Researchers have, for the first time, looked at the merger of two galaxies in which one dwarf galaxy is swallowing another smaller galaxy.
This research has been done by two independent groups, one led by David Martínez-Delgado of the Max Planck Institute for Astronomy (MPIA), the other by Michael Rich of UCLA, and published online in the February 8 issue of the Journal Nature.
Researchers have found that small companion of the dwarf galaxy NGC 4449, present in the constellation Canes Venatici, is another smaller dwarf galaxy that has been firstly swallowed by its large neighbor and then disrupted.
In this research, the group of Martínez-Delgado used Jay GaBany’s 0.5 m telescope at Black Bird Observatory for observations between April 2010 and January 2011 while the group of Michael Rich used the Saturn Lodge 0.7m telescope on the grounds of the Polaris Observatory Association for observations from May to June 2011.
Martínez-Delgado said, “A number of models predict that dwarfs should eat dwarfs. But this is the first clear example of such a feast that has been actually observed: We’ve found a key piece of the puzzle of galaxy evolution. Also, the fact that NGC 4449 is quite close to us shows that processes like this are still happening. They need to be taken into account if we want to describe our cosmic neighbourhood.”
MPIA’s Michelle Collins, who worked with Michael Rich on analyzing the dwarf galaxy’s shape, added, “Knowing what a half-digested dwarf galaxy looks like should help us find additional examples of dwarfs eating dwarfs. Finding a fair number of examples should put our models of the first stages of galactic growth on a firm footing – or show what we’re missing.”
R. M. Rich, M. L. M. Collins, C. M. Black, F. A. Longstaff, A. Koch, A. Benson & D. B. Reitzel, (2012). A tidally distorted dwarf galaxy near NGC 4449. Nature, doi:10.1038/nature10837