CGM${}^2$ $+$ CASBaH: The Mass Dependence of H~I Ly$\alpha$-Galaxy Clustering and the Extent of the CGM

Abstract

We combine datasets from the CGM${}^2$ and CASBaH surveys to model a transition point, $R_{\mathrm{cross}}$, 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$\alpha$. Our best-fitting model is an exclusionary 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 $R_{\mathrm{cross}}$ as a function of galaxy stellar mass, which can be interpreted as the boundary between the CGM and IGM. For galaxies with $10^8\le M_{\star }/M_{\odot }\le 10^{10.5}$, we find that $R_{\mathrm{cross}}(M_{\star })\approx 2\pm 0.6R_{\mathrm{vir}}$. Additionally, we find excellent agreement between $R_{\mathrm{cross}}(M_{\star })$ 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 $T\approx 10^4$K gas to distances beyond the virial radius.

Submitted to ApJ, 17 pages, 8 figures

References in corpus (27)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Simba: Cosmological Simulations with Black Hole Growth and Feedback
• The Circumgalactic Medium
• The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-Redshift Circumgalactic Medium
• Rotation-Dependent Catastrophic Disruption of Gravitational Aggregates
• The COS-Halos Survey: Metallicities in the Low-Redshift Circumgalactic Medium
• A High-Resolution Survey of Low-Redshift QSO Absorption Lines: Statistics and Physical Conditions of O VI Absorbers
• The COS-Dwarfs Survey: The Carbon Reservoir Around sub-L* Galaxies
• Splashback in accreting dark matter halos
• The pseudo-evolution of halo mass
• Quasars Probing Quasars II: The Anisotropic Clustering of Optically Thick Absorbers around Quasars
• Characterizing the UV-to-NIR shape of the dust attenuation curve of IR luminous galaxies up to z$\sim$2
• The Impact of Cosmic Rays on Thermal Instability in the Circumgalactic Medium
• The CAMELS Multifield Dataset: Learning the Universe's Fundamental Parameters with Artificial Intelligence
• CGM${}^2$ I: The Extent of the Circumgalactic Medium Traced by Neutral Hydrogen
• The splashback boundary of haloes in hydrodynamic simulations
• The Co-Evolution of Galaxies and the Cool Circumgalactic Medium Probed with the SDSS and DESI Legacy Imaging Surveys
• The COS Absorption Survey of Baryon Harbors: Unveiling the Physical Conditions of Circumgalactic Gas through Multiphase Bayesian Ionization Modeling
• Revealing the Dark Threads of the Cosmic Web
• Cross correlation of Lyman-alpha absorbers with gas-rich galaxies
• Environmental Dependence of Galactic Properties Traced by Ly$\alpha$ Forest Absorption: Diversity among Galaxy Populations
• The COS Absorption Survey of Baryon Harbors: The Galaxy Database and Cross-Correlation Analysis of OVI Systems
• The Bimodal Absorption System Imaging Campaign (BASIC) I. A Dual Population of Low-metallicity Absorbers at z $<1$
• The evolution of the low-density HI intergalactic medium from z=3.6 to 0: Data, transmitted flux and HI column density
• On the relation between Lya absorbers and local galaxy filaments
• Constraints on precipitation-limited hot halos from massive galaxies to galaxy clusters
• How are Lyman $\alpha$ absorbers in the cosmic web related to gas-rich galaxies?

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