H II Regions Within a Compact High Velocity Cloud. A Nearly Starless Dwarf Galaxy
2015
Within the SECCO survey we identified a candidate stellar counterpart to the Ultra Compact
High Velocity Cloud(UCHVC) HVC274.68+74.70-123 that was suggested by Adams et al. to be a possible mini halo within the
Local Groupof galaxies. The spectroscopic follow-up of the brightest sources within the candidate reveals the presence of two
H ii regionswhose radial velocity is compatible with a physical association with the UVHVC. The available data do not allow us to give a definite answer on the nature of the newly identified system. A few alternative hypotheses are discussed. However, the most likely possibility is that we have found a new faint
dwarf galaxyresiding in the
Virgo clusterof galaxies, which we name SECCO 1. Independently of its actual distance, SECCO 1 displays a ratio of neutral hydrogen mass to V luminosity of {{M}H I}/{{L}V}≳ 20, by far the largest among local dwarfs. Hence, it appears to be a nearly starless galaxy and it may be an example of the missing links between normal dwarfs and the dark mini halos that are predicted to exist in large numbers according to the currently accepted cosmological model. Based on data acquired using the
Large Binocular Telescope(LBT). The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are The University of Arizona on behalf of the Arizona
university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University; and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.
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