Quick search Find article
Quick search
Find article

Hubble Space Telescope Images of Red Mergers: How Dry Are They?

FREE ISSUE

Katherine E. Whitaker1 and Pieter G. van Dokkum1

Show affiliations


Mergers between red galaxies are observed to be common in the nearby universe, and are thought to be the dominant mechanism by which massive galaxies grow their mass at late times. These "dry" mergers can be readily identified in very deep ground-based images, thanks to their extended low surface brightness tidal features. However, ground-based images lack the required resolution to determine the morphologies of the merging galaxies, and to measure the amount of dust and associated gas. We present HST ACS and WFPC2 observations of a sample of 31 bulge-dominated red-sequence galaxies at z ~ 0.1, comprised of ongoing mergers, merger remnants, and undisturbed galaxies. Nearly all galaxies have early-type morphologies and most are well-fit by r1/4 law surface brightness profiles. We find that only 10% of the galaxies show evidence for the presence of dust. The amount of cold gas (or its upper limit) is calculated from the mean color excess, assuming a simple relation between gas mass and dust mass. The gas mass is low for all galaxies, and we find that Mgas/Mstellar lesssim 3 × 104. We infer that red mergers in the nearby universe mostly involve early-type galaxies containing little cold gas and dust. This may imply that the progenitors were mostly devoid of gas and/or that feedback mechanisms are very effective in preventing the gas to cool. The lack of gas in these objects may also imply a relatively large fraction of binary black holes in the centers of massive ellipticals.

Subject headings

galaxies: elliptical and lenticular, cD; galaxies: evolution; galaxies: formation


Dates

Issue 2 (2008 April 1)

Received 2008 January 15, accepted for publication 2008 February 14

Published 2008 March 6



  1. Hubble Space Telescope Images of Red Mergers: How Dry Are They?

    Katherine E. Whitaker and Pieter G. van Dokkum 2008 ApJ 676 L105

  2. Orbital Solutions and Absolute Elements of the Eclipsing Binary AY Camelopardalis

    Richard M. Williamon et al. 2004 The Astronomical Journal 128 1319

  3. HD 71636, A Newly Discovered Eclipsing Binary

    Gregory W. Henry et al. 2006 The Astronomical Journal 132 2489

  4. The Eclipsing Binary System AR Monocerotis

    Richard M. Williamon et al. 2005 The Astronomical Journal 129 2798

  5. ΛCDM-based Models for the Milky Way and M31. I. Dynamical Models

    Anatoly Klypin et al. 2002 ApJ 573 597

Users also read

What's this?
This innovative new feature generates a list of articles 'also read' by other users based on them reading the original article. Article abstracts citations and references are all considered and weighted accordingly. We hope that this will help you find relevant papers for your research.

  1. The Age Spread of Quiescent Galaxies with the NEWFIRM Medium-band Survey: Identification of the Oldest Galaxies Out to z ~ 2
  2. The NEWFIRM Medium-band Survey: Photometric Catalogs, Redshifts, and the Bimodal Color Distribution of Galaxies out to z ~ 3

View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.