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Forward modeling of a multi-tracer cosmological survey

Grant number: 19/01631-0
Support type:Scholarships in Brazil - Master
Effective date (Start): May 01, 2019
Effective date (End): February 28, 2021
Field of knowledge:Physical Sciences and Mathematics - Astronomy - Extragalactic Astrophysics
Principal Investigator:Luis Raul Weber Abramo
Grantee:Francisco Germano Maion
Home Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil


The great question of modern cosmology is the source of cosmic acceleration: is it some new form of matter/energy, called dark energy? Or is it due to some modification in the laws of gravity? The large investment in new astronomical instruments has been fueling a dramatic growth in the quantity and quality of cosmological data. However, the richness and complexity of that data demands new ideas, tools and methods with which we can extract meaningful information from the observations. The goal of this project is to perform the forward modeling of a cosmological survey, from the basic properties of the galaxy catalog to the extraction of cosmological parameters from multiple populations of different tracers of large-scale structure. This effort will take into account mainly the uncertainties in the selection and classification of objects (star/galaxy/quasar separation), in the photometric redshifts (for imaging surveys), and in the selection function. The main application will be for the J-PAS survey, which depends on ``pseudo-spectra'' (imaging in narrow-band filters) in order to classify objects and to obtain estimates of the redshifts. This new type of data means that J-PAS will deliver a catalog of probabilities that each individual object is of a certain type, and within each type, a probability distribution function for its photometric redshift. The consequences of such a new dataset for cosmology are unknown -- and this is what we want to explore, in particular as it pertains the detection of baryon acoustic oscillations and redshift-space distortions.