Multi-Wavelength Image of the Environment of J1818 in Radio (red), Infrared (green) and X-Ray (blue). Image courtesy of Loren Anderson (West Virginia University).
The baby magnetar, named Swift J1818.0-1607 (or J1818 for
short), lies in our galaxy and was discovered in March of 2020 by NASA’s Neil Gehrels Swift Observatory. In the middle of the pandemic, when the whole world
was under lockdown, the magnetar decided to make an appearance by suddenly
lighting up in X-rays and soft gamma rays. The Swift detection caught
astronomers’ attention because the source launched a series of intense,
millisecond duration high-energy bursts in our direction, announcing the
discovery of this new kid on the block. Scientists have identified only 31
magnetars, while there are over 3,000 known neutron stars.
“We have a very young magnetar emitting both in
high-energy and radio, one of only five such sources known so far. Our Chandra
study reveals that J1818 is a transient source behaving both like a young
rotation-powered pulsar and a magnetar, a rare scenario where its powering
engine swings between rotation and magnetic energy,” said Harsha Blumer of West
Virginia University’s Center for Gravitational Waves and Cosmology and lead
author of the Astrophysical Journal Letters paper publishing these
“J1818 is a newly discovered magnetar with a super strong magnetic field and may be the youngest of its kind known—only about 470 years old, which is a ‘baby’ compared with the age of other objects in the universe that can be millions of years old or older. The fact that J1818 is the youngest discovered allows astronomers to watch it ‘grow up,’ as most magnetars are already at an advanced age when they are first seen,” explains co-author Samar Safi-Harb of the University of Manitoba.
"This discovery underscores how much we still have to learn about the magnetar population" Duncan Lorimer
“This is a really unusual object in that we can study it
across the electromagnetic spectrum - with each new frequency of observation,
we’ll learn more about its emission mechanism and environment, and the exotic
physics at play” notes Maura McLaughlin, Director for the Center for
Gravitational Waves and Cosmology. “Dr. Blumer’s paper will be an
extremely valuable contribution to our understanding of these objects. ”
Blumer notes that Chandra’s high arcsecond resolution
enabled them to study its complex environment and discover a compact, tiny
nebula that would have been easily missed with any other telescope. The nebula
is believed to be the dust scattering halo from the magnetar burst, but there
could be a weak pulsar wind nebula—charged particles outflowing from the
The interdisciplinary collaborations within the Center
for Gravitational Waves and Cosmology are evident including the expertise from
Center researcher, Loren Anderson. Since the unknown is intriguing, he
further notes that “magnetars are created in
supernova explosions. Since magnetars are young, they may still be
associated with the debris from such explosions. There is a candidate supernova remnant (SNR)
in the vicinity of J1818, although without knowing the distance to either the
SNR or J1818, we cannot say if they are related. Future observations will
hopefully allow us to determine the association, possibly shedding light on the
birth of J1818.”
Blumer concludes “We learn new and exciting things about space every day and discovering more such sources would also be key to understanding the connection between magnetars and fast radio bursts.” Fast radio bursts, or FRBs, are powerful millisecond duration flashes of radio waves from space discovered in 2007 by a team led by Duncan Lorimer at WVU, but their origin is still a mystery.
"This discovery underscores how much we still have
to learn about the magnetar population," said Lorimer, WVU Associate Dean
for Research, who along with McLaughlin, co-discovered the first FRB with former
WVU undergraduate student David Narkevic.
Their study of Swift J1818.0−1607 was published in the journal Astrophysical Journal Letters.