Connecting Lyman-$\alpha$ and ionizing photon escape in the Sunburst Arc
Abstract
We investigate the Lyman- (Ly) and Lyman continuum (LyC) properties of the Sunburst Arc, a gravitationally lensed galaxy with a multiply-imaged, compact region leaking LyC and a triple-peaked Ly profile indicating direct Ly escape. Non-LyC-leaking regions show a redshifted Ly peak, a redshifted and central Ly peak, or a triple-peaked Ly profile. We measure the properties of the Ly profile from different regions of the galaxy using Magellan/MagE spectra. We compare the Ly spectral properties to LyC and narrowband Ly maps from Hubble Space Telescope (HST) imaging to explore the subgalactic LyLyC connection. We find strong correlations (Pearson correlation coefficient ) between the LyC escape fraction () and Ly (1) peak separation , (2) ratio of the minimum flux density between the redshifted and blueshifted Ly peaks to continuum flux density , and (3) equivalent width. We favor a complex \ion{H}{1} geometry to explain the Ly profiles from non-LyC-leaking regions and suggest two \ion{H}{1} geometries that could diffuse and/or rescatter the central Ly peak from the LyC-leaking region into our sightline across transverse distances of several hundred parsecs. Our results emphasize the complexity of Ly radiative transfer and its sensitivity to the anisotropies of \ion{H}{1} gas on subgalactic scales. Large differences in the physical scales on which we observe spatially variable direct escape Ly, blueshifted Ly, and escaping LyC photons in the Sunburst Arc underscore the importance of resolving the physical scales that govern Ly and LyC escape.
Cite
@article{arxiv.2410.03660,
title = {Connecting Lyman-$\alpha$ and ionizing photon escape in the Sunburst Arc},
author = {M. Riley Owens and Keunho J. Kim and Matthew B. Bayliss and T. Emil Rivera-Thorsen and Keren Sharon and Jane R. Rigby and Alexander Navarre and Michael Florian and Michael D. Gladders and Jessica G. Burns and Gourav Khullar and John Chisholm and Guillaume Mahler and Hakon Dahle and Christopher M. Malhas and Brian Welch and Taylor A. Hutchison and Raven Gassis and Suhyeon Choe and Prasanna Adhikari},
journal= {arXiv preprint arXiv:2410.03660},
year = {2024}
}
Comments
Submitted to The Astrophysical Journal with revisions from the first referee report. Comments welcome