Published February 10, 2012 | Version v1
Journal article Metadata-only

ORIGIN OF MULTIPLE NUCLEI IN ULTRALUMINOUS INFRARED GALAXIES

Creators

  • 1. Center for Computational Astrophysics, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
  • 2. Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
  • 3. Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan)
  • 4. Graduate School of Commerce and Management, Hitotsubashi University, Naka 2-1 Kunitachi, Tokyo 186-8601 (Japan)
  • 5. Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan)
  • 6. Institute for the Physics and Mathematics of the Universe, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

Description

Ultraluminous infrared galaxies (ULIRGs) with multiple (≥3) nuclei are frequently observed. It has been suggested that these nuclei are produced by multiple major mergers of galaxies. The expected rate of such mergers is, however, too low to reproduce the observed number of ULIRGs with multiple nuclei. We have performed high-resolution simulations of the merging of two gas-rich disk galaxies. We found that extremely massive and compact star clusters form from the strongly disturbed gas disks after the first or second encounter between the galaxies. The mass of such clusters reaches ∼108 M☉ and their half-mass radii are 20-30 pc. Since these clusters consist of young stars, they appear as several bright cores in the galactic central region (∼kpc). The peak luminosity of these clusters reaches ∼10% of the total luminosity of the merging galaxy. These massive and compact clusters are consistent with the characteristics of the observed multiple nuclei in ULIRGs. Multiple mergers are not necessary to explain multiple nuclei in ULIRGs.

Availability note (English)

Available from http://dx.doi.org/10.1088/0004-637X/746/1/26

Additional details

Identifiers

DOI
10.1088/0004-637X/746/1/26;

Publishing Information

Journal Title
Astrophysical Journal
Journal Volume
746
Journal Issue
1
Journal Page Range
[11 p.]
ISSN
0004-637X
CODEN
ASJOAB

INIS

Country of Publication
United States
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
43098948
Subject category
S79: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;
Descriptors DEI
COMPUTERIZED SIMULATION; GALACTIC EVOLUTION; GALAXIES; LUMINOSITY; STAR CLUSTERS; STARS
Descriptors DEC
EVOLUTION; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; SIMULATION