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We have modelled Atacama Large Millimeter/sub-millimeter Array (ALMA) long baseline imaging of the strong gravitational lens system H-ATLAS J090311.6+003906 (SDP.81). We have reconstructed the distribution of band 6 and 7 continuum emission…

We present a method to derive positions of molecular clouds along the lines of sight from a quantitative comparison between 2.6 mm CO emission lines and 18 cm OH absorption lines, and apply it to the central kiloparsecs of the Milky Way.…

Astrophysics · Physics 2009-11-10 T. Sawada , T. Hasegawa , T. Handa , R. J. Cohen

ALMA imaging of the cold molecular medium in the nearby starburst galaxy NGC 1808 is presented. The observations reveal the distribution of molecular gas, traced by $^{12}$CO (1-0) and $^{12}$CO (3-2), and continuum (93 and 350 GHz) across…

Astrophysics of Galaxies · Physics 2017-11-15 Dragan Salak , Yuto Tomiyasu , Naomasa Nakai , Nario Kuno , Yusuke Miyamoto , Hiroyuki Kaneko

Emission from carbon monoxide (CO) is ubiquitously used as a tracer of dense star forming molecular clouds. There is, however, growing evidence that a significant fraction of CO emission originates from diffuse molecular gas. Quantifying…

Astrophysics of Galaxies · Physics 2016-03-09 Julia Roman-Duval , Mark Heyer , Christopher Brunt , Paul Clark , Ralf Klessen , Rahul Shetty

Detecting cold molecular gas in metal-poor starbursts remains a major challenge. Low carbon and oxygen abundances hinder CO formation, while low dust content reduces shielding against UV photodissociation. Consequently, CO, the main tracer…

A large fraction of the gas in the Galaxy is cold, dense, and molecular. If all this gas collapsed under the influence of gravity and formed stars in a local free-fall time, the star formation rate in the Galaxy would exceed that observed…

Astrophysics of Galaxies · Physics 2017-10-04 Mordecai-Mark Mac Low , Andreas Burkert , Juan C. Ibáñez-Mejía

We measure the velocity dispersion, $\sigma$, and surface density, $\Sigma$, of the molecular gas in nearby galaxies from CO spectral line cubes with spatial resolution $45$-$120$ pc, matched to the size of individual giant molecular…

Star formation in molecular clouds is intimately linked to their internal mass distribution. We present an unprecedentedly detailed analysis of the column density structure of a high-mass, filamentary molecular cloud, namely IRDC…

Astrophysics of Galaxies · Physics 2015-06-16 J. Kainulainen , S. E. Ragan , T. Henning , A. Stutz

Molecular clouds (MCs) in galaxies are complex places with many phases. It is, therefore, essential to study the physics and kinematics of the MCs using multiple emission lines. We probe the physics of the molecular gas and dust in the…

Astrophysics of Galaxies · Physics 2022-03-25 Selçuk Topal

Aims: We resolve the small-scale structure around the high-mass hot core region G351.77-0.54 to investigate its disk and fragmentation properties. Methods: Using ALMA at 690GHz with baselines exceeding 1.5km, we study the dense gas, dust…

Astrophysics of Galaxies · Physics 2017-07-05 H. Beuther , A. J. Walsh , K. G. Johnston , Th. Henning , R. Kuiper , S. N. Longmore , C. M. Walmsley

To complement the optical absorption-line survey of diffuse molecular gas in Paper I, we obtained and analyzed far ultraviolet H$_2$ and CO data on lines of sight toward stars in Cep OB2 and Cep OB3. Possible correlations between column…

Astrophysics · Physics 2009-11-13 K. Pan , S. R. Federman , Y. Sheffer , B. -G. Andersson

The massive infrared dark cloud G0.253+0.016 projected 45pc from the Galactic centre contains ~10^5Msun of dense gas whilst being mostly devoid of observed star-formation tracers. To scrutinise the physical properties, dynamics and…

Astrophysics of Galaxies · Physics 2014-11-12 K. G. Johnston , H. Beuther , H. Linz , A. Schmiedeke , S. E. Ragan , Th. Henning

The CO-dark molecular gas (DMG), which refers to the molecular gas not traced by CO emission, is crucial for the evolution of the interstellar medium (ISM). While the gas properties of DMG have been widely explored in the Solar…

Astrophysics of Galaxies · Physics 2024-05-22 Gan Luo , Di Li , Zhi-yu Zhang , Thomas G. Bisbas , Ningyu Tang , Lingrui Lin , Yichen Sun , Pei Zuo , Jing Zhou

We use the moving mesh code AREPO coupled to a time-dependent chemical network to investigate the formation and destruction of molecular gas in simulated spiral galaxies. This allows us to determine the characteristics of the gas that is…

Astrophysics of Galaxies · Physics 2015-06-19 Rowan J. Smith , Simon C. O. Glover , Paul C. Clark , Ralf S. Klessen , Volker Springel

We present $^{12}$CO ($J$ = 2-1), $^{13}$CO ($J$ = 2-1), and C$^{18}$O ($J$ = 2-1) observations toward GMC-8, one of the most massive giant molecular clouds (GMCs) in M33 using ALMA with an angular resolution of 0".44 $\times$ 0".27…

We present ALMA observations of the CO(1-0) and CO(3-2) line emission tracing filaments of cold molecular gas in the central galaxy of the cluster PKS0745-191. The total molecular gas mass of 4.6 +/- 0.3 x 10^9 solar masses, assuming a…

The mass of molecular gas in an interstellar cloud is often measured using line emission from low rotational levels of CO, which are sensitive to the CO mass, and then scaling to the assumed molecular hydrogen H_2 mass. However, a…

Astrophysics of Galaxies · Physics 2015-05-18 Mark G. Wolfire , David Hollenbach , Christopher F. McKee

The central molecular zone (CMZ) hosts some of the most massive and dense molecular clouds and star clusters in the Galaxy, offering an important window into star formation under extreme conditions. Star formation in this extreme…

Astrophysics of Galaxies · Physics 2017-02-22 J. D. Henshaw

Clouds more massive than about $10^5$ M$_\odot$ are potential sites of massive cluster formation. Studying the properties of such clouds in the early stages of their evolution offers an opportunity to test various cluster formation…

Astrophysics of Galaxies · Physics 2023-03-10 Vineet Rawat , M. R. Samal , D. L. Walker , A. Zavagno , A. Tej , G. Marton , D. K. Ojha , Davide Elia , W. P. Chen , J. Jose , C Eswaraiah

A deep, wide-field, near-infrared imaging survey was used to construct an extinction map of the southeastern part of the California Molecular Cloud (CMC) with $\sim$ 0.5 arc min resolution. The same region was also surveyed in the…

Astrophysics of Galaxies · Physics 2015-05-27 S. Kong , C. J. Lada , E. A. Lada , C. Román-Zúñiga , J. H. Bieging , M. Lombardi , J. Forbrich , J. F. Alves