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Meet the GLAST Fellows: Vasiliki Pavlidou
Photo of Vasiliki PavlidouPhoto of Vasiliki Pavlidou. Credit: Vasiliki Pavlidou is a Postdoctoral Fellow at the Kavli Institute of Cosmological Physics and the Enrico Fermi Institute at The University of Chicago.

Her research is focused on the non-thermal sky. Her areas of concentration include theoretical and multi-wavelength/multi-messenger studies of high-energy astrophysical phenomena and astrophysical accelerators. She has studied problems on gamma-ray astrophysics, cosmic-ray astrophysics, structure formation, and and nucleosynthesis.

As a GLAST fellow, Pavlidou will concentrate on population studies of gamma-ray emitters, such as blazars, starforming galaxies, structure-formation shocks, and Galactic compact objects, as well as theoretical studies of diffuse gamma-ray backgrounds.

The extragalactic gamma-ray background (EGRB) between 100 MeV and 20 GeV encodes important information about extragalactic gamma-ray emitters. For blazars (active galaxies with jets aligned with the line of sight), it constitutes an important independent constraint on their cosmological distribution and evolution. For classes of sources with few or no individually resolved members, such as starforming galaxies, starburst galaxies, clusters of galaxies, or annihilating dark matter density spikes, it constitutes the primary observational constraint on their properties.

However, if EGRB observations are to be effectively used to extract the most information possible on these classes of sources, the guaranteed contribution from unresolved blazars needs to be subtracted from the observed EGRB. Therefore, to maximize the scientific return of GLAST's Large Area Telescope (LAT) data, it is of critical importance to study as comprehensively as possible the relation between the EGRB and the most populated class of extragalactic emitters, blazars.

Pavlidou will use the expected LAT observations of ~1000 resolved blazars to derive detailed gamma-ray--loud blazar population models, and use them to predict the cumulative contribution of blazars below the LAT sensitivity threshold to the EGRB. The impact of this research is therefore expected to be twofold, involving both a wealth of information on blazars physics, as well as the possibility to maximize the information on extragalactic hypothesized sources, sources with few members, and exotic physics, that can be extracted from the EGRB.

Related Links:

> Vasiliki Pavlidou's home page
> Pavlidou's Publications
Email Dr. Pavildou

Rob Gutro
Goddard Space Flight Center