May 11, 2021
The quest of finding their astrophysical origin of merging black-hole binaries is now a key open problem in modern astrophysics. Stars are the natural progenitor of black holes: at the end of their lives, the core collapses and leaves behind … Continue reading
April 26, 2021
Hierarchical mergers are the new black. LIGO is seeing black holes that are just too big to be there. The reason is that stars, which collapse and produce black holes, do some funny things when they get too massive. Notably, … Continue reading
March 31, 2021
General Relativity works well. But we still want to test it, and I guess that’s because it actually works too well (you know, all those quantum things that don’t really fit, etc). And we want to test it with gravitational-wave … Continue reading
March 31, 2021
This is a quick update some of our group activities… In the past few months we’ve been busy learning about the formation of stellar-mass black-hole binaries in the disks of active galactic nuclei. We organized a journal club and studied … Continue reading
March 9, 2021
Here is the latest in our (by now long) series of papers on black-hole binaries spin precession. This work was is championed by two outstanding PhD students, Daria (in my group) and Nate (UT Dallas). The key idea behind this … Continue reading
January 29, 2021
Orbital eccentricity in gravitational-wave observations has been long neglected. And with good reasons! Gravitation-wave emission tends to circularize sources. By the time black holes are detectable by LIGO/Virgo/LISA/whatever, they should have had ample time to become circular. Unless something exciting … Continue reading
January 22, 2021
We are running a virtual workshop with my group (Bham) and Emanuele Berti’s group at Johns Hopkins University (Hop). It’s an attempt to feel a bit less lonely during the COVID pandemic. Hope this is the opportunity to start new … Continue reading
December 15, 2020
[Intro music…Now imagine one of those voices from a TV show trailer…] Up-down instability S01-E03.“Previously on the up-down instability. After finding out that the instability exists (S01-E01) and calculating its analytic endpoint (S01-E02), one terrifying prospect remains. What if it’s … Continue reading
November 25, 2020
Spin precession is cool, and we want to measure it. In General Relativity, the orbital plane of a binary is not fixed but moves around. This effect is related to the spin of the orbiting black holes and contains a … Continue reading
November 16, 2020
It’s a great pleasure to welcome Nicola Giacobbo, who starts his postdoc with us today. Nicola completed his PhD and first postdoc year in Padova, and is an expert in population-synthesis simulations, compact binary progenitors, stellar physics, and all those … Continue reading
November 10, 2020
If you want to know what’s out there, you need to figure out what’s missing. And gravitational-wave astronomy is no exception. We are trying to infer how things like black holes and neutron stars behave in the Universe given a … Continue reading
September 25, 2020
I am truly honored to receive this year’s research prize of the Italian Culture Ministry and the Lincei National Academy. The prize is given to Italian researchers in various fields, and this year was awarded in the physical sciences. For more information see here and … Continue reading
September 17, 2020
I was awarded a Starting Grant from the European Research Council for my program titled “Gravitational-wave data mining”. My team and I will look into gravitational-wave data, machine-learning tools, black-hole binary dynamics, stellar-evolution simulations, etc. The total awarded amount is … Continue reading
September 14, 2020
I am very happy to welcome Daria Gangardt back in my group. We worked together last summer for a short but successful summer project. Now Daria is starting her PhD. I’m honored we can be part together of the next … Continue reading
September 11, 2020
Congratulations to my Master’s students that graduate this year: Abdullah Aziz and Julian Chan from the University of Birmingham, and Beatrice Basset from the University of Lyon. Well done all, and good luck with your future adventures.
July 30, 2020
And here is the latest episode in the series of our massive scalar-tensor gravity papers… After stellar collapse, we now look at how neutron stars look like in this strange theory of gravity (recap: “massive scalar-tensor” means that gravity is … Continue reading
July 15, 2020
And here is my latest lockdown effort: some experiments in the wonderful and perilous world of machine learning. The idea of this paper is to teach a computer to figure out by itself if a gravitational-wave signal will be detectable … Continue reading
June 12, 2020
Supermassive black hole inspiral and spin evolution are deeply connected. In the early stages when black holes are brought together by star scattering and accretion, spin orientations can change because of interactions with the environment. Later on, when gravitational waves … Continue reading
May 20, 2020
If General Relativity is too boring, couple it to something else. In this paper we study what happens to stellar collapse and supernova explosions if gravity is transmitted not only with the usual metric of Einstein’s theory (aka the graviton) … Continue reading
May 12, 2020
The latest news from our LIGO/Virgo friends (including some colleagues here in Birmingham) was an astrophysical surprise. The black-hole binary GW190412 is just different from every other one we have had so far. One of the two black holes is about three times larger … Continue reading
May 6, 2020
A black-hole binary starts its life as two single black holes, and finish it as a single black hole. In between there’s all the complicated dynamics predicted by General Relativity: many orbits, dissipation of energy via gravitational waves, spins that … Continue reading
April 8, 2020
New paper today! We’ve been working on this for a very long time but three weeks of lockdown forced us to finish it. It’s about distorted (aka warped) accretion discs surrounding black holes. If the black hole is spinning and … Continue reading
April 3, 2020
We’ve been knowing about the mass gap for a while, but I bet “spin gap” sounds new to you, uh? The gap in the spectrum of binary black hole masses is due to pair-instability supernovae (i.e. what happens if a … Continue reading
March 16, 2020
I am the recipient of the 2020 IUPAP General Relativity and Gravitation Young Scientist Prize. The prize is awarded by the International Society on General Relativity and Gravitation (ISGRG) through it affiliation with the International Union of Pure and Applied … Continue reading
March 5, 2020
Sometimes you have to look into things twice. We found the up-down instability back in 2015 and still did not really understand what was going on. Three out of four black hole binaries with spins aligned to the orbital angular … Continue reading
February 26, 2020
The LISA data analysis problem is going to be massive: tons of simultaneous sources all together at the same time. In Birmingham we are developing a new scheme to tackle the problem, and here are the first outcomes. We populate … Continue reading
February 26, 2020
The Milky Way, our own Galaxy, is not alone. We’re part of a galaxy cluster, but closer in we have some satellites. The bigger ones are the Large and Small Magellanic Clouds (which unfortunately I’ve never seen because they are … Continue reading
January 28, 2020
LISA is going to be cool. And not just for your astro-related dreams. Theoretical physicists can have fun too! This community-wide manifesto illustrates just how cool things are going to be with LISA. LISA will constitute a major milestone to … Continue reading
December 13, 2019
The Institute for Gravitational Wave Astronomy at the University of Birmingham, UK, invites applications for postdoctoral positions. The Institute provides a vibrant and diverse environment with expertise covering theoretical and experimental gravitational-wave research, with applications to present and future-generation detectors, … Continue reading
December 12, 2019
My Leverhulme Trust grant proposal titled “Black-hole spins and accretion discs with gravitational waves from space” has been selected for funding (PI Davide Gerosa, University of Birmingham). The total awarded amount is GBP 191,417 over 3 years.
December 4, 2019
I was recently interviewed for Scientific American about my recent paper on multiple-generation black holes in stellar clusters. Here is the article: “Black Hole Factories May Hide at Cores of Giant Galaxies”. Very happy to be quoted saying “I don’t … Continue reading
November 20, 2019
I was selected by the European Space Agency to join the Voyage 2050 Topical Teams. Voyage 2050 is ESA’s long-term programmatic plan to select scientific missions to be launched between 2035 and 2050. I am part of the review panel … Continue reading
November 1, 2019
We’re accepting applications from prospective PhD students. The deadline is Dec 31, 2019 for positions starting in the Fall of 2020. General information on the PhDs in our department PhD projects and prospective supervisors Here below is my project description: Astrophysics and … Continue reading
October 28, 2019
This week I am organizing the GrEAT PhD winter school. GrEAT (which stands for Gravitational-wave Excellence through Alliance Training) is a synergy network between the UK and China. Our program features informal talks in the mornings and hands-on sessions in … Continue reading
October 6, 2019
Two close collaborators will be visiting my group this winter. Vijay Varma, postdoc at Caltech and expert of numerical relativity surrogate models, will be here on October 7-11. Get ready for his talk “Binary black hole simulations: from supercomputers to … Continue reading
October 3, 2019
Today’s paper is about superkicks. These are extreme configurations of black hole binaries which receive a large recoil. Black hole recoils work much like those of, say, a cannon. As the cannonball flies, the cannon recoils backwards. Here the binary … Continue reading
September 20, 2019
I am very excited to welcome Matthew Mould in my research group. Matt is starting his Ph.D. with me in Birmingham. We already have too many ideas…
September 17, 2019
Gravitational-wave astronomy is, seems obvious to say, about doing astronomy with gravitational waves. One has gravitational-wave observations (thanks LIGO and Virgo!) on hand and astrophysical models on the other hand. The more closely these two sides interact, the more we … Continue reading
September 13, 2019
What’s in between neutron stars and black holes? It looks like neutron stars have a maximum mass of about 2 solar masses while black holes have a minimum mass of about 5. So what’s in between? That’s the popular issue … Continue reading
June 21, 2019
This summer I’ll be working with two undergraduate research students. Luca Reali is finishing his master at my alma mater (University of Milan, Italy) and is visiting Birmingham with a scholarship from the HPC Europa 3 cluster. Daria Gangardt just … Continue reading
June 14, 2019
Funny things happen in supernova explosions. Funny and complicated. If the star is too massive, the explosion is unstable. The black hole it formed it not as massive as it could have been. In gravitational-wave astronomy, this means that we … Continue reading
June 12, 2019
LIGO and Virgo are up and running like crazy. They started their third observing run (O3) and in just a few months doubled the catalogs of observing events. And there’s so much more coming! In this paper we try to … Continue reading
May 30, 2019
Spoiler alert: this paper is a bit sad. Stellar-mass black-hole binaries are now detected by LIGO on a weekly basis. It would be really cool if LISA (a future space mission targeting low-frequencies gravitational waves) could see them as well. … Continue reading
May 28, 2019
Where do black holes come from? Sounds like a scify book title, but it’s real. These days, that’s actually the million dollar question in gravitational-wave astronomy. LIGO sees (lots of!) black holes in binaries, and those data encode information on … Continue reading
May 24, 2019
Surrogate models are the best of both worlds. Numerical-relativity simulations are accurate but take forever. Waveform models have larger errors but can be computed cheaply, which means they can be used in the real world and compared with data. Surrogates … Continue reading
March 19, 2019
We moved (back) to the UK. I’m now a lecturer at the University of Birmingham (which is equivalent to assistant professor in the US). Really excited to start this new adventure! My group is part of the Birmingham Institute for Gravitational … 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
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
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