California Institute of Technology | 2019 Jan 09
New research looks at possible links between magnetars and extragalactic radio bursts
In a new Caltech-led study, researchers from campus and the Jet Propulsion Laboratory (JPL) have analyzed pulses of radio waves coming from a magnetar—a rotating, dense, dead star with a strong magnetic field—that is located near the supermassive black hole at the heart of the Milky Way galaxy. The new research provides clues that magnetars like this one, lying in close proximity to a black hole, could perhaps be linked to the source of "fast radio bursts," or FRBs. FRBs are high-energy blasts that originate beyond our galaxy but whose exact nature is unknown. ...
The research team ... looked at the magnetar named PSR J1745-2900, located in the Milky Way's galactic center, using the largest of NASA's Deep Space Network radio dishes in Australia. PSR J1745-2900 was initially spotted by NASA's Swift X-ray telescope, and later determined to be a magnetar by NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), in 2013. ...
Magnetars are a rare subtype of a group of objects called pulsars; pulsars, in turn, belong to a class of rotating dead stars known as neutron stars. Magnetars are thought to be young pulsars that spin more slowly than ordinary pulsars and have much stronger magnetic fields, which suggests that perhaps all pulsars go through a magnetar-like phase in their lifetime.
The magnetar PSR J1745-2900 is the closest-known pulsar to the supermassive black hole at the center of the galaxy, separated by a distance of only 0.3 light-year, and it is the only pulsar known to be gravitationally bound to the black hole and the environment around it.
In addition to discovering similarities between the galactic-center magnetar and FRBs, the researchers also gleaned new details about the magnetar's radio pulses. Using one of the Deep Space Network's largest radio antennas, the scientists were able to analyze individual pulses emitted by the star every time it rotated, a feat that is very rare in radio studies of pulsars. They found that some pulses were stretched, or broadened, by a larger amount than predicted when compared to previous measurements of the magnetar's average pulse behavior. Moreover, this behavior varied from pulse to pulse. ...
Pulse Morphology of the Galactic Center Magnetar PSR J1745-2900 ~ Aaron B. Pearlman et al
- Astrophysical Journal 866(2):160 (2018 Oct 20) DOI: 10.3847/1538-4357/aade4d
arXiv.org > astro-ph > arXiv:1809.02140 > 06 Sep 2018 (v1), 25 Oct 2018 (v2)