A peculiar hard X-ray counterpart of a Galactic fast radio burst. (arXiv:2005.11178v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Ridnaia_A/0/1/0/all/0/1">A. Ridnaia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Svinkin_D/0/1/0/all/0/1">D. Svinkin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Frederiks_D/0/1/0/all/0/1">D. Frederiks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bykov_A/0/1/0/all/0/1">A. Bykov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Popov_S/0/1/0/all/0/1">S. Popov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aptekar_R/0/1/0/all/0/1">R. Aptekar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Golenetskii_S/0/1/0/all/0/1">S. Golenetskii</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lysenko_A/0/1/0/all/0/1">A. Lysenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tsvetkova_A/0/1/0/all/0/1">A. Tsvetkova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ulanov_M/0/1/0/all/0/1">M. Ulanov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cline_T/0/1/0/all/0/1">T. Cline</a>
Fast radio bursts are bright, millisecond-scale radio flashes of yet unknown
physical origin. Recently, their extragalactic nature has been demonstrated and
an increasing number of the sources have been found to repeat. Young, highly
magnetized, isolated neutron stars – magnetars – have been suggested as the
most promising candidates for fast radio burst progenitors owing to their
energetics and high X-ray flaring activity. Here we report the detection with
the Konus-Wind of a hard X-ray event of April 28, 2020, temporarily coincident
with a bright, two-peak radio burst from the Galactic magnetar SGR~1935+2154
with properties remarkably similar to those of fast radio bursts. We show that
two peaks of the double-peaked X-ray burst coincide in time with the radio
peaks, confirming that the X-ray and radio emission most likely have a common
origin. Thus, this is the first simultaneous detection of a fast radio burst
from a Galactic magnetar and its high-energy counterpart. The total energy
emitted in X-rays in this burst is typical of bright short magnetar bursts, but
an unusual hardness of its energy spectrum strongly distinguish the April 28
event among multiple “ordinary” flares detected from SGR~1935+2154 previously.
This, and a recent non-detection of radio emission from about one hundred
typical soft bursts from SGR 1935+2154 favors the idea that bright, FRB-like
magnetar signals are associated with rare, hard-spectrum X-ray bursts, which
implied rate ($sim$ 0.04 yr$^{-1}$ magnetar$^{-1}$) appears consistent with
the rate estimate of SGR 1935+2154-like radio bursts (0.007 – 0.04 yr$^{-1}$
magnetar$^{-1}$).
Fast radio bursts are bright, millisecond-scale radio flashes of yet unknown
physical origin. Recently, their extragalactic nature has been demonstrated and
an increasing number of the sources have been found to repeat. Young, highly
magnetized, isolated neutron stars – magnetars – have been suggested as the
most promising candidates for fast radio burst progenitors owing to their
energetics and high X-ray flaring activity. Here we report the detection with
the Konus-Wind of a hard X-ray event of April 28, 2020, temporarily coincident
with a bright, two-peak radio burst from the Galactic magnetar SGR~1935+2154
with properties remarkably similar to those of fast radio bursts. We show that
two peaks of the double-peaked X-ray burst coincide in time with the radio
peaks, confirming that the X-ray and radio emission most likely have a common
origin. Thus, this is the first simultaneous detection of a fast radio burst
from a Galactic magnetar and its high-energy counterpart. The total energy
emitted in X-rays in this burst is typical of bright short magnetar bursts, but
an unusual hardness of its energy spectrum strongly distinguish the April 28
event among multiple “ordinary” flares detected from SGR~1935+2154 previously.
This, and a recent non-detection of radio emission from about one hundred
typical soft bursts from SGR 1935+2154 favors the idea that bright, FRB-like
magnetar signals are associated with rare, hard-spectrum X-ray bursts, which
implied rate ($sim$ 0.04 yr$^{-1}$ magnetar$^{-1}$) appears consistent with
the rate estimate of SGR 1935+2154-like radio bursts (0.007 – 0.04 yr$^{-1}$
magnetar$^{-1}$).
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