A&A letters. 4 pages, 2 figures, 1 table
openalex created_date 2017/04/14 · openalex publication_date 2017/05/01 · arxiv created 2017/05/08 · arxiv updated 2017/05/24 · openalex updated_date 2026/08/05
We report on the results of radio observations in the 21 cm emission line of atomic hydrogen (HI) of four relatively isolated ultra-diffuse galaxies (UDGs): DGSAT I, R-127-1, M-161-1, and SECCO-dI-2. Our Effelsberg observations resulted in non-detections for the first three UDGs, and a clear detection for the last. DGSAT I, R-127-1, and M-161-1 are quiescent galaxies with gas fractions that are much lower than those of typical field galaxies of the same stellar mass. On the other hand, SECCO-dI-2 is a star forming gas-rich dwarf, similar to two other field UDGs that have literature HI data: SECCO-dI-1 and UGC 2162. This group of three gas-rich UDGs have stellar and gaseous properties that are compatible with a recently proposed theoretical mechanism for the formation of UDGs, based on feedback-driven outflows. In contrast, the physical characteristics of R-127-1 and M-161-1 are puzzling, given their isolated nature. We interpret this dichotomy in the gaseous properties of field UDGs as a sign of the existence of multiple mechanisms for their formation, with the formation of the quiescent gas-poor UDGs remaining a mystery.