2016/04/30 by Blakesley Burkhart, Abraham Loeb · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #RADIUS #Ram pressure #Virgo Cluster #Virial theorem #astro-ph.GA
paper · pdf · doi:10.3847/2041-8205/824/1/l7
Accepted to ApJL
arxiv created 2016/05/13 · openalex publication_date 2016/06/03 · arxiv updated 2016/06/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
ABSTRACT Using data from the ALFALFA AGES Arecibo HI survey of galaxies and the Virgo cluster X-ray pressure profiles from XMM-Newton , we investigate the possibility that starless dark HI clumps, also known as “dark galaxies,” are supported by external pressure in the surrounding intercluster medium. We find that the starless HI clump masses, velocity dispersions, and positions allow these clumps to be in pressure equilibrium with the X-ray gas near the virial radius of the Virgo cluster. We predict the sizes of these clumps to range from 1 to 10 kpc, in agreement with the range of sizes found for spatially resolved HI starless clumps outside of Virgo. Based on the predicted HI surface density of the Virgo sources, as well as a sample of other similar resolved ALFALFA HI dark clumps with follow-up optical/radio observations, we predict that most of the HI dark clumps are on the cusp of forming stars. These HI sources therefore mark the transition between starless HI clouds and dwarf galaxies with stars.