Thijs Coenen et al., "The LOFAR pilot surveys for pulsars and fast radio transients," Astronomy & Astrophysics, V570, no. A60, pp1-16, October 2014.
abstract:
We have conducted two pilot surveys for radio pulsars and fast
transients with the Low-Frequency Array (LOFAR) around 140 MHz and
here report on the first low-frequency fast-radio burst limit and the
discovery of two new pulsars. The first survey, the LOFAR Pilot Pulsar
Survey (LPPS), observed a large fraction of the northern sky, ~ 1.4 x 104 deg2, with 1 h dwell times. Each observation
covered ~75 deg2 using 7 independent fields formed by
incoherently summing the high-band antenna fields. The second pilot
survey, the LOFAR Tied-Array Survey (LOTAS), spanned ~600
deg2, with roughly a 5-fold increase in sensitivity
compared with LPPS. Using a coherent sum of the 6 LOFAR “Superterp”
stations, we formed 19 tied-array beams, together covering 4
deg2 per pointing. From LPPS we derive a limit on the
occurrence, at 142 MHz, of dispersed radio bursts of < 150
day-1sky-1, for bursts brighter than S > 107 Jy
for the narrowest searched burst duration of 0.66 ms. In LPPS, we
re-detected 65 previously known pulsars. LOTAS discovered two pulsars,
the first with LOFAR or any digital aperture array. LOTAS also
re-detected 27 previously known pulsars. These pilot studies show that
LOFAR can efficiently carry out all-sky surveys for pulsars and fast
transients, and they set the stage for further surveying efforts using
LOFAR and the planned low-frequency component of the Square Kilometer
Array.
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