Netherlands Institute for Radio Astronomy (ASTRON) | 2017 Sep 05
Astronomers have discovered two rapidly rotating radio pulsars with the Low-Frequency Array (LOFAR) radio telescope in the Netherlands by investigating unknown gamma-ray sources uncovered by NASA’s Fermi Gamma-ray Space Telescope. The first pulsar (PSR J1552+5437) rotates 412 times per second. The second pulsar (PSR J0952-0607) rotates 707 times per second, making it the fastest-spinning pulsar in the disk of our Galaxy and the second-fastest known spinning-pulsar overall.
- The Low-Frequency Array (LOFAR), a network of thousands of linked radio antennas, primarily located in the Netherlands, has discovered two new millisecond pulsars by investigating previously unknown gamma-ray sources uncovered by NASA's Fermi Gamma-ray Space Telescope. Pulsar J0952-0607, highlighted near center right, rotates 707 times a second and now ranks as second-fastest pulsar known. The location of LOFAR's first millisecond pulsar discovery, J1552+5437, which spins 412 times a second, is shown at upper left. Radio emission from both pulsars dims quickly at higher radio frequencies, making them ideally suited for LOFAR. The top of this composite image shows a portion of the gamma-ray sky as seen by Fermi. At the bottom is the LOFAR "superterp" near Exloo, the Netherlands, which houses the facility's core antenna stations.
Credits: NASA/DOE/Fermi LAT Collaboration and ASTRON
Pulsars are neutron stars, the remnants of massive stars that exploded as a supernova, which emit radio waves from their magnetic poles that sweep past Earth as they rotate. As a result, they act like lighthouses where we see pulses of radio emission for each rotation. Neutron stars are the size of a city packed in more mass than the Sun. That’s why they are used to study the behaviour of matter under extreme densities. By studying the fastest-spinning pulsars, astronomers hope to discover more about the internal structure of neutron stars and the extremes of the Universe.
Pulsars shine the brightest at low frequency radio waves and this makes LOFAR an ideal telescope for studying them. “However, finding pulsars with LOFAR is extra hard work because gas and dust between stars disrupts low frequency radio waves,” says Cees Bassa from ASTRON, the Netherlands Institute for Radio Astronomy. That’s why astronomers usually look for pulsars at higher radio frequencies.
Bassa and his colleagues have now found a way to overcome this problem. “We have developed a new processing technique, which uses graphics cards (originally designed for gaming) in the large DRAGNET computer cluster in Groningen to process the LOFAR data.” This cluster is funded through an ERC starting grant to Jason Hessels from ASTRON and the University of Amsterdam. ...
'Extreme' Telescopes Find the Second-fastest-spinning Pulsar
NASA | GSFC | Fermi | 2017 Sep 05
A Millisecond Pulsar Discovery in a Survey of Unidentified Fermi γ-Ray Sources with LOFAR - Z. Pleunis et al
- Astrophysical Journal Letters 846(2):L19 (2017 Sep 10) DOI: 10.3847/2041-8213/aa83ff
arXiv.org > astro-ph > arXiv:1709.01452 > 05 Sep 2017
- Astrophysical Journal Letters 846(2):L20 (2017 Sep 10) DOI: 10.3847/2041-8213/aa8400
arXiv.org > astro-ph > arXiv:1709.01453 > 05 Sep 2017