Abstract Details
| Name: Narendra Nath Patra Affiliation: NCRA-TIFR Conference ID: ASI2016_771 Title : Dark galaxies and their dark matter content Authors and Co-Authors : Jayaram N. Chengalur, NCRA-TIFR Abstract Type : Poster Abstract Category : Extragalactic astronomy Abstract : The long standing 'missing satellite' problem is one of the few hard challenges which poses significant difficulties in our understanding of galaxy formation and evolution under Lambda-CDM cosmology. The number of low mass galaxies predicted by Lambda-CDM, is far more in numbers than observed. Recent deep surveys (optical and radio) have started detecting very faint galaxies though, the discrepancy largely remains. Possibilities could be, the Lambda-CDM prediction is incorrect, or the galaxies are not forming stars efficiently to be detected by our observation (dark: dark galaxies/clouds). In the absence of star formation, these galaxies could be detected in HI and large surveys are planned in several leading radio telescopes to hunt these dark galaxies. Due to very similar gas properties and their proximity to large galaxies (hierarchical structure formation model), dark galaxies very often confused with Compact High Velocity Clouds (CHVCs). In fact, many of the suspected dark galaxies are ruled out due to their proximity to large galaxies. Existence of an associated dark matter halo with dark clouds can be used as a strong indicator of its cosmological origin. We solve hydrostatic equilibrium equation and reconstruct column density and velocity dispersion profiles of dark clouds in the presence and absence of a dark matter halo and demonstrate that inspecting the observable MOMNT profiles it is possible to identify a dark galaxy with associated dark matter halo. Further, we show that the dark matter density structures also could be recovered by cross-matching the MOMNT profiles using Monte-Carlo simulations. |