Aula U2-2016
Daniele Sorini (Durham)
Title: The impact of baryons on the internal structure of haloes and their environments
Abstract: Simulations indicate that stellar and AGN feedback processes significantly influence star formation and the distribution of baryons in the Universe. Despite this consensus, there is no agreement on the exact model for these processes. The Simba suite of hydrodynamical cosmological simulations (box size 74 Mpc, gas mass resolution 1.82X10^7 M_sun) includes variants with various stellar/AGN feedback models, providing an ideal testbed for assessing the impact of different processes on key observables. I will present the predictions of the different Simba runs on the distribution of baryons within and around haloes, as a function of halo mass and redshift. My results show a distinctive signature of AGN-driven jets on the slope of the gas density profile of groups and clusters. I will also show preliminary results on the impact of baryonic physics on the concentration-mass relationship of dark matter density profiles in the IllustrisTNG and MillenniumTNG simulations. Thanks to the large box size of the MillenniumTNG simulation (740 Mpc), it is possible to probe an expansive range of halo masses (10^9.5 – 10^15.5 M_sun), over a wide redshift range (0<z<7).
Abhishek Chowdhuri (IIT, Gandhinagar)
Title: Exploring non-GR signatures using GWs
Abstract: Gravitational waves (GWs) emitted during the merger of two compact objects within a binary system mark a groundbreaking discovery observed by advanced LIGO and Virgo detectors,
unveiling a novel realm in astrophysics. Presently, the collaborative efforts of LIGO, Virgo, and Kagra (LVK) have announced numerous events involving the merger of stellar black holes (SBH) and neutron stars (NS-NS), with more anticipated on the horizon, all events being studied with a
bigger aim of understanding whether GR is the ultimate theory of gravity or not. However, there are astrophysical inquiries into phenomena such as dark energy, dark matter, and inflation which often prompt reconsideration of General Relativity (GR) on cosmic scales. Binary dynamics, then,
offer a crucial testing ground for potential modifications to GR: Scalar tensor theories being one of them. This presentation delves into the exploration of binaries in non-GR signatures, investigating the parameters beyond GR that contributes to GW emissions. Our focus extends to
eccentric systems, broadening the scope of discussion, and also includes extreme mass ratio inspirals, offering insights into spacetime geometries. By scrutinizing these non-GR parameters, we aim to explore the distinct waveforms characteristic of alternate gravity theories.