Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies

Huan Yang, Sangeeta Malhotra, Max Gronke, James E. Rhoads, Claus Leitherer, Aida Wofford, Tianxing Jiang, Mark Dijkstra, V. Tilvi, Junxian Wang

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

We studied Lyman-α (Lyα) escape in a statistical sample of 43 Green Peas with HST/COS Lyα spectra. Green Peas are nearby star-forming galaxies with strong [O iii]λ5007 emission lines. Our sample is four times larger than the previous sample and covers a much more complete range of Green Pea properties. We found that about two-thirds of Green Peas are strong Lyα line emitters with rest-frame Lyα equivalent width . The Lyα profiles of Green Peas are diverse. The Lyα escape fraction, defined as the ratio of observed Lyα flux to intrinsic Lyα flux, shows anti-correlations with a few Lyα kinematic features - both the blue peak and red peak velocities, the peak separations, and the FWHM of the red portion of the Lyα profile. Using properties measured from Sloan Digital Sky Survey optical spectra, we found many correlations - the Lyα escape fraction generally increases at lower dust reddening, lower metallicity, lower stellar mass, and higher [O iii]/[O ii] ratio. We fit their Lyα profiles with the H i shell radiative transfer model and found that the Lyα escape fraction is anti-correlated with the best-fit N H i. Finally, we fit an empirical linear relation to predict from the dust extinction and Lyα red peak velocity. The standard deviation of this relation is about 0.3 dex. This relation can be used to isolate the effect of intergalactic medium (IGM) scatterings from Lyα escape and to probe the IGM optical depth along the line of sight of each Lyα emission-line galaxy in the James Webb Space Telescope era.

Original languageEnglish (US)
Article number171
JournalAstrophysical Journal
Volume844
Issue number2
DOIs
StatePublished - Aug 1 2017

Fingerprint

escape
dust
galaxies
profiles
prediction
predictions
intergalactic media
optical depth
radiative transfer
kinematics
extinction
scattering
probe
Lyman spectra
shell
James Webb Space Telescope
stellar mass
optical thickness
line of sight
metallicity

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Yang, H., Malhotra, S., Gronke, M., Rhoads, J. E., Leitherer, C., Wofford, A., ... Wang, J. (2017). Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies. Astrophysical Journal, 844(2), [171]. https://doi.org/10.3847/1538-4357/aa7d4d

Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies. / Yang, Huan; Malhotra, Sangeeta; Gronke, Max; Rhoads, James E.; Leitherer, Claus; Wofford, Aida; Jiang, Tianxing; Dijkstra, Mark; Tilvi, V.; Wang, Junxian.

In: Astrophysical Journal, Vol. 844, No. 2, 171, 01.08.2017.

Research output: Contribution to journalArticle

Yang, H, Malhotra, S, Gronke, M, Rhoads, JE, Leitherer, C, Wofford, A, Jiang, T, Dijkstra, M, Tilvi, V & Wang, J 2017, 'Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies', Astrophysical Journal, vol. 844, no. 2, 171. https://doi.org/10.3847/1538-4357/aa7d4d
Yang H, Malhotra S, Gronke M, Rhoads JE, Leitherer C, Wofford A et al. Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies. Astrophysical Journal. 2017 Aug 1;844(2). 171. https://doi.org/10.3847/1538-4357/aa7d4d
Yang, Huan ; Malhotra, Sangeeta ; Gronke, Max ; Rhoads, James E. ; Leitherer, Claus ; Wofford, Aida ; Jiang, Tianxing ; Dijkstra, Mark ; Tilvi, V. ; Wang, Junxian. / Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies. In: Astrophysical Journal. 2017 ; Vol. 844, No. 2.
@article{90a1e924c71f4f1c8bafa462e9044e01,
title = "Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies",
abstract = "We studied Lyman-α (Lyα) escape in a statistical sample of 43 Green Peas with HST/COS Lyα spectra. Green Peas are nearby star-forming galaxies with strong [O iii]λ5007 emission lines. Our sample is four times larger than the previous sample and covers a much more complete range of Green Pea properties. We found that about two-thirds of Green Peas are strong Lyα line emitters with rest-frame Lyα equivalent width . The Lyα profiles of Green Peas are diverse. The Lyα escape fraction, defined as the ratio of observed Lyα flux to intrinsic Lyα flux, shows anti-correlations with a few Lyα kinematic features - both the blue peak and red peak velocities, the peak separations, and the FWHM of the red portion of the Lyα profile. Using properties measured from Sloan Digital Sky Survey optical spectra, we found many correlations - the Lyα escape fraction generally increases at lower dust reddening, lower metallicity, lower stellar mass, and higher [O iii]/[O ii] ratio. We fit their Lyα profiles with the H i shell radiative transfer model and found that the Lyα escape fraction is anti-correlated with the best-fit N H i. Finally, we fit an empirical linear relation to predict from the dust extinction and Lyα red peak velocity. The standard deviation of this relation is about 0.3 dex. This relation can be used to isolate the effect of intergalactic medium (IGM) scatterings from Lyα escape and to probe the IGM optical depth along the line of sight of each Lyα emission-line galaxy in the James Webb Space Telescope era.",
author = "Huan Yang and Sangeeta Malhotra and Max Gronke and Rhoads, {James E.} and Claus Leitherer and Aida Wofford and Tianxing Jiang and Mark Dijkstra and V. Tilvi and Junxian Wang",
year = "2017",
month = "8",
day = "1",
doi = "10.3847/1538-4357/aa7d4d",
language = "English (US)",
volume = "844",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2",

}

TY - JOUR

T1 - Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies

AU - Yang, Huan

AU - Malhotra, Sangeeta

AU - Gronke, Max

AU - Rhoads, James E.

AU - Leitherer, Claus

AU - Wofford, Aida

AU - Jiang, Tianxing

AU - Dijkstra, Mark

AU - Tilvi, V.

AU - Wang, Junxian

PY - 2017/8/1

Y1 - 2017/8/1

N2 - We studied Lyman-α (Lyα) escape in a statistical sample of 43 Green Peas with HST/COS Lyα spectra. Green Peas are nearby star-forming galaxies with strong [O iii]λ5007 emission lines. Our sample is four times larger than the previous sample and covers a much more complete range of Green Pea properties. We found that about two-thirds of Green Peas are strong Lyα line emitters with rest-frame Lyα equivalent width . The Lyα profiles of Green Peas are diverse. The Lyα escape fraction, defined as the ratio of observed Lyα flux to intrinsic Lyα flux, shows anti-correlations with a few Lyα kinematic features - both the blue peak and red peak velocities, the peak separations, and the FWHM of the red portion of the Lyα profile. Using properties measured from Sloan Digital Sky Survey optical spectra, we found many correlations - the Lyα escape fraction generally increases at lower dust reddening, lower metallicity, lower stellar mass, and higher [O iii]/[O ii] ratio. We fit their Lyα profiles with the H i shell radiative transfer model and found that the Lyα escape fraction is anti-correlated with the best-fit N H i. Finally, we fit an empirical linear relation to predict from the dust extinction and Lyα red peak velocity. The standard deviation of this relation is about 0.3 dex. This relation can be used to isolate the effect of intergalactic medium (IGM) scatterings from Lyα escape and to probe the IGM optical depth along the line of sight of each Lyα emission-line galaxy in the James Webb Space Telescope era.

AB - We studied Lyman-α (Lyα) escape in a statistical sample of 43 Green Peas with HST/COS Lyα spectra. Green Peas are nearby star-forming galaxies with strong [O iii]λ5007 emission lines. Our sample is four times larger than the previous sample and covers a much more complete range of Green Pea properties. We found that about two-thirds of Green Peas are strong Lyα line emitters with rest-frame Lyα equivalent width . The Lyα profiles of Green Peas are diverse. The Lyα escape fraction, defined as the ratio of observed Lyα flux to intrinsic Lyα flux, shows anti-correlations with a few Lyα kinematic features - both the blue peak and red peak velocities, the peak separations, and the FWHM of the red portion of the Lyα profile. Using properties measured from Sloan Digital Sky Survey optical spectra, we found many correlations - the Lyα escape fraction generally increases at lower dust reddening, lower metallicity, lower stellar mass, and higher [O iii]/[O ii] ratio. We fit their Lyα profiles with the H i shell radiative transfer model and found that the Lyα escape fraction is anti-correlated with the best-fit N H i. Finally, we fit an empirical linear relation to predict from the dust extinction and Lyα red peak velocity. The standard deviation of this relation is about 0.3 dex. This relation can be used to isolate the effect of intergalactic medium (IGM) scatterings from Lyα escape and to probe the IGM optical depth along the line of sight of each Lyα emission-line galaxy in the James Webb Space Telescope era.

UR - http://www.scopus.com/inward/record.url?scp=85027414641&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85027414641&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/aa7d4d

DO - 10.3847/1538-4357/aa7d4d

M3 - Article

AN - SCOPUS:85027414641

VL - 844

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 171

ER -