English

Scaling Relations Between Warm Galactic Outflows and Their Host Galaxies

Astrophysics of Galaxies 2015-10-07 v1 Cosmology and Nongalactic Astrophysics

Abstract

We report on a sample of 51 nearby, star-forming galaxies observed with the Cosmic Origin Spectrograph on the Hubble Space Telescope. We calculate Si II kinematics and densities arising from warm gas entrained in galactic outflows. We use multi-wavelength ancillary data to estimate stellar masses (M_\ast), star-formation rates (SFR), and morphologies. We derive significant correlations between outflow velocity and SFR0.1^{\sim 0.1}, M0.1_\ast^{\sim 0.1} and vcirc1/2_\text{circ}^{\sim 1/2}. Some mergers drive outflows faster than these relations prescribe, launching the outflow faster than the escape velocity. Calculations of the mass outflow rate reveal strong scaling with SFR1/2^{\sim 1/2} and M1/2_\ast^{\sim 1/2}. Additionally, mass-loading efficiency factors (mass outflow rate divided by SFR) scale approximately as M1/2_\ast^{-1/2}. Both the outflow velocity and mass-loading scaling suggest that these outflows are powered by supernovae, with only 0.7% of the total supernovae energy converted into the kinetic energy of the warm outflow. Galaxies lose some gas if log(M_\ast/M_\odot) < 9.59.5, while more massive galaxies retain all of their gas, unless they undergo a merger. This threshold for gas loss can explain the observed shape of the mass-metallicity relation.

Keywords

Cite

@article{arxiv.1412.2139,
  title  = {Scaling Relations Between Warm Galactic Outflows and Their Host Galaxies},
  author = {John Chisholm and Christina A. Tremonti and Claus Leitherer and Yanmei Chen and Aida Wofford and Britt Lundgren},
  journal= {arXiv preprint arXiv:1412.2139},
  year   = {2015}
}

Comments

28 pages, 15 figures, submitted to ApJ

R2 v1 2026-06-22T07:22:16.638Z