Dust in the Wind: Composition and Kinematics of Galaxy Outflows at the
Peak Epoch of Star Formation
T. Jones, D. Stark, и R. Ellis. (2018)cite arxiv:1805.01484Comment: 24 pages, 18 figures (plus appendix), submitted to ApJ.
Аннотация
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
physical properties with rest-frame ultraviolet spectra of nine gravitationally
lensed z=2-3 star forming galaxies taken with Keck/ESI. Using transitions
spanning a range of optical depths and atomic elements, we study the
kinematics, covering fractions, and composition of the interstellar medium in
our sample. The interstellar medium seen in absorption 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. Our sample spans an order of magnitude in column
density yet ionic abundance patterns show remarkably little scatter, revealing
a distinct "chemical fingerprint" of outflows. Gas phase Si abundances are
significantly super-solar relative to Fe and Ni (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 DLAs at similar redshifts, suggesting that these extreme systems are
associated with galactic outflows at small impact parameters. We discuss
implications of the abundance patterns in z=2-3 galaxies and the role of
outflows at this epoch.
%0 Generic
%1 jones2018composition
%A Jones, Tucker
%A Stark, Daniel P.
%A Ellis, Richard S.
%D 2018
%K composition kinematics outflow spectra
%T Dust in the Wind: Composition and Kinematics of Galaxy Outflows at the
Peak Epoch of Star Formation
%U http://arxiv.org/abs/1805.01484
%X 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
physical properties with rest-frame ultraviolet spectra of nine gravitationally
lensed z=2-3 star forming galaxies taken with Keck/ESI. Using transitions
spanning a range of optical depths and atomic elements, we study the
kinematics, covering fractions, and composition of the interstellar medium in
our sample. The interstellar medium seen in absorption 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. Our sample spans an order of magnitude in column
density yet ionic abundance patterns show remarkably little scatter, revealing
a distinct "chemical fingerprint" of outflows. Gas phase Si abundances are
significantly super-solar relative to Fe and Ni (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 DLAs at similar redshifts, suggesting that these extreme systems are
associated with galactic outflows at small impact parameters. We discuss
implications of the abundance patterns in z=2-3 galaxies and the role of
outflows at this epoch.
@misc{jones2018composition,
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
physical properties with rest-frame ultraviolet spectra of nine gravitationally
lensed z=2-3 star forming galaxies taken with Keck/ESI. Using transitions
spanning a range of optical depths and atomic elements, we study the
kinematics, covering fractions, and composition of the interstellar medium in
our sample. The interstellar medium seen in absorption 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. Our sample spans an order of magnitude in column
density yet ionic abundance patterns show remarkably little scatter, revealing
a distinct "chemical fingerprint" of outflows. Gas phase Si abundances are
significantly super-solar relative to Fe and Ni ([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 DLAs at similar redshifts, suggesting that these extreme systems are
associated with galactic outflows at small impact parameters. We discuss
implications of the abundance patterns in z=2-3 galaxies and the role of
outflows at this epoch.},
added-at = {2018-05-07T16:29:56.000+0200},
author = {Jones, Tucker and Stark, Daniel P. and Ellis, Richard S.},
biburl = {https://www.bibsonomy.org/bibtex/2a7bbe13324044cc834be7d34f7abde5a/miki},
interhash = {a4006e7017f68fefbe2081f52e5a97e4},
intrahash = {a7bbe13324044cc834be7d34f7abde5a},
keywords = {composition kinematics outflow spectra},
note = {cite arxiv:1805.01484Comment: 24 pages, 18 figures (plus appendix), submitted to ApJ},
timestamp = {2018-05-07T16:29:56.000+0200},
title = {Dust in the Wind: Composition and Kinematics of Galaxy Outflows at the
Peak Epoch of Star Formation},
url = {http://arxiv.org/abs/1805.01484},
year = 2018
}