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

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 -150 km/s. 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. Of order 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 super-solar ([Si/Fe]$\gtrsim$0.4) indicating a combination of $\alpha$-enhancement and dust depletion. 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 kpc. We discuss implications of the abundance patterns in z=2-3 galaxies and the role of outflows at this epoch.

32 pages, 28 figures, 5 tables (including appendix), published in ApJ

References in corpus (26)

• Cosmic Star Formation History
• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• The Mass-Metallicity Relation at z~2
• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• The GALAH Survey: Second Data Release
• Metallicity Effects on Dust Properties in Starbursting Galaxies
• The MUSE Hubble Ultra Deep Field Survey: I. Survey description, data reduction and source detection
• The MOSDEF Survey: Mass, Metallicity, and Star-formation Rate at z~2.3
• Velocity-Metallicity Correlation for high-z DLA Galaxies: Evidence for a Mass-Metallicity Relation?
• The GALAH Survey: Observational Overview and Gaia DR1 companion
• Metal-line absorption around $z\approx$2.4 star-forming galaxies in the Keck Baryonic Structure Survey
• Disentangling the Galactic Halo with APOGEE: I. Chemical and Kinematical Investigation of Distinct Metal-Poor Populations
• The Assembly Histories of Quiescent Galaxies Since z=0.7 from Absorption Line Spectroscopy
• The Cosmic Horseshoe: Discovery of an Einstein Ring around a Giant Luminous Red Galaxy
• The SINFONI MgII Program for Line Emitters (SIMPLE): Discovering starbursts near QSO sight-lines
• On the HI content, dust-to-gas ratio and nature of MgII absorbers
• Two New Large Separation Gravitational Lenses from SDSS
• The SDSS-DR12 large-scale cross-correlation of Damped Lyman Alpha Systems with the Lyman Alpha Forest
• The redshift evolution of rest-UV spectroscopic properties in Lyman Break Galaxies at z ~ 2-4
• Unveiling the Secrets of Metallicity and Massive Star Formation Using DLAs along Gamma-ray Bursts
• The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MEGaSaURA) I: The Sample and the Spectra
• Chemical abundances of damped Lyman alpha systems in the XQ-100 survey
• Probing feedback in protogalaxies: Multiphase gas in a DLA at z~2.4
• X-ray selected galaxy clusters in the Pan-STARRS Medium-Deep Survey
• Quasar 2175 Å dust absorbers I: metallicity, depletion pattern, and kinematics
• Revealing the host galaxy of a quasar 2175 Å dust absorber at z = 2.12

Cited by in corpus (23)

• Cool Outflows in Galaxies and their Implications
• The MOSDEF Survey: The Evolution of the Mass-Metallicity Relation from $z=0$ to $z\sim 3.3$
• A Nearby Galaxy Perspective on Dust Evolution. Scaling relations and constraints on the dust build-up in galaxies with the DustPedia and DGS samples
• A Review of Recent Observations of Galactic Winds Driven by Star Formation
• Probing the existence of very massive first stars
• Observational and theoretical constraints on the formation and early evolution of the first dust grains in galaxies at 5 < z < 10
• The connection between galactic outflows and the escape of ionizing photons
• Ionized gas kinematics and chemical abundances of low-mass star-forming galaxies at $z\sim 3$
• Dust depletion of metals from local to distant galaxies I: Peculiar nucleosynthesis effects and grain growth in the ISM
• The DUVET Survey: Resolved Maps of Star Formation Driven Outflows in a Compact, Starbursting Disk Galaxy
• MusE GAs FLOw and Wind (MEGAFLOW) V. The dust/metallicity-anisotropy of the Circum-Galactic Medium
• Kinematics of the Circumgalactic Medium of a $z=0.77$ Galaxy from MgII Tomography
• Exploring the Physical Properties of the Cool Circumgalactic Medium with a Semi-Analytic Model
• The Mean Absorption Line Spectra of a Selection of Luminous z~6 Lyman Break Galaxies
• Rest-frame UV Properties of Luminous Strong Gravitationally Lensed Ly$\alpha$ Emitters from the BELLS GALLERY Survey
• Kinematics, Structure, and Mass Outflow Rates of Extreme Starburst Galactic Outflows
• Spectroscopy of CASSOWARY gravitationally-lensed galaxies in SDSS: characterisation of an extremely bright reionization-era analog at $z=1.42$
• Metal content of the circumgalactic medium around star-forming galaxies at z $\sim$ 2.6 as revealed by the VIMOS Ultra-Deep Survey
• Probing IGM accretion onto faint Lyα emitters at z~2.8
• The Baltimore Oriole's Nest: Cool Winds from the Inner and Outer Parts of a Star-Forming Galaxy at z=1.3
• Pixel-level modelling of group-scale strong lens CASSOWARY 19
• Disentangling the physical origin of emission line ratio offsets at high redshift with spatially resolved spectroscopy
• The AGEL Survey: Spectroscopic Confirmation of Strong Gravitational Lenses in the DES and DECaLS Fields Selected Using Convolutional Neural Networks