Logo image
Back
The Lyα Halos of Galaxies at z ≈ 2-3 in the Keck Baryonic Structure Survey
Journal article   Open access   Peer reviewed

The Lyα Halos of Galaxies at z ≈ 2-3 in the Keck Baryonic Structure Survey

Ryan F. Trainor, Noah R. Lamb, Charles C. Steidel, Yuguang Chen, Dawn K. Erb, Elizabeth Trenholm, Rebecca L. McClain and Io Kovach
The Astrophysical journal, v 1006(1), 36
20 Jul 2026
DOI: https://doi.org/10.3847/1538-4357/ae75e0
url
https://doi.org/10.3847/1538-4357/ae75e0View
Published, Version of Record (VoR) Open

Abstract

Astronomy & Astrophysics Science & Technology Physical Sciences
We present the large-scale spatial Ly alpha profiles of galaxies from the Keck Baryonic Structure Survey (KBSS) at 2 < z < 3. This work also describes the Ly alpha imaging for the KBSS-Ly alpha survey for the first time. Our sample includes 548 Ly alpha-selected galaxies and 120 continuum-selected galaxies with Ly alpha narrowband imaging, and we measure the spatial morphology of Ly alpha and continuum emission for stacked subsamples of these two populations. These samples allow us to study the variation in Ly alpha emission profiles over a broad range of UV continuum luminosities and Ly alpha equivalent widths (EWLy alpha), including systems with net Ly alpha absorption in slit spectroscopy. We characterize the spatial profiles using two techniques: directly fitting an exponential function to the stacked profile, and a multicomponent forward-modeling technique using the empirical large-scale point-spread function. We find that both methods yield similar results and that the forward-modeling technique self-consistently fits profiles exhibiting central Ly alpha emission or Ly alpha absorption, with the spatial scale of central Ly alpha approximately matching that of the continuum emission. We also find extended Ly alpha emission such that all of our subsamples-including central Ly alpha absorbers-are net Ly alpha emitters on scales comparable to the circumgalactic medium (R greater than or similar to 50 kpc, theta greater than or similar to 6 ''). We find that the scale length of the Ly alpha halo is not strongly dependent on the properties of the central galaxy, including its net continuum luminosity or EWLy alpha; although, we find a possible weak tendency of continuum-faint, high-EWLy alpha galaxies to exhibit larger Ly alpha halos in contrast with previous work.

Metrics

1 Record Views

Details

Logo image