M.Sc. in Astronomy, 1991, UNLP, Argentina
Ph.D. in Astronomy, 1995, UNLP, Argentina, "High-energy components in the
regions of Upper-Sco and Ara"
Current position: Researcher (CONICET)
Google Scholar profile
Since 1992 I have been working on topics related to the high-energy
astrophysics and radio astronomy. These subjects include:
- Unidentified gamma-ray sources. One of the most exciting mysteries of
astronomy involves the large number of unidentified gamma-ray (EGRET) sources
whose nature is unknown. Search for radio counterparts of these detections can
give us additional information about the structure of the ISM in the line of
sight to these sources. By eliminating the background diffuse radiation
originated by the galactic disk from the radio images, with filtering
techniques, we have unveiled possible radio counterparts of several gamma-ray
objects and gathered information on the high-energy radiation mechanisms.
- Multifrequency investigations of new Supernova Remnants (SNRs), discovered
from 408 MHz, 1.4 GHz and 2.4 GHz surveys. Several candidates for SNRs have
been detected in the southern sky at these frequencies after removing the
diffuse background radiation permeating the Galaxy. We have used these data to examine spectral index characteristics over faint and extended regions of SNRs.
- Studies on the origin of galactic and extragalactic cosmic rays (CR). The
origin of the highest energy cosmic rays detected in the neighborhood of Earth
is still an unsettled issue. In the last years our work have been directed to
the use of multifrequency observations in order to estimate the arrival energy
of protons accelerated by strong shock fronts in the outer parts of radio
galaxies and in the terminal shock of galactic superwinds generated in
starburst galaxies. In a series of papers on possible source candidates,
different energy losses have been discussed for the rays as well as the
associated changes in the arrival spectra.
- Radio and optical microvariability of Active Galactic Nuclei (AGNs).
Intraday variability of AGNs like quasars and BL Lac objects was discovered 10
years ago during extensive monitoring campaigns of large samples of northern
objects. The origin of these variations is still unknown. Shocks propagating
down the parsec-scale jet of the objects have been suggested as a possible
cause, but the most extreme cases of variability impose severe constraints on
the shock thickness and required Doppler factors. Extrinsic models invoke
refractive interstellar scintillation and gravitational microlensing. Since
1990s we have made numerous observations of rapid variability in southern AGNs,
detecting many outstanding outbursts (including the first observation of
extreme intraday events with brightness temperatures above 1021 K).
- The radio environment of accreting sources. The sources in this category
are neutron stars or black holes -the results of a supernova explosion- which
orbit a normal star. These sources are powered by the energy released when
matter is transferred from the normal star to the compact star. I am interested
in the study of the surrounding of LMXRBs and HMXRBs. These investigations can
be made searching for the presence of SNRs, cavities, shocks, or large-scale
jets using radio continuum and HI observations.