Constraining the scatter in the galaxy-halo connection at Milky Way masses

Abstract

We develop and implement two new methods for constraining the scatter in the relationship between galaxies and dark matter halos. These new techniques are sensitive to the scatter at low halo masses, making them complementary to previous constraints that are dependent on clustering amplitudes or rich galaxy groups, both of which are only sensitive to more massive halos. In both of our methods, we use a galaxy group finder to locate central galaxies in the SDSS main galaxy sample. Our first technique uses the small-scale cross-correlation of central galaxies with all lower mass galaxies. This quantity is sensitive to the satellite fraction of low-mass galaxies, which is in turn driven by the scatter between halos and galaxies. The second technique uses the kurtosis of the distribution of line-of-sight velocities between central galaxies and neighboring galaxies. This quantity is sensitive to the distribution of halo masses that contain the central galaxies at fixed stellar mass. Theoretical models are constructed using peak halo circular velocity, $V_{\mathrm{peak}}$, as our property to connect galaxies to halos. The cross-correlation technique yields a constraint of $\sigma [M_{\ast }|V_{\mathrm{peak}}]=0.27\pm 0.05$ dex, corresponding to a scatter in $\log M_{\ast }$ at fixed $M_h$ of $\sigma [M_{\ast }|M_h]=0.38\pm 0.06$ dex at $M_h=10^{11.8}$ Msun. The kurtosis technique yields $\sigma [M_{\ast }|V_{\mathrm{peak}}]=0.30\pm 0.03$, corresponding to $\sigma [M_{\ast }|M_h]=0.34\pm 0.04$ at $M_h=10^{12.2}$ Msun. The values of $\sigma [M_{\ast }|M_h]$ are significantly larger than the constraints at higher masses, in agreement with the results of hydrodynamic simulations. This increase is only partly due to the scatter between $V_{\mathrm{peak}}$ and $M_h$, and it represents an increase of nearly a factor of two relative to the values inferred from clustering and group studies at high masses.

14 pages, 13 figures, submitted to MNRAS

References in corpus (10)

• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• The DESI Experiment Part I: Science,Targeting, and Survey Design
• PRIMUS: Constraints on Star Formation Quenching and Galaxy Merging, and the Evolution of the Stellar Mass Function From z=0-1
• On the galaxy stellar mass function, the mass-metallicity relation, and the implied baryonic mass function
• Assessing Colour-dependent Occupation Statistics Inferred from Galaxy Group Catalogues
• Velocity distributions in clusters of galaxies
• Comparing galaxy formation in semi-analytic models and hydrodynamical simulations
• Are Halo and Galaxy Formation Histories Correlated?
• Testing Galaxy Quenching Theories with Scatter in the Stellar to Halo Mass Relation
• RedMaPPer: Evolution and Mass Dependence of the Conditional Luminosity Functions of Red Galaxies in Galaxy Clusters

Cited by in corpus (10)

• The SAGA Survey. II. Building a Statistical Sample of Satellite Systems around Milky Way-like Galaxies
• A Self-Calibrating Halo-Based Group Finder: Application to SDSS
• On the halo-mass and radial scale dependence of the lensing is low effect
• GAMA+KiDS: Empirical correlations between halo mass and other galaxy properties near the knee of the stellar-to-halo mass relation
• Hyper Suprime-Cam Low Surface Brightness Galaxies II: A Hubble Space Telescope Study of the Globular Cluster Systems of Ultra-Diffuse Galaxies in Groups
• Probing the galaxy-halo connection with total satellite luminosity
• A UNIONS view of the brightest central galaxies of candidate fossil groups
• Why do semi-analytic models predict higher scatter in the stellar mass-halo mass relation than cosmological hydrodynamic simulations?
• Galaxy assembly bias and large-scale distribution: a comparison between IllustrisTNG and a semi-analytic model
• Zangetsu: A Candidate of Isolated, Quiescent, and Backsplash Ultra-Diffuse Galaxy in the COSMOS Field