2023/07/03 by Fiona McCarthy, McCarthy, Fiona, J. Colin Hill +1 · 5 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Dark Matter and Cosmic Phenomena #FOS: Physical sciences
paper · pdf · doi:10.48550/arxiv.2307.01043
openalex publication_date 2023/07/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We use the full-mission Planck PR4 data to construct maps of the thermal Sunyaev--Zel'dovich effect (Compton-y parameter) in our Universe. To do so, we implement a custom needlet internal linear combination (NILC) pipeline in a Python package, pyilc, which we make publicly available. We publicly release our Compton-y maps, which we construct using various constrained ILC ("deprojection") options in order to minimize contamination from the cosmic infrared background (CIB) in the reconstructed signal. In particular, we use a moment-based deprojection which minimizes sensitivity to the assumed frequency dependence of the CIB. Our code pyilc performs needlet or harmonic ILC on mm-wave sky maps in a flexible manner, with options to deproject various components on all or some scales. We validate our maps and compare them to the official Planck 2015 y-map, finding that we obtain consistent results on large scales and 10-20% lower noise on small scales. We expect that these maps will be useful for many auto- and cross-correlation analyses; in a companion paper, we use them to measure the tSZ -- CMB lensing cross-correlation. We anticipate that pyilc will be useful both for data analysis and for pipeline validation on simulations to understand the propagation of foreground components through a full NILC pipeline.
pyilc