Are Dry Mergers Dry, Moist, or Wet?

Details Are Dry Mergers Dry, Moist, or Wet? Are Dry Mergers Dry, Moist, or Wet?

2009-08-18

arxiv.org/abs/0908.2548v1

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

19 pages, 9 figures, 4 tables. Accepted for publication in MNRAS

Scientific paper

We present a spectral analysis of a sample of red-sequence galaxies identified by van Dokkum (2005) as dry merger remnants and ongoing dry mergers. Kinematics, stellar population absorption features, and ionisation from emission lines, are derived. We find that approximately half of the sample showing strong tidal features have younger stellar populations than a control sample at a given velocity dispersion. Conversely, galaxies with weak tidal tails and/or ongoing mergers -- with the exception of one galaxy -- do not show this young component. This seems to indicate that the young stellar populations observed in a significant fraction of ellipticals is the consequence of star formation triggered by mergers. This young component is consistent with a light "frosting" of young stars (<2% by mass) superimposed upon a dominant, old (~11 Gyr), stellar population. In terms of stellar populations, these mergers are, in fact, fairly dry. We found, however, that merger remnants with young stellar populations are supported by rotation, contrary to the expectations of a major dry merger. This suggests that the small amount of gas involved has been sufficient to produce a dynamically cold stellar component. Half of the galaxies with strong tidal distortion, however, are slow rotating and have stellar populations compatible with the control sample at a given velocity dispersion. Remarkably, none of the galaxies with velocity dispersions in excess of 250 km/s have a young stellar component, independent of the merger stage.

Affiliated with

Also associated with

No associations

Rating

Are Dry Mergers Dry, Moist, or Wet? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Are Dry Mergers Dry, Moist, or Wet?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Are Dry Mergers Dry, Moist, or Wet? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-8587