Universities Space Research Association | Arecibo Observatory | 2017 Jan 04
A new discovery has upended the widely held view that all pulsars are orderly ticking clocks of the universe. A survey done at the Arecibo Observatory in Puerto Rico has fortuitously discovered two extremely strange pulsars that undergo a "cosmic vanishing act." Sometimes they are there, and then for very long periods of time, they are not.
Recognizing the existence of this strange behavior was fortuitous in itself. It took great patience on the part of a team of radio astronomers at Jodrell Bank in the UK led by Professor Andrew Lyne of the University of Manchester to confirm the existence of these mostly invisible pulsars.
Pulsars are rapidly rotating, highly magnetized neutron stars. They are about 20 miles across with masses of about 500,000 Earths. The rotation sends charged particles streaming out from the magnetic poles, causing beams of radio waves to sweep around the sky -- like the light beams from a lighthouse. This results in pulses, which can be received by terrestrial radio telescopes.
Intermittent pulsars are a rarely observed population of pulsars, which have two states -- one when they pulse like normal pulsars (the ON state), and another when they mysteriously fail to work, producing no radio waves at all (the OFF state). ...
A 34-member pulsar study team, including Dr. Andrew Seymour, a USRA postdoc at Arecibo, used the 7-beam receiver to conduct routine pulsar searches in what they call the PALFA (Pulsar Arecibo L-Band Feed Array) Survey. The two recently discovered intermittent pulsars spend most of their time in the OFF state. Three other similar pulsars are also known, but they are mostly ON. ...
Two Long-Term Intermittent Pulsars Discovered in the PALFA Survey - A. G. Lyne et al
- Astrophysical Journal 834(1):72 (2017 Jan 01) DOI: 10.3847/1538-4357/834/1/72
arXiv.org > astro-ph > arXiv:1608.09008 > 31 Aug 2016 (v1), 08 Dec 2016 (v4)