Five Gas-rich Ultrafaint Dwarf Galaxy Candidates Discovered in WIYN Imaging of ALFALFA Sources
- Department of Astronomy, Indiana University, 727 E. Third Street, Bloomington, IN 47405 (United States)
- International Centre for Radio Astronomy Research, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia)
- ASTRON, The Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands)
- Cornell Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, 122 Sciences Drive, Ithaca, NY 14853 (United States)
- Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States)
We present results from the analysis of WIYN pODI imaging of 23 ultracompact high-velocity clouds (UCHVCs), which were identified in the ALFALFA H i survey as possible dwarf galaxies in or near the Local Group. To search for a resolved stellar population associated with the H i gas in these objects, we carried out a series of steps designed to identify stellar overdensities in our optical images. We identify five objects that are likely stellar counterparts to the UCHVCs, at distances of ∼350 kpc to ∼1.6 Mpc. Two of the counterparts were already described in Janesh et al.; the estimated distance and detection significance for one of them changed in the final analysis of the full pODI data set. At their estimated distances, the detected objects have H i masses from 2 × 10{sup 4} to 3 × 10{sup 6} M {sub ⊙}, M {sub V} from −1.4 to −7.1, and stellar masses from 4 × 10{sup 2} to 4 × 10{sup 5} M {sub ⊙}. None of the objects shows evidence of a young stellar population. Their properties would make the UCHVCs some of the most extreme objects in and around the Local Group, comparable to ultrafaint dwarf galaxies in their stellar populations, but with significant gas content. Such objects probe the extreme end of the galaxy mass function and provide a test bed for theories regarding the baryonic feedback processes that impact star formation and galaxy evolution in this low-mass regime.
- OSTI ID:
- 22897376
- Journal Information:
- Astronomical Journal (Online), Vol. 157, Issue 5; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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