CO Multi-line Imaging of Nearby Galaxies (COMING). X. Physical conditions of molecular gas and the local SFR-Mass relation

摘要: We investigate the molecular gas properties of galaxies across main sequence star-forming (SF) in local Universe using $^{12}$CO($J=1-0$) (hereafter $^{12}$CO) and $^{13}$CO($J=1-0$) ($^{13}$CO) mapping data 147 nearby obtained COMING project, a legacy project Nobeyama Radio Observatory. In order to improve signal-to-noise ratios both lines, we stack all pixels where $^{12}$CO emission is detected after aligning line center expected from first-moment map $^{12}$CO. As result, $^{13}$CO successfully 80 with ratio larger than three. The error-weighted mean integrated-intensity lines ($R_{1213}$) $10.9$ standard deviation $7.0$. find that (1) $R_{1213}$ positively correlates specific star-formation rate (sSFR) correlation coefficient $0.46$, (2) flux IRAS 60~$\mu$m 100~$\mu$m ($f_{60}/f_{100}$) inclination-corrected linewidth stacked spectra ($\sigma_{{\rm ^{12}CO},i}$) also correlate sSFR for measurement. Our results support scenario variation mainly caused by changes molecular-gas such as temperature turbulence. consequent CO-to-H$_2$ conversion factor SF not large enough completely extinguish known correlations between $M_{\rm mol}/M_{\rm star}$ ($\mu_{\rm mol}$) or efficiency (SFE) reported previous studies, while this would strengthen (weaken) sSFR-SFE (sSFR-$\mu_{\rm correlation.