Merging galaxies with multiple nuclei from HST ULIRGs snapshot survey
Abstract
The ultra-luminous IRAS galaxies (ULIRGs) are strong interacting or merging galaxies. There is also the evidence both from observational and theoretical sides that the remnants of merger could be ellipticals. However, it is not clear that these merging remnants ellipticals are from major merger of two spiral galaxies or from multi-merger of group of galaxies. We investigate a ULIRGs image sample from a high resolution (0.1-0.2'') HST I-band snapshot survey. Given there a lot of knots for most of our sample galaxies and these knots are supposed to be massive star forming region, and very bright and large, we built a criteria to separate the galaxy nuclei from knots based on the I-band luminosity of 2x109 L⊙ and the size of 250pc which is the largest star formation region in near starburst galaxy M82. Based on these criteria, the percentage of multi-nuclei in this 120 ULIRGs sample is more than 20% and the percentage of two nuclei is more than 30%. The distribution of project distance of two nuclei shows that the time scale for nuclei merger is not so short as some people suggested.
- Publication:
-
Galaxies and their Constituents at the Highest Angular Resolutions
- Pub Date:
- January 2001
- Bibcode:
- 2001IAUS..205..172C