Year: 2011
Type: article
Abstract: Nearby spiral galaxies show an extremely tight correlation between tracers of molecular hydrogen (H 2 ) in the interstellar medium and tracers of recent star formation, but it is unclear whether this correlation is fundamental or accidental. In the galaxies that have been surveyed to date, H 2 resides predominantly in gravitationally bound clouds cooled by carbon monoxide (CO) molecules, but in galaxies of low metal content the correlations between bound clouds, CO, and H 2 break down, and it is unclear if the star formation rate (SFR) will then correlate with H 2 or with some other quantity. Here, we show that star formation will continue to follow H 2 independent of metallicity. This is not because H 2 is directly important for cooling, but instead because the transition from predominantly atomic hydrogen (H i ) to H 2 occurs under the same conditions as a dramatic drop in gas temperature and Bonnor–Ebert mass that destabilizes clouds and initiates collapse. We use this model to compute how SFR will correlate with total gas mass, with mass of gas where the hydrogen is H 2 , and with mass of gas where the carbon is CO in galaxies of varying metallicity, and show that preliminary observations match the trend we predict.
Source: The Astrophysical Journal
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: THE FORMATION OF HIGH-MASS STARS AND THEIR FEEDBACK EFFECTS THE FORMATION OF MASSIVE STARS REMAINS ONE OF THE MOST SIGNIFICANT UNSOLVED PROBLEMS IN, G58316358, CAREER: Toward a Predictive Theory of Star Formation, G6671297155, The Hidden Lives of Massive Protostars: Fragmentation, Disks, and Feedback, G767601387, Theoretical Studies in Star Formation
OpenAlex ID: W1984072856