Weak Gravitational Lensing in Archival Subaru Telescope Data

8-m single-mirror telescope on Mauna Kea, HI.

Weak lensing measurements of low-mass clusters are more numerous and provide a less biased measurement of large-scale clustering, however they require imagers capable of reaching faint and small galaxies. My work utilizes the large amount of deep and excellent-seeing imaging freely available from Subaru’s Suprime-Cam to probe over 12 sq-deg of the sky at high source density. Dozens of cluster candidates were identified for the first time, and many others only previously seen through non-lensing techniques performed in the same fields, were cross-checked against our analysis.

The scale of this project necessitated the invention of numerous automated data reduction algorithms, and a comprehensive pipeline optimizing the shape and size distributions of deep-field galaxies in available fields. Most notably, a novel brightness-independent identification system for stars was created in order to find ideal stellar objects necessary for accurate PSF circularization, which, to process a large data volume, and deal with wide, variant expanses of the sky in a single exposure, required no human input. Selected clusters were also chosen out of this dataset for deeper 2D mass reconstruction and analysis, and multiple hitherto unknown strong lenses were identified.

Areas of the sky examined in my thesis.

Ryan Michney

Barus & Holley Building
Room 717