I am a computational/theoretical astrophysicist in TAPIR, which is part of the
Walter Burke Institute for
Theoretical Physics at Caltech, working at the interface of
numerical relativity, nuclear/neutrino astrophysics, and
gravitational-wave physics. My current primary research interests are
(1) explosions of massive stars in core-collapse supernovae and long
gamma-ray bursts and their multi-messenger signatures in neutrinos,
gravitational waves, and photons, (2) the formation of stellar mass
and supermassive black holes, and (3) binary black hole and neutron
I lead the Caltech portion (~20 researchers, including research faculty, postdocs, grad students, and undergrads) of the Simulating eXtreme Spacetimes (SXS) collaboration and also work closely with the Einstein Toolkit team.
Another line of my research is concerned with the observation and interpretation of gravitational waves using the LIGO interferometers and I am a member of the LIGO Scientific Collaboration.
I am presently leading an
Trainees/Mentees that won national postdoctoral fellowships:
Evan O'Connor (Hubble 2014, Caltech PhD 2012), Christine Corbett Moran (NSF 2015), Philipp Mösta (Einstein 2015), Christian Reisswig (Einstein 2012), Luke Roberts (Einstein 2013).
Postdocs shipped off to faculty positions:
Luke Roberts (Michigan State University, deferred to 2016), Sebastiano Bernuzzi (University of Parma, 2015), Sean Couch (Michigan State University, 2015), Ernazar Abdikamalov (Nazarbayev University, Kasachstan, 2014)
Some background on me:
I entered theoretical astrophysics in 2001 when I was an exchange student at The University of Arizona and met Adam Burrows who trained me in core-collapse supernova theory and in many of the other things it takes to be a scientist. I received a Diploma in Physics from Heidelberg University in 2003 and obtained a Dr. rer. nat. (PhD equivalent) in 2007 at the Max Planck Institute for Gravitational Physics under Bernard Schutz's and Ed Seidel's supervision. I was a Joint Institute for Nuclear Astrophysics postdoctoral fellow with Adam Burrows at The University of Arizona before joining Caltech. More details can be found in my CV.
Follow me on Twitter: Follow @hypercott
Read my blog: Blowing Up Stars
|Senior Thesis:||If you are a Caltech undergrad and interested in doing a senior thesis in Ay or Ph, please come see me! I am happy to advise senior thesis work and have a number of interesting projects available.|
|Prospective Summer Undergrads:||We work with the LIGO REU program. Please see the projects and application procedures listed there. Caltech undergrads should contact me directly about SURF possibilities.|
|Prospective Grad Students:||
If you are interested in our research and would like to join us, please apply to the Caltech
and/or the Caltech Physics
graduate programs. Please do not send me your application
materials -- these should go to the graduate program. The admission
decision will be made by the graduate admission committees.|
We are presently looking for graduate students interested in working with us on a variety of topics in massive star evolution, core-collapse supernovae, gravitational wave astrophysics, binary black hole collisions, and neutron star mergers.
2013/14 Spring term: Ay102 - Interstellar Medium.
2013/14 Winter term: Ay190 - Computational Astrophysics.
2013/14 Fall term: Ay121 - Radiative Processes (with Gregg Hallinan)
2012/13 Fall term. Ay121 - Radiative Processes (with Gregg Hallinan).
2012 Spring term. Ay125 -- High-Energy Astrophysics (with Alan Weinstein).
2010/2011 Winter term. Ay190 -- Computational Astrophysics
2011/2012 Fall term. FS 001 -- Freshman Seminar on Cosmic Explosions and Their Multi-Messenger Signals
2009/2010 Winter term: Ay 215 -- Seminar in Theoretical Astrophysics: Interacting Binaries. Check out the course webpage!
Snapshot from a 3D GR black hole formation simulation (Ott et al. 2011, PRL)
I co-organized the 4th Microphysics in Computational
Relativistic Astrophysics Workshop (MICRA 2015)
at Stockholm University, August 17-21, 2015.
Chris Pethick and I started the MICRA series of workshops in 2009 to bring together people from the numerical relativity/computational astro community and from the nuclear physics community. The goal of this is to increase communication and collaboration between these communities in order to bring more realistic microphysics (nuclear physics, neutrino physics etc.) to simulations.
Caltech was well represented: Grad students Sherwood Richers and Jonas Lippuner, postdoc David Radice, and I attended. It was also great to catch up with former group members Roland Haas (AEI), Philipp Mösta (Berkeley), Sebastiano Bernuzzi (Parma), and Evan O'Connor (Hubble Fellow, NC State).
60 students from 11 countries had a great time thanks to 16 lecturers and 17 dedicated local colleagues at Caltech who helped make CGWAS 2015 happen. Lecture slides/notes, exercises, and solutions are available on the CGWAS website.
|The Caltech Gravitational Wave Astrophysics School 2015 (CGWAS 2015) is taking place July 6-10 at the Cahill Center for Astronomy Astrophysics. I am excited to welcome a diverse and international group of 40 graduate and undergraduate students to CGWAS 2015.|
Jonathan receives this
well deserved honor in recognition of his groundbreaking work
in reduced order modeling at
the interface of numerical relativity and gravitational-wave
et al. 2014
Blackman et al. 2015 (submitted to PRL), and Blackman et
al. 2015 (submitted to PRL).
The Garmire (and the Neugebauer) Scholar are newly established and endowed distinctions for outstanding graduate student research in Physics at Caltech. They come with a discretionary research fund of $2,500.
Congrats to Hannah! Hannah is a senior in the physics program at Caltech and has been working with us since her Freshman year. Her research is on rotating core collapse and gravitational wave emission from its postbounce ring-down phase. Hannah will take her CSGF to one of the schools she is currently considering for graduate school and we hope to continue to collaborate with her in the future!
|I had the pleasure of joining the Astronomy & Space Exploration Society for their 12th Annual Symposium at the University of Toronto on January 23, 2015. ASX is an undergraduate-run organization that organizes regular seminars on topics related to astronomy and space and they put together their yearly symposium that is always under a special theme. This year's symposium had the theme "Stellar Graveyard" -- of course that's a topic I have something to say about. I gave a lecture on The Theory of Stellar Death and Explosion. The symposium was a lot of fun! A broad and diverse audience of about 450 people attended and most stayed until the end of my talk (at 10:15 pm!).|
What drives hypernovae, extreme supernova explosions that have many times the explosion energy of a garden-variety supernova from a massive star?
Detailed simulations show that the standard mechanism for core-collapse supernovae -- the neutrino mechanism -- seems to lack the efficiency to drive such powerful explosions.
A possibly more powerful alternative could be the magnetorotational mechanism. In this scenario, rapid rotation (a proto-neutron star with a millisecond spin period) in combination with a very strong toroidal magnetic field (1015-1016 G) are expected to push out energetic bipolar outflows along the axis of rotation.
Our team has just completed the first set of full 3D, dynamical-spacetime GR-magnetohydrodynamic simulations of magnetorotational core-collapse supernovae. This work was led by postdoc Philipp Mösta and grad student Sherwood Richers (DOE Computational Science Graduate Fellow) made important contributions.
In collaboration with other team members, Philipp and Sherwood showed that the configuration that leads to strong jets in axisymmetry is unstable in 3D to an MHD kink instability, leading to a spiral deformation of the outflow. The volume rendering the left shows the entropy distribution at some 160 milliseconds after core bounce. Red indicates high entropy (about >10 kB/baryon), blue low entropy (a few kB/baryon). The vertical axis is the vertical and the scale is 1600 km. Instead of a clean jet, two huge lobes develop that move out secularly as the proto-neutron star pushes spiral streams of out hot, highly magnetized plasma into polar regions.