Dynamical masses in luminous infrared galaxies

J. L. Hinz, George H. Rieke

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

We have studied the dynamics and masses of a sample of 10 nearby luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs, respectively) using 2.3 μm 12CO-absorption line spectroscopy and near-infrared H- and Ks-band imaging. By combining velocity dispersions derived from the spectroscopy, disk scale lengths obtained from the imaging, and a set of likely model density profiles, we calculate dynamical masses for each LIRG. For the majority of the sample, it is difficult to reconcile our mass estimates with the large amounts of gas derived from millimeter observations and from a standard conversion between 12CO emission and H2 mass. Our results imply that LIRGs do not have huge amounts of molecular gas (10 10-1011 M) at their centers and support previous indications that the standard conversion of 12CO to H 2 probably overestimates the gas masses and cannot be used in these environments. This in turn suggests much more modest levels of extinction in the near-infrared for LIRGs than previously predicted (Av ∼ 10-20 vs. Av ∼ 100-1000). The lower gas mass estimates indicated by our observations imply that the star formation efficiency in these systems is very high and is triggered by cloud-cloud collisions, shocks, and winds rather than by gravitational instabilities in circumnuclear gas disks.

Original languageEnglish (US)
Pages (from-to)872-880
Number of pages9
JournalAstrophysical Journal
Volume646
Issue number2 I
DOIs
StatePublished - Aug 1 2006

Fingerprint

galaxies
gas
gases
near infrared
spectroscopy
gravitational instability
molecular gases
estimates
star formation
indication
extinction
collision
shock
collisions
profiles

Keywords

  • Galaxies: kinematics and dynamics
  • Galaxies: starburst
  • Galaxies: stellar content
  • Infrared: galaxies

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Dynamical masses in luminous infrared galaxies. / Hinz, J. L.; Rieke, George H.

In: Astrophysical Journal, Vol. 646, No. 2 I, 01.08.2006, p. 872-880.

Research output: Contribution to journalArticle

Hinz, J. L. ; Rieke, George H. / Dynamical masses in luminous infrared galaxies. In: Astrophysical Journal. 2006 ; Vol. 646, No. 2 I. pp. 872-880.
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