Differences between emission and absorption tracers of spatially resolved outflows in clumpy z ~ 0.1 star-forming galaxies

Abstract

We present spatially resolved Keck/LRIS spectroscopy of three clumpy star-forming galaxies at $z\sim 0.1$, comparing outflow properties traced by H$\alpha$ and Mg II emission with those probed by Mg II and Na I D absorption. Outflow velocities measured using Mg II absorption ($⟨v_{\mathrm{out}}⟩=-560\pm 30$~\kms) are consistently higher than those traced by H$\alpha$ emission ($⟨v_{\mathrm{out}}⟩=-124\pm 3$~\kms) across $\sim$5 kpc${}^2$ regions. Despite this offset, the correlation between $v_{\mathrm{out}}$ and galaxy properties, such as SFR and ${\Sigma }_{\mathrm{SFR}}$, show similar slopes for both tracers, with Mg II absorption systematically offset by $\sim 0.4$ dex. In two galaxies, Mg II emission is also detected, yielding velocities consistent with H$\alpha$. In one galaxy we also detect outflows in Na I D absorption and find similar velocities as Mg II in absorption, which leads to a $\sim$0.4 dex higher Na I D outflow velocities compared to those measured in emission. Our spatially resolved results are consistent with those found for galactic-scale measurements, implying the outflow relationships are similar from the sales of $\sim$1-2 kpc to global measurements. Combined with literature measurements, these results suggest that the offset in velocities is driven not by ionisation state, but rather by the systematics associated to how absorption and emission measures trace the gas density.

6 pages, 5 figures

References in corpus (38)

• The Origin of the Mass--Metallicity Relation: Insights from 53,000 Star-Forming Galaxies in the SDSS
• Galactic Winds
• The SINS survey of z~2 galaxy kinematics: properties of the giant star forming clumps
• Mapping Large-Scale Gaseous Outflows in Ultraluminous Galaxies with Keck II ESI Spectra: Variations in Outflow Velocity with Galactic Mass
• Evidence for Ubiquitous Collimated Galactic-Scale Outflows along the Star-Forming Sequence at z~0.5
• The Metallicity-Luminosity Relation, Effective Yields, and Metal Loss in Spiral and Irregular Galaxies
• The Systematic Properties of the Warm Phase of Starburst-Driven Galactic Winds
• The radial and azimuthal profiles of Mg II absorption around 0.5 < z < 0.9 zCOSMOS galaxies of different colors, masses and environments
• The Relation Between Quasar and Merging Galaxy Luminosity Functions and the Merger-Induced Star Formation Rate of the Universe
• Effects of Supernova Feedback on the Formation of Galaxy Disks
• The Metallicity of Galaxy Disks: Infall versus Outflow
• Outflows in AGN/Starburst-Composite Ultraluminous Infrared Galaxies
• The SINS/zC-SINF survey of z~2 galaxy kinematics: Outflow properties
• Ionized gas outflows and global kinematics of low-z luminous star forming galaxies
• The KMOS^3D Survey: Demographics and Properties of Galactic Outflows at z = 0.6 - 2.7
• Absorption-line probes of the prevalence and properties of outflows in present-day star-forming galaxies
• MASSIV: Mass Assembly Survey with SINFONI in VVDS - II. Kinematics and close environment classification
• Scaling Relations Between Warm Galactic Outflows and Their Host Galaxies
• The Properties and Prevalence of Galactic Outflows at z = 1 in the Extended Groth Strip
• DYNAMO I: A Sample of Ha-Luminous Galaxies with Resolved Kinematics
• The dependence of Galactic outflows on the properties and orientation of zCOSMOS galaxies at z ~ 1
• First results from SMAUG: Characterization of Multiphase Galactic Outflows from a Suite of Local Star-Forming Galactic Disk Simulations
• Physical Conditions in the Low-Ionization Component of Starburst Outflows: The Shape of Near-Ultraviolet and Optical Absorption-Line Troughs in Keck Spectra of ULIRGs
• Kiloparsec Scale Properties of Star-Formation Driven Outflows at z~2.3 in the SINS/zC-SINF AO Survey
• DYNAMO-HST Survey: Clumps in Nearby Massive Turbulent Disks and the Effects of Clump Clustering on Kiloparsec Scale Measurements of Clumps
• The EDGE-CALIFA Survey: Molecular and Ionized Gas Kinematics in Nearby Galaxies
• JADES: The incidence rate and properties of galactic outflows in low-mass galaxies across 3 < z < 9
• New Perspective on Galaxy Outflows From the First Detection of Both Intrinsic and Traverse Metal-Line Absorption
• Systematic difference between ionized and molecular gas velocity dispersion in $z\sim 1-2$ disks and local analogues
• SILCC VII -- Gas kinematics and multiphase outflows of the simulated ISM at high gas surface densities
• Spatially resolved kinematics, galactic wind, and quenching of star formation in the luminous infrared galaxy IRAS F11506-3851
• DYNAMO II: Coupled Stellar and Ionized Gas Kinematics in Two Low Redshift Clumpy Disks
• Supernova-Driven Outflows in NGC 7552: A Comparison of H-alpha and UV Tracers
• Kinematic Modelling of Disc Galaxies using Graphics Processing Units
• The DUVET Survey: Resolved Maps of Star Formation Driven Outflows in a Compact, Starbursting Disk Galaxy
• The multiphase starburst-driven galactic wind in NGC 5394
• Physical Origins of Outflowing Cold Clouds in Local Star-forming Dwarf Galaxies
• Ultra-strong MgII absorbers trace both inflowing and outflowing gas: insights from dual down-the-barrel and quasar sightlines