Measurement of Galaxy Cluster Integrated Comptonization and Mass Scaling Relations with the South Pole Telescope

• Published in: The Astrophysical Journal
• Main Authors: Saliwanchik, B. R., Lueker, M., Padin, S., Shirokoff, E., Vieira, J. D.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Astronomical Society 2015
• Subjects: galaxies: clusters: general; methods: data analysis; X-rays: galaxies: clusters; Kavli; South Pole; South pole
• Online Access: https://doi.org/10.1088/0004-637X/799/2/137

We describe a method for measuring the integrated Comptonization (Y_(SZ)) of clusters of galaxies from measurements of the Sunyaev-Zel'dovich (SZ) effect in multiple frequency bands and use this method to characterize a sample of galaxy clusters detected in the South Pole Telescope (SPT) data. We use a Markov Chain Monte Carlo method to fit a β-model source profile and integrate Y_(SZ) within an angular aperture on the sky. In simulated observations of an SPT-like survey that include cosmic microwave background anisotropy, point sources, and atmospheric and instrumental noise at typical SPT-SZ survey levels, we show that we can accurately recover β-model parameters for inputted clusters. We measure Y_(SZ) for simulated semi-analytic clusters and find that Y_(SZ) is most accurately determined in an angular aperture comparable to the SPT beam size. We demonstrate the utility of this method to measure Y_(SZ) and to constrain mass scaling relations using X-ray mass estimates for a sample of 18 galaxy clusters from the SPT-SZ survey. Measuring Y_(SZ) within a 0.'75 radius aperture, we find an intrinsic log-normal scatter of 21% ± 11% in Y_(SZ) at a fixed mass. Measuring Y_(SZ) within a 0.3 Mpc projected radius (equivalent to 0.'75 at the survey median redshift z = 0.6), we find a scatter of 26% ± 9%. Prior to this study, the SPT observable found to have the lowest scatter with mass was cluster detection significance. We demonstrate, from both simulations and SPT observed clusters that Y_(SZ) measured within an aperture comparable to the SPT beam size is equivalent, in terms of scatter with cluster mass, to SPT cluster detection significance. © 2015 American Astronomical Society. Received 2013 December 10; accepted 2014 November 20; published 2015 January 22. The South Pole Telescope program is supported by the National Science Foundation through grant ANT-0638937. Partial support is also provided by the NSF Physics Frontier Center grant PHY-0114422 to the Kavli Institute of Cosmological Physics at the ...