학술논문
Molecular gas and dust properties of galaxies from the Great Observatories All-sky LIRG Survey
Document Type
Working Paper
Author
Herrero-Illana, R.; Privon, G. C.; Evans, A. S.; Díaz-Santos, T.; Pérez-Torres, M. Á.; U, V.; Alberdi, A.; Iwasawa, K.; Armus, L.; Aalto, S.; Mazzarella, J.; Chu, J.; Sanders, D. B.; Barcos-Muñoz, L.; Charmandaris, V.; Linden, S. T.; Yoon, I.; Frayer, D. T.; Inami, H.; Kim, D. -C.; Borish, H. J.; Conway, J.; Murphy, E. J; Song, Y.; Stierwalt, S.; Surace, J.
Source
A&A 628, A71 (2019)
Subject
Language
Abstract
We present IRAM-30m Telescope $^{12}$CO and $^{13}$CO observations of a sample of 55 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in the local universe. This sample is a subset of the Great Observatory All-Sky LIRG Survey (GOALS), for which we use ancillary multi-wavelength data to better understand their interstellar medium and star formation properties. Fifty-three (96%) of the galaxies are detected in $^{12}$CO, and 29 (52%) are also detected in $^{13}$CO above a 3$\sigma$ level. The median full width at zero intensity (FWZI) velocity of the CO line emission is 661km s$^{-1}$, and $\sim$54% of the galaxies show a multi-peak CO profile. Herschel photometric data is used to construct the far-IR spectral energy distribution of each galaxy, which are fit with a modified blackbody model that allows us to derive dust temperatures and masses, and infrared luminosities. We make the assumption that the gas-to-dust mass ratio of (U)LIRGs is comparable to local spiral galaxies with a similar stellar mass (i.e., gas/dust of mergers is comparable to their progenitors) to derive a CO-to-H$_2$ conversion factor of $\langle\alpha\rangle=1.8^{+1.3}_{-0.8}M_\odot$(K km s$^{-1}$pc$^{2}$)$^{-1}$; such a value is comparable to that derived for (U)LIRGs based on dynamical mass arguments. We derive gas depletion times of $400-600$Myr for the (U)LIRGs, compared to the 1.3Gyr for local spiral galaxies. Finally, we re-examine the relationship between the $^{12}$CO/$^{13}$CO ratio and dust temperature, confirming a transition to elevated ratios in warmer systems.
Comment: 32 pages, 10 figures. Accepted for publication in Astronomy & Astrophysics
Comment: 32 pages, 10 figures. Accepted for publication in Astronomy & Astrophysics