| Title | ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions - IV. Radio recombination lines and evolution of star formation efficiencies |
| Authors | Zhang, C. Evans, Neal J. Liu, T. Wu, J-W Wang, Ke Liu, H-L Zhu, F-Y Ren, Z-Y Dewangan, L. K. Lee, Chang Won Li, Shanghuo Bronfman, L. Tej, A. Li, D. |
| Affiliation | Taiyuan Normal Univ, Dept Phys, Jinzhong 030619, Peoples R China Taiyuan Normal Univ, Inst Computat & Appl Phys, Jinzhong 030619, Peoples R China Univ Texas Austin, Dept Astron, 2515 Speedway,Stop C1400, Austin, TX 78712 USA Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100049, Peoples R China Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China Peking Univ, Kavli Inst Astron & Astrophys, 5 Yiheyuan Rd, Beijing 100871, Peoples R China Yunnan Univ, Dept Astron, Kunming 650091, Yunnan, Peoples R China Phys Res Lab, Ahmadabad 380009, Gujarat, India Korea Astron & Space Sci Inst, 776 Daedeokdaero, Daejeon 34055, South Korea Univ Sci & Technol, 217 Gajeong Ro, Daejeon 34113, South Korea Univ Chile, Dept Astron, Casilla 36-D, Santiago 8320168, Chile Indian Inst Space Sci & Technol, Thiruvananthapuram 695547, Kerala, India Univ KwaZulu Natal, NAOC UKZN Computat Astrophys Ctr, ZA-4000 Durban, South Africa |
| Keywords | GHZ FREE-FREE DENSE GAS SPIRAL ARMS MILKY-WAY EMISSION GALAXIES HCN STARBURST ATLASGAL CLUMPS |
| Issue Date | 20-Jan-2022 |
| Publisher | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY |
| Abstract | We report the detection of radio recombination line (RRL) H-40 alpha towards 75 sources, with data obtained from ACA (Atacama Compact 7 m Array) observations in the ATOMS (ALMA Three-millimeter Observations of Massive Star-forming regions) survey of 146 active Galactic star-forming regions. We calculated ionized gas mass and star formation rate (SFR) with H-40 alpha, line emission. The mass of ionized gas is significantly smaller than molecular gas mass, indicating that ionized gas is negligible in the star-forming clumps of the ATOMS sample. The SFR estimated with RRL H-40 alpha, agrees well with that calculated with the total bolometric luminosity (L-bol) when SFR >= 5 M-circle dot Myr(-1), suggesting that millimetre RRLs could well sample the upper part of the initial mass function and thus be good tracers of SFR. We also study the relationships between L-bo1 and the molecular line luminosities (L-bo1) of CS J = 2-1 and HC3N J = 11-10 for all the 146 ATOMS sources. The L-bo1-L'(mol) correlations of both the CS J = 2-1 and HC3N J = 11-10 lines appear approximately linear and these transitions have success in predicting Lbol similar to that of more commonly used transitions. The L-bol-to-L'(mol) ratios or SFR-to-mass ratios (star formation efficiency) do not change with galactocentric distances (R-GC). Sources with H-40 alpha emission (or H II regions) show higher L-bol-to-L'(mol )ratios than those without H-40 alpha emission, which may be an evolutionary effect. |
| URI | http://hdl.handle.net/20.500.11897/638883 |
| ISSN | 0035-8711 |
| DOI | 10.1093/mnras/stab2733 |
| Indexed | SCI(E) |
| Appears in Collections: | 科维理天文与天体物理研究所 |
