Related papers: The Schmidt Law at High Molecular Densities
There are two major theoretical issues for the star formation law (the relation between the surface densities of molecular gas and star formation rate on a galaxy scale): (i) At low metallicity, it is not obvious that star-forming regions…
The gas mass fraction (fg) of spiral galaxies is strongly correlated with the central surface brightness of their disks. There exist many dim galaxies with long gas consumption time scales and fg > 0.5. This resolves the gas consumption…
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, $\epsilon_{\rm…
We extend existing semi-analytic models of galaxy formation to track atomic and molecular gas in disk galaxies. Simple recipes for processes such as cooling, star formation, supernova feedback, and chemical enrichment of the stars and gas…
The star formation rate (SFR) is tightly connected to the amount of dense gas in molecular clouds. However, it is not fully understood how the relationship between dense molecular gas and star formation varies within galaxies and in…
Extragalactic studies have demonstrated there is a moderately tight ($\approx$0.3 dex) relationship between galaxy stellar mass ($M_{\star}$) and star formation rate (SFR) that holds for star-forming galaxies at $M_{\star} \sim 3 \times…
We present new $^{12}$CO(J=1-0) observations of the barred galaxy NGC 4303 using the Nobeyama 45m telescope (NRO45) and the Combined Array for Research in Millimeter-wave Astronomy (CARMA). The H$\alpha$ images of barred spiral galaxies…
We show that the gas mass fraction of spiral galaxies is strongly correlated with luminosity and surface brightness. It is not correlated with linear size. Gas fraction varies with luminosity and surface brightness at the same rate,…
We combine new sensitive, wide-field CO data from the HERACLES survey with ultraviolet and infrared data from GALEX and Spitzer to compare the surface densities of H2, Sigma_H2, and recent star formation rate, Sigma_SFR, over many thousands…
Having to have low thermal energy, the molecular gas in galaxies is expected to settle in a thin disc near the midplane. However, contradicting this understanding, recent studies have revealed considerably thick molecular discs in nearby…
Whilst the star formation rate (SFR) of molecular clouds and galaxies is key in understanding galaxy evolution, the physical processes which determine the SFR remain unclear. This uncertainty about the underlying physics has resulted in…
Studying star formation beyond the optical radius of galaxies allows us to test empirical relations in extreme conditions with low average gas density and low molecular fraction. Previous studies discovered galaxies with extended…
Stars form from cold molecular interstellar gas. Since this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of…
Using the IRAM 30m telescope, we have surveyed an unbiased sample of 47 nearby spiral galaxies of very late (Scd-Sm) Hubble-type for emission in the CO(1-0) and CO(2-1) lines. The sensitivity of our data (a few mK) allows detection of about…
We present an analysis of the relation between star formation rate (SFR) surface density (sigmasfr) and mass surface density of molecular gas (sigmahtwo), commonly referred to as the Kennicutt-Schmidt (K-S) relation, at its intrinsic…
We compare atomic gas, molecular gas, and the recent star formation rate (SFR) inferred from H-alpha in the Small Magellanic Cloud (SMC). By using infrared dust emission and local dust-to-gas ratios, we construct a map of molecular gas that…
We use the star formation rate-stellar mass relation ($SFR - {M_ * }$) of galaxies to measure their luminosity distances as well as estimate cosmological parameters. We compile a sample of 341 high-redshift galaxies at $5 < z < 14$ and an…
Star formation depends on the available gaseous "fuel" as well as galactic environment, with higher specific star formation rates where gas is predominantly molecular and where stellar (and dark matter) densities are higher. The partition…
We report the first results of a detailed study of the star formation law in a sample of 32 nearby spiral galaxies with well-measured rotation curves, HI and H$_2$ (as traced by CO) surface density profiles, and new \Ha CCD photometry. Our…
The conversion of gas into stars is a fundamental process in astrophysics and cosmology. Stars are known to form from the gravitational collapse of dense clumps in interstellar molecular clouds, and it has been proposed that the resulting…