English
Related papers

Related papers: Molecular Cloud Formation and the Star Formation E…

200 papers

We used CO (2-1) and CO (1-0) data cubes to identify molecular clouds and study their kinematics and dynamics in three nearby galaxies and the inner Milky Way. When observed at similar spatial and velocity resolutions, molecular clouds in…

Astrophysics of Galaxies · Physics 2025-11-03 J. W. Zhou , Sami Dib

We estimate the star formation efficiency per gravitational free fall time, $\epsilon_{\rm ff}$, from observations of nearby galaxies with resolution matched to the typical size of a Giant Molecular Cloud. This quantity, $\epsilon_{\rm…

We estimate the conversion factor relating CO emission to H2 mass, alpha_CO, in five Local Group galaxies that span approximately an order of magnitude in metallicity - M31, M 33, the Large Magellanic Cloud (LMC), NGC 6822, and the Small…

This study presents a catalog of 8107 molecular clouds that covers the entire Galactic plane and includes 98% of the $^{12}$CO emission observed within $b\pm5^\circ$. The catalog was produced using a hierarchical cluster identification…

Astrophysics of Galaxies · Physics 2017-01-11 Marc-Antoine Miville-Deschênes , Norman Murray , Eve J. Lee

We present maps and spectra of the HCN(1-0) and HCO$^+$(1-0) lines in the extreme outer Galaxy, at galactocentric radii between 14 and 22 kpc, with the 13.7 meter Delingha telescope. The 9 molecular clouds were selected from a CO/$^{13}$CO…

Astrophysics of Galaxies · Physics 2023-08-09 Jonathan Braine , Yan Sun , Yoshito Shimajiri , Floris F. S. van der Tak , Min Fang , Philippe André , Hao Chen , Yu Gao

We have observed the $^{12}$CO J=2-1, J=3-2, and $^{13}$CO J=2-1 lines in a sample of seven giant molecular clouds in the Local Group spiral galaxy M33. The $^{12}$CO/$^{13}$CO J=2-1 line ratio is constant across the entire sample, while…

Astrophysics · Physics 2009-10-30 C. D. Wilson , C. E. Walker , M. D. Thornley

The inner few hundred parsecs of the Milky Way harbours gas densities, pressures, velocity dispersions, an interstellar radiation field and a cosmic ray ionisation rate orders of magnitude higher than the disc; akin to the environment found…

Astrophysics of Galaxies · Physics 2017-06-21 A. T. Barnes , S. N. Longmore , C. Battersby , J. Bally , J. M. D. Kruijssen , J. D. Henshaw , D. L. Walker

We present high resolution large scale observations of the molecular and atomic gas in the Local Group Galaxy M33. The observations were carried out using the HERA at the 30m IRAM telescope in the CO(2-1) line achieving a resolution of…

We aim to better understand the emission of molecular tracers of the diffuse and dense gas in giant molecular clouds and the influence that metallicity, optical extinction, density, far-UV field, and star formation rate have on these…

[abridged] While observations of Local Group galaxies show a very simple, local star formation law in which the star formation rate per unit area in each patch of a galaxy scales linearly with the molecular gas surface density, recent…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Mark R. Krumholz , Avishai Dekel , Christopher F. McKee

We present $^{12}$CO(J=1--0) line observations of 22 low-luminosity spiral galaxies in the Virgo cluster. These data, together with 244 others available in the literature, allow us to build a large sample that we use to study the molecular…

Astrophysics · Physics 2009-08-21 A. Boselli , J. Lequeux , G. Gavazzi

We report on a study of young star cluster complexes in the spiral galaxy M51. Recent studies have confirmed that star clusters do not form in isolation, but instead tend to form in larger groupings or complexes. We use {\it HST} broad and…

Astrophysics · Physics 2009-11-11 Nate Bastian , Mark Gieles , Yuri N. Efremov , Henny J. G. L. M. Lamers

We present a complete survey of CO 1->0 emission in the Local Group dwarf irregular IC 10. The survey, conducted with the BIMA interferometer, covers the stellar disk and a large fraction of the extended HI envelope with the sensitivity and…

Astrophysics · Physics 2009-11-11 A. Leroy , A. D. Bolatto , F. Walter , L. Blitz

We measure the star formation efficiency (SFE), the star formation rate per unit gas, in 23 nearby galaxies and compare it to expectations from proposed star formation laws and thresholds. We use HI maps from THINGS and derive H2 maps from…

The process of atomic-to-molecular (HI-to-H$_2$) gas conversion is fundamental for molecular-cloud formation and star formation. 21 cm observations of the star-forming region W43 revealed extremely high HI column densities, of 120-180…

Astrophysics of Galaxies · Physics 2017-02-01 Shmuel Bialy , Simon Bihr , Henrik Beuther , Thomas Henning , Amiel Sternberg

Knowledge of the molecular component of the ISM is fundamental to understand star formation. The H2 component appears to dominate the gas mass in the inner parts of galaxies, while the HI component dominates in the outer parts. Observation…

Astrophysics · Physics 2009-10-31 F. Combes

We present the ALMA survey of CO(2-1) emission from the 1/5 solar metallicity, Local Group dwarf galaxy NGC 6822. We achieve high (0.9 arcsec ~ 2 pc) spatial resolution while covering large area: four 250 pc x 250 pc regions that encompass…

Two selected regions in the molecular gas spiral arms in M51 were mapped with the Owens Valley Radio Observatory (OVRO) mm-interferometer in the 12CO(2-1), 13CO(1-0), C18O(1-0), HCN(1-0) and HCO+(1-0) emission lines. The CO data have been…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 E. Schinnerer , A. Weiss , S. Aalto , N. Z. Scoville

The extended ultraviolet (XUV) disk galaxies are one of the most interesting objects studied in the last few years. The UV emission, revealed by GALEX, extends well beyond the optical disk, after the drop of H$\alpha$ emission, the usual…

Astrophysics of Galaxies · Physics 2019-03-06 Isadora C. Bicalho , Francoise Combes , Monica Rubio , Celia Verdugo , Philippe Salome

(Abridged) We present a comprehensive analysis of the relationship between star formation rate surface density (SFR SD) and gas surface density (gas SD) at sub-kpc resolution in a sample of 18 nearby galaxies. We use high resolution HI data…