April 18, 2025
The 2017 paper “Are merging black holes born from stellar collapse or previous mergers?” that I wrote with Emanuele Berti was selected 2025 Frontiers of Science Award. These prizes are awarded by the International Congress of Basic Science (ICBS), sponsored by the City … Continue reading
February 4, 2019
The prospect of multiband gravitational-wave astronomy is so so so exciting (I mean, really!). So exciting that we want to make sure once again it’s true; and this is today’s paper. Multiband means seeing the same black hole binary with … Continue reading
January 7, 2019
The COST action GWverse is an impressive network of European researchers and institutions tackling gravitational waves, black holes, etc (i.e. the things I like… sweet!). Together with conferences and outreach, they support collaborative visits between the network members, so here … Continue reading
November 15, 2018
As you can imagine, I’m kind of obsessed with black hole binaries. So easy (let’s face it, a black hole is easy! Just mass and spin), but at the same time so terribly complicated… Happy to present our attempt to … Continue reading
November 14, 2018
Latest in the series of our spin-precession papers, here we found a thing that was worthy of a new name: wide nutation (we had wide precession before, but this is better). These are black-hole binary configurations where the angle between any … Continue reading
September 24, 2018
Black hole mergers are like a scattering problem. Two black holes come in, and one black hole comes out. The difference is a bunch of gravitational waves. Those are nice, of course, but the remnant black hole is important too! … Continue reading
September 13, 2018
We all know Doppler shifts, right? That’s like the biibouuubiiiiboouuuuuu of an ambulance. That happens to gravitational waves as well. Suppose you have a merging binary which is emitting gravitational waves (bibooou). If that binary is going somewhere (say it’s … Continue reading
August 7, 2018
Today’s paper celebrates the wedding of startrack and precession (the nickname for this project was pretrack 😉 ). We use population synthesis evolution from startrack to predict the parameters of spinning black-hole binaries observed by LIGO. The spin distribution is … Continue reading
June 29, 2018
LISA is going to be amazing: supermassive black-holes, galactic white dwarfs, EMRIs… Besides all of that, LISA can help us doing LIGO’s science better. Some LIGO sources (notably, things like GW150914) will show up in LISA years in advance. LISA … Continue reading
June 21, 2018
Gravitational-wave astronomy is moving. Quickly. In a few years we are going to have large catalogs of many detections, and a whole lot of information to extract from them. Instead of focussing on parameters (masses, spins, redshifts) of single sources, … Continue reading
June 13, 2018
This is a massive review born out of the European COST Action CA16104 Gravitational waves, black holes and fundamental physics (GWverse). We summarize the status of the field of gravitational-wave astronomy and lie down a roadmap for the immediate future. Leor … Continue reading
May 4, 2018
LIGO can measure spins. Well, effective spins actually. These are special combinations of the two spins (magnitude and direction) and the binary mass ratio. There’s a ton of astrophysics that can be done just with this quantity, but one should … Continue reading
February 12, 2018
Surrogate models are fancy interpolation schemes developed to provide accurate (well, really accurate) waveforms directly from numerical relativity simulations. The first surrogate able to model fully precessing systems came up recently (and it’s really an amazing work!). Here we exploit … Continue reading
December 18, 2017
These are proceedings of the IAU Symposium 338 “Gravitational Wave Astrophysics”, held in Baton Rouge LA on October 16-19, 2017. My contribution is based on arXiv:1707.04637, where we look at the first binary black hole data using different Bayesian priors. During that … Continue reading
November 27, 2017
These are my proceedings for the 12th Edoardo Amaldi Conference on Gravitational Waves (July 9-14, 2017, Pasadena CA). I summarize how to use black-hole spin dynamics to learn about the lives of stars using gravitational-wave data. There are surprises… Before the … Continue reading
September 6, 2017
Natal kicks imparted to neutron stars and black holes at birth can be constrained using LIGO data. Kicks cause misalignments between the spins and the orbital angular momentum. Here we compare large banks of population synthesis simulations to LIGO data … Continue reading
August 11, 2017
Supernova can be used to test gravity! …and if there’s a massive scalar field around, things get terribly interesting. Here we generalize arXiv:1602.06952 to study stellar collapse in massive scalar-tensor theories of gravity (that is, the graviton is coupled to a … Continue reading
July 14, 2017
Bayesian statistics is really cool. It lets you specify clearly and openly all the assumptions that enter an analysis. What’s the effect of these prior assumptions on current inference with gravitational-wave data from black-hole binaries? Here we tackle this question … Continue reading
June 21, 2017
Looks like some of the LIGO black holes have low spins (better, low effective spins). In this paper we show these values can be accommodated with standard “field binaries”, i.e. formation channels where binary black holes form from binary stars. … Continue reading
May 5, 2017
Part of our series of spin precession papers, here we study nutational resonances. Those are configurations where the precession of L about J, and that of the two spins are in resonance with each other. These configurations are very generic … Continue reading
April 12, 2017
Black-hole data can be used to probe the lives of stars. That’s the promise of gravitational-wave astronomy, right? Here we give it a go. We present a (admittedly) very simple model showing that the misalignment of GW151226 can be easily … Continue reading
March 30, 2017
My little latex project to compile bibliographies in a smart way was published by JOSS. I really liked JOSS: it’s an innovative way to get recognition for your carefully crafted software, encouraging open science and good code practice. It’s really … Continue reading
March 18, 2017
What if the black holes LIGO sees are the results of a merger? I mean, we see mergers, but maybe those are second-generation ones, and the two merging black holes come from first-generation mergers. Or (more likely…) stellar mass black … Continue reading
December 16, 2016
Equal-mass binaries correspond to a discontinuous limit in the spin precession equations. A new constant of motion pops up, which can be exploited to study the dynamics. This is a really neat calculation done with Jakub, a Cambridge undergraduate student. Also, … Continue reading