Multi-probe analysis of high resolution observations of galaxy clusters by the NIKA camera
Résumé
Thermal Sunyaev-Zeldovich effect (tSZ) is a powerful probe that has been proved to be complementary with respect to traditional observables (e.g. X-ray, optical) used for cluster astrophysics characterization. Previous arcmin resolution tSZ observations (e.g. SPT, ACT and Planck) only allowed detailed studies of the intracluster medium (ICM) morphology for low redshift clusters (z < 0.2). Thus, the development of precision cosmology with clusters requires high angular resolution observations to extend the understanding of galaxy cluster towards high redshift. NIKA2 is a wide-field (6.5 arcmin field of view) dual-band camera, installed on the IRAM 30-m telescope and containing ~ 3300 KIDs (Kinetic Inductance Detectors), designed to observe the millimeter sky at 150 and 260 GHz, with an angular resolution of 18 and 12 arcsec respectively.
As a pathfinder for NIKA2, several galaxy clusters have already been observed with the NIKA prototype to cover the various observation conditions expected for NIKA2. Statistical methods have been developed to reduce the raw data and characterize the different systematics coming from point source contamination, atmospheric noise subtraction, etc. One of the NIKA2 data analysis challenges is the characterization of the observed clusters ICM astrophysics using multi-probe statistical analysis (e.g. MCMC) and appropriate ICM descriptions beyond the standard halo model.
I will focus on the analysis of recent tSZ observations with the NIKA prototype and present the forthcoming tSZ large program with the NIKA2 camera.