Large Binocular Telescope Observatory | 2016 Aug 09
Wide-Field images obtained with the Large Binocular Telescope reveal that small galaxies with masses deemed too low to attract material from their surroundings are capable of accreting mass from nearby objects.
[c][attachment=0]fig1[1].jpg[/attachment][/c][hr][/hr]Even a dwarf galaxy with very low mass is capable of accreting smaller nearby galaxies, according to an international team of astronomers led by Francesca Annibali of INAF, the Italian National Institute for Astrophysics. This result has been achieved thanks to observations of the region surrounding the dwarf galaxy DDO 68, which has a total stellar mass of only 100 million solar masses, roughly one thousandth of our Milky Way.
Within the scenario of hierarchical galaxy formation, theoretical models predict that galaxies form by successive mergers of smaller systems at all scales. However, until now, direct observational evidence confirming these predictions was available only for massive galaxies and their smaller companions.
In the new study, Annibali and collaborators took advantage of the sensitivity and the large field of view of the Large Binocular Telescope, or LBT, located on Mt. Graham in southeastern Arizona (U.S.). The team discovered that DDO 68, a dwarf galaxy located in an isolated region of space defined as a “void,” is actually surrounded by a number of smaller satellite galaxies, and is accreting them.
“In a way, what we saw reminded us of a quote by Jonathan Swift,” Annibali said. “‘So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ‘em; and so proceed ad infinitum.’ It turns out that even the smallest of galaxies feed on companions that are even smaller, and so our paper bears that quote in its title.” ...
DDO 68: A Flea with Smaller Fleas that on Him Prey - F. Annibali et al
- Astrophysical Journal Letters 826(2):L27 (2016 Aug 01) DOI: 10.3847/2041-8205/826/2/L27
arXiv.org > astro-ph > arXiv:1607.02628 > 09 Jul 2016
