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CGM2 + CASBaH: The Mass Dependence of H i Lyα–Galaxy Clustering and the Extent of the CGM

Authors :
Matthew C. Wilde
Kirill Tchernyshyov
Jessica K. Werk
Todd M. Tripp
Joseph N. Burchett
J. Xavier Prochaska
Nicolas Tejos
Nicolas Lehner
Rongmon Bordoloi
John M. O’Meara
Jason Tumlinson
J. Christopher Howk
Source :
The Astrophysical Journal, Vol 948, Iss 2, p 114 (2023)
Publication Year :
2023
Publisher :
IOP Publishing, 2023.

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.

Details

Language :
English
ISSN :
15384357
Volume :
948
Issue :
2
Database :
Directory of Open Access Journals
Journal :
The Astrophysical Journal
Publication Type :
Academic Journal
Accession number :
edsdoj.9a8d954e82c5453e9042fea1021e8262
Document Type :
article
Full Text :
https://doi.org/10.3847/1538-4357/acc85b