THE CLUSTERING CHARACTERISTICS OF H I-SELECTED GALAXIES FROM THE 40% ALFALFA SURVEY

• Published in: The Astrophysical journal Vol. 750; no. 1; pp. 1 - 11
• Main Authors: MARTIN, Ann M, GIOVANELLI, Riccardo, HAYNES, Martha P, GUZZO, Luigi
• Format: Journal Article
• Language: English
• Published: Bristol IOP 01.05.2012
• Subjects: Alfalfa; ASTRONOMY; ASTROPHYSICS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Clustering; COMPUTERIZED SIMULATION; Correlation analysis; CORRELATION FUNCTIONS; DISTANCE; Earth, ocean, space; Exact sciences and technology; GALACTIC EVOLUTION; GALAXIES; GALAXY CLUSTERS; Legacy; Mathematical models; Occupation; RED SHIFT; Small scale; UNIVERSE; Galaxy evolution; Red shift; galaxies: clusters: general; Function space; Galaxies; Radio galaxies; Covariance analysis; Estimator; surveys; Correlation functions; Large-scale structure; Galaxy clusters; radio lines: galaxies; galaxies: distances and redshifts; Astronomical catalogues; Cosmic radio sources; Models; Power law; large-scale structure of universe
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/750/1/38

The 40% Arecibo Legacy Fast ALFA survey catalog ( alpha .40) of ~10, 150 H I-selected galaxies is used to analyze the clustering properties of gas-rich galaxies. By employing the Landy-Szalay estimator and a full covariance analysis for the two-point galaxy-galaxy correlation function, we obtain the real-space correlation function and model it as a power law, [xi](r) = (r/r sub(0)) super(- gamma ), on scales <10 h super(-1) Mpc. As the largest sample of blindly H I-selected galaxies to date, alpha .40 provides detailed understanding of the clustering of this population. We find gamma = 1.51 + or - 0.09 and r sub(0) = 3.3 + 0.3, -0.2 h super(-1) Mpc, reinforcing the understanding that gas-rich galaxies represent the most weakly clustered galaxy population known; we also observe a departure from a pure power-law shape at intermediate scales, as predicted in [Lambda]CDM halo occupation distribution models. Furthermore, we measure the bias parameter for the alpha .40 galaxy sample and find that H I galaxies are severely antibiased on small scales, but only weakly antibiased on large scales. The robust measurement of the correlation function for gas-rich galaxies obtained via the alpha .40 sample constrains models of the distribution of H I in simulated galaxies, and will be employed to better understand the role of gas in environmentally dependent galaxy evolution.