The Star Formation Rate-Radius Connection: Data and Implications for Wind Strength and Halo Concentration

Authors

• Lin Lin, Shanghai Astronomical Observatory Chinese Academy of Sciences
• S. M. Faber, University of California, Santa Cruz
• David C. Koo, University of California, Santa Cruz
• Samir Salim, Indiana University Bloomington
• Aaron A. Dutton, NYU Abu Dhabi
• Jerome J. Fang, Orange Coast College
• Fangzhou Jiang, Hebrew University of Jerusalem
• Christoph T. Lee, University of California, Santa Cruz
• Aldo Rodríguez-Puebla, Universidad Nacional Autónoma de México
• A. van der Wel, Universiteit Gent
• Yicheng Guo, University of Missouri
• Guillermo Barro, University of the PacificFollow
• Joel R. Primack, University of California, Santa Cruz
• Avishai Dekel, Hebrew University of Jerusalem
• Zhu Chen, Shanghai Normal University
• Yifei Luo, University of California, Santa Cruz
• Viraj Pandya, University of California, Santa Cruz
• Rachel S. Somerville, Simons Foundation
• Henry C. Ferguson, Space Telescope Science Institute
• Susan Kassin, Space Telescope Science Institute
• Anton M. Koekemoer, Space Telescope Science Institute
• Norman A. Grogin, Space Telescope Science Institute

Document Type

Article

Publication Title

Astrophysical Journal

Department

Physics

ISSN

15384357

Volume

899

Issue

2

DOI

10.3847/1538-4357/aba755

First Page

1

Last Page

16

Publication Date

8-17-2020

Abstract

This paper is one in a series that explores the importance of radius as a second parameter in galaxy evolution. The topic investigated here is the relationship between star formation rate (SFR) and galaxy radius (Re) for main-sequence star-forming galaxies. The key observational result is that, over a wide range of stellar mass and redshift in both CANDELS and SDSS, there is little correlation between SFR and Re at fixed stellar mass. The Kennicutt-Schmidt law, or any similar density-related star formation law, then implies that smaller galaxies must have lower gas fractions than larger galaxies (at fixed M∗), and this is supported by observations of gas in local star-forming galaxies. We investigate the implications by adopting the equilibrium "bathtub"model: the ISM gas mass is assumed to be constant over time, and the net SFR is the difference between the accretion rate of gas onto the galaxy from the halo and the outflow rate due to winds. To match the observed null correlation between SFR and radius, the bathtub model requires that smaller galaxies at fixed mass have weaker galactic winds. Our hypothesis is that galaxies are a two-parameter family whose properties are set mainly by halo mass and concentration. These determine the radius and gas accretion rate, which in turn predict how wind strength needs to vary with Re to keep the SFR constant.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Lin, Lin; Faber, S. M.; Koo, David C.; Salim, Samir; Dutton, Aaron A.; Fang, Jerome J.; Jiang, Fangzhou; Lee, Christoph T.; Rodríguez-Puebla, Aldo; van der Wel, A.; Guo, Yicheng; Barro, Guillermo; Primack, Joel R.; Dekel, Avishai; Chen, Zhu; Luo, Yifei; Pandya, Viraj; Somerville, Rachel S.; Ferguson, Henry C.; Kassin, Susan; Koekemoer, Anton M.; and Grogin, Norman A., "The Star Formation Rate-Radius Connection: Data and Implications for Wind Strength and Halo Concentration" (2020). Pacific Faculty Work. 302.
https://scholarlycommons.pacific.edu/all-faculty/302