The MALATANG survey: The L GAS–L IR correlation on sub-kiloparsec scale in six nearby star-forming galaxies as traced by HCN J = 4 → 3 and HCO+ J = 4 → 3
| Autor: | Junfeng Wang, Hao Chen, Xue-Jian Jiang, Ashley Bemis, Joanna Bulger, Satoki Matsushita, Erik Rosolowsky, Sherry Yeh, Jianfa Wang, Harriet Parsons, Yong Shi, Bumhyun Lee, Jinhua He, Jianjie Qiu, David Eden, Qinghua Tan, C. Yang, Yinghe Zhao, Junzhi Wang, Scott Chapman, Michał J. Michałowski, Mark G. Rawlings, Walter Kieran Gear, Qian Jiao, Aeree Chung, Qiusheng Gu, Matthew Smith, Daizhong Liu, Kotaro Kohno, Thomas R. Greve, Xiao-Hu Li, Timothy A. Davis, Christine D. Wilson, Dimitra Rigopoulou, Richard de Grijs, Malcolm J. Currie, Yu Gao, Zhi-Yu Zhang, Elias Brinks, Ming Zhu, Luis C. Ho, Yiping Ao, Masatoshi Imanishi, Giulio Violino, Quang Nguyen-Luong, Lijie Liu |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Luminous infrared galaxy Star formation Spatially resolved FOS: Physical sciences Astronomy and Astrophysics Quasar Astrophysics 01 natural sciences Astrophysics - Astrophysics of Galaxies Flux ratio Galaxy Full width at half maximum Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences 010306 general physics 010303 astronomy & astrophysics James Clerk Maxwell Telescope QC QB |
| Zdroj: | The Astrophysical Journal |
| ISSN: | 1538-4357 0004-637X 0004-6361 1538-3873 1538-3881 0067-0049 0004-6264 0034-4885 |
| Popis: | We present HCN J=4-3 and HCO^+ J=4-3 maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2 arcmin $\times$ 2 arcmin region at 14 arcsec (FWHM) resolution (corresponding to linear scales of ~ 0.2-1.0 kpc). The L_IR-L'_dense relation, where the dense gas is traced by the HCN J=4-3 and the HCO^+ J=4-3 emission, measured in our sample of spatially-resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, L_IR/L'_dense, shows systematic variations with L_IR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between L_IR/L'_dense ratio and the warm-dust temperature gauged by the 70 \mu m/100 \mu m flux ratio. We find the luminosity ratios of IR/HCN(4-3) and IR/HCO^+(4-3), which can be taken as a proxy for the efficiency of star formation in the dense molecular gas (SFE_dense), appears to be nearly independent of the dense-gas fraction (f_dense) for our sample of galaxies. The SFE of the total molecular gas (SFE_mol) is found to increase substantially with f_dense when combining our data with that on local (ultra)luminous infrared galaxies and high-z quasars. The mean L'_HCN(4-3)/L'_HCO^+(4-3) line ratio measured for the six targeted galaxies is 0.9+/-0.6. No significant correlation is found for the L'_HCN(4-3)/L'_HCO^+(4-3) ratio with the SFR as traced by L_IR, nor with the warm-dust temperature, for the different populations of galaxies. Comment: 29 pages, 12 figures, accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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