Molecular Star Formation Rate Indicators in Galaxies

摘要: We derive a physical model for the observed relations between star formation rate (SFR) and molecular line (CO HCN) emission in galaxies show how these are reflective of underlying law. do this by combining 3D non-LTE radiative transfer calculations with hydrodynamic simulations isolated disk galaxy mergers. demonstrate that SFR-molecular driven relationship gas density anchored index Schmidt law controlling SFR galaxy. Lines low critical densities (e.g., CO -->J = 1–0) typically thermalized trace faithfully. In cases, will be related to luminosity an similar index. high greater than mean most emitting clouds 3–2, HCN have only small amount consequently superlinear ( -->Lmol) ($o{n}$ -->). This results SFR-line less tracers. One observational consequence is significant redistribution light from pockets dense, diffuse along sight, prodigious subthermally excited gas. At highest rates, SFR- -->Lmol slope tends index, regardless transition. The fundamental relation Kennicutt-Schmidt law, rather luminosity. Our quantitatively reproduces slopes SFR-CO 1–0), 3–2), when ~1.5 describes SFR. use make imminently testable predictions unobserved transitions.