Dust in the Wind: Composition and Kinematics of Galaxy Outflows at the Peak Epoch of Star Formation

Tucker Jones, Daniel P Stark, Richard S. Ellis

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Galactic-scale outflows regulate the stellar mass growth and chemical enrichment of galaxies, yet key outflow properties such as the chemical composition and mass-loss rate remain largely unknown. We address these properties with Keck/ESI echellete spectra of nine gravitationally lensed z ≃ 2-3 star-forming galaxies, probing a range of absorption transitions. Interstellar absorption in our sample is dominated by outflowing material with typical velocities of ∼-150 . Approximately 80% of the total column density is associated with a net outflow. Mass-loss rates in the low-ionization phase are comparable to or in excess of the star formation rate, with total outflow rates likely higher when accounting for ionized gas. On the order of half of the heavy element yield from star formation is ejected in the low-ionization phase, confirming that outflows play a critical role in regulating galaxy chemical evolution. Covering fractions vary and are in general non-uniform, with most galaxies having incomplete covering by the low ions across all velocities. Low-ion abundance patterns show remarkably little scatter, revealing a distinct "chemical fingerprint" of outflows. Gas-phase Si/Fe abundances are significantly supersolar ([Si/Fe] ≳ 0.4), indicating a combination of α-enhancement and dust depletion. The derived properties are comparable to the most kinematically broad, metal-rich, and depleted intergalactic absorption systems at similar redshifts, suggesting that these extreme systems are associated with galactic outflows at impact parameters conservatively within a few tens of kiloparsecs. We discuss implications of the abundance patterns in z ≃ 2-3 galaxies and the role of outflows at this epoch.

Original languageEnglish (US)
Article number191
JournalAstrophysical Journal
Volume863
Issue number2
DOIs
StatePublished - Aug 20 2018

Fingerprint

star formation
outflow
kinematics
dust
time measurement
galaxies
coverings
ionization
chemical evolution
ionized gases
heavy elements
star formation rate
stellar mass
chemical composition
ions
depletion
ion
vapor phases
stars
gas

Keywords

  • galaxies: evolution
  • galaxies: ISM

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Dust in the Wind : Composition and Kinematics of Galaxy Outflows at the Peak Epoch of Star Formation. / Jones, Tucker; Stark, Daniel P; Ellis, Richard S.

In: Astrophysical Journal, Vol. 863, No. 2, 191, 20.08.2018.

Research output: Contribution to journalArticle

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