VLBA Makes First Direct Distance Measurement to Magnetar

Parallax Magnetar

Artist’s conception of a magnetar — a superdense neutron star with an especially robust magnetic area. In this illustration, the magnetar is emitting a burst of radiation. Credit: Sophia Dagnello, NRAO/AUI/NSF

Astronomers utilizing the National Science Foundation’s Very Long Baseline Array (VLBA) have made the primary direct geometric measurement of the space to a magnetar inside our Milky Way Galaxy — a measurement that might assist decide if magnetars are the sources of the long-mysterious Fast Radio Bursts (FRBs).

Magnetars are a wide range of neutron stars — the superdense stays of large stars that exploded as supernovae — with extraordinarily robust magnetic fields. A typical magnetar magnetic area is a trillion instances stronger than the Earth’s magnetic area, making magnetars essentially the most magnetic objects within the Universe. They can emit robust bursts of X-rays and gamma rays, and just lately have turn into a number one candidate for the sources of FRBs.

A magnetar referred to as XTE J1810-197, found in 2003, was the primary of solely six such objects discovered to emit radio pulses. It did so from 2003 to 2008, then ceased for a decade. In December of 2018, it resumed emitting vibrant radio pulses.

A crew of astronomers used the VLBA to recurrently observe XTE J1810-197 from January to November of 2019, then once more throughout March and April of 2020. By viewing the magnetar from reverse sides of the Earth’s orbit across the Sun, they had been in a position to detect a slight shift in its obvious place with respect to background objects rather more distant. This impact, referred to as parallax, permits astronomers to make use of geometry to immediately calculate the article’s distance.

Parallax Magnetar

By observing an object from reverse sides of the Earth’s orbit across the Sun, as illustrated on this artist’s conception, astronomers had been in a position to detect the slight shift within the object’s obvious place with respect to rather more distant background objects. This impact, referred to as parallax, permits scientists then to make use of geometry to immediately calculate the space to the article — on this case a magnetar inside our personal Milky Way galaxy. The illustration is to not scale. Credit: Sophia Dagnello, NRAO/AUI/NSF

“This is the first parallax measurement for a magnetar, and shows that it is among the closest magnetars known — at about 8100 light-years — making it a prime target for future study,” stated Hao Ding, a graduate pupil on the Swinburne University of Technology in Australia.

On April 28, a unique magnetar, referred to as SGR 1935+2154, emitted a quick radio burst that was the strongest ever recorded from inside the Milky Way. While not as robust as FRBs coming from different galaxies, this burst recommended to astronomers that magnetars might generate FRBs.

Fast radio bursts had been first found in 2007. They are very energetic, and final at most a couple of milliseconds. Most have come from exterior the Milky Way. Their origin stays unknown, however their traits have indicated that the acute atmosphere of a magnetar might generate them.

“Having a precise distance to this magnetar means that we can accurately calculate the strength of the radio pulses coming from it. If it emits something similar to an FRB, we will know how strong that pulse is,” stated Adam Deller, additionally of Swinburne University. “FRBs vary in their strength, so we would like to know if a magnetar pulse comes close or overlaps with the strength of known FRBs,” he added.

“A key to answering this question will be to get more distances to magnetars, so we can expand our sample and obtain more data. The VLBA is the ideal tool for doing this,” stated Walter Brisken, of the National Radio Astronomy Observatory.

In addition, “We know that pulsars, such as the one in the famous Crab Nebula, emit ‘giant pulses,’ much stronger than their usual ones. Determining the distances to magnetars will help us understand this phenomenon, and learn if maybe FRBs are the most extreme example of giant pulses,” Ding stated.

The final aim is to find out the precise mechanism that produces FRBs, the scientists stated.

Ding, Deller, Brisken, and their colleagues reported their leads to the Monthly Notices of the Royal Astronomical Society.

Reference: “A magnetar parallax” by H Ding, A T Deller, M E Lower, C Flynn, S Chatterjee, W Brisken, N Hurley-Walker, F Camilo, J Sarkissian and V Gupta, 21 August 2020, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/staa2531

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated underneath cooperative settlement by Associated Universities, Inc.

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