Astrophys. J., 777, 126 (2013/November-2)
Luminous infrared galaxies with the submillimeter array. IV. 12CO J = 6-5 observations of VV 114.
SLIWA K., WILSON C.D., KRIPS M., PETITPAS G.R., IONO D., JUVELA M., MATSUSHITA S., PECK A. and YUN M.
Abstract (from CDS):
We present high-resolution (∼2.''5) observations of 12CO J = 6-5 toward the luminous infrared galaxy VV 114 using the Submillimeter Array. We detect 12CO J = 6-5 emission from the eastern nucleus of VV 114 but do not detect the western nucleus or the central region. We combine the new 12CO J = 6-5 observations with previously published or archival low-J CO observations, which include 13CO J = 1-0 Atacama Large Millimeter/submillimeter Array cycle 0 observations, to analyze the beam-averaged physical conditions of the molecular gas in the eastern nucleus. We use the radiative transfer code RADEX and a Bayesian likelihood code to constrain the temperature (Tkin), density (nH2), and column density (N12CO) of the molecular gas. We find that the most probable scenario for the eastern nucleus is a cold (Tkin= 38 K), moderately dense (nH2 = 102.89/cm3) molecular gas component. We find that the most probable 12CO to 13CO abundance ratio ([12CO]/[13CO]) is 229, which is roughly three times higher than the Milky Way value. This high abundance ratio may explain the observed high 12CO/ 13CO line ratio (>25). The unusual 13CO J = 2-1/J = 1-0 line ratio of 0.6 is produced by a combination of moderate 13CO optical depths (τ = 0.4-1.1) and extremely subthermal excitation temperatures. We measure the CO-to-H2conversion factor, αCO, to be 0.5–0.3+0.6 M☉(K.km/s.pc2)–1, which agrees with the widely used factor for ultra luminous infrared galaxies of Downes & Solomon (αCO= 0.8 M☉(K.km/s.pc2)–1).
galaxies: individual (VV114, IC 1623, Arp 236, IRAS 01053-1746) - galaxies: interactions - galaxies: starburst - radiative transfer - submillimeter: galaxies
View the reference in ADS
To bookmark this query, right click on this link: simbad:2013ApJ...777..126S and select 'bookmark this link' or equivalent in the popup menu