Galaxy clusters and protoclusters at HSC-SSP survey: a catalog of targets for PFS up to z < 2

• Grant number: 22/11456-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: March 01, 2023
• End date: February 29, 2024
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Extragalactic Astrophysics
• Principal Investigator: Laerte Sodré Junior
• Grantee: Marcelo Ciani Vicentin
• Supervisor: Michael Abram Strauss
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Princeton University, United States
• Associated to the scholarship: 21/06590-0 - GALAXY CLUSTERS AND PROTOCLUSTERS AT HSC-SSP SURVEY: A CATALOG OF TARGETS FOR PFS UP TO z ~ 2, BP.DR

Abstract

We plan to perform systematic searches in the Hyper Suprime-Cam – Subaru Strategic Program (HSC-SSP) data for clusters and protoclusters of galaxies at 0< z r 2. Our strategy consists of extensive use of realistic mock data to validate selection criteria and tuning probabilistic model parameters in order to calculate the probability of a given galaxy being the cluster's dominant one (BCG) and, sub-sequently, to determine which galaxies are the probable cluster members. We will use deep learning techniques to estimate the photometric redshifts and local density measurements to calculate the likelihood of a galaxy being the BCG. The cluster candidates obtained by this cluster finder will serve as an ancillary database to select targets for the Prime Focus Spectrograph (PFS) Subaru Strategic Program, which will start its operations in 2023. In this BEPE, we are proposing a one-year (2023) internship in one of the main institutions of the PFS collaboration, the Princeton University, NJ, USA. The student will work at the Department of Astrophysical Sciences under the supervision of Professor Michael Strauss, an experienced researcher worldwide recognized for his contributions in extragalactic astrophysics and observational cosmology, who is also a member of the PFS's steering committee together with Professor Laerte Sodré Jr. The Princeton's Department of Astrophysical Sciences has several Professors and post-docs that are deeply involved preparing PFS, what will offer a unique opportunity of interaction with these researchers. By the date of travel, we plan to have a working prototype of the cluster finder algorithm. In this way, the student will initially focus on presenting the methods and preliminary results to the Princeton collaborators, who will be able to evaluate and point out possible improvements in the algorithm. This interplay should lead to specific gains, such as the joint elaboration of methods to find galaxy cluster candidates and their physical characterization, and also general gains, such as the strengthening of the Brazilian participation in the PSF science and a greater approximation between IAG/USP and Princeton's Department of Astrophysical Sciences. (AU)