AARTFAAC discovery of extreme-fluence pulses from PSR B0950+08. (arXiv:2003.00720v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kuiack_M/0/1/0/all/0/1">Mark J. Kuiack</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wijers_R/0/1/0/all/0/1">Ralph A.M.J. Wijers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rowlinson_A/0/1/0/all/0/1">Antonia Rowlinson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shulevski_A/0/1/0/all/0/1">Aleksandar Shulevski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Huizinga_F/0/1/0/all/0/1">Folkert Huizinga</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Molenaar_G/0/1/0/all/0/1">Gijs Molenaar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prasad_P/0/1/0/all/0/1">Peeyush Prasad</a>
Here we report on the detection of extreme-fluence pulses (EFP) from PSR
B0950+08 with the Amsterdam-Astron Radio Transient Facility And Analysis Center
(AARTFAAC), a parallel transient detection instrument operating as a subsystem
of the LOw Frequency ARray (LOFAR). During processing of our Northern
Hemisphere survey for low frequency (58.3 and 61.8 MHz) radio transients, a
sample of 275 pulses with fluences ranging from 42k to 177k Jy ms were detected
in one-second snapshot images. The brightest pulses are more than two orders of
magnitude brighter than those previously reported at 42 and 74 MHz. Although
the power-law pulse-energy distribution index agrees well with the previous
results, the average rate of EFPs is much higher. Given the number of EFPs
observed, and the power-law index of the pulse-fluence distribution at high
fluence, a single power-law cannot be extended to the typical pulse population.
Activity was found to be highly variable, with only two three-hour observations
accounting for nearly half of the pulses detected in the 96 hours surveyed. The
rate of EFPs varied from 0 to 30 detected per hour between consecutive days of
observation. However, no clustering was observed within a single active
three-hour span. The spectra appear intrinsically structured with narrow band
emission, confined, at times, within 195.3 kHz sub-bands, and dynamic, with the
pulse spectra changing on timescale of $sim$10 minutes. This narrow emission
bandwidth provides strong evidence that the EFPs are intrinsically higher
energy, rather than being magnified by propagation effects.
Here we report on the detection of extreme-fluence pulses (EFP) from PSR
B0950+08 with the Amsterdam-Astron Radio Transient Facility And Analysis Center
(AARTFAAC), a parallel transient detection instrument operating as a subsystem
of the LOw Frequency ARray (LOFAR). During processing of our Northern
Hemisphere survey for low frequency (58.3 and 61.8 MHz) radio transients, a
sample of 275 pulses with fluences ranging from 42k to 177k Jy ms were detected
in one-second snapshot images. The brightest pulses are more than two orders of
magnitude brighter than those previously reported at 42 and 74 MHz. Although
the power-law pulse-energy distribution index agrees well with the previous
results, the average rate of EFPs is much higher. Given the number of EFPs
observed, and the power-law index of the pulse-fluence distribution at high
fluence, a single power-law cannot be extended to the typical pulse population.
Activity was found to be highly variable, with only two three-hour observations
accounting for nearly half of the pulses detected in the 96 hours surveyed. The
rate of EFPs varied from 0 to 30 detected per hour between consecutive days of
observation. However, no clustering was observed within a single active
three-hour span. The spectra appear intrinsically structured with narrow band
emission, confined, at times, within 195.3 kHz sub-bands, and dynamic, with the
pulse spectra changing on timescale of $sim$10 minutes. This narrow emission
bandwidth provides strong evidence that the EFPs are intrinsically higher
energy, rather than being magnified by propagation effects.
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