Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:astro-ph/0610378)
· References in the article
· Citations to the Article (33) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (6)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Molecular Gas in Extreme Star-Forming Environments: The Starbursts Arp 220 and NGC 6240 as Case Studies
Authors:
Greve, T. R.; Papadopoulos, P. P.; Gao, Y.; Radford, S. J. E.
Affiliation:
AA(Max-Planck Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany ; California Institute of Technology, Pasadena, CA 91125, USA ; ), AB(Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, 53121 Bonn, Germany ), AC(Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China ), AD(California Institute of Technology, Pasadena, CA 91125, USA )
Publication:
The Astrophysical Journal, Volume 692, Issue 2, pp. 1432-1446 (2009). (ApJ Homepage)
Publication Date:
02/2009
Origin:
IOP
ApJ Keywords:
galaxies: individual: Arp 220 NGC 6240, galaxies: starburst, ISM: molecules
DOI:
10.1088/0004-637X/692/2/1432
Bibliographic Code:
2009ApJ...692.1432G

Abstract

We report single-dish multitransition measurements of the 12CO, HCN, and HCO+ molecular line emission as well as HNC J = 1-0 and HNCO in the two ultraluminous IR galaxies Arp 220 and NGC 6240. Using this new molecular line inventory, in conjunction with existing data in the literature, we compiled the most extensive molecular line data sets to date for such galaxies. The many rotational transitions, with their different excitation requirements, allow the study of the molecular gas over a wide range of different densities and temperatures with significant redundancy, and thus allow good constraints on the properties of the dense gas in these two systems. The mass (~ (1-2)×1010 M sun) of dense gas (gsim105-6 cm-3) found accounts for the bulk of their molecular gas mass, and is consistent with most of their IR luminosities powered by intense starbursts while self-regulated by O, B star cluster radiative pressure onto the star-forming dense molecular gas. The highly excited HCN transitions trace a gas phase ~ (10-100)× denser than that of the subthermally excited HCO+ lines (for both galaxies). These two phases are consistent with an underlying density-size power law found for Galactic giant molecular clouds (but with a steeper exponent), with HCN lines tracing denser and more compact regions than HCO+. Whether this is true in IR-luminous, star-forming galaxies in general remains to be seen, and underlines the need for observations of molecular transitions with high critical densities for a sample of bright (U)LIRGs in the local universe—a task for which the HI-FI instrument on board Herschel is ideally suited to do.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints