Bibliographic Details
| Title: |
The molecular gas content and fuel efficiency of starbursts at z ~ 1.6 with ALMA |
| Authors: |
Silverman, J., Rujopakarn, W., Daddi, E., Renzini, A., Rodighiero, G., Liu, D., Puglisi, A., Sargent, M., Mancini, C., Kartaltepe, J., Kashino, D., Koekemoer, A., Arimoto, N., Bethermin, M., Jin, S., Magdis, G., Nagao, T., Onodera, M., Sanders, D., Valentino, F. |
| Publication Year: |
2018 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Astrophysics of Galaxies |
| More Details: |
We present an analysis of the molecular gas properties, based on CO(2 - 1) emission, of twelve starburst galaxies at z~1.6 selected by having a boost (>~4x) in their star formation rate (SFR) above the average star-forming galaxy at an equivalent stellar mass. ALMA observations are acquired of six additional galaxies than previously reported through our effort. As a result of the larger statistical sample, we significantly detect, for the first time at high-z, a systematically lower L'_CO/L_IR ratio in galaxies lying above the star-forming `main sequence' (MS). Based on an estimate of alpha_CO (i.e., the ratio of molecular gas mass to L'_CO(1-0)), we convert the observational quantities (e.g., L'_CO/L_IR) to physical units (M_gas/SFR) that represent the gas depletion time or its inverse, the star formation efficiency. We interpret the results as indicative of the star formation efficiency increasing in a continuous fashion from the MS to the starburst regime, whereas the gas fractions remain comparable to those of MS galaxies. Although, the balance between an increase in star-formation efficiency or gas fraction depends on the adopted value of alpha_CO as discussed.
Comment: 16 pages, 8 figures |
| Document Type: |
Working Paper |
| DOI: |
10.3847/1538-4357/aae25e |
| Access URL: |
http://arxiv.org/abs/1810.01596 |
| Accession Number: |
edsarx.1810.01596 |
| Database: |
arXiv |
