-Conference and Seminar Talk List
Gravitational Waveform Catalog
Since May 2008 I am working as an expert for safety analysis of nuclear
reactors for the company AREVA NP GmbH
in Erlangen, Germany. Previously, I was a Marie Curie fellow at the
Section of Astrophysics, Astronomy & Mechanics
Aristotle University of Thessaloniki in Greece.
Before that I was a postdoctoral researcher in the Relativistic Hydrodynamics Group of the
Max Planck Institute for Astrophysics in Garching.
Until January 2007, I was also a member of the German research network
SFB Transregio 7 "Gravitational Wave Astronomy",
I was a former member of the German research network
SFB 375 "Astro-Particle Physics",
and I was a previous informal member of the European Union Research and Training Network "Sources of Gravitational Waves".
My research interest was on relativistic hydrodynamics and numerical
relativity, with particular focus on compact sources of gravitational
waves, numerical methods in computational fluid dynamics, and
applications of such methods in simulations of stellar gravitational
collapse and rotating neutron star models. A very useful external
resource on this subject is the
Stellar Collapse Website.
Numerical simulations of stellar gravitational collapse are usually
performed on parallel supercomputers like for instance the ones at the
Garching Computing Center of the Max Planck Society,
the Leibniz Computing Center of the Bavarian Academy of Sciences,
or the National Computing Center of Supercomputing Applications
of the University of Illinois at Urbana-Champaign.
Such simulations are based on methods also utilized in the field of
acoustics, aerodynamics, combustion theory, hydrology, geology,
automotive safety, and even the financing sector. For this schemes are
employed which are specificly tailored for the use in astrophysics and
general relativity, and for example accomodate for the fact that in a
strong gravitational field spacetime is curved.
The investigated scenarios are a promising source of
gravitational radiation. These distortions of spacetime are planned to
be measured by laser interferometers or resonant bar detectors in the
near future. Such experiments
(like GEO 600,
have recently started very sensitive measurements. Many of my projects
involve providing the data analysis groups of these detectors
with templates of the expected waveforms, which are crucial for a
successful detection of the signals.
In the development of numerical codes for simulations of general relativistic
hydrodynamics (like the powerful, modern and robust three-dimensional
which has been used for many projects I have been involved in), I closely collaborated with scientists from
the Departamento de Astronomía y Astrofísica at the
Universidad de Valencia in Spain, from the Laboratoire de l'Univers et de ses Théories at the Observatoire de Paris in
France, and from the
Numerical Relativity Group
Max Planck Institute for Gravitational Physics in Potsdam, Germany.
In addition, I was the technical editor of the online journal
Living Reviews in Relativity,
which is a peer reviewed journal offered by the Max Planck Institute for Gravitational Physics in Potsdam.
It publishes reviews of research in the theory of relativity as a free
service to the scientific community.
This journal is one of three journals of the Living Reviews journal family,
which is hosted and supported by the Heinz Nixdorf Center for Information Management of the
Max Planck Society.
This is a selection of previous and current projects pursued by me and
Simulations of the Accretion-Induced Gravitational Collapse of White Dwarfs
Accretion of matter from a companion star may trigger the
collapse of a white dwarf to a proto-neutron star. We have found
that this process is accompanied by the emission of
gravitational radiation with a particular signal structure.
The signal waveform could also give information about the
occurence of rotational instabilities in the nascent
Reconstruction of Gravitational Wave Burst Signals with Bayesian Inference Techniques
The gravitational waveform burst emitted during the formation of the
proto-neutron star in a stellar core collapse has a complicated
structure. To be able to employ efficient filtering techniques in the
search pipelines of wave detectors, we have proposed a statistical method
to accurately reconstruct such waveforms using a small set of basis
Dynamic Migration of Rotating Neutron Stars due to a Phase Transition Instability
In their early life, rapidly rotating neutron stars (like
e.g. magnetars) can possibly encounter an instability that results in
a dynamic migration to a new stable equilibrium after a collapse and a
sequence of ring-down pulsations. Using fully dynamical numerical
simulations, we have investigated such a scenario, where also strong
gravitational waves with a complicated frequency spectrum could be
A Solution for the Nonuniqueness Problem of the Spacetime Constraint Equations
The otherwise very successful CFC scheme for approximating the
Einstein equations in simulations of compact astrophysical objects
fail at very high densities. We have found a reformulation which
solves this problem and extends the applicability of CFC to e.g. black
Phase-Transition-Induced Collapse of a Rotating Neutron Star to a Hybrid Quark Star
E.B. Abdikamalov, H. Dimmelmeier, L. Rezzolla, J.C. Miller
If rotating neutron stars undergo a phase transition
from regular matter to quarks in their core, the
subsequent collapse can be a strong source of
gravitational waves. We have performed the first-ever
general relativistic simulations of this scenario,
and find that resonance effects can even enhance the
emission of gravitational radiation.
Simulations of Rotational Stellar Core Collapse in General Relativity with Microphysics
H. Dimmelmeier, C.D. Ott, H.-T. Janka, A. Marek,
I. Hawke, B. Zink, E. Schnetter, and E. Müller
We have performed the first 2D and 3D simulations of rotating stellar
core collapse to a neutron star in general relativity with microphysics.
We have found that the resulting gravitational wave signals are much
more generic than previously anticipated.
Nonlinear Axisymmetric Pulsations of Rotating Relativistic Stars
H. Dimmelmeier, N. Stergioulas, J.A. Font
With the axisymmetric version of the "Mariage des Maillages" code
we have for the first time simulated pulsations in uniformly and differentially rotating
neutron star models in general relativistic gravity and identified important
nonlinear effects. We have also investigated the issue of
detectability of gravitational wave emitted by such oscillations.
Gravitational Radiation from Relativistic Rotational Core Collapse
H. Dimmelmeier, J.A. Font, E. Müller
We have succeeded for the first time to simulate the
collapse of a rotating stellar core to a neutron star including
the effects of general relativity, making a major step forward
towards realistic predictions of gravitational wave signals.
Over the years, I have acquired professional experience in a number
of fields, including
- computational fluid dynamics in astrophysics and nuclear engineering,
- electronic publishing,
- system administration, and
- research and development in automotive safety.
More on my expertise in these fields can be found in a detailed description.
My curriculum vitae can be downloaded in PDF format and gzipped PS format.
List of Publications:
Here is a list of my scientific publication track record.
List of Attendance at Scientific
Conferences, Invited Seminar Talks, and Summer Schools:
Here is a list of my attendance at scientific conferences and summer schools, and invited seminar talks.
Comments to: Harald Dimmelmeier firstname.lastname@example.org