General Information
Welcome to PhD in Astrophysics, Cosmology, and Gravitation (PPGCosmo) at Ufes
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In the context of relativistic astrophysics, our focus is to explore the properties of compact stars, such as neutron stars and white dwarfs, in scenarios of extreme gravity, rotation, and magnetism. We employ ray-tracing techniques in relativistic metrics to model the propagation of light and radiation around these objects, enabling a detailed analysis of phenomena such as gravitational lensing and the formation of multiple images. We also investigate the light curves resulting from electromagnetic emission, especially in situations modulated by rotation, matter accretion, and thermal pulses. With the advancement of detector sensitivity and the imminent arrival of new instruments for electromagnetic, gravitational wave, and ultra-high-energy particle observations, a new era of precise exploration of white dwarfs, neutron stars, and black holes is opening. This line of research is also dedicated to investigating fundamental questions of the new era of astronomy, including the presence of dark matter in galaxies, using rotation curves as the main observable. We also analyze small-scale anomalies, such as the cusp/core problem, missing satellites, and the "too big to fail" issue, as well as explore modified gravity models like MOND and TeVeS. On extragalactic scales, we study the dynamics of galaxies in clusters and the role of dark matter and dark energy in virialized structures, developing numerical and semi-analytical simulations for a deeper understanding of these phenomena. With multi-messenger astronomy, we have significantly advanced our understanding of gravitational waves, compact objects, and high-energy physics. Compact stars are established as ideal laboratories for investigating the micro and macrophysics of superdense matter. Multi-messenger observations, encompassing X-rays, gamma rays, radio waves, gravitational waves, and neutrinos, have been essential in expanding our understanding of the structure of these extreme objects. Since the discovery of pulsars, our understanding of these bodies has deepened, although many mysteries still persist. Pulsars remain fundamental for studying physics under extreme conditions, characterized by intense gravity, high magnetic fields, and elevated densities. Our project focuses on investigating the structure of compact stars, analyzing the effects of intense magnetic fields, high rotation, matter accretion, and electromagnetic counterparts of gravitational wave events. Our goal is to improve the understanding of the observed phenomenology and the theoretical mechanisms that underpin these extreme phenomena.
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In this line of research, we address the issues of dark matter and dark energy by investigating models of modified gravity, models with non-canonical scalar fields, backreaction models, interaction models in the dark sector, and unified dark matter/energy models. We seek to identify characteristic signatures for each class of these models and aim to discriminate between them using observational data. The goal is to obtain more robust evidence regarding the nature of dark matter and dark energy. The tests of theoretical cosmological models using the different available observational data include the CMB, the correlation of large-scale structures, weak lensing, and correlations between these observables. The analysis of modified gravity theories encompasses Horndeski gravity, f(R) theories, non-conservative theories, and gravitational models with torsion and Weyl gravity. This research line also involves studying cosmological inflation and its observational signatures in the CMB. In particular, we investigate extensions of the Starobinsky model and Linde’s alpha-attractors. Besides inflation models, we are also interested in scenarios where there is no singularity (Big Bang), but rather a bounce (bouncing universe). In this case, we focus on predictions for scalar and tensor spectra, non-Gaussianities, and their imprints on the cosmic microwave background, as well as the production of primordial particles and magnetic fields during the bounce.
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This line of research encompasses general relativity, extensions of general relativity, and quantum effects in gravitation. Among the extensions of general relativity of interest are scalar-tensor theories, theories that violate the usual conservation of the energy-momentum tensor, unimodular gravity, and other more complex approaches. The study of quantum effects in gravitation is motivated by quantum field theory in curved spacetimes, quantum gravity, or different interpretations of quantum mechanics. The developments considered range from more theoretical aspects, focused on foundations and the search for new solutions, to tests using post-Newtonian expansions in the solar system or beyond, gravitational waves, and observational data from neutron stars and black holes. Active participation in international gravitational wave collaborations, particularly LIGO-Virgo-KAGRA and the Einstein Telescope, is also highlighted.
This international PhD program in Astrophysics, Cosmology, and Gravitation (PPGCosmo) aims to offer PhD students the opportunity to develop a successful scientific career on the international stage.
The research topics cover both theoretical and observational aspects of Astrophysics, Cosmology, and Gravitation, including participation in international collaborations such as LIGO, VIRGO, Einstein Telescope, J-PAS, Euclid, LSST, Pierre Auger Observatory, SWGO, and CTA. More information is available here.
PPGCosmo is the first Physics PhD program to receive an initial rating of 5 from the Brazilian agency CAPES.
The program is based in Vitória-ES, offering the course of PhD in Astrophysics, Cosmology e and Gravitation since 2016 and has an academic qualification profile certified by CAPES, receiving 5 on its last evaluation.
The program already has 15 doctors and counts with 27 students regularly enrolled, all being in the doctorate.
