Poster by Liu+ Liu & Gao 2011 arXiv:1106.2813 Dense H2 show the best correlation with SFR (linear Liu & Gao 2011).
Bi-modal SF laws in high-z gals (Daddi+2010; Genzel+2010) also exist in local gals
Introduction and Outline 1. R=CO/13CO line intensity ratios: R ~2-5 Galactic Ring Survey 13CO (Jackson+06; Simon+01) UMass-StonyBrook CO survey (Sanders+86), ~5-10 Galactic center GMCs + normal spirals, ~10-20 Starbursts (eg, Aalto+1995) ~30-50 (U)LIRGs (few 13CO published; Papadopoulos+11) high R 10 associated with small, warm but compact molecular clouds of low to moderate optical depth, or the high [ 12 CO/ 13 CO] abundance ratio 2. Best case studies: Arp220 (Greve+09; Matsushita+09), NGC6240(Greve+09; U+11) 3. Resolved measurements in Antennae galaxies (Gao+01; Zhu+03), Taffy (Gao+03; Braine+03; Zhu+07); nearby gals. (Tan+11) 4. Supernova remnant (SNR) IC 443: GMC-SNR interactions (Wang+Scoville92; Zhang+10) 5. Implications: the molecular gas conditions in (U)LIRGs
Zhang, Gao & Wang arXiv: 0911.4815 70um and 160um overlaid with CO(1-0)
Zhang, Gao & Wang arXiv: 0911.4815 HI and radio continuum images overlaid with CO(1-0)
CO/13CO Line Ratio & FIR Maps [FeII], [SI], H 2 0-0 S(0) [OI][CII] + Dust? Spitzer 24 um Spitzer 70 um Spitzer 160 um 1. Line ratios are much higher in shocked regions than in the rest regions. 2. Line ratio maps in IC443 are strikingly well matched with the FIR images.
SNR IC443 Yellow: 12 CO Blue: 13 CO Background: Spitzer 24μm Spectra Analysis
5. Implications to (U)LIRGs Concentrated molecular gas of ~10^10Msun in ~1kpc (vs. >10 kpc 10^9 Msun H2 in the Galaxy) (~10^3) Packed with dense cores (HCN-FIR) and even intercloud (or inter-dense-core) medium is highly molecular SNe rates in ULIRGs ~100 times that of the Milky Way Most dense cores are shocked by SNRs in ULIRGs (~10^5xMW) besides strong galaxy-galaxy collisions Highly shocked regions higher R=CO/13CO in LIRGs The abnormally high ratios of R (& CO/C18O) found in SNR IC443 of shock-origin are comparable to the observed values in starbursts and (U)LIRGs, likely implying their same physical origin. Gao & Solomon 04, Gao+07: Dense H 2 Dense Cores