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Day V

DAY V:   Thursday, August 22  2019

Venue:  AULA FEDERMAN, Physical Department  of the University of Buenos Aires  (DF-UBA), Pabellón I, Ciudad Universitaria -C.A.B.A- Argentina.   


10.00-11.00 Paula Kornecki (PuMa Collaboration)

Title:   Going after pulsar radio-observations from the southern hemisphere

Abstract: PuMa (Pulsar Monitoring in Argentina) is a scientific collaboration dedicated to the observation of pulsars (rapidly-rotating and highly-magnetized neutron stars) using the antennas from the Argentine Institute of Radio astronomy (IAR). The IAR is equipped with two single-dish 30 m antennas capable of performing daily observations of pulsars and radio transients in the southern hemisphere at 1.4 GHz. 

The main goal of this collaboration is to perform a long-term observational campaign of pulsars in order to better understand their physics and to contribute to the detection of very low-frequency gravitational waves through Pulsar Timing Array techniques. The primary sources of low-frequency gravitational waves are supermassive black-hole binaries, presumed to exist in the universe at the centers of galaxies. The detection of these gravitational waves will improve our knowledge of galaxy formation and evolution, and it will help us to draw a better picture of the Universe’s history through cosmic time.

In order to achieve high-quality timing observations the two antennas at IAR have been refurbished.
In this presentation we show the IAR observatory capacities for investigations in numerous areas of pulsar radio astronomy, such as high precision timing observations, monitoring of magnetars and glitching pulsars.

11.00-11.30 Coffe

11.30-12.30 Martin Makler (CBPF & ICAS)

Title: Dark Matter and Strong Lensing Constraints on Cosmology

Abstract: Dark matter is one of the most active fields in cosmology and particle physics, involving astrophysical observations, experiments and theoretical modelling. As the Weakly Interacting Massive Particle paradigm became empirically disfavoured, o pandora box of Dark Matter models and experiments was opened. In this talk I will discuss one technique to explore Dark Matter properties, namely, strong gravitational lensing. This effect produces highly distorted, magnified and/or multiple images of distant sources, whose light bundles are affected by the gravitational field of a foregournd galaxy or galaxy cluster acting as a lens. More generally, SL can be used to constrain cosmological parameters and to test modifications of General Relativity aimed at explaining Dark Energy. I briefly review the state-of-the-art of these applications and present our recent results on constraints on a wCDM model using the strong lensing cluster Abell S1063. I will also briefly discuss the search and modelling of strong lenses using deep learning and present wide-field imaging surveys in which we are involved. Finally, I will touch upon other methods to constrain Dark Matter.

12.30-14.30 Lunch

14.30-15.30 Daniel LOPEZ-Fogliani (IFIBA-UBA, &UCA)

Title: Searching for new physics

Abstract: The Standard Model of particle Physics, SM, is in fantastic  agreement with experimental results. However, dark matter and neutrino  physics are not described by the SM. We discuss theoretical motivations  for physics beyond the standard model and the state of the art in  particle physics experiments. We discuss possible discrepancies with SM  model predictions and searches for new physics.

16.00-17.00 Lucila Kraiselburd (FCAG-UNLP)

Title: Screening effect on theories of gravity f (R) in the solar system.

Abstract: f (R) theories of gravity depend on the chameleonic mechanism to pass the solar system tests. The methods used in the literature are based on a scalar-tensor identification in the Einstein frame. This approach has a disadvantage because it implies the definition of new variables where the inversion of the old ones is not always well defined. To avoid this problem, we develop a novel and consistent method that starts from a simple system but completely relativistic of differential equations for a compact object in a static and spherically symmetric space-time, with suitable linearization for non-relativistic objects such as the Sun. We demonstrate that under certain conditions there is an effect of screening that can lead to a prediction of the post-Newtonian parameter γ that is compatible with observational constrains. To illustrate this new method, we analyze several specific f (R) models and show which of them are capable of satisfying those constrains.