No radio emission from soft gamma repeater SGR 0418+5729
ATel #2096; D. R. Lorimer (WVU), S. Edel (WVU), V. I. Kondratiev (WVU), M. A. McLaughlin (WVU), J. R. Boyles (WVU), D. A. Ludovici (WVU), J. P. Ridley (WVU)
on 24 Jun 2009; 01:12 UT
Credential Certification: Duncan Lorimer (duncan.lorimer@mail.wvu.edu)
Subjects: Radio, Soft Gamma-ray Repeater
Following the Fermi/Konus/Swift discovery of bursts from the Soft
Gamma Repeater SGR 0418+5729 (van der Horst et al. 2009; Atel #2077)
and the identification of coherent 9-s pulsations with RXTE (Gogus et
al. 2009; Atel #2076), we carried out a 72-min observation of the new
source with the Green Bank Telescope (GBT) on June 19. Data were
acquired with the Green Bank Ultimate Pulsar Processor which
sampled a 200 MHz wide band centered at 820 MHz. Due to the long
period of the source, a relatively low sampling rate was employed for
these observations and 1024 spectral channels were detected every 5.2
ms. We have carried out blind periodicity, single pulse and direct
folding searches aimed at detecting radio pulsations from this source
and were sensitive to dispersion measures in the range 0-1000
pc/cc. No periodic signals with signal-to-noise greater than five were
found and we place an upper limit of 0.1*sqrt(delta) mJy for a
periodic signal of duty cycle delta. The single pulse search was
optimally sensitive to boxcar pulses of widths (2^n)*5.2 ms,
where n is an integer in the range 0-9. No individual pulses with
signal-to-noise greater than ten were found and we place an upper
limit of 200 mJy / sqrt(2^n) for individual events.
