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LIGO and Virgo find another surprising binary system

The harvest of exceptional gravitational-wave events from LIGO’s and Virgo’s third observing run (O3) grows. A new signal published today comes from the merger of a 23-solar-mass black hole with an object 9 times lighter. The second object is mysterious: its measured mass puts it in the so-called “mass gap” between the heaviest known neutron stars and the lightest known black holes. While the researchers cannot be sure about its true nature, one thing is clear: the observation of this unusual pair challenges the current understanding of how such systems are born and evolve.

On the occasion of the 236th meeting of the American Astronomical Society the LISA Consortium launched a new movie about ESA´s LISA mission. LISA is a space mission led by ESA with contributions from NASA and many ESA member states. LISA will observe gravitational waves in space with three satellites connected by laser beams forming a constellation in a heliocentric orbit.

LIGO and Virgo detectors catch first gravitational wave from binary black hole merger with unequal masses

The expectations of the gravitational-wave research community have been fulfilled: gravitational-wave discoveries are now part of their daily work as they have identified in the past observing run, O3, new gravitational-wave candidates about once a week. But now, the researchers have published a remarkable signal unlike any of those seen before: GW190412 is the first observation of a binary black hole merger where the two black holes have distinctly different masses of about 8 and 30 times that of our Sun. This not only has allowed more precise measurements of the system’s astrophysical properties, but it has also enabled the LIGO/Virgo scientists to verify a so far untested prediction of Einstein’s theory of general relativity.

Visit founding director Prof Bernard F Schutz´ blog for the story:

Find out more about the O3 commissioning break, GW190425 and more here:

International team led by Max Planck researchers finds promising new candidates for gravitational waves from binary black hole mergers in public LIGO/Virgo data

Researchers from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hannover together with international colleagues have published their second Open Gravitational-wave Catalog (2-OGC). They used improved search methods to dig deeper into publicly available data from LIGO’s and Virgo’s first and second observation runs. Apart from confirming the ten known binary black hole mergers and one binary neutron star merger, they also identify four promising black hole merger candidates, which were missed by initial LIGO/Virgo analyses. These results demonstrate the value of searches in public LIGO/Virgo data by research groups independent of the LIGO/Virgo collaborations. The research team also makes available its complete catalogue in addition to detailed analysis of more than a dozen possible binary black hole mergers.

International team uses a novel approach combining gravitational-wave observations, multi-messenger astronomy, and nuclear physics to obtain the best measurement of neutron star size to date.

An international research team led by members of the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) has obtained new measurements of how big neutron stars are. To do so, they combined a general first-principles description of the unknown behavior of neutron star matter with multi-messenger observations of the binary neutron star merger GW170817. Their results, which appeared in Nature Astronomy today, are more stringent by a factor of two than previous limits and show that a typical neutron star has a radius close to 11 kilometers. They also find that neutron stars merging with black holes are in most cases likely to be swallowed whole, unless the black hole is small and/or rapidly rotating. This means that while such mergers might be observable as gravitational-wave sources, they would be invisible in the electromagnetic spectrum.

Jahed Abedi, a postdoctoral researcher at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute), shares the $10,000 First Prize of the annual 2019 Buchalter Cosmology Prize with Niayesh Afshordi (University of Waterloo and Perimeter Institute for Theoretical Physics). The winners of the prize have been announced on 6 January 2020 at the 235th meeting of the American Astronomical Society in Honolulu.

The international gravitational-wave detector network has observed what is most likely its second signal from merging neutron stars. The signal dubbed GW190425 was identified as a highly significant event by the LIGO Livingston and the Virgo detector on April 25, 2019. The signal comes from a distance of about 520 million light-years, four times farther away than the first gravitational wave from a binary neutron star merger detected in August 2017. No observations by electromagnetic or neutrino observatories related to this signal have been reported. While a binary neutron star merger is the most likely explanation, the combined mass of the system is much higher than that of other known such systems. This could be due to special formation circumstances of the system. It is also possible that one or both objects are light-weight black holes not previously observed.

A group of 47 researchers in Germany received a NASA award for their teamwork on the novel and very successful Laser Ranging Interferometer on board the GRACE Follow-On satellite tandem. Among them are 13 researchers from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) and the Institute for Gravitational Physics at Leibniz Universität Hannover. The NASA Group Achievement Award was presented to the team at the Jet Propulsion Laboratory at the end of October for “dedication and excellence in developing and successfully deploying” the laser instrument on board the GRACE Follow-On mission.

A squeezed-light source developed by researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) for the Virgo gravitational-wave detector near Pisa has impressively demonstrated its capabilities in recent months. This is shown by the latest data published from the third observation run (O3) of the international detector network. The squeezed-light source reduces the dominant quantum mechanical detector background noise by about one third. This allows Virgo, for example, to detect gravitational waves from merging neutron stars up to 26% more frequently. The use of squeezed light also plays an important role for planned third-generation detectors such as the Einstein Telescope. The squeezed-light source was delivered and commissioned at the beginning of 2018. Since the start of O3 on April 1, 2019, it has provided significantly improved Virgo sensitivity.

Anna Ijjas, leader of the recently established Lise Meitner Research Group “Gravitational Theory and Cosmology” at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute / AEI) in Hannover, and Paul Steinhardt, Albert Einstein Professor in Science at Princeton University, receive 1.3 million US-dollars for four years from the Simons Foundation. The goal of the newly funded initiative “New Directions in Cosmology and Gravitational Theory” is to develop and test theories of the origin, evolution, and future of the universe that challenge the standard view that the universe began with a big bang about 14 billion years ago. Ijjas’ group at the AEI Hannover receives 500 000 US-dollars that she will use towards building her research team, including support for graduate students and postdocs, workshops, conferences, and visitors.

Prof. Karsten Danzmann, Director at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hannover and Director of the Institute for Gravitational Physics at Leibniz University Hannover, has been accepted into the Manager Magazine’s “Hall of Fame of German Research”. The award recognizes his lifelong, outstanding contributions to the advancement of research. The award was presented on 29 October in Berlin.

An international research team led by the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hannover has discovered that the radio pulsar J0952-0607 also emits pulsed gamma radiation. J0952-0607 spins 707 times in one second and is 2nd in the list of rapidly rotating neutron stars. By analyzing about 8.5 years worth of data from NASA’s Fermi Gamma-ray Space Telescope, LOFAR radio observations from the past two years, observations from two large optical telescopes, and gravitational-wave data from the LIGO detectors, the team used a multi-messenger approach to study the binary system of the pulsar and its lightweight companion in detail. Their study published in Astrophysical Journal Letters today shows that extreme pulsar systems are hiding in the Fermi catalogues and motivates further searches. Despite being very extensive, the analysis also raises new unanswered questions about this system.