Galaxy Interactions and Galaxy Formation

The interactions of giant galaxies are common throughout the Universe in environments ranging from clusters to the field. In the environments of compact groups of galaxies, PSU graduate student S. Hunsberger, Prof. Jane Charlton, and collaborators have found that these interactions may provide a clue for galaxy formation. Numerous dwarf galaxy candidates have been discovered in the tidal debris of Hickson compact groups. Some of these dwarfs will be flung out into the group, thus enhancing the population of dwarfs (click here for details). Long slit spectra obtained at the Kitt Peak National Observatory 2.1-m are being analyzed to yield the metallicities of the dwarf candidates. The group expects to obtain images of Stephan's quintet (the most famous Hickson compact group) with the Hubble Space Telescope (HST) this summer and fall.

Many dwarf galaxies may form in the tidal debris of interacting galaxies. Interactions are also known to give rise to globular star clusters and the young clusters are concentrated near the centers of the mergers. Do globular clusters also form in tidal debris? There is a suggestion that the mass of the star forming region increases with distance outward along the tail. By comparing radio HI maps to optical images from the HST, Charlton and collaborators hope to better understand the mechanism for formation of stellar systems in merging and interacting galaxies.

---

Web page by Jane Charlton (charlton@astro.psu.edu)
Last update: 1998, February 25