Lugar de encuentro: SALÓN MERIDIANO de la Facultad de Ciencias Astronómicas y Geofísicas de la Universidad Nacional de La Plata. Argentina.
PROGRAMA:
10.00-11.00 Carlos Argüelles (IALP-CONICET)
Título: Elementary particle-based models for dark matter on galaxy scales ("Modelos de materia oscura basados en partículas elementales, en escalas de galaxias")
Resumen:
The problem of describing dark matter (DM) halos in terms of self-gravitating (fundamental) particles has gained considerable attention in the last years, given they may provide solutions to many of the unsuccessful predictions of the cold dark matter (CDM) paradigm arising below ~10 kpc scales. Such models are mainly comprised between (i) The case of ultra light bosons with masses in the range m~1-100x10^(-22) eV; and (ii) The case of keV fermions including for temperature as well as relativistic effects (i.e. the RAR model). The main consequence of incorporating the quantum (pressure) effects when dealing with either the case of bosons or fermions under self-gravity, is in the novel core-halo morphology of the density profiles. I will describe the underlying physical properties of the above theories, their astrophysical consequences to DM halos in galaxies and structure formation, as well as the tensions and success when contrasted with different observational data-sets.
11.00-11.30 Café
11.30-12.30 Gastón Giribet (Universidad de Buenos Aires FCEyN-UBA)
Título: Observational constraints on modified gravity theories from supermassive black hole shadows ("Cotas observacionales sobre teorías de gravedad modificada, a partir de la sombra de un agujero negro supermasivo")
Resumen:
In this talk, after a brief review of the recently obtained image of a supermassive black hole by the Event Horizon Telescope collaboration, I will talk about my work done in collaboration with the people from IAFE, in which, almost ten years ago, we already anticipated how the scrutiny of the shape of the shadow casted by a supermassive black hole could allow us to constrain deviations from general relativity. I will also discuss other observational bounds on modified gravity theories coming from other astrophysical phenomena, such as the Primakoff effect in stars.
12.30-14.30 Almuerzo
14.30-15.30 Gabriel Bengochea (IAFE)
Título: Desafíos actuales en la determinación de la constante de Hubble
Resumen:
Uno de los debates actuales en la cosmología enfrenta la tensión existente entre, por un lado, el valor obtenido para la constante de Hubble (Ho) a través de observaciones del fondo cósmico de microondas (CMB) y, por otro lado, el valor correspondiente determinado mediante observaciones locales, tales como distancias luminosas inferidas a partir del empleo de supernovas del tipo Ia. Recientemente, fue reportada la mayor discrepancia entre estos dos enfoques, ubicando la tensión en 4.4 sigmas en el nivel de confianza.
En esta charla haré una breve revisión del debate y mencionaré algunos aspectos observacionales relacionados con las supernovas del tipo Ia que podrían conducir (o no) a la reducción de la tensión actual entre diferentes determinaciones de Ho.
15.30-16.00 Café
16.00-17.00 Ezequiel Alvarez (ICAS)
Título: GW detectors to explore Quantum Gravity and Dark Matter: how far we are. ("Detectores de ondas gravitacionales para explorar la gravedad cuántica y la materia oscura: que tan lejos hemos llegado")
Resumen:
We have a new amazing working tool: the Gravitation Wave detectors. We pose the question of whether, in addition to their original main purpose of detecting GWs, there is more information that can be extracted form their data. In this talk we discuss in particular how far are we of having a hint on Quantum Gravity using their data, and if they could be used to detect Dark Matter lumps passing through them. As it could be expected, results are of course very negative; however I think that it is interesting to pose the discussion and explore if we can further develop ideas that could lead us to more interesting results.