Open AccessMeasuring the galaxy–galaxy‐mass three‐point correlation function with weak gravitational lensing
Author(s) -
Johnston David E.
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10011.x
Subject(s) - physics , astrophysics , weak gravitational lensing , galaxy , interacting galaxy , gravitational lens , astronomy , lenticular galaxy , mass distribution , galaxy merger , dark matter , brightest cluster galaxy , galaxy formation and evolution , redshift
ABSTRACT We discuss the galaxy–galaxy‐mass three‐point correlation function (GGM3PCF) and show how to measure it with weak gravitational lensing. The method entails choosing a large number of pairs of foreground lens galaxies and constructing a mean shear map with respect to their axes, by averaging the ellipticities of background source galaxies. An average mass map can be reconstructed from this shear map and this will represent the average mass distribution around pairs of galaxies. We show how this mass map is related to the projected GGM3PCF. Using a large N ‐body dark matter simulation populated with galaxies using the halo occupation distribution bias prescription, we compute these correlation functions, mass maps, and shear maps. The resultant mass maps are distinctly bimodal, tracing the galaxy centres and remaining anisotropic up to scales much larger than the galaxy separation. We estimate the signal‐to‐noise ratio of the reconstructed mass maps for a survey of depth similar to the Sloan Digital Sky Survey (SDSS) and conclude that the GGM3PCF should be measurable with the current SDSS weak‐lensing data. Measurements of this three‐point function, along with galaxy–galaxy lensing and galaxy auto‐correlation functions, will provide new constraints on galaxy bias models.