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Title: Molecular gas in the x-ray bright group NGC 5044 as revealed by ALMA

An ALMA observation of the early-type galaxy NGC 5044, which resides at the center of an X-ray bright group with a moderate cooling flow, detected 24 molecular structures within the central 2.5 kpc. The masses of the molecular structures vary from 3 × 10{sup 5} M {sub ☉} to 10{sup 7} M {sub ☉} and the CO(2-1) linewidths vary from 15 to 65 km s{sup –1}. Given the large CO(2-1) linewidths, the observed structures are likely giant molecular associations (GMAs) and not individual giant molecular clouds (GMCs). Only a few of the GMAs are spatially resolved and the average density of these GMAs yields a GMC volume filling factor of about 15%. The masses of the resolved GMAs are insufficient for them to be gravitationally bound, however, the most massive GMA does contain a less massive component with a linewidth of 5.5 km s{sup –1} (typical of an individual virialized GMC). We also show that the GMAs cannot be pressure confined by the hot gas. Given the CO(2-1) linewidths of the GMAs (i.e., the velocity dispersion of the embedded GMCs) they should disperse on a timescale of about 12 Myr. No disk-like molecular structures are detected and all indications suggestmore » that the molecular gas follows ballistic trajectories after condensing out of the thermally unstable hot gas. The 230 GHz luminosity of the central continuum source is 500 times greater than its low frequency radio luminosity and probably reflects a recent accretion event. The spectrum of the central continuum source also exhibits an absorption feature with a linewidth typical of an individual GMC and an infalling velocity of 250 km s{sup –1}.« less
Authors:
; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ; ;  [5] ;  [6] ; ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13] ;  [14]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
  2. Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong)
  3. Observatoire de Paris, LERMA, CNRS, 61 Avenue de l'Observatoire, F-75014 Paris (France)
  4. LERMA Observatoire de paris, CNRS, 61 rue de l'Observatoire, F-75014 Paris (France)
  5. Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
  6. Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)
  7. INAF - IASF-Milano, Via E. Bassini 15, I-20133 Milano (Italy)
  8. Astrophysics Branch, NASA/Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States)
  9. Remote Sensing Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)
  10. Academia Sinica, Institute of Astronomy and Astrophysics, Taiwan (China)
  11. University of California Observatories/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
  12. Dipartimento di Astronomia, Universit di Bologna, via Ranzani 1, I-40127 Bologna (Italy)
  13. Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
  14. Institute of Physics, Vietnamese Academy of Science and Technology, 10 DaoTan Street, BaDinh, Hanoi (Viet Nam)
Publication Date:
OSTI Identifier:
22365139
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 792; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; CARBON MONOXIDE; COOLING; DISPERSIONS; GALAXIES; GALAXY CLUSTERS; GHZ RANGE; LUMINOSITY; MASS; MOLECULAR STRUCTURE; SPECTRA; TRAJECTORIES; VELOCITY; X RADIATION