AEI scientist Holger Pletsch awarded one million Euros
New Emmy Noether group for outstanding researcher
The astrophysicist Holger Pletsch, leader of an independent research group at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) and the Institute for Gravitational Physics at Leibniz Universität Hannover, develops efficient methods for the discovery of unknown gravitational-wave and gamma-ray pulsars. Starting in April 2014, his excellent research is supported by the Emmy Noether program of the Deutsche Forschungsgemeinschaft (DFG) with a total of one million Euros for a duration of five years.
Fundamental research with pulsars
Pulsars are rapidly rotating neutron stars and play a crucial role in the understanding of several key questions in fundamental physics and astrophysics. “Since the discovery of the first pulsars in the 1960s most known pulsars have been discovered in radio waves,” explains Holger Pletsch. “In 2008 the NASA's Fermi Gamma-ray Space Telescope has opened up a new window onto the universe in the gamma-ray range, providing unique opportunities for pulsar searches and to advance our understanding of neutron stars.”
Fermi has catalogued several hundreds of still unidentified gamma-ray sources, many of which are likely to be pulsars. However finding these hidden treasures represents a tremendous computational challenge. Pletsch is an expert in this field and has already contributed several important breakthroughs.
Innovative and interdisciplinary
In recent years, Pletsch has led the development of new search methods with unprecedented sensitivity. In an interdisciplinary approach he combined techniques from gravitational-wave, gamma-ray and radio astronomy. The novel data analysis methods are highly efficient and very sensitive, and thus facilitate the extremely compute intensive searches for gamma-ray pulsars. In some cases, only those new methods make the discovery of pulsars possible, which previously were completely inaccessible.
Using the volunteer computing system Einstein@Home and the Atlas computer cluster at the AEI, Pletsch's team has already discovered 15 new gamma-ray pulsars – about half of the known gamma-ray-only population. Among them is the current record holder for the pulsar in the tightest orbit with its companion.
“The flexible research grant of the DFG's Emmy Noether program allows us to consequently extend this successful approach,” says Pletsch. “We will refine and also expand our analysis methodologies, which opens up the exciting prospect of discovering completely new pulsar systems.” Pletsch's team cooperates with partners in Germany, France, Poland, and the USA. Their search also employs Einstein@Home, which harnesses idle compute cycles on volunteers' computers from all around the world. More than 360,000 participants put Einstein@Home's aggregated computing power on par with the world's largest supercomputers.
A new era of astronomy
These methods can also be applied to the search for gravitational waves. Gravitational waves are a prediction from Einstein's general theory of relativity, tiny ripples in space time that so far have only been seen indirectly. Following an upgrade, an international network of dedicated detectors will soon start taking data more sensitive than ever before. Their first direct measurements will usher in a new era of astronomy.
The methods developed by Pletsch's team can be used to filter out the faint gravitational-wave signals emitted by rapidly rotating neutron stars – so-called gravitational-wave pulsars – from the long-duration data streams. “Thereby we multiply our scientific returns and are also optimally positioned to make significant contributions to gravitational-wave astronomy in these forthcoming exciting times.”
Internationally awarded scientist
After studying physics at the TU Kaiserslautern and at the University of Wisconsin-Milwaukee, Holger Pletsch did his doctoral studies at the AEI and obtained a PhD with highest praise from Leibniz Universität Hannover in 2009. His dissertation was awarded two prizes. As youngest PhD student with an excellent degree in 2009, the Max Planck society awarded Holger Pletsch the Dieter-Rampacher Prize. In the same year the Gravitational Wave International Committee (GWIC) awarded him the international GWIC-Thesis Prize for the best dissertation in the field of gravitational-wave astronomy. Since 2013 he has been working as an Independent Research Group Leader at the AEI. In 2013 he was awarded the renowned Heinz Maier-Leibnitz Prize by the DFG and the Federal Ministry of Education and Research (BMBF).
Neutron stars as instruments of fundamental research
Neutron stars provide astronomers with laboratories for testing fundamental physics in extreme conditions. Because of their strong gravitational field they are ideal test beds for Einstein's general theory of relativity. Their high density allows scientists to study matter in conditions not attainable in laboratories on Earth. As remnants of exploded stars they shed light on their unusual “paths of life” and deepen our understanding of stellar evolution. Neutron stars also are considered a promising source for gravitational waves, whose direct detection will usher in a new era of astronomy.
The Emmy Noether program
The aim of the DFG's Emmy Noether program is to give outstanding young researchers the opportunity to swiftly qualify for a leading scientific role, in particular as university teacher. The program combines the self-responsible leadership of a research group and qualification-relevant teaching. The requirements are an excellent research project, a swiftly completed academic training, substantial experience in international research collaborations, and significant publications in important international scientific journals.