Quasar 3C 186 strikes back! Matteo and I got interested in this funny quasar last year (see this one). When our paper hit the arxiv, we got contacted by the real astronomers who take actual data, who told us they … Continue reading
February 3, 2025
Author Archives: Davide
January 31, 2025
Reconstructing parametric gravitational-wave population fits from non-parametric results without refitting the data
Gravitational-wave population people talk all the time about parametric vs non-parametric methods. Parametric methods mean imposing our astrophysical knowledge on how we look at GW data. This is great, we do want to extract astrophysical knowledge, but what if we … Continue reading
January 27, 2025
Super Viola!
I’m so so proud to see my PhD student Viola De Renzis defending her PhD thesis today. Viola’s thesis is titled “Gravitational-wave astronomy at the crossroads: from current to future detectors, from single events to populations” and was examined by … Continue reading
January 27, 2025
GWsnowballs was amazing!
Together with Ilya Mandel, last week I organized a workshop titled “Gravitational-wave snowballs, populations, and models” in Sexten (Italy). Both the science and the scenery were just stellar! We had almost zero talks, and the entire conference was made of … Continue reading
January 5, 2025
Alex got a fellowship
Congrats to Alex Toubiana, postdoc with us, who was just awarded an independent fellowship from the Italian Research Ministry. The scheme is called Young Researcher 2024 and will fund Alex and his research for 3 years.
December 20, 2024
2024 Wrapped!
In 2024…. We welcomed Tristan, Chiara, Caroline, Rodrigo, Alex, Federico, and Zachos (group accretion at the Eddington limit). Michele started a faculty in Marseille, Daria graduated, Viola almost graduated and is fighting the paperwork in Marseille, Giulia went to Cambridge, … Continue reading
December 15, 2024
FIS 3 grant opportunity
FIS (“Fondo Italiano per la Scienza”) is an Italian grant opportunity which is conceptually similar to the ERC. The amount of these grants is >= 1M EUR and grant holders are offered a tenure-track or tenured position. The deadline for … Continue reading
November 18, 2024
Scientific computing with Python, here we go again
This semester I’m back teaching my “Scientific computing with Python” module to PhD students. It’s a really really fun class to teach (and it’s just 8 lectures, short and sweet!). If you’re curious: github.com/dgerosa/scientificcomputing_bicocca_2024
November 4, 2024
Orbital eccentricity in general relativity from catastrophe theory
Black holes on eccentric orbits… what does it even mean? The hard (but fun) thing is that we work in General Relativity, where coordinates don’t have a physics inside. One can always change the coordinates as they want, so they … Continue reading
October 24, 2024
Forecasting the population properties of merging black holes
Our “popfisher” paper is finally out! (and now Viola can submit her PhD thesis). This is about next-generation (aka 3G) gravitational wave detectors. Those beasts will measure millions of black holes… and with so many of them who cares about … Continue reading
October 24, 2024
4+1: October graduations
Four BSc students and one MSc student defended their research project with us this month. Thanks all for spending some time in our research group!
October 21, 2024
Nick and Arianna are the new “Giovani Talenti”
Huge congrats to Arianna Renzini and Nick Loutrel who won two of this year’s “Giovani Talenti” (Young Talents) prizes from the University of Milano-Bicocca. These are internal grants for postdocs: there were four grants awarded in Physics in total and two of … Continue reading
October 15, 2024
A test for LISA foreground Gaussianity and stationarity. I. Galactic white-dwarf binaries
LISA will see a gazillion white dwarfs, but we won’t, or at least not individually. Those signals will actually pile up together in a mashed potato thing called foreground. But this mashed potato won’t be smooth (translate: the gravitational-wave signal … Continue reading
October 8, 2024
Group accretion (close to the Eddington limit)
Our group is accreting people at the Eddington rate! There are 5 new postdocs and 2 PhD students who have just started or are about to start: Group meetings are funny and busy these days, with too many ideas going … Continue reading
September 26, 2024
Minimum gas mass accreted by spinning intermediate-mass black holes in stellar clusters
This is a fun IMBH story we worked out when Kostas and Luca were visiting last summer from JHU. What if (one day, who knows) we observe a highly spinning intermediate-mass black hole? If that happens, is going to be … Continue reading
September 23, 2024
Stars or gas? Constraining the hardening processes of massive black-hole binaries with LISA
To Stars or to gas, that is the question.Whether ’tis nobler in the hardening to sufferThe slings and arrows of passing stars,Or to dissipate against a sea of gasAnd by disk end them. To inspiral — to merge,No more; and … Continue reading
September 20, 2024
Cecilia et al.
Four students just graduated with projects in our group… First, huge congrats to Cecilia Fabbri who got her MSc in Astrophysics. Cecilia (you might remember her) worked on an exciting applied statistics problem (which has already ended up in a … Continue reading
September 13, 2024
Which is which? Identification of the two compact objects in gravitational-wave binaries.
All right I think this is great (but it took me a long time to convince myself and the others that’s the case!) In gravitational-wave astronomy we measure binaries, that is, pairs of two objects. Our signals have information about … Continue reading
August 9, 2024
postmerger: A flexible mapping of ringdown amplitudes for non-precessing binary black holes
The ringdown is the final bit of a gravitational-wave signal, after the two black holes have merged. It’s nice because it’s clean; GR is so powerful that all that comes out after a black hole merger has specific frequencies, the … Continue reading
July 22, 2024
Computer-science graduation
Usually my students graduate in Physics, but not this time… Together with Matteo Boschini, I had the pleasure of supervising a student majoring in Computer Science. Alessandro Crespi got his BSc degree with a project on Simulation Design, which is … Continue reading
July 16, 2024
Many visitors
We’re having a few visitors this summer, with lots of science going around. Welcome Jam Sadiq from SISSA (Italy), Rossella Gamba from Berkeley (USA), Abhishek Chowdhuri from IIT Gandhinagar (India), Luca Reali from JHU (USA), and Kostas Kritos also from … Continue reading
July 8, 2024
Go Daria go!
Daria Gangardt has just defended her PhD thesis at the University of Birmingham. The thesis is called “Black-hole dynamics and their environments” and jumps from black-hole spins all the way to AGN discs. Daria, it has been a true pleasure … Continue reading
July 1, 2024
Challenges and future perspectives in gravitational-wave astronomy: O4 and beyond
The workshop “Challenges and future perspectives in gravitational-wave astronomy: O4 and beyond” will take place at the Lorentz Center (Leiden, Netherlands) from October 14th to October 18th, 2024. Our goal is to foster an interdisciplinary discussion (with astrophysicists, data analysts, … Continue reading
June 23, 2024
One population fit to rule them all
Three fits for the non-parametric under data sky,Seven for the astrophysicists in their clusters of stars,Nine for powerlaw+peaks doomed to die,One for the sampler on his python throneIn the land of LIGO where the data lie.One population fit to rule … Continue reading
May 27, 2024
Residual eccentricity as a systematic uncertainty on the formation channels of binary black holes
The orbits of binary black holes could be eccentric, but in practice they’re not. At least when we observe them, and that’s because of a relativistic effect that circularizes the orbit. Even if astrophysics formed black holes eccentric, relativity makes … Continue reading
May 23, 2024
Gravitational-wave snowballs, populations, and models
We are organizing “Gravitational-wave snowballs, populations, and models” — a workshop to be held in Sexten, in the Dolomites region of Italy, January 20-24, 2025:https://sites.google.com/unimib.it/gwsnowballs Our goal is to bring together researchers at the forefront of both forward astrophysical modeling of … Continue reading
April 29, 2024
Quick recipes for gravitational-wave selection effects
… and we’re back to selection effects. That means modeling what you cannot see. The black holes that gravitational-wave detectors observe are not representative of those that are out there in the Universe. Some are easier to see, some are … Continue reading
April 18, 2024
Linking Advances in our Understanding of Theoretical Astrophysics and Relativity to Observations (LAUTARO)
This week we’re hosting researchers from the Gran Sasso Science Institute (GSSI) for a joint mini-conference / workshop / group meeting. More here: davidegerosa.com/lautaro This is part of a PRIN grant we have together (thanks Italy) with support from other … Continue reading
April 16, 2024
Classifying binary black holes from Population III stars with the Einstein Telescope: a machine-learning approach
Population 3 stars are like “the original” stars. Those formed with material that comes straight from the Big Bang. It would be very (like, a lot!) cool to see them with gravitational-wave detectors. But can we tell them apart? Or … Continue reading
April 12, 2024
PhDs with us! 2024 admissions
The University of Milano-Bicocca welcomes applications for PhD scholarships. This year’s application deadline is May 14th, 2024 (noon CEST) for positions starting in the Fall of 2024: https://en.unimib.it/education/postgraduates/doctoral-research-phd-programmes/applying-doctorate/calls-application In particular, we are looking for highly motivated candidates to join our … Continue reading
March 23, 2024
Three more
Three more students graduated in March with research projects completed in our group!
March 6, 2024
Teaching for the new AI degree
On top of “astrostats” for the MSc degree in Astrophysics, this semester I’m excited to start teaching for the new BSc degree in Artificial Intelligence. This course is delivered jointly by the University of Milano-Bicocca (my place), the University of … Continue reading
March 6, 2024
“Astrostatistics and Machine Learning” v2024
The teaching semester is back and I’ll be delivering my “Astrostatistics and Machine Learning” class once more. This is designed for our MSc program in Astrophysics. Astro-data freaks, go here! github.com/dgerosa/astrostatistics_bicocca_2024
March 4, 2024
pAGN: the one-stop solution for AGN disc modeling
And the second paper on the arxiv today is Daria’s masterpiece! pAGN (which Daria says you should read “pagan”) is a brand new, super cool code that implements the hydrodynamics of AGN disks, at least in their most popular one-dimensional … Continue reading
March 4, 2024
Probing AGN jet precession with LISA.
This is the first of two papers on the arxiv today: it’s fun when two long, very different projects by different people just happen to be done on the same day! This paper is by my former colleague Nate Steinle … Continue reading
February 28, 2024
Primordial black holes by Lisa (not LISA…)
Our student Lisa Merlo defended her BSc 3rd year project today! Lisa worked with Pippa Cole and me on computing rates for mergers of primordial black holes, also considering a new detector prototype that the experimental group here is developing … Continue reading
February 21, 2024
We got (another!) Marie Curie Fellowship!
Huge huge congrats to Zacharias Roupas who was awarded a Marie Curie Fellowship with us! Zachos is currently based at the British University in Egypt and will be joining my group in Milan in the Fall of 2024. The Marie … Continue reading
February 16, 2024
Astrophysical and relativistic modeling of the recoiling black-hole candidate in quasar 3C 186
Not sure what happened here, how the hell did I end up writing a paper with actual radio data that needed to be reduced… Call me an ambulance. The guy here is 3C186 which is not a postcode but a … Continue reading
January 23, 2024
Tenured professorship in Astrophysics at the University of Milano-Bicocca (Italy)
The University of Milano-Bicocca (Milan, Italy) will be opening a tenured professorship in astrophysics, with a focus on gravitational-wave data analysis and exploitation. With this notice, we invite expressions of interest from potential candidates. Milano-Bicocca hosts a large group in … Continue reading
January 17, 2024
In memory of Chris Belczynski
Hey Chris, just wanted to say thanks because you wanted to understand what was going on, for that ski run down the Highland Bowl in Aspen, for sending me yet another version of those StarTrack files I had to postprocess, … Continue reading
December 31, 2023
2023 Wrapped!
Much like Spotify, here is our group “Wrapped”, 2023 edition! Some of the group highlights include… We welcomed Pippa, Nick, Arianna, Sshorab, and Matteo. We said bye to Matt who moved to MIT and Nate who moved to Canada, while Daria … Continue reading
November 22, 2023
Calibrating signal-to-noise ratio detection thresholds using gravitational-wave catalogs
In the gravitational-wave world, we usually say a binary merger is detected if it has a sufficiently large SNR (signal-to-noise ratio). But is that true? Detection pipelines are far more complicated than that. Here we try to figure out a … Continue reading
November 21, 2023
Starting a new class! “Scientific computing” for PhD students
I’m teaching the first lecture of a new class today. This is “Scientific computing with Python,” a 16h module for PhD students. To the (many) PhD students who signed up: thanks for your interest, hope you’ll like this. BTW the … Continue reading
November 20, 2023
November graduations: 4 Bsc projects with us
We had another graduation session in November, and a whopping 4 people graduated with research projects in our group. Here are the new BSc physicists who just defended: Congrats all (and twice congrats to Marco and Serena, who graduated with … Continue reading
November 17, 2023
Top 2% scientists
Looks like my name is on a list of the 2% top scientists worldwide. Take these rankings with a grain (or a block) of salt… but this is kind of cool! The list was compiled by Stanford University and bounced … Continue reading
November 3, 2023
Waveform modelling for the Laser Interferometer Space Antenna
This is the latest of the amazing reviews coming out on the LISA space mission. Short post to say that the LISA signal modeling is challenging but so fascinating. Everything you ever wanted to know it’s in here. Niaesh Afshordi, … Continue reading
October 31, 2023
Spin-eccentricity interplay in merging binary black holes
I’m obsessed with spinning black-hole binaries but, guys, spinning and eccentric black holes are even better! This is the first first-author paper by Giulia, who is not only a rising GW astronomer but also a semi-professional baker… So take two … Continue reading
October 28, 2023
2 Masters + 2 Undegrads
We’ve had four amazing research students graduating with us in October! After the Master’s defenses, students turned the graduation party into a football supporter thing, with chants and all the rest!
October 14, 2023
Arianna on a national newspaper
Arianna Renzini (Marie Curie Fellow in my group) is on the Italian national newspaper “Corriere della Sera” today! Here is the online version: Arianna Renzini, la studiosa di Astrofisica corteggiata da tutto il mondo: «Basta cervelli in fuga, lavorerò a … Continue reading
October 11, 2023
Catalog variance of testing general relativity with gravitational-wave data
…and we’re back to testing GR. We’ve got many gravitational-wave events and would like to use them all together to figure out if our equations for gravity are correct. And here is the issue: there’s only one set (aka catalog) … Continue reading