Green Peas are nearby analogs of high-redshift Ly$\alpha$-emitting galaxies.
To probe their Ly$\alpha$ escape, we study the spatial profiles of Ly$\alpha$
and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins
Spectrograph (COS) on Hubble Space Telescope (HST). We extract the spatial
profiles of Ly$\alpha$ emission from their 2D COS spectra, and of UV continuum
from both the 2D spectra and NUV images. The Ly$\alpha$ emission shows more
extended spatial profiles than the UV continuum in most Green Peas. The
deconvolved Full Width Half Maximum (FWHM) of the Ly$\alpha$ spatial profile is
about 2 to 4 times that of the UV continuum in most cases. The Ly$\alpha$ light
shows significant offsets from the UV continuum in four galaxies and central
absorption in one galaxy. We also compare the spatial profiles of Ly$\alpha$
photons at blueshifted and redshifted velocities in eight Green Peas with
sufficient data quality, and find the blue wing of the Ly$\alpha$ line has a
larger spatial extent than the red wing in four Green Peas with comparatively
weak blue Ly$\alpha$ line wings. These results together indicate that most
Ly$\alpha$ photons escape out of Ly$\alpha$-emitting galaxies through many
resonant scatterings in the HI gas. Five Lyman continuum (LyC) leakers in this
sample have similar Ly$\alpha$ to UV continuum size ratios ($\sim1.4-4.3$) to
the other Green Peas, indicating their LyC emission escape through ionized
holes in the interstellar medium.
Description
[1610.05767] Ly$\alpha$ and UV Sizes of Green Pea Galaxies
%0 Generic
%1 yang2016lyalpha
%A Yang, Huan
%A Malhotra, Sangeeta
%A Rhoads, James E.
%A Leitherer, Claus
%A Wofford, Aida
%A Jiang, Tianxing
%A Wang, Junxian
%D 2016
%K Lya UV size
%T Ly$\alpha$ and UV Sizes of Green Pea Galaxies
%U http://arxiv.org/abs/1610.05767
%X Green Peas are nearby analogs of high-redshift Ly$\alpha$-emitting galaxies.
To probe their Ly$\alpha$ escape, we study the spatial profiles of Ly$\alpha$
and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins
Spectrograph (COS) on Hubble Space Telescope (HST). We extract the spatial
profiles of Ly$\alpha$ emission from their 2D COS spectra, and of UV continuum
from both the 2D spectra and NUV images. The Ly$\alpha$ emission shows more
extended spatial profiles than the UV continuum in most Green Peas. The
deconvolved Full Width Half Maximum (FWHM) of the Ly$\alpha$ spatial profile is
about 2 to 4 times that of the UV continuum in most cases. The Ly$\alpha$ light
shows significant offsets from the UV continuum in four galaxies and central
absorption in one galaxy. We also compare the spatial profiles of Ly$\alpha$
photons at blueshifted and redshifted velocities in eight Green Peas with
sufficient data quality, and find the blue wing of the Ly$\alpha$ line has a
larger spatial extent than the red wing in four Green Peas with comparatively
weak blue Ly$\alpha$ line wings. These results together indicate that most
Ly$\alpha$ photons escape out of Ly$\alpha$-emitting galaxies through many
resonant scatterings in the HI gas. Five Lyman continuum (LyC) leakers in this
sample have similar Ly$\alpha$ to UV continuum size ratios ($\sim1.4-4.3$) to
the other Green Peas, indicating their LyC emission escape through ionized
holes in the interstellar medium.
@misc{yang2016lyalpha,
abstract = {Green Peas are nearby analogs of high-redshift Ly$\alpha$-emitting galaxies.
To probe their Ly$\alpha$ escape, we study the spatial profiles of Ly$\alpha$
and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins
Spectrograph (COS) on Hubble Space Telescope (HST). We extract the spatial
profiles of Ly$\alpha$ emission from their 2D COS spectra, and of UV continuum
from both the 2D spectra and NUV images. The Ly$\alpha$ emission shows more
extended spatial profiles than the UV continuum in most Green Peas. The
deconvolved Full Width Half Maximum (FWHM) of the Ly$\alpha$ spatial profile is
about 2 to 4 times that of the UV continuum in most cases. The Ly$\alpha$ light
shows significant offsets from the UV continuum in four galaxies and central
absorption in one galaxy. We also compare the spatial profiles of Ly$\alpha$
photons at blueshifted and redshifted velocities in eight Green Peas with
sufficient data quality, and find the blue wing of the Ly$\alpha$ line has a
larger spatial extent than the red wing in four Green Peas with comparatively
weak blue Ly$\alpha$ line wings. These results together indicate that most
Ly$\alpha$ photons escape out of Ly$\alpha$-emitting galaxies through many
resonant scatterings in the HI gas. Five Lyman continuum (LyC) leakers in this
sample have similar Ly$\alpha$ to UV continuum size ratios ($\sim1.4-4.3$) to
the other Green Peas, indicating their LyC emission escape through ionized
holes in the interstellar medium.},
added-at = {2016-10-20T09:56:29.000+0200},
author = {Yang, Huan and Malhotra, Sangeeta and Rhoads, James E. and Leitherer, Claus and Wofford, Aida and Jiang, Tianxing and Wang, Junxian},
biburl = {https://www.bibsonomy.org/bibtex/2480e7b7ff389b83db95295b5120801b6/miki},
description = {[1610.05767] Ly$\alpha$ and UV Sizes of Green Pea Galaxies},
interhash = {afd6faf36c7392196b47249dcc60aae6},
intrahash = {480e7b7ff389b83db95295b5120801b6},
keywords = {Lya UV size},
note = {cite arxiv:1610.05767Comment: 7 pages, 5 figures. Submitted to ApJ},
timestamp = {2016-10-20T09:56:29.000+0200},
title = {Ly$\alpha$ and UV Sizes of Green Pea Galaxies},
url = {http://arxiv.org/abs/1610.05767},
year = 2016
}