| 9th of September 2024 |
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| Eighteen new fast radio bursts in the High Time Resolution Universe survey |
| by Trudu et al. |
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Current observational evidence indicates that fast radio bursts (FRBs)
exhibit bandwidths ranging from a few dozen MHz to several
GHz. Traditional FRB searches primarily employ matched filter methods
on time series collapsed across the entire observational
bandwidth. However, with modern ultra-wideband receivers featuring
GHz-scale observational bandwidths, this approach may overlook a
significant number of events.
Trudu et al. investigate the efficacy of sub-banded searches for
FRBs, a technique seeking bursts within limited portions of the
bandwidth. These searches aim to enhance the significance of FRB
detections by mitigating the impact of noise outside the targeted
frequency range, thereby improving signal-to-noise ratios.
The team performed a complete reprocessing of the high-latitude
segment of the High Time Resolution Universe South survey (HTRU-S)
data taken with Murriyang, the Parkes radio telescope, using
sub-banded search techniques.
This reprocessing led to the confident detection of eighteen new bursts, nearly tripling the count of FRBs found in this survey. These results underscore the importance of employing sub-banded search methodologies to effectively address the often modest spectral occupancy of these signals. The figure above shows narrow-band bursts detected in the HTRU sub-band search. For each burst, the bottom panel shows the dedispersed waterfall plot of the data, with two green lines delimiting the sub-band area in which the burst has been detected. The mid-lower panel shows the Dispersion-Measure -- time (butterfly) plot of the burst, and the mid-upper panel is the waterfall plot of the sub-banded dedispersed data. Lastly, the top panel shows the frequency-averaged time series along the sub-band. The blank rows in all the waterfall plots represent excised channels due to RFI. |