TY - JOUR
T1 - The ellipticity of galaxy cluster haloes from satellite galaxies and weak lensing
AU - Shin, Tae Hyeon
AU - Clampitt, Joseph
AU - Jain, Bhuvnesh
AU - Bernstein, Gary
AU - Neil, Andrew
AU - Rozo, Eduardo
AU - Rykoff, Eli
N1 - Funding Information:
Wewould like to thank Eric Baxter, Joe DeRose, Ian Dell'Anotonio, Daniel Gruen, Hung-Jin Huang, Benjamin Joachimi, Andrey Kravtsov, Rachel Mandelbaum, Surhud More, Yuedong Fang, Mike Jarvis, Masahiro Takada, Joop Schaye, Frank van den Bosch, Mark Vogelsberger, Anja von der Linden, and Risa Wechsler for helpful discussions. We are very grateful to Erin Sheldon for allowing us to use his SDSS shear catalogues and source photometric redshift distributions. J.C., B.J., and G.B. are partially supported by the US Department of Energy grant DE-SC0007901 and funds from the University of Pennsylvania.
PY - 2018/4/1
Y1 - 2018/4/1
N2 - We study the ellipticity of galaxy cluster haloes as characterized by the distribution of cluster galaxies and as measured with weak lensing. We use Monte Carlo simulations of elliptical cluster density profiles to estimate and correct for Poisson noise bias, edge bias and projection effects. We apply our methodology to 10 428 Sloan Digital Sky Survey clusters identified by the redMaPPer algorithm with richness above 20.We find a mean ellipticity=0.271 ± 0.002 (stat) ±0.031 (sys) corresponding to an axis ratio = 0.573 ± 0.002 (stat) ±0.039 (sys).We compare this ellipticity of the satellites to the halo shape, through a stacked lensing measurement using optimal estimators of the lensing quadrupole based on Clampitt and Jain (2016). We find a best-fitting axis ratio of 0.56 ± 0.09 (stat) ±0.03 (sys), consistent with the ellipticity of the satellite distribution. Thus, cluster galaxies trace the shape of the dark matter halo to within our estimated uncertainties. Finally, we restack the satellite and lensing ellipticity measurements along the major axis of the cluster central galaxy's light distribution. From the lensing measurements, we infer a misalignment angle with an root-mean-square of 30° ± 10° when stacking on the central galaxy. We discuss applications of halo shape measurements to test the effects of the baryonic gas and active galactic nucleus feedback, as well as dark matter and gravity. The major improvements in signal-to-noise ratio expected with the ongoing Dark Energy Survey and future surveys from Large Synoptic Survey Telescope, Euclid, and Wide Field Infrared Survey Telescope will make halo shapes a useful probe of these effects.
AB - We study the ellipticity of galaxy cluster haloes as characterized by the distribution of cluster galaxies and as measured with weak lensing. We use Monte Carlo simulations of elliptical cluster density profiles to estimate and correct for Poisson noise bias, edge bias and projection effects. We apply our methodology to 10 428 Sloan Digital Sky Survey clusters identified by the redMaPPer algorithm with richness above 20.We find a mean ellipticity=0.271 ± 0.002 (stat) ±0.031 (sys) corresponding to an axis ratio = 0.573 ± 0.002 (stat) ±0.039 (sys).We compare this ellipticity of the satellites to the halo shape, through a stacked lensing measurement using optimal estimators of the lensing quadrupole based on Clampitt and Jain (2016). We find a best-fitting axis ratio of 0.56 ± 0.09 (stat) ±0.03 (sys), consistent with the ellipticity of the satellite distribution. Thus, cluster galaxies trace the shape of the dark matter halo to within our estimated uncertainties. Finally, we restack the satellite and lensing ellipticity measurements along the major axis of the cluster central galaxy's light distribution. From the lensing measurements, we infer a misalignment angle with an root-mean-square of 30° ± 10° when stacking on the central galaxy. We discuss applications of halo shape measurements to test the effects of the baryonic gas and active galactic nucleus feedback, as well as dark matter and gravity. The major improvements in signal-to-noise ratio expected with the ongoing Dark Energy Survey and future surveys from Large Synoptic Survey Telescope, Euclid, and Wide Field Infrared Survey Telescope will make halo shapes a useful probe of these effects.
KW - Dark matter
KW - Galaxies: clusters: general
KW - Galaxies: haloes
KW - Gravitational lensing: weak
KW - Large-scale structure of Universe
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U2 - 10.1093/mnras/stx3366
DO - 10.1093/mnras/stx3366
M3 - Article
AN - SCOPUS:85045896301
VL - 475
SP - 2421
EP - 2437
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -