What controls the star formation in luminous starburst mergers?
TANIGUCHI Y. and OHYAMA Y.
Abstract (from CDS):
In order to understand what controls the star formation process in luminous starburst mergers (e.g., NGC 6240, Arp 220, and so on), we investigate observational properties of two samples of high-luminosity starburst galaxies mapped in CO J=1-0 independently using both the Owens Valley Radio Observatory (Scoville et al.) and the IRAM interferometer (Downes & Solomon). We find that the surface density of far-infrared luminosity, Σ(FIR), is proportional linearly to the H2 surface mass density, Σ(H2), for the two samples; ΣFIR∝ΣH21.01±0.06 with a correlation coefficient of 0.96. It is often considered that Σ(FIR) provides a good measure of the star formation rate per unit area, Σ(SFR). It is also known that molecular gas is dominated in circumnuclear regions in the luminous starburst mergers; i.e., Σgas≃ΣH2. Therefore, the above relationship suggests a star formation law; ΣSFR∝Σgas. We suggest that this star formation law favors the gravitational instability scenario rather than the cloud-cloud collision one.