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This content will become publicly available on November 23, 2018

Title: Intrinsic alignment in redMaPPer clusters – II. Radial alignment of satellites towards cluster centres

We study the orientations of satellite galaxies in redMaPPer clusters constructed from the Sloan Digital Sky Survey at 0.1 < z < 0.35 to determine whether there is any preferential tendency for satellites to point radially towards cluster centres. Here, we analyse the satellite alignment (SA) signal based on three shape measurement methods (re-Gaussianization, de Vaucouleurs, and isophotal shapes), which trace galaxy light profiles at different radii. The measured SA signal depends on these shape measurement methods. We detect the strongest SA signal in isophotal shapes, followed by de Vaucouleurs shapes. While no net SA signal is detected using re-Gaussianization shapes across the entire sample, the observed SA signal reaches a statistically significant level when limiting to a subsample of higher luminosity satellites. We further investigate the impact of noise, systematics, and real physical isophotal twisting effects in the comparison between the SA signal detected via different shape measurement methods. Unlike previous studies, which only consider the dependence of SA on a few parameters, here we explore a total of 17 galaxy and cluster properties, using a statistical model averaging technique to naturally account for parameter correlations and identify significant SA predictors. We find that the measured SA signal ismore » strongest for satellites with the following characteristics: higher luminosity, smaller distance to the cluster centre, rounder in shape, higher bulge fraction, and distributed preferentially along the major axis directions of their centrals. Finally, we provide physical explanations for the identified dependences and discuss the connection to theories of SA.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States). McWilliams Center for Cosmology, Dept. of Physics
  2. Carnegie Mellon Univ., Pittsburgh, PA (United States). McWilliams Center for Cosmology, Dept. of Physics; Carnegie Mellon Univ., Pittsburgh, PA (United States). McWilliams Center for Cosmology, Dept. of Statistics
  3. Univ. of Washington, Seattle, WA (United States). Dept. of Statistics
  4. Univ. of Arizona, Tucson, AZ (United States). Dept. of Physics
  5. SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-76SF00515; AST-1313169
Type:
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 474; Journal Issue: 4; Journal ID: ISSN 0035-8711
Publisher:
Royal Astronomical Society
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF); National Aeronautic and Space Administration (NASA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: clusters: general; large-scale structure of Universe
OSTI Identifier:
1423518