-
Raffaella Schneider1/14/20, 9:15 AMTalk
The existence of massive stellar black hole binaries, with primary black hole (BH) masses greater than 30 -35 Msun was proven by the detection of the gravitational wave (GW) event GW150914 during the first LIGO/Virgo observing run (O1), and successively confirmed by seven additional GW signals discovered by independent analyses of the O1 and O2 data. Recently reported O3 alerts suggest that...
Go to contribution page -
Dr Lumen Boco (SISSA)1/14/20, 10:00 AMTalk
In this talk I will discuss a novel mechanism to grow supermassive black hole seeds in star-forming ETG progenitors at z >1. This envisages the migration and merging of stellar compact remnants, via gaseous dynamical friction, toward the central regions of such galaxies. I will show that this process can build up central BH masses of order 10^4 − 10^6 Msun in a timescale shorter than 10^8 yr,...
Go to contribution page -
Mr Alberto Mangiagli (University of Milan - Bicocca)1/14/20, 10:15 AMTalk
In current stellar evolutionary models, the occurrence of pair-instability supernovae plays a key role in shaping the resulting black hole (BH) mass population, preventing the formation of remnants between about $[60, \, 120] \rm M_\odot$.
Go to contribution page
We develop a simple approach to describe BHs beyond the pair-instability gap, by convolving the initial mass function and star formation rate with the... -
Laura Sberna (Perimeter Institute)1/14/20, 10:30 AMTalk
We study the impact of mass accretion in the evolution of LIGO-like black hole binaries. Based on simulated catalogues of binary populations, we estimate that a fraction of the events will have a detectable imprint of Eddington-level accretion, when detected by LISA or by LISA and ground-based detectors (multiband). Accretion can also induce bias in the binary parameters, such as the masses...
Go to contribution page -
Francisco Duque (GRiT/CENTRA, Instituto Superior Técnico, Universidade de Lisboa)1/14/20, 10:45 AMTalk
The tidal deformability of compact objects by an external field has a detectable imprint in the gravitational waves emitted by a binary system, which is encoded in the so-called Tidal Love Numbers (TLNs). For a particular theory of gravity, the TLNs depend solely on the object's internal structure and, remarkably, they vanish for black holes in general relativity. This fact has gathered...
Go to contribution page -
Béatrice Bonga (Radboud University)1/14/20, 11:30 AMTalk
This will be an overview talk about the Bondi-Metzner-Sachs group, which is the symmetry group of asymptotically flat spacetimes. After having reviewed its main properties, I will discuss some applications such as the memory effect. Next, I will discuss the BMS algebra in other contexts such as higher dimensions and black hole horizons. The latter is conjectured to be key in solving the...
Go to contribution page -
Francois Foucart1/15/20, 9:15 AMTalk
The first detection of a binary neutron star star system through gravitational waves and electromagnetic signals (gamma-ray burst, kilonova, radio) recently demonstrated the feasibility and usefulness of multi-messenger astronomy. In this talk, I will provide an overview of the physics of neutron star-neutron star and black hole-neutron star mergers, and of what we can learn from gravitational...
Go to contribution page -
Dr Ali Seraj (ULB)1/15/20, 10:00 AMTalk
Asymptotically flat spacetimes admit infinite dimensional BMS symmetries which complete the Poincare symmetry algebra with super-translation and super-Lorentz generators. We show that each of these symmetries lead to a flux-balance equation at null infinity, which we compute to all orders in the post-Minkowskian expansion in terms of radiative multipole moments. The ten Poincare flux-balance...
Go to contribution page -
Manuel Hohmann (University of Tartu)1/15/20, 10:15 AMTalk
The parameterized post-Newtonian (PPN) formalism is an invaluable tool to assess the viability of gravity theories using a number of constant parameters. These parameters form a bridge between theory and experiment, as they have been measured in various solar system experiments and can be calculated for any given theory of gravity. The practical calculation, however, can become rather...
Go to contribution page -
Ms Mekhi Dhesi (University of Southampton)1/15/20, 10:30 AMTalk
We are working to provide accurate modelling of the dynamics and gravitational-wave signatures of black hole inspirals in the intermediate-mass-ratio regime (IMIRIs) (1:100-1:1000). In doing so we hope to bridge the gap between the accurate modelling of extreme-mass-ratio inspirals achieved through black hole perturbation theory, and that of comparable-mass inspirals using numerical...
Go to contribution page -
Mr Thanasis Giannakopoulos (Instituto Superior Técnico)1/15/20, 10:45 AMTalk
Characteristic formulations of General Relativity (GR) have advantages over more standard spacelike foliations in a number of situations. For instance, the Bondi-Sachs formalism is at the base of codes that aim to produce gravitational waveforms of high accuracy, exploiting the fact that null hypersurfaces reach future null infinity and hence avoid systematic errors of extrapolation...
Go to contribution page -
Daniela Doneva (University of Tuebingen)1/15/20, 11:30 AMTalk
Spontaneous scalarization is a very interesting mechanism endowing the compact object with nontrivial scalar field. This mechanism is designed to work only in the strong gravity regime while remaining the weak field regime practically unaltered. While scalarization was discussed mainly for neutrons stars in the last few decades, it was recently discovered that black holes in Gauss-Bonnet...
Go to contribution page -
Maximiliano Isi1/16/20, 9:15 AM
Gravitational waves may allow us to experimentally probe the structure of black holes, with important implications for fundamental physics. One of the most promising ways to do so is by studying the spectrum of quasinormal modes emitted by the remnant from a binary black hole merger. This program, known as black hole spectroscopy, could allow us to test general relativity and the nature of...
Go to contribution page -
Miguel Bezares (SISSA)1/16/20, 10:00 AMTalk
The direct detection of gravitational waves (GWs) by the LIGO and VIRGO interferometric detectors has begun a new era of GW astronomy, allowing us to study the strong regime of gravity through GW signals produced by coalescence of compact objects. In this talk, I will present our numerical studies on coalescence of binary Exotic Compact Objects (ECOs) performed by solving the Einstein...
Go to contribution page -
Daniele Pranzetti (Perimeter Institute)1/16/20, 10:15 AMTalk
In this talk I will show how to derive an effective Hamiltonian constraint for the Schwarzschild geometry starting from the full loop quantum gravity Hamiltonian constraint and computing its expectation value on coherent states sharply peaked around a spherically symmetric geometry. I then use this effective Hamiltonian to study the interior region of a Schwarzschild black hole, where a...
Go to contribution page -
Mr Alexandre Toubiana (APC/IAP)1/16/20, 10:30 AMTalk
Black holes mimickers, e.g. neutron stars or boson stars, are compact objects with similar properties to black holes.
Go to contribution page
The gravitational wave signal emitted by a binary of such putative objects during the inspiral phase is difficult to
distinguish from the one emitted by a black hole binary. Nevertheless, significant differences might appear in the
post merger signal. Inspired by the known... -
Sayak Datta (IUCAA)1/16/20, 10:45 AMTalk
With the observation of the multiple binary inspirals, we begin to question whether the components of the binary are black holes or some exotic compact objects (ECO). The black holeness or the deviation from it can be tested in several ways. The distinguishing feature of a black hole from other exotic compact objects is the presence of the horizon. This surface acts as a one-way membrane, that...
Go to contribution page -
Luciano Rezzolla1/16/20, 11:30 AMTalk
I will briefly discuss how the first image of a black hole was obtained
Go to contribution page
by the EHT collaboration. In particular, I will describe the theoretical
aspects that have allowed us to model the dynamics of the plasma
accreting onto the black hole and how such dynamics was used to generate
synthetic black-hole images. I will also illustrate how the comparison
between the theoretical images and the...
Choose timezone
Your profile timezone: