Theoretical Astrophysics and Cosmology:
B.Sc. University of Sao Paulo, Brazil (1988)
M.Sc. National Space Science Institute (INPE), Brazil (1992)
Ph.D. INPE/Lawrence Berkeley National Laboratory (1996)
Topology of the Universe:
CMB Data Mining:
Galactic Structure and Microwave Foregrounds:
Galactic free-free emission is believed to originate mainly within a few hundred pc of the Galactic plane, whereas diffuse synchrotron and dust emission extends further from the plane, with a scale height of a several kpc. Nearby supernova remnants can complicate the picture with synchrotron emission also at high galactic latitudes, often highly polarized. We are unfortunately a long way from having a self-consistent three-dimensional model of the the ISM and the magnetic field, including a model for the variations in density, temperature and magnetic field on various scales. However, upcoming multifrequency CMB measurements at various Galactic latitudes (both unpolarized and polarized) will offer a valuable tool for building such a model, especially when combined with maps of radio, dust and H-alpha emission. As a long-term project, I am interested in using such measurements to refine our knowledge of the structure of the Milky Way.
Our ability to measure cosmological parameters from upcoming CMB experiments will only be as good as our understanding of microwave foregrounds. By cross-correlating different CMB maps with foreground templates, I have quantified the level of foreground contamination at 10 and 15 GHz, 19 GHz, 30 and 40 GHz, evaluating its effect on published CMB measurements. My detection of a dust-correlated component at 30 and 40 GHz (with the Saskatoon data), also detected by Kogut et al using the COBE/DMR maps, puzzled many people in the community and triggered Draine & Lazarian to investigate the possibility of a fourth component of Galactic emission, from rotating dust grains. I am currently continuing my work on CMB foregrounds, quantifying the contamination in the QMAP (30-40 GHz) and MAT (30, 40 and 120 GHz) data sets to hopefully determine whether this observed correlation of CMB and dust maps is due to the free-free or rotational dust emission.
Because of the above-mentioned work and results from the COBE team and other groups during the last few years, models of unpolarized forergrounds went from being based largely on extrapolations to being founded on actual foreground detections at CMB frequencies. I am now focusing my attention on what I see as the next major challenge: to do the same with polarized foregrounds, i.e., to detect them and measure their power spectrum at CMB frequencies. I have also worked on the foreground contamination due to extragalactic point sources, and plan to do further work on this topic using the FIRST survey.