I'm an astronomer at ESO
, where I started in late 2014 as an ESO Fellow.
Before that I was a Postdoctoral Research Fellow at the University of Toronto
with Marten van Kerkwijk
I finished my thesis, titled
"Type Ia Supernovae: Progenitors and explosions"
2011 with Brian Schmidt
the Australian National University.
focuses on stars before, during and
after explosion (exploding stars are known as supernovae). My two
particular topics in this field are the search for surviving companions in
ancient supernova remnants and synthesizing and fitting spectra of supernovae.
I also have an interest in the nuclear star cluster of our own Milky Way.
and I are trying to
understand the origin of this dense and massive cluster.
Finally, I am working with the Science Data Group at ESO to think about novell
ways to extract measurements from raw data. In particular, I am developing a
method to use all available information using a statistical framework when extracting
All of this research is tied together with an interest in numerical methods,
machine learning and the idea of open software as well as
The history of the Universe begins with the Big Bang and thus the creation
of large quantities of the primordial building blocks of our cosmos:
hydrogen and helium. It continues with the creation of the first stars –
gravitationally bound gas spheres that become dense and hot enough for nuclear fusion,
transforming the primordial hydrogen via helium to carbon and oxygen for
lower mass stars and to iron for the most massive ones. Supernovae return
these elements to the interstellar medium – and provide the extreme
conditions required to make many of the heavier ones such as iron or silicon.
Since the elements beyond helium are crucial to the formation of rocky
planets such as the Earth – and for life as we know it – understanding
supernovae thus is an integral part of understanding how our Universe came to be the one we observe today.
Supernovae have been seen by humankind throughout the ages, with famous
examples recorded in 1572 by Tycho, and in 1604 by Kepler, but only the
last century had seen the necessary technological and scientific advances
to start understanding these most energetic events. There are two basic classes of
supernovae, those with hydrogen and those without:
Those with hydrogen were designated Type II and those without Type I.
Today we understand that the collapse of massive stars (ten times more massive than the sun)
powers the Type II supernova. It now also seems obvious that these supernovae
would show hydrogen as it is the the most abundant element in the Universe and thus stars.
The lack of hydrogen in Type I supernovae is a bit of a mystery. In addition,
this class of supernovae splits itself into two further subclasses named
Type Ia and Type Ibc. My research focuses on Type Ia supernovae that are
characterized by showing silicon.
The mysteries surrounding Type Ia supernovae
Why would certain types of exploding stars not exhibit the