Center for Radio Astronomy and Astrophysics at Mackenzie

CRAAM

Main Areas

Studies of physical mechanisms of acceleration of particles to high energies in accelerators and in magnetoactive solar plasmas. Mechanisms of solar wind acceleration, kinetic evolution of these plasmas and effects of charged dust particles on the propagation of electromagnetic waves in the interplanetary environment.

Theoretical studies of mechanisms of electron and positron production during high energy nuclear processes and their possible contribution to the radiation spectrum of solar flares, particularly in the sub-millimeter range (THz frequencies). Non-perturbative renormalization methods and effective theories for nuclear forces. Theoretical studies of properties and mechanisms of elementary particle production in collisions of relativistic heavy ions and in processes involving cosmic rays, aiming to describe the formation and evolution of thermodynamics and hydrodynamics of the matter produced in nuclear reactions at high energies. These studies are particularly relevant for the proposition, analysis, and understanding of signatures of (new) states of matter that are believed to be important phases in the process of evolution of the primordial universe, such as quarks and gluons plasma and color glass condensate.

Searches for active galaxies and quasars. Variability of signals from quasars and active nuclei of galaxies through the radio waves they emit. Diagnostics and models testing. Investigation of rapid variations of brightness and superluminal motion in these objects and their association to plasma jets with speeds very close to that of light. Identification of spatial structures of quasars that can serve as reference for VLBI-geodesic, and their applications in the monitoring of the rotation of the Earth and impact in spatial geodesy.

Stellar activity and extrasolar planets

Stars other than the Sun also have spots, which are regions of high intensity magnetic fields. Using planetary transits observations of satellites such as CoRoT and Kepler it is possible to infer the properties of these spots like position, size, temperature and magnetic field. Currently we believe that most solar-type stars have planets around them.

More than 3600 planets are known today and of these approximately 75% eclipse their host star. When passing in front of the star, the planet may occult a spot on the surface of the star causing a slight variation in the light curve during a transit. Through a model that simulates the transit of a planet in front of a star with spots, it is possible to characterize these spots. These small signatures (see figure) in the light curve due to the spots provide the physical parameters of the spots such as size, intensity, temperature, magnetic field and temporal evolution. By monitoring the detection of the same spot on several transits one can estimate the rotation period of the star and even if the star present differential rotation, like our Sun.

This method has already been applied to stars