Wednesday, February 23, 2011, 11:00 am, Pratt Conference Room
Evidence of Induced Star Formation
from the Optical Colours of SDSS Galaxy Pairs
Dr. Dave Patton (Trent University)
| Galaxy-galaxy interactions play an important role in the evolution of galaxies. Along with triggering changes in morphology and nuclear activity, these close encounters are capable both of inducing and (eventually) quenching star formation. To further explore the effects of interactions on the star forming properties of galaxies, we have assembled a high quality catalog of global and central colours for ~ 20,000 galaxies with close companions from the SDSS, along with a much larger control sample. We detect clear differences in the colours of paired and control galaxies which are consistent with the presence of enhanced star formation (ongoing or recent) in the centres of galaxies with close companions. These enhancements diminish as pair separation increases, and are absent in the control sample and in close projected pairs (i.e., interlopers). These results are consistent with a scenario in which close peri-centre passages trigger star formation in the centres of galaxies which are sufficiently gas rich, after which time the galaxies gradually redden as they separate and their starbursts age. |
