Gaia Space Mission:preparation and scientific exploration

• Grant number: 23/12426-4
• Support Opportunities: Regular Research Grants
• Start date: January 01, 2024
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Positional Astronomy and Celestial Mechanics
• Principal Investigator: Ramachrisna Teixeira
• Grantee: Ramachrisna Teixeira
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This project comprises the continuity of distinct but related works that can be separated in two topics: 1- my participation in what we call preparation of the Gaia Space Mission which is carried out within the scope of Gaia - Data Processing and Analysis Consortium (Gaia - DPAC), more precisely in the Extended Objects (EO) group of which I am one of the founders; 2 - scientific exploration of Gaia data associated with others produced by the Gaia Gravitational Lenses group (Gaia GraL) and literature data.My participation in the Gaia - DPAC started in 2011 with the creation of "Gaia Extended Objects - EO" group. Here, we seek to take advantage of the detections of galaxies by the Gaia satellite, including those that host quasars, to determine their brightness profiles and we also study the sky surroundings of quasars that have already been confirmed or not. This study should allow us to recover components of gravitational lenses filtered in the "Gaia data releases" and the definition of probable candidates for gravitational lenses researches. In the last data release, Gaia DR3 - June 2022, we published our first results: brightness profiles for 800,000 galaxies, treatment of 60,000 quasar host galaxies with brightness profiles for 15,000 of them.Considering the scientific exploration of Gaia data and other data, I am a member and I was one of the founders of the Gaia GraL group. This group, involving researchers from various parts of the world, was constituted with the primary purpose of building a survey of strong gravitational lenses of quasars across the whole sky with an unprecedented resolution of 180 mas. The first step of this work consists of elaborating, based on Gaia astrometry and other data both from Gaia and from the literature, lists of candidates to be, later, observed spectroscopically, aiming to their confirmation or not. Up to date, of the 399 known strong gravitational lenses of quasars, 84 have been discovered by us in various telescopes around the world: 18 out of a total of 81 with four components and 66 out of 318 with two components. More recently, on an observational mission at NTT/ESO - August/23, we roughly confirmed 7 to 9 new lenses. These data still need be analyzed more rigorously. Naturally, the scientific exploration of these lenses is also on the horizon of the Gaia GraL group, but not necessarily within the scope of this project. On the other hand, the abundance and the quality of the data from the Gaia satellite also led me to make efforts towards the segregation of stellar population in some regions of the Galaxy and thus a richer characterization and a better understanding of its structure and formation. (AU)