TY - JOUR
T1 - The MALATANG Survey
T2 - 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
AU - Tan, Qing-Hua
AU - Gao, Yu
AU - Zhang, Zhi-Yu
AU - Greve, Thomas R.
AU - Jiang, Xue-Jian
AU - Wilson, Christine D.
AU - Yang, Chen-Tao
AU - Bemis, Ashley
AU - Chung, Aeree
AU - Matsushita, Satoki
AU - Shi, Yong
AU - Ao, Yi-Ping
AU - Brinks, Elias
AU - Currie, Malcolm J.
AU - Davis, Timothy A.
AU - Grijs, Richard de
AU - Ho, Luis C.
AU - Imanishi, Masatoshi
AU - Kohno, Kotaro
AU - Lee, Bumhyun
AU - Parsons, Harriet
AU - Rawlings, Mark G.
AU - Rigopoulou, Dimitra
AU - Rosolowsky, Erik
AU - Bulger, Joanna
AU - Chen, Hao
AU - Chapman, Scott C.
AU - Eden, David
AU - Gear, Walter K.
AU - Gu, Qiu-Sheng
AU - He, Jin-Hua
AU - Jiao, Qian
AU - Liu, Dai-Zhong
AU - Liu, Li-Jie
AU - Li, Xiao-Hu
AU - Michalowski, Michal J.
AU - Nguyen-Luong, Quang
AU - Qiu, Jian-Jie
AU - Smith, Matthew W. L.
AU - Violino, Giulio
AU - Wang, Jian-Fa
AU - Wang, Jun-Feng
AU - Wang, Jun-Zhi
AU - Yeh, Sherry
AU - Zhao, Ying-He
AU - Zhu, Ming
N1 - This is an author-created, un-copyedited version of an article published in The Astrophysical Journal.
The Version of Record is available online at https://doi.org/10.3847/1538-4357/aac512.
PY - 2018/6/25
Y1 - 2018/6/25
N2 - 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 2×2 region at 14 (FWHM) resolution (corresponding to linear scales of ∼0.2-1.0 kpc). The LIR-Ldense 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, LIR/Ldense, shows systematic variations with LIR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between LIR/Ldense ratio and the warm-dust temperature gauged by the 70 μm/100 μm flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO+ (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas (SFE
dense), appear to be nearly independent of the dense gas fraction ( f
dense) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with f
dense when combining our data with those on local (ultra)luminous infrared galaxies and high-z quasars. The mean LHCN(4-3) LHCO+(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 star formation rate as traced by L
IR, nor with the warm-dust temperature, for the different populations of galaxies.
AB - 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 2×2 region at 14 (FWHM) resolution (corresponding to linear scales of ∼0.2-1.0 kpc). The LIR-Ldense 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, LIR/Ldense, shows systematic variations with LIR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between LIR/Ldense ratio and the warm-dust temperature gauged by the 70 μm/100 μm flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO+ (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas (SFE
dense), appear to be nearly independent of the dense gas fraction ( f
dense) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with f
dense when combining our data with those on local (ultra)luminous infrared galaxies and high-z quasars. The mean LHCN(4-3) LHCO+(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 star formation rate as traced by L
IR, nor with the warm-dust temperature, for the different populations of galaxies.
KW - galaxies: ISM
KW - galaxies: star formation
KW - infrared: galaxies
KW - ISM: molecules
KW - radio lines: galaxies
UR - http://www.scopus.com/inward/record.url?scp=85049221000&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aac512
DO - 10.3847/1538-4357/aac512
M3 - Article
SN - 0004-637X
VL - 860
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 2
M1 - 165
ER -