TY - JOUR
T1 - The intrinsic alignment of galaxy clusters and impact of projection effects
AU - Shi, Jingjing
AU - Sunayama, Tomomi
AU - Kurita, Toshiki
AU - Takada, Masahiro
AU - Sugiyama, Sunao
AU - Mandelbaum, Rachel
AU - Miyatake, Hironao
AU - More, Surhud
AU - Nishimichi, Takahiro
AU - Johnston, Harry
N1 - Publisher Copyright:
© The Author(s) 2024.
PY - 2024/2/1
Y1 - 2024/2/1
N2 - Galaxy clusters, being the most massive objects in the Universe, exhibit the strongest alignment with the large-scale structure. However, mis-identification of members due to projection effects from the large-scale structure can occur. We studied the impact of projection effects on the measurement of the intrinsic alignment of galaxy clusters, using galaxy cluster mock catalogues. Our findings showed that projection effects result in a decrease of the large-scale intrinsic alignment signal of the cluster and produce a bump at rp ∼ 1 h-1 Mpc, most likely due to interlopers and missed member galaxies. This decrease in signal explains the observed similar alignment strength between bright central galaxies and clusters in the SDSS redMaPPer cluster catalogue. The projection effect and cluster intrinsic alignment signal are coupled, with clusters having lower fractions of missing members or having higher fraction of interlopers exhibiting higher alignment signals in their projected shapes. We aim to use these findings to determine the impact of projection effects on galaxy cluster cosmology in future studies.
AB - Galaxy clusters, being the most massive objects in the Universe, exhibit the strongest alignment with the large-scale structure. However, mis-identification of members due to projection effects from the large-scale structure can occur. We studied the impact of projection effects on the measurement of the intrinsic alignment of galaxy clusters, using galaxy cluster mock catalogues. Our findings showed that projection effects result in a decrease of the large-scale intrinsic alignment signal of the cluster and produce a bump at rp ∼ 1 h-1 Mpc, most likely due to interlopers and missed member galaxies. This decrease in signal explains the observed similar alignment strength between bright central galaxies and clusters in the SDSS redMaPPer cluster catalogue. The projection effect and cluster intrinsic alignment signal are coupled, with clusters having lower fractions of missing members or having higher fraction of interlopers exhibiting higher alignment signals in their projected shapes. We aim to use these findings to determine the impact of projection effects on galaxy cluster cosmology in future studies.
KW - cosmology: observations
KW - cosmology: theory
KW - galaxies: clusters: general
KW - large-scale structure of Universe
UR - http://www.scopus.com/inward/record.url?scp=85184145726&partnerID=8YFLogxK
U2 - 10.1093/mnras/stae064
DO - 10.1093/mnras/stae064
M3 - Article
AN - SCOPUS:85184145726
SN - 0035-8711
VL - 528
SP - 1487
EP - 1499
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -