Research Interests

Gravitational Wave Progenitors: It Takes Two

Gravitational Waves are probably the most important discovery of modern astronomy and it has opened a whole new field of study. The observation of the merger of a 35 solar mass with a 30 solar mass black hole in the event GW150914 was not only historic, it was puzzling: how do you even make such a system?

In order to understand where gravitational wave progenitors come from and their initial properties, we need to use population synthesis codes, and binarity is a crucial ingredient to take into account.

My main responsibility besides science is now to create software that will make this analysis easier and faster for the whole community!

A 3 Dimensional View of Core Collapse Supernovae

Core Collapse Supernovae are the explosions resulting from the death of (most) stars born with a mass > 8 solar masses.

One of the ways we can help constrain their explosion models is through a better understanding of their explosion geometry. Since supernovae are unresolved at early days, however, this is not possible through direct imaging.

Using spectropolarimetry, we are able to deduce information about the global shape of the ejecta, as well as smaller scale, element specific, asymmetries.

My work, started in 2015 when I began my PhD, has mainly focused on stripped envelope supernovae: those whose progenitors lost a significant portion of their outer layers before exploding.

I’ve worked a lot on type IIb SNe (a bit of hydrogen early in the spectrum which then disappears after a couple of weeks to become helium dominated), which are an important transitional type between the more common type II SNe (not stripped) and the less common type Ib/c SNe (stripped). I’ve also had the chance to study the best data set ever obtained — so far — for a broad-lined type Ic (no hydrogen no helium + very fast ejecta).

It used to be thought that asymmetry in SN ejecta increased as the core of the explosion was revealed, however, my work on these objects as showed me that the picture is much more complex: jets and plumes rising from the core of the explosion can cause significant asymmetries in the outer layers of the ejecta, and oddly symmetric geometries have been found towards the core.

There is so much to be discovered, and supernova spectropolarimetry is still a young field, which I can’t wait to see (and help) evolve and grow.


Research Interests (in plain English)

Gravitational Wave Progenitors: It Takes Two

We have known for over a 100 years, thanks to Einstein, that dense and heavy objects have the ability to significantly warp the fabric of space-time around them.

If two very massive, very dense objects rotate around each other very quickly, this will create ripples in space that propagate through the Universe: Gravitational Waves.

During the merger of two black holes or two neutron stars, a tremendous amount of energy is released into these Gravitational Waves, which we can then detect from the Earth to learn about the objects that merged and their by-product.

What I will be working on in the next few years is trying to understand were the progenitor black holes and neutrons stars have come from: What where the properties of the stars before they even formed the black holes / neutron stars that eventually merged?

A 3 Dimensional View of Core Collapse Supernovae

Core Collapse Supernovae are the explosions of very massive stars at the end of their lives, when their core has run out of fuel.

They are not only very impressive objects (they can shine as bright as a whole galaxy, eject material at speeds around 10,000 km/s), they are a crucial step in the Universe’s history towards life as we know it: The oxygen in your lungs, the iron in your blood, the calcium in your bones, the aluminium in your soda… were released by a supernova!

The problem is that we don’t fully understand how they explode, and the way we can better our understanding is to compare the results of simulations to what we observe in real life. On of these “observables” is the shape of the explosion, but there is the rub: Supernovae are so far away that, on the sky, they just look like a dot!

Fortunately, there is a clever technique called spectropolarimetry which allows us to deduce 3 dimensional information about the shape of the explosion as a whole, as well as some more detailed intricacies related to specific elements.

This is what I’ve been working on since the end of 2015, and I’m not done yet!