Modeling galaxy cluster triaxiality in stacked cluster weak lensing analyses
[1];
[2];
[3];
[4];
[6];
[9];
[10];
- University of Chicago, IL (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
- Boise State University, ID (United States)
- Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
- Stanford University, CA (United States)
- Stanford University, CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- University of Trieste (Italy); INAF-Osservatorio Astronomico di Trieste, Trieste (Italy); Institute for Fundamental Physics of the Universe, Trieste (Italy)
- Stanford University, CA (United States). Kavli Institute for Particle Astrophysics & Cosmology; SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- University of Chicago, IL (United States)
- Santa Cruz Institute for Particle Physics , Santa Cruz, CA (United States)
- University of Michigan, Ann Arbor, MI (United States)
- University of Arizona, Tucson, AZ (United States)
Counts of galaxy clusters offer a high-precision probe of cosmology, but control of systematic errors will determine the accuracy of this measurement. Using Buzzard simulations, we quantify one such systematic, the triaxiality distribution of clusters identified with the redMaPPer optical cluster finding algorithm, which was used in the Dark Energy Survey Year-1 (DES Y1) cluster cosmology analysis. We test whether redMaPPer selection biases the clusters’ shape and orientation and find that it only biases orientation, preferentially selecting clusters with their major axes oriented along the line of sight. Modeling the richness–mass relation as log-linear, we find that the log-richness amplitude ln (A) is boosted from the lowest to highest orientation bin with a significance of 14σ, while the orientation dependence of the richness-mass slope and intrinsic scatter is minimal. We also find that the weak lensing shear-profile ratios of cluster-associated dark halos in different orientation bins resemble a “bottleneck” shape that can be quantified with a Cauchy function. We test the correlation of orientation with two other leading systematics in cluster cosmology—miscentering and projection—and find a null correlation. The resulting mass bias predicted from our templates confirms the DES Y1 finding that triaxiality is a leading source of bias in cluster cosmology. However, the richness-dependence of the bias confirms that triaxiality does not fully resolve the tension at low-richness between DES Y1 cluster cosmology and other probes. Therefore our model can be used for quantifying the impact of triaxiality bias on cosmological constraints for upcoming weak lensing surveys of galaxy clusters.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Grant/Contract Number:
- AC02-07CH11359; AC02-05CH11231
- OSTI ID:
- 1854863
- Report Number(s):
- FERMILAB-PUB-22-085-PPD; arXiv:2202.08211; oai:inspirehep.net:2033847
- Journal Information:
- Monthly Notices of the Royal Astronomical Society, Vol. 523, Issue 2; ISSN 0035-8711
- Publisher:
- Oxford University PressCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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