Welcome!

I am an Assistant Professor of Theoretical Astrophysics in TAPIR at Caltech. I joined the TAPIR group at Caltech as a Sherman Fairchild Postdoctoral Fellow in July 2008. In June 2008, I accepted a faculty position and joined the faculty on September 30, 2009.

I work primarily on finding ways to blow up massive stars, that is, make core-collapse supernovae and gamma-ray bursts and their compact remnants, black holes and neutron stars. I have also done extensive work on the signature of massive star collapse and core-collapse supernovae in gravitational waves.

Much of my work is based on computational modeling and I am running simulation codes (written in C, C++, and Fortran) at national and international supercomputing centers. Check out this movie (~20 MB) of a collapsing stellar core to get a feeling for the types of simulations my collaborators and I are running.

Before moving to Caltech, I was a postdoctoral research associate and Joint Institute for Nuclear Astrophysics postdoctoral fellow in the Department of Astronomy at the University of Arizona in Tucson. And before that, I spent ~3 years as student at the Albert Einstein Institute (Max Planck Institute for Gravitational Physics) where I got my PhD with Bernard Schutz.

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Teaching Info I'll be teaching Ay 215 -- Seminar in Theoretical Astrophysics: Interacting Binaries in the Winter term. Check out the course webpage!

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New Stuff (in quasi-chronological order)

• Exciting news: I have just learned that Classical and Quantum Gravity has selected my recent review on the gravitational wave signature of core-collapse supernovae (CQG 26, 063001, 2009) as part of the journal's Highlights of 2008 and 2009. This means that you can download my article for free!
• Another new paper! (2009/10/16) We have just submitted a long paper on GR simulations of the accretion-induced collapse of massive white dwarfs to neutron stars:
  

  E. Abdikamalov, C. D. Ott, L. Rezzolla, L. Dessart, H. Dimmelmeier, A. Marek, and H.-T. Janka

  Axisymmetric General Relativistic Simulations of the Accretion-Induced Collapse of White Dwarfs

  Submitted to Phys. Rev. D. (ads/arXiv)

  We worked very hard on this paper for more than a year. It includes more than 100 new axisymmetric GR simulations. Key results are that (a) rapidly rotating AIC has a distinctive GW signature, (b) protoneutron stars formed in AIC are likely to be unstable to a variety of nonaxisymmetric rotational instabilities, and (c) rapidly differentially spinning white dwarfs lead to protoneutron stars with massive accretion disks, but the AIC uniformly spinning WDs won't yield massive disks at all.
• New paper!

  CQG has just (2009/10/06) published my new article "Probing the Core-Collapse Supernova Mechanism with Gravitational Waves," (CQG) in which I lay out how gravitational waves may be used to constrain the core-collapse supernova mechanism. It turns out that even the non-detection of gravitational waves from a galactic core collapse event would give us important clues on what is driving core-collapse supernovae! The article is available for free for 30 days! Hurry up and get your copy!

• Topical Review published!

  Today (Feb 23, 2009), Classical and Quantum Gravity published my review article on the gravitational-wave signature of core-collapse supernova. It is a comprehensive summary of what has been happening in the field in the past couple of years as more and more people are becoming aware that some great supernova science can be done with gravitational-wave astronomy. I hope you enjoy reading it. (The electronic version of the article is available for free for 30 days after Feb 23!)

• On November 26, 2008, I had the pleasure to give a seminar in the seminar series of the Caltech-JPL Association for Gravitational Wave Research (CaJAGWR). I spoke about how we can learn about the core-collapse supernova explosion mechanism with the help of gravitational waves. A copy of my talk is available in pdf format: Ott_CAJAGWR_20081125.pdf.
  Specifically for this talk I made a few new plots, showing on log-log scale the single-detector optimal signal-to-noise ratio (SNR) as a function of distance for a variety of gravitational wave emission processes in core-collapse supernovae.
  
  
  
  The scaling of the SNR with distance is of course trivial, but it is interesting to see out to visualize it and see out to which distance a given GW emission process may be detectable (SNR significantly larger than 1) by various detectors. The widths of the SNR "band" is set by the spread in possible SNR for variations in source parameters that people have studied. A particularly narrow band (as in the rotational instability case) just reflects the fact that only very few models (in this case, just 1) were used to make the SNR estimates. More on gravitational wave emission processes and the way I compute the SNR can be found in my recent review.
• In late June, I was invited to attend the Max Planck Society's yearly Generalversammlung which this year took place in Dresden. The MPG awarded me with a pretty nice piece of metal -- the Otto Hahn Medal:
  
• I am moving! I accepted a Caltech Sherman-Fairchild Prize Fellowship earlier this year and will be starting my new position in the Tapir group at Caltech on July 15.
  
  I also accepted an offer of an assistant professor position in the Niels Bohr International Academy (NBIA) at the Niels Bohr Institute in Copenhagen, Denmark. I will become a member of the NBIA this September, but will be on leave to Caltech for a year.
• Interested in supernovae? Then you probably know the well maintained IAU list on recent supernovae hosted at Harvard. Unfortunately, this important SN web page is plain old html and does not provide an RSS feed. If you are using an RSS reader to stay up to date, you can now use this feed that I created with the help of feed43.com.
• APS April Meeting 08: If you are interested, please download the talk I presented at the APS meeting in St. Louis -- Core-Collapse Supernova Mechanisms and their Signature in Gravitational Waves.
• New Paper:
  On March 31, 2008 we finally submitted to ApJ our Ott, Burrows, Dessart, Livne study on angle-dependent multi-group neutrino radiation hydrodynamics in the postbounce core-collapse supernova context. The paper is available on arXiv.org [arXiv:0804.0239] and a version with high-resolution figures can be downloaded here.
  Here are some Hammer-type map projections of the neutrino specific intensity shown for electron neutrinos at 12.6 MeV and at equatorial radii of 30, 60, 120, and 240 km:
  
  Besides looking at the momentum-space angular distributions, we also carried out long-term postbounce calculations with both angle-dependent transport and multi-group flux-limited diffusion and compared the two schemes in the core-collapse SN context.
  For details, please take a look at the paper!
  Update: On June 24, 2008, the paper has been accepted for publication in the Astrophysical Journal.
• Exciting News:
  

  I have won the Postdamer Nachwuchs-Wissenschaftspreis (Young Scientist Prize of the City of Potsdam). I received the prize at the Einsteintag of the Berlin-Brandenburg Academy of Sciences (the former Prussian Academy) on December 14, 2007. Read the entire story in German on the City of Potsdam Website.

• The European Union FP7 Marie Curie Intra-European Career Development Fellowship proposal that I have jointly submitted with the School of Mathematics (Applied Math / GR Group) of the University of Southampton, UK was rated at 93/100 and was graded A (very likely to receive funding) in the preliminary EU commission report (12/07/2007).
• I have recently had the pleasure of participating in the Trento ECT* workshop on "Matter at Extreme Densities and Gravitational Waves from Compact Objects". A pdf-variant of my talk can be downloaded from here (6 MB).
• Gravitational Waves from Stellar Core Collapse and Core-Collapse Supernovae. Two new gravitational waveform catalogs are online.
  
  
  • MPA Garching catalog, put together by Harry Dimmelmeier, based on general relativistic simulations by Dimmelmeier et al., PRL in press (2007), Ott et al., CQG 24, S139 (2007), and Ott et al., PRL in press (2007).
  • Ott/Burrows Princeton/Caltech Catalog, put together by myself and based on the Newtonian radiation-hydrodynamics core-collapse supernova calculations of Burrows et al., ApJ 655, 416 (2007), Burrows et al., ApJ 640, 878 (2006), Ott et al., PRL 96, 201102 (2006), Dessart et al., ApJ 644, 1063 (2006), and on the Newtonian core-collapse study of Ott et al., ApJ 600, 834 (2004).
• The gravitational wave signature of rotating stellar iron core collapse is generic! For details, read Dimmelmeier et al., PRL 98,251101 (2007), Ott et al., CQG 24, S139 (2007), and Ott et al., PRL 98, 261101 (2007).
• On March 30, 2007, I defended my PhD thesis entitled Stellar Iron Core Collapse in 3+1 General Relativity and The Gravitational Wave Signature of Core-Collapse Supernovae and by that obtained the degree of Dr. rer. nat. (Dr. of Science / PhD equivalent) from the University of Potsdam. If you are interested, please download a copy of my thesis (beware: 310 pages; ~45 MB in pdf; does not print well on Windows machines).
• A New Mechanism for Gravitational-Wave Emission in Core-Collapse Supernovae:
  Ott, Burrows, Dessart, Livne, PRL 96, 201102 (2006; we made the cover!)
  

  Abstract We present a new theory for the gravitational-wave signatures of core-collapse supernovae. Previous studies identified axisymmetric rotating core collapse, core bounce, postbounce convection, and anisotropic neutrino emission as the primary processes and phases for the radiation of gravitational waves. Our results, which are based on axisymmetric Newtonian supernova simulations, indicate that the dominant emission process of gravitational waves in core-collapse supernovae may be the oscillations of the protoneutron star core. The oscillations are predominantly of g mode character, are excited hundreds of milliseconds after bounce, and typically last for several hundred milliseconds. Our results suggest that even nonrotating core-collapse supernovae should be visible to current LIGO-class detectors throughout the Galaxy, and depending on progenitor structure, possibly out to megaparsec distances.

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Some Current Projects and Collaborations

• I work with the Princeton supernova group (led by Adam Burrows) on various topics in core-collapse supernova theory. The current focus is on magneto-hydrodynamics and the effects of various approximations to neutrino radiation transport in the core-collapse supernova phenomenon. My direct collaborators on this project are Adam Burrows (Princeton), Luc Dessart (Princeton/Marseille), Eli Livne (Jerusalem), Ivan Hubeny (Arizona), Timothy Brandt (Princeton), and Jason Nordhaus (Princeton).
• With Jeremiah W. Murphy (Astronomy Department, University of Washington) I work on multi-D simulations of stellar collapse and supernova explosions using Jeremiah's BetheHydro code and focussing on the gravitational wave signature from multi-D postbounce dynamics (convection / SASI etc.). We recently finished a study and submitted a new paper to ApJ: A Model for Gravitational Wave Emission from Neutrino-Driven Core-Collapse Supernovae (ads).
• I am working with Harald Dimmelmeier (MPA Garching and Areva/Siemens/Framatom) on general relativistic calculations of rotating iron core collapse and and accretion-induced collapse (in 2D [axisymmetry] and 3D) and the corresponding gravitational wave signal. Additional collaborators are Thomas Janka (MPA), Andreas Marek (MPA), Ewald Müller (MPA), Ernazar Abdikamalov (SISSA), and Luciano Rezzolla (AEI).
• I am working with the numerical relativity and high-performance computing group at the Center for Computation and Technology at Louisana State University on a multi-block approach to general-relativistic hydrodynamics and core-collapse supernova calculations. My collaborators are Erik Schnetter (CCT/LSU), Joel Tohline (LSU), Ian Hawke (Southampton), and Frank Löffler (CCT/LSU).
• With the Caltech-Cornell Simulating eXtreme Spacetimes (SXS) collaboration I am studying the merger of neutron star - neutron star and black hole - nuetron star binaries.
• I am a co-developer of the mesh-refinement package Carpet for the Cactus computational infrastructure. My principal collaborators are Erik Schnetter (LSU), Thomas Radke (AEI), and Ian Hawke (Southampton).
• I am a co-developer of the Whisky code, a general-relativistic hydrodynamics code within the Cactus infrastructure. My principal collaborators are Ian Hawke (University of Southampton), Luciano Rezzolla (Albert-Einstein-Institut, AEI), Luca Baiotti (AEI), Bruno Giacomazzo (AEI), Thorsten Kellermann (AEI), and Burkhard Zink (LSU).

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Recent refereed Publications

(Complete ADS list), (only refereed ADS publications).

• C. D. Ott, "Probing the Core-Collapse Supernova Mechanism with Gravitational Waves ". Class. Quant. Grav. 26, 204015, 2009 (ads)
• C. D. Ott, "The Gravitational Wave Signature of Core-Collapse Supernovae," topical review, Class. Quant. Grav. 26, 063001, 2009, (ads)
• L. Dessart, C. D. Ott, A. Burrows, and E. Livne, "Neutrino signatures and the neutrino-driven wind in Binary Neutron Star Mergers,", accepted for publication in ApJ, (ads)
• H. Dimmelmeier, C. D. Ott, A. Marek, and H.-T. Janka, "The Gravitational Wave Burst Signal from Core Collapse of Rotating Stars," Phys. Rev. D 78, 065056, 2008(ads)
• C. D. Ott, A. Burrows, L. Dessart, and E. Livne, "2D Multi-Angle, Multi-Group Neutrino Radiation-Hydrodynamic Simulations of Postbounce Supernova Cores," ApJ 685, 1069, 2008. (ads)
• T. Z. Summerscales, A. Burrows, C. D. Ott, and L. S. Finn, "Maximum Entropy for Gravitational Wave Data Analysis: Inferring the Physical Parameters of Core-Collapse Supernovae," ApJ 678, 1142, 2008. (ads)
• L. Dessart, A. Burrows, E. Livne, and C. D. Ott, "The Proto-Neutron Star Phase of the Collapsar Model and the Route to Long-Soft Gamma-Ray Bursts and Hypernovae," ApJ L673, 585, 2008 (ads)
• L. Dessart, A. Burrows, C. D. Ott, and E. Livne, "Magnetically-driven explosions of rapidly-rotating white dwarfs following Accretion-Induced Collapse," ApJ 669, 585, 2007 (ads)
• C. D. Ott, H. Dimmelmeier, A. Marek, H.-T. Janka, I. Hawke, B. Zink, and E. Schnetter, "3D Collapse of Rotating Stellar Iron Cores in General Relativity Including Deleptonization and a Nuclear Equation of State," PRL 98, 261101, 2007. (ads)
• A. Burrows, E. Livne, L. Dessart, C. D. Ott, and J. Murphy, "Simulations of Magnetically-Driven Supernova and Hypernova Explosions in the Context of Rapid Rotation," ApJ 664, 416, 2007. (ads)
• H. Dimmelmeier, C. D. Ott, A. Marek, H.-T. Janka, and E. Müller, "Gravitational-Wave Signals from the Collapse of Rotating Stellar Cores," PRL 98, 251101, 2007. (ads)
• C. D. Ott, H. Dimmelmeier, A. Marek, H.-T. Janka, I. Hawke, B. Zink, and E. Schnetter, "Rotating Collapse of Stellar Iron Cores in General Relativity," refereed proceedings of the New Frontiers in Numerical Relativity Conference, Albert-Einstein-Institut, Potsdam. CQG 24, S139, 2007. (ads)
• B. Zink, N. Stergioulas, I. Hawke, C. D. Ott, E. Schnetter, E. Müller, "Non-axisymmetric instability and fragmentation of general relativistic quasi-toroidal stars," PRD 76, 204019, 2007. (ads)
• A. Burrows, E. Livne, L. Dessart, C. D. Ott, and J. Murphy, "Features of the Acoustic Mechanism of Core-Collapse Supernova Explosions," ApJ 655, 416, 2007. (ads)
• C. D. Ott, A. Burrows, L. Dessart, and E. Livne, "A New Mechanism for the Gravitational Wave Emission in Core-Collapse Supernovae," PRL 96, 201102, 2006. (ads)
• A. Burrows, E. Livne, L. Dessart, C. D. Ott, and J. Murphy, "A New Mechanism for Core-Collapse Supernova Explosions,", ApJ 640, 878, 2006. (ads)
• L. Dessart, A. Burrows, E. Livne, and C. D. Ott, "Multi-Dimensional Radiation/Hydrodynamic Simulations of Protoneutron Star Convection," ApJ 645, 534, 2006. (ads)
• C. D. Ott, A. Burrows, T. Thompson, E. Livne, and R. Walder, "The Spin Periods and Rotational Profiles of Neutron Stars at Birth," ApJS 164, 130, 2006. (ads)
• L. Dessart, A. Burrows, C. D. Ott, and E. Livne, "Multi-Dimensional Simulations of the Accretion-Induced Collapse of White Dwarfs to Neutron Stars," ApJ 644, 1063, 2006 (ads)
• B. Zink, N. Stergioulas, I. Hawke, C. D. Ott, E. Schnetter, E. Müller, "Black hole formation through fragmentation of toroidal polytropes", PRL 96, 161101, 2006. (ads)
• R. Walder, A. Burrows, C. D. Ott, E. Livne, M. Jarrah, "Anisotropies in the Neutrino Fluxes and Heating Profiles in Two-dimensional, Time-dependent, Multi-group Radiation Hydrodynamics Simulations of Rotating Core-Collapse Supernovae," ApJ 626, 317, 2005. (ads)
• C. D. Ott, S. Ou, J. E. Tohline, A. Burrows, "One-armed Spiral Instability in a Slowly Rotating, Post-Bounce Supernova Core", ApJ 625, L119, 2005. (ads)
• C. D. Ott, A. Burrows, E. Livne, and R. Walder, "Gravitational Waves from Axisymmetric, Rotational Stellar Core Collapse," ApJ 600, 834, 2004. (ads)

Preprints

• E. Abdikamalov, C. D. Ott, L. Rezzolla, L. Dessart, H. Dimmelmeier, A. Marek, and H.-T. Janka, "Axisymmetric General Relativistic Simulations of the Accretion-Induced Collapse of White Dwarfs," (ads/arXiv)
• J. Murphy, C. D. Ott, and A. Burrows, "A Model for Gravitational Wave Emission from Neutrino-Driven Core-Collapse Supernovae". (ads/arXiv)