Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Einstein@Home discovers first millisecond pulsar visible only in gamma rays


The distributed computing project Einstein@Home aggregates the computing power donated by tens of thousands of volunteers world wide. In a survey of the gamma-ray sky, this network has now discovered two previously unknown pulsarsd in data from the Fermi space telescope. While all other such millisecond pulsars have also been observed with radio telescopes, one of the two discoveries is the first detectable solely through its pulsed gamma-ray emission. The findings raise hopes of detecting other new millisecond pulsars, e.g., from a predicted population towards the Galactic centre. Scientists from the AEI in Hannover and the MPIfR in Bonn closely collaborated to enable the discoveries.

“We made these two new discoveries in our large-scale Einstein@Home gamma-ray pulsar survey. This feat was only possible by using novel and more efficient search methods, improved Fermi Large Area Telescope (LAT) data, and the huge computing power provided by Einstein@Home,” says Dr. Colin Clark from Jodrell Bank Centre for Astrophysics, lead author of the paper published in Science Advances, who was a doctoral student at the Max Planck Institute for Gravitational Physics when he made the discoveries.

The entire Gamma-ray sky with the two new pulsars discovered by Einstein@Home. The flags in the insets show the nationalities of the volunteers whose computers found the pulsars.

Knispel/Clark/Max Planck Institute for Gravitational Physics/NASA/DOE/Fermi LAT Collaboration

Artist’s view of a gamma-ray pulsar with gamma radiation (violet) and radio waves (green). The rotation of the system is making the pulsar light up periodically in the sky.

NASA/Fermi/Cruz de Wilde

“After we found the two millisecond pulsars with Einstein@Home we pointed a large radio telescope at them and expected to find their pulsed radio emission. That was the case for every other millisecond pulsar known until then. To our surprise one of our discoveries remained entirely radio-quiet.”

This shows that these “blind” gamma-ray pulsar searches have the potential to discover a hitherto unknown population of radio-quiet millisecond pulsars. These might be behind other unidentified Fermi-LAT sources, or the gamma-ray glow seen towards the center of our Galaxy.

Born in supernova explosions

Neutron stars are compact remnants from supernova explosions and consist of exotic, extremely dense matter. They measure about 20 kilometers across and weigh more than our Sun. Because of their strong magnetic fields and fast rotation they emit beamed radio waves and energetic gamma rays similar to a cosmic lighthouse. If these beams point towards Earth during the neutron star’s rotation, it becomes visible as a pulsating radio or gamma-ray source – a so-called pulsar.

Millisecond pulsars form when a pulsar is spun up by accreting matter from a companion star. The inflow of material from the partner star can accelerate the pulsar up to hundreds of rotations in a single second. Once the accretion ends, the rapidly rotating neutron star can be observed as a millisecond pulsar.

Two new millisecond pulsars

The new publication describes the discovery of two previously unknown gamma-ray pulsars, which are called PSR J1035−6720 and PSR J1744−7619 after their respective sky positions. The first of the two city-sized neutron stars spins a dazzling 348 times each second, and the latter 213 times each second. After the initial discoveries, their astrophysical parameters were refined by a re-analysis of the Fermi-LAT data.

These improved parameters were used to search for the radio pulsations of the two sources in archival radio telescope data and in new observations with the Parkes Radio Telescope. While PSR J1035−6720 was discovered as an unusually faint radio millisecond pulsar, no radio waves at all were detected from PSR J1744−7619. This makes it the first radio-quiet millisecond pulsar ever discovered.

A hidden pulsar population

It is possible that the lighthouse-like radio beams of PSR J1744−7619 do not point towards Earth, while the gamma-ray beams do. The researchers addressed this question by comparing the observed gamma-ray emission with theoretical models. They showed that the models that describe the gamma-ray emission well, predict a detectable radio signal. Its absence means that PSR J1744−7619 must either be extremely radio-faint, or that the models must be incomplete.

According to some predictions, the observed excess of high-energy gamma-radiation from the central region of the Milky Way could be due to a hidden population of thousands of millisecond pulsars. While only a handful might be detectable with current large radio telescopes, gamma-ray searches might have a better chance of finding more of these sources.

Einstein@Home searches for gamma-ray pulsars hidden in binary systems

“With the help of our volunteers we searched through 152 unidentified pulsar-like sources from the Fermi-LAT Catalog,” says Prof. Dr. Bruce Allen, director of Einstein@Home and director at the Max Planck Institute for Gravitational Physics in Hanover. “We have shown that 19 of these do not only look like pulsars, they in fact are pulsars and in some cases quite unusual to boot. Personally, I would bet that many of the remaining 133 are also pulsars, but hidden in binary systems, where they are more difficult to find. At the moment Einstein@Home is chasing after those binary pulsars and I hope we will soon find some.”

“This is a marvelous example of modern-day astrophysics: we use expertise from gravitational wave astronomy to cleverly analyze gamma-ray data in order to reveal sources that complement our knowledge from radio observations. Brilliant,” concludes Michael Kramer, director at Max Planck Institute for Radio Astronomy, head of its “Fundamental Physics in Radio Astronomy” research department, and co-author of the paper.

Who made the discoveries?

The discoveries were enabled by tens of thousands of Einstein@Home volunteers who have donated their CPU time to the project. Without them this survey could not have been performed and these discoveries could not have been made. The team is especially grateful to those volunteers whose computers discovered the 2 pulsars reported in the Science Advances publication (where the volunteer’s name is unknown or private, we give the Einstein@Home username in quotation marks):

• PSR J1035−6720: “WSyS”; Kurt Kovacs, of Seattle Washington, USA; and the ATLAS Cluster, AEI, Hannover, Germany.
• PSR J1744−7619: Darrell Hoberer, of Gainesville, TX, USA; the ATLAS Cluster, AEI, Hannover, Germany; Igor Yakushin of Chicago, IL, USA and the LIGO Laboratory, USA; and Keith Pickstone of Oldham, UK.

Original Paper:

Clark, C. J. et al. „Einstein@Home Discovers a Radio-quiet Gamma-ray Millisecond Pulsar”, Science Advances (2018)

Science Contacts:

Dr. Colin Clark
Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester
phone:+49 511 762-17187

Prof. Dr. Bruce Allen
Director of the “Observational Relativity and Cosmology” Division; Einstein@Home director
Max Planck Institute for Gravitational Physics Hannover
phone:+49 511 762-17148

Prof. Dr. Michael Kramer
Director and Head of “Fundamental Physics in Radio Astronomy” research division
Max-Planck-Institut für Radioastronomie, Bonn.
Fon: +49 228 525-278

Media Contacts:

Dr. Benjamin Knispel
Press Officer
Max Planck Institute for Gravitational Physics Hannover
phone:+49 511 762-19104

Dr. Norbert Junkes,
Press and Public Outreach
Max-Planck-Institut für Radioastronomie, Bonn.
Fon: +49 228 525-399

Weitere Informationen:

Norbert Junkes | Max-Planck-Institut für Radioastronomie

More articles from Physics and Astronomy:

nachricht Disrupting crystalline order to restore superfluidity
12.10.2018 | Universität Hamburg

nachricht Novel Topological Insulator
11.10.2018 | Julius-Maximilians-Universität Würzburg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Disrupting crystalline order to restore superfluidity

When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.

We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...

Im Focus: Micro energy harvesters for the Internet of Things

Fraunhofer IWS Dresden scientists print electronic layers with polymer ink

Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...

Im Focus: Dynamik einzelner Proteine

Neue Messmethode erlaubt es Forschenden, die Bewegung von Molekülen lange und genau zu verfolgen

Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...

Im Focus: Dynamics of individual proteins

New measurement method allows researchers to precisely follow the movement of individual molecules over long periods of time

The function of proteins – the molecular tools of the cell – is governed by the interplay of their structure and dynamics. Advances in electron microscopy have...

Im Focus: Researchers discover how fatal biofilms form

By severely curtailing the effects of antibiotics, the formation of organized communities of bacterial cells known as biofilms can be deadly during surgeries and in urinary tract infections. Yale researchers have just come a lot closer to understanding how these biofilms develop, and potentially how to stop them.

Biofilms form when bacterial cells gather and develop structures that bond them in a gooey substance. This glue can protect the cells from the outside world...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

5th International Conference on Cellular Materials (CellMAT), Scientific Programme online

02.10.2018 | Event News

Major Project: The New Silk Road

01.10.2018 | Event News

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

Latest News

The future of electronic devices: Strong and self-healing ion gels

12.10.2018 | Materials Sciences

Light switch: Scientists develop method to control nanoscale manipulation in high-powered microscopes

12.10.2018 | Materials Sciences

Smaller, more frequent eruptions affect volcanic flare-ups

12.10.2018 | Earth Sciences

Science & Research
Overview of more VideoLinks >>>