GBT24B-417

Exploring the Environment around J0613+52

Abstract

J0613+52 is a galaxy-sized cloud of rotating gas which has an optical surface brightness of mu(0)< $25.5 g mag/sq.arcsec. Found by the GBT as part of a galaxy survey, J0613+52 is unique in that, unlike all other "almost-dark" galaxies found to date, it is isolated, with its nearest neighbor at least 100 Mpc away. J0613+52's inclination-uncorrected HI line width indicates and organized, gas-rich structure, but the galaxy clearly has a very diffuse stellar content. Looking at J0613+52's properties as a whole, the most likely reason for J0613+52's low star formation is a combination of its isolation and diffuse nature. That is, the HI gas density of J0613+52 is likely too low to readily support star formation, and the lack of nearby galaxies means there has been no external trigger to stimulate star formation within the galaxy. As a result, J0613+52 may be the first example that has been found of an undisturbed, very slowly evolving galaxy in the local universe. Here we propose to use the GBT to search for any previously unidentified companions of J0613+52. Our results from the GBT will be combined with ongoing optical imaging, to gain a complete picture of the environment around this object.

Investigators

Name	Institution
Karen O'Neil *	Green Bank Observatory
Stephen Schneider	Massachusetts at Amherst, University of
Wim van Driel	Paris, Observatoire de

* indicates the PI