From The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE)
April 07, 2022
Dr. Aditya Parthasarathy
adityapartha3112@mpifr.de
Max-Planck-Institut für Radioastronomie, Bonn
Dr. Matthew Kerr
+1 202 294-9761 matthew.kerr@nrc.gov
U.S. Naval Research Laboratory (NRL)
Prof. Dr. Michael Kramer
Director and Head of “Fundamental Physics in Radio Astronomy”
Research Department
+49 228 525-278
mkramer@mpifr.de
Max Planck Institute for Radio Astronomy, Bonn
Dr. Norbert Junkes
Press and Public Outreach +49 228 525-399
njunkes@mpifr.de
Max Planck Institute for Radio Astronomy, Bonn
NASA’s FERMI Satellite Hunts for Extremely Long-wavelength Gravitational Wave Signals.
Coalescing supermassive black holes in the centers of merging galaxies fill the universe with low-frequency gravitational waves. Astronomers have been searching for these waves by using large radio telescopes to look for the subtle effect these spacetime ripples have on radio waves emitted by pulsars within our Galaxy. Now, an international team of scientists has shown that the high-energy light collected by NASA’s Fermi Gamma-ray Space Telescope can also be used in the search. Using gamma rays instead of radio waves yields a clearer view to the pulsars and provides an independent and complementary way to detect gravitational waves.
The findings of an international team of scientists including Aditya Parthasarathy and Michael Kramer from the Max Planck Institute of Radio Astronomy in Bonn, Germany, are published in Science this week.
Fig. 1: Orbiting 500 km above the earth, the Fermi Large Area Telescope collects gamma rays from millisecond pulsars. As these high-energy photons travel across the Milky Way, they encounter a sea of low-frequency gravitational waves produced by pairs of supermassive black holes coalescing in the centers of merged galaxies. The spacetime ripples, with wavelengths extending beyond 100 trillion kilometers, cause each photon to arrive slightly earlier or slightly later than expected. Monitoring the gamma rays from many of these millisecond pulsars—an experiment known as a pulsar timing array—can reveal this telltale signature. Pulsar timing arrays have previously only used sensitive radio telescopes. Now, data from Fermi are enabling a gamma-ray based pulsar timing array and giving a new, clear view of these gravitational waves. © Daniëlle Futselaar/MPIfR (artsource.nl).
A Sea of Gravitational Waves
At the heart of most galaxies—collections of hundreds of billions of stars like our own Milky Way—lies a supermassive black hole. Galaxies are drawn to each other by their immense gravitation, and when they merge their black holes sink to the new center. As the black holes spiral inward and coalesce, they create long gravitational waves that stretch out hundreds of trillions of kilometers between wave crests. The universe is full of such merging supermassive black holes, and they fill it with a sea of low-frequency spacetime ripples.
Astronomers have been searching for these waves for decades by observing the pulses from pulsars, the dense remnants of massive stars. Pulsars rotate with extreme regularity and astronomers know exactly when to expect each pulse. The sea of gravitational waves, however, subtly alters when the pulses arrive at the earth, and precisely monitoring many pulsars across the sky can reveal its presence.
Previous searches for these waves have exclusively used large radio telescopes, which collect and analyze radio waves. But now an international team of scientists has looked for these minute variations in more than ten years of data collected with NASA’s Fermi Gamma-ray Space Telescope, and their analysis shows that detecting these waves may be possible with just a few years of additional observations.
“Fermi studies the universe in gamma rays, the most energetic form of light. We’ve been surprised at how good it is at finding the types of pulsars we need to look for these gravitational waves—over 100 so far!” said Matthew Kerr, a research physicist at the U.S. Naval Research Laboratory in Washington. “Fermi and gamma rays have some special characteristics that together make them a very powerful tool in this investigation.”
The results of the study, co-led by Kerr and Aditya Parthasarathy, a researcher at the MPG Institute for Radio Astronomy (MPIfR) in Bonn, Germany, were published in the April 07 issue of Science.
Cosmic Clocks
Light takes on many forms. Low-frequency radio waves can pass through some objects, while high-frequency gamma rays explode into energetic particle showers when they encounter matter. Gravitational waves also cover a wide spectrum, and more massive objects tend to generate longer waves.
It is impossible to build a detector large enough to detect the trillion-kilometer waves powered by merging supermassive black holes, so astronomers use naturally-occurring detectors called pulsar timing arrays. These are collections of millisecond pulsars that shine in both radio waves and gamma rays and which rotate hundreds of times each second. Like lighthouses, these beams of radiation appear to pulse regularly as they sweep over the earth, and as they pass through the sea of gravitational waves they are imprinted with the faint rumble of distant, massive black holes.
A Unique Probe
Pulsars were originally discovered using radio telescopes, and pulsar timing array experiments with radio telescopes have been operating for nearly two decades.
These big dishes provide the most sensitivity to the effects of gravitational waves, but interstellar effects complicate the analysis of radio data. Space is mostly empty, but in crossing the vast distance between a pulsar and the earth, radio waves still encounter many electrons. Similarly to the way a prism bends visible light, interstellar electrons bend the radio waves and alter their arrival time. The energetic gamma rays aren’t affected in this way, so they provide a complementary and independent method of pulsar timing.
“The Fermi results are already 30% as good as the radio pulsar timing arrays when it comes to potentially detecting the gravitational wave background,” Parthasarathy said. “With another five years of pulsar data collection and analysis, it’ll be equally capable with the added bonus of not having to worry about all those stray electrons.”
A gamma-ray pulsar timing array, not envisioned before the launch of Fermi, represents a powerful new capability in gravitational wave astrophysics.
“Detecting the gravitational wave background with pulsars is within reach but remains difficult. An independent method, shown here unexpectedly through Fermi is great news, both for confirming future findings and in demonstrating its synergies with radio experiments”, concludes Michael Kramer, a director at the MPIfR and head of its Fundamental Physics in Radio Astronomy research department.
Additional Information
The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by The National Aeronautics and Space Agency’s Goddard Space Flight Center in Greenbelt, Maryland. Fermi was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the United States.
The FERMI-LAT collaboration comprises an international team of scientists including Aditya Parthasarathy and Michael Kramer, both from, the Max Planck Institute for Radio Astronomy.
See the full article here .
five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.
The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie] (DE) is located in Bonn, Germany. It is one of 80 institutes in the MPG Society.
By combining the already existing radio astronomy faculty of the University of Bonn led by Otto Hachenberg with the new MPG institute the MPG Institute for Radio Astronomy was formed. In 1972 the 100-m radio telescope in Effelsberg was opened. The institute building was enlarged in 1983 and 2002.
The institute was founded in 1966 by the MPG Society as the “MPG Institut für Radioastronomie (MPIfR) (DE)”.
The foundation of the institute was closely linked to plans in the German astronomical community to construct a competitive large radio telescope in (then) West Germany. In 1964, Professors Friedrich Becker, Wolfgang Priester and Otto Hachenberg of the Astronomische Institute der Universität Bonn submitted a proposal to the Stiftung Volkswagenwerk for the construction of a large fully steerable radio telescope.
In the same year the Stiftung Volkswagenwerk approved the funding of the telescope project but with the condition that an organization should be found, which would guarantee the operations. It was clear that the operation of such a large instrument was well beyond the possibilities of a single university institute.
Already in 1965 the MPG Society decided in principle to found the MPG Institut für Radioastronomie. Eventually, after a series of discussions, the institute was officially founded in 1966.
MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.
According to its primary goal, the MPG Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) MPG Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.
The MPG Institutes focus on excellence in research. The MPG Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the MPG institutes fifth worldwide in terms of research published in Nature journals (after Harvard University, The Massachusetts Institute of Technology, Stanford University and The National Institutes of Health). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by The Chinese Academy of Sciences [中国科学院](CN), The Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the MPG Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.
The MPG Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.
History
The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.
The MPG Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the MPG Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and The DOE’s Argonne National Laboratory.
The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.
MPG Institutes and research groups
The MPG Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
The MPG Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.
Internally, MPG Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.
In addition, there are several associated institutes:
International Max Planck Research Schools
Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
• Cologne Graduate School of Ageing Research, Cologne
• International Max Planck Research School for Intelligent Systems, at the Max Planck Institute for Intelligent Systems located in Tübingen and Stuttgart
• International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
• International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
• International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPI for Astronomy
• International Max Planck Research School for Astrophysics, Garching at the MPI for Astrophysics
• International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
• International Max Planck Research School for Computer Science, Saarbrücken
• International Max Planck Research School for Earth System Modeling, Hamburg
• International Max Planck Research School for Elementary Particle Physics, Munich, at the MPI for Physics
• International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the Max Planck Institute for Terrestrial Microbiology
• International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
• International Max Planck Research School “From Molecules to Organisms”, Tübingen at the Max Planck Institute for Developmental Biology
• International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
• International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPI for Gravitational Physics
• International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the Max Planck Institute for Heart and Lung Research
• International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
• International Max Planck Research School for Language Sciences, Nijmegen
• International Max Planck Research School for Neurosciences, Göttingen
• International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
• International Max Planck Research School for Marine Microbiology (MarMic), joint program of the Max Planck Institute for Marine Microbiology in Bremen, the University of Bremen, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
• International Max Planck Research School for Maritime Affairs, Hamburg
• International Max Planck Research School for Molecular and Cellular Biology, Freiburg
• International Max Planck Research School for Molecular and Cellular Life Sciences, Munich
• International Max Planck Research School for Molecular Biology, Göttingen
• International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
• International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster and the Max Planck Institute for Molecular Biomedicine
• International Max Planck Research School on Multiscale Bio-Systems, Potsdam
• International Max Planck Research School for Organismal Biology, at the University of Konstanz and the Max Planck Institute for Ornithology
• International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion
• International Max Planck Research School for Science and Technology of Nano-Systems, Halle at Max Planck Institute of Microstructure Physics
• International Max Planck Research School for Solar System Science at the University of Göttingen hosted by MPI for Solar System Research
• International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPI for Radio Astronomy (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
• International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
• International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at Max Planck Institute for Iron Research GmbH
• International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg
Max Planck Schools
• Max Planck School of Cognition
• Max Planck School Matter to Life
• Max Planck School of Photonics
Max Planck Center
• The Max Planck Centre for Attosecond Science (MPC-AS), POSTECH Pohang
• The Max Planck POSTECH Center for Complex Phase Materials, POSTECH Pohang
Max Planck Institutes
Among others:
• Max Planck Institute for Neurobiology of Behavior – caesar, Bonn
• Max Planck Institute for Aeronomics in Katlenburg-Lindau was renamed to Max Planck Institute for Solar System Research in 2004;
• Max Planck Institute for Biology in Tübingen was closed in 2005;
• Max Planck Institute for Cell Biology in Ladenburg b. Heidelberg was closed in 2003;
• Max Planck Institute for Economics in Jena was renamed to the Max Planck Institute for the Science of Human History in 2014;
• Max Planck Institute for Ionospheric Research in Katlenburg-Lindau was renamed to Max Planck Institute for Aeronomics in 1958;
• Max Planck Institute for Metals Research, Stuttgart
• Max Planck Institute of Oceanic Biology in Wilhelmshaven was renamed to Max Planck Institute of Cell Biology in 1968 and moved to Ladenburg 1977;
• Max Planck Institute for Psychological Research in Munich merged into the Max Planck Institute for Human Cognitive and Brain Sciences in 2004;
• Max Planck Institute for Protein and Leather Research in Regensburg moved to Munich 1957 and was united with the Max Planck Institute for Biochemistry in 1977;
• Max Planck Institute for Virus Research in Tübingen was renamed as Max Planck Institute for Developmental Biology in 1985;
• Max Planck Institute for the Study of the Scientific-Technical World in Starnberg (from 1970 until 1981 (closed)) directed by Carl Friedrich von Weizsäcker and Jürgen Habermas.
• Max Planck Institute for Behavioral Physiology
• Max Planck Institute of Experimental Endocrinology
• Max Planck Institute for Foreign and International Social Law
• Max Planck Institute for Physics and Astrophysics
• Max Planck Research Unit for Enzymology of Protein Folding
• Max Planck Institute for Biology of Ageing
sciencesprings 