Weighing Galaxy Clusters with Weak Lensing in Hyper Suprime-Cam Survey
Elinor Medezinski (Princeton)
Abstract:
The most fundamental question in observational cosmology today is what
is the nature of dark energy and dark matter. Clusters of galaxies
serve as beacons to the growth of structure over cosmic scales, making
them a sensitive cosmological tool. However, accurately measuring
their masses has been notoriously difficult. Weak lensing provides the
best direct probe of the cluster mass, both the baryonic and dark
components, but it requires high-quality wide-field imaging and
careful control of systematics. With its unprecedentedly deep and
exquisite seeing, the Subaru Hyper Suprime-Cam (HSC) survey is an
ongoing campaign to observe 1,400 square degrees to r~26, providing
the closest precursor to LSST. In this talk, I will present our new
field-leading results from the first HSC data release of ~150 square
degrees that encompass thousands of clusters. Harnessing our new HSC
survey, I measure benchmark weak lensing cluster masses with improved
methodology, and reconcile previous tension on cosmological parameters
between the SZ and CMB within the Planck survey. In the next decade,
LSST and WFIRST will discover hundreds of thousands of galaxy
clusters, peering deep to the epoch of formation. I will describe
these surveys and the multifold breakthrough science we will achieve
in the new era of astronomy.