Galaxy alignment as a probe of large-scale filaments

Abstract

The orientations of the red galaxies in a filament are aligned with the orientation of the filament. We thus develop a location-alignment-method (LAM) of detecting filaments around clusters of galaxies, which uses both the alignments of red galaxies and their distributions in two-dimensional images. For the first time, the orientations of red galaxies are used as probes of filaments. We apply LAM to the environment of Coma cluster, and find four filaments (two filaments are located in sheets) in two selected regions, which are compared with the filaments detected with the method of \cite{Falco14}. We find that LAM can effectively detect the filaments around a cluster, even with $3\sigma$ confidence level, and clearly reveal the number and overall orientations of the detected filaments. LAM is independent of the redshifts of galaxies, and thus can be applied at relatively high redshifts and to the samples of red galaxies without the information of redshifts. We also find that the images of background galaxies (interlopers) which are lensed by the gravity of foreground filaments are amplifiers to probe the filaments.

11 pages, 11 figures. Accepted to MNRAS after moderate expansion to further strengthen the main conlusions of the previous version

References in corpus (9)

• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• Properties of Dark Matter Haloes in Clusters, Filaments, Sheets and Voids
• The Evolution of Dark Matter Halo Properties in Clusters, Filaments, Sheets and Voids
• Spin alignment of dark matter haloes in filaments and walls
• The alignment of satellite galaxies and cosmic filaments: observations and simulations
• Filaments from the galaxy distribution and from the velocity field in the local universe
• The Variation of Galaxy Morphological Type with the Shear of Environment
• A New Dynamical Mass Measurement for the Virgo Cluster using the Radial Velocity Profile of the Filament Galaxies
• Statistical properties of filaments in weak gravitational lensing

Cited by in corpus (11)

• From voids to filaments: environmental transformations of galaxies in the SDSS
• Alignment of galaxies relative to their local environment in SDSS-DR8
• Intrinsic alignments in redMaPPer clusters -- I. Central galaxy alignments and angular segregation of satellites
• On the relative effect of nodes and filaments of the cosmic web on the quenching of galaxies and the orientation of their spin
• Wide-Field Optical Spectroscopy of Abell 133: A Search for Filaments Reported in X-ray Observations
• Intrinsic Morphology of Ultra-diffuse Galaxies
• Properties of brightest group galaxies in cosmic web filaments
• The complex case of MACSJ0717.5+3745 and its extended filament: intra-cluster light, galaxy luminosity function, and galaxy orientations
• Exploring the origin of ultra-diffuse galaxies in clusters from their primordial alignment
• Distinguishing cosmologies using the turn-around radius near galaxy clusters
• The Next Generation Fornax Survey (NGFS): VI. The Alignment of Dwarf Galaxies in The Fornax Cluster