CGM 2 + CASBaH: The Mass Dependence of H i Lyα–Galaxy Clustering and the Extent of the CGM
Abstract We combine data sets from the CGM 2 and CASBaH surveys to model a transition point, R cross , between circumgalactic and intergalactic media (CGM and IGM, respectively). In total, our data consist of 7244 galaxies at z < 0.5 with precisely measured spectroscopic redshifts, all having imp...
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Published in | The Astrophysical journal Vol. 948; no. 2; p. 114 |
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Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
01.05.2023
|
Online Access | Get full text |
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Summary: | Abstract
We combine data sets from the CGM
2
and CASBaH surveys to model a transition point,
R
cross
, between circumgalactic and intergalactic media (CGM and IGM, respectively). In total, our data consist of 7244 galaxies at
z
< 0.5 with precisely measured spectroscopic redshifts, all having impact parameters of 0.01–20 comoving Mpc from 28 QSO sightlines with high-resolution UV spectra that cover H
i
Ly
α
. Our best-fitting model is a two-component model that combines a 3D absorber–galaxy cross-correlation function with a simple Gaussian profile at inner radii to represent the CGM. By design, this model gives rise to a determination of
R
cross
as a function of galaxy stellar mass, which can be interpreted as the boundary between the CGM and IGM. For galaxies with 10
8
≤
M
⋆
/
M
⊙
≤ 10
10.5
, we find that
R
cross
(
M
⋆
) ≈ 2.0 ± 0.6
R
vir
. Additionally, we find excellent agreement between
R
cross
(
M
⋆
) and the theoretically determined splashback radius for galaxies in this mass range. Overall, our results favor models of galaxy evolution at
z
< 0.5 that distribute
T
≈ 10
4
K gas to distances beyond the virial radius. |
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ISSN: | 0004-637X 1538-4357 |
DOI: | 10.3847/1538-4357/acc85b |