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We report the detection of CO(1-0) and CO(2-1) emission from the central region of nearby 3CR radio galaxies (z$<$ 0.03). Out of 21 galaxies, 8 have been detected in, at least, one of the two CO transitions. The total molecular gas content…

Astrophysics · Physics 2009-09-25 S. Leon , J. Lim , F. Combes , D. Van-Trung

We simultaneously measured the spatially-resolved CO-to-H$_{2}$ conversion factor ($\alpha_\mathrm{CO}$) and dust-to-gas ratio (DGR) in nearby galaxies on a kiloparsec scale. In this study, we used $^{12}$CO($J=1-0$) data obtained by the…

Carbon-bearing molecules, particularly CO, have been widely used as tracers of molecular gas in the interstellar medium (ISM). In this work, we aim to study the properties of molecules in diffuse, cold environments, where CO tends to be…

Spectra in the CH $^2\Pi_{1/2}$, J=1/2, F=1-1 transition at 3335 MHz were obtained in three 5-point crosses centered on the Galactic plane at $\ell =$ 50$\arcdeg$, 100$\arcdeg$, and 110$\arcdeg$. The lines of sight traverse both Giant…

Astrophysics · Physics 2008-11-26 L. Magnani , S. Lugo , T. M. Dame

The CO-to-H$_2$ conversion factor ($\alpha_\rm{CO}$) is central to measuring the amount and properties of molecular gas. It is known to vary with environmental conditions, and previous studies have revealed lower $\alpha_\rm{CO}$ in the…

We present a self-consistent cross-calibration of the three main molecular gas mass tracers in galaxies, the $\rm ^{12}CO$(1-0), [CI]($^3P_1$-$^3P_0$) lines, and the submm dust continuum emission, using a sample of 407 galaxies, ranging…

Astrophysics of Galaxies · Physics 2022-09-14 L Dunne , S J Maddox , P P Papadopoulos , R J Ivison , H L Gomez

Carbon monoxide (CO) is widely used as a tracer of molecular hydrogen (H2) in metal-rich galaxies, but is known to become ineffective in low metallicity dwarf galaxies. Atomic carbon has been suggested as a superior tracer of H2 in these…

Astrophysics of Galaxies · Physics 2016-01-20 Simon C. O. Glover , Paul C. Clark

Disentangling the different stages of the star-formation process, in particular in the high-mass regime, is a challenge in astrophysics. Chemical clocks could help alleviating this problem, but their evolution strongly depends on many…

Astrophysics of Galaxies · Physics 2020-01-08 S. Bovino , S. Ferrada-Chamorro , A. Lupi , G. Sabatini , A. Giannetti , D. R. G. Schleicher

For investigating the relationship between the star formation rate and gas surface density, we develop a Bayesian linear regression method that rigorously treats measurement uncertainties and accounts for hierarchical data structure. The…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Rahul Shetty , Brandon C. Kelly , Frank Bigiel

While molecular gas mass is usually derived from $^{12}$CO($J$=1-0) - the most fundamental line to explore molecular gas - it is often derived from $^{12}$CO($J$=2-1) assuming a constant $^{12}$CO($J$=2-1)/$^{12}$CO($J$=1-0) line ratio…

We investigate the multi-phase gas surrounding QSOs traced by 33 absorption lines (e.g., Ly$\alpha$, C\,\textsc{iv}, Fe\,\textsc{ii}, Mg\,\textsc{ii}, etc.) in the stacked spectra of background sources, using the early data release from the…

Astrophysics of Galaxies · Physics 2025-06-18 Zeyu Chen , Enci Wang , Hu Zou , Haoran Yu , Zhicheng He , Huiyuan Wang , Yang Gao , Cheqiu Lyu , Cheng Jia , Chengyu Ma , Weiyu Ding , Runyu Zhu , Xu Kong

We model the intensity of emission lines from the CO molecule, based on hydrodynamic simulations of spirals, mergers, and high-redshift galaxies with very high resolutions (3pc and 10^3 Msun) and detailed models for the phase-space…

Astrophysics of Galaxies · Physics 2015-02-25 F. Bournaud , E. Daddi , A. Weiss , F. Renaud , C. Mastropietro , R. Teyssier

The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with…

Astrophysics of Galaxies · Physics 2018-10-01 Nick Indriolo , E. A. Bergin , J. R. Goicoechea , J. Cernicharo , M. Gerin , A. Gusdorf , D. C. Lis , P. Schilke

We use the CARMA millimeter interferometer to map the Antennae Galaxies (NGC4038/39), tracing the bulk of the molecular gas via the 12CO(1-0) line and denser molecular gas via the high density transitions HCN(1-0), HCO+(1-0), CS(2-1), and…

CO is thought to be the main reservoir of volatile carbon in protoplanetary disks, and thus the primary initial source of carbon in the atmospheres of forming giant planets. However, recent observations of protoplanetary disks point towards…

Earth and Planetary Astrophysics · Physics 2019-06-12 Kamber R. Schwarz , Edwin A. Bergin , L. Ilsedore Cleeves , Ke Zhang , Karin I. Öberg , Geoffrey A. Blake , Dana E. Anderson

Stars form in cold molecular clouds. However, molecular gas is difficult to observe because the most abundant molecule (H2) lacks a permanent dipole moment. Rotational transitions of CO are often used as a tracer of H2, but CO is much less…

Theoretical and observational investigations have indicated that the abundance of carbon monoxide (CO) is very sensitive to intrinsic properties of the gaseous medium, such as density, metallicity, and the background UV field. In order to…

Astrophysics of Galaxies · Physics 2015-05-20 Rahul Shetty , Simon C. Glover , Cornelis P. Dullemond , Ralf S. Klessen

The arm structure of the Milky Way remains somewhat of an unknown, with observational studies hindered by our location within the Galactic disc. In the work presented here we use smoothed particle hydrodynamics (SPH) and radiative transfer…

Astrophysics of Galaxies · Physics 2015-06-24 Alex R. Pettitt , Clare L. Dobbs , David M. Acreman , Matthew R. Bate

We present the Combined Array for Research in Millimeter Astronomy (CARMA) ATLAS3D molecular gas imaging survey, a systematic study of the distribution and kinematics of molecular gas in CO-rich early-type galaxies. Our full sample of 40…

Cosmic rays (CRs) play a major role in the dynamics of the interstellar medium (ISM). Their interactions and transport ionize, heat, and push the ISM thereby coupling different regions of it. The spatial distribution of CRs depends on the…