Identifying ‘real’ FRATs J. Emilio Enriquez R. Heino Falcke, Sander ter Veen, Anya Bilous, Arthur Corstanje, Jörg Rachen, Pim Schellart LOFAR TKP Meeting 2014-01-09 1 

FRATs : Fast Radio Transients ž  Millisecond radio pulses —  ○  —  —  —  —  —  —  2014-01-09 2 

FRATs : Fast Radio Transients ž  Millisecond radio pulses possibly originating from: —  Lorimer Bursts (FRBs) ○  one time extragalactic burst —  Pulsars and RRATS —  Flaring stars —  Lightning from Saturn —  Jupiter aurora radio emission —  Exoplanets? —  ETI ?? 2014-01-09 3 

FRATs : Fast Radio Transients Detection and Verification ž  Detection —  Past and present: ○  FRATs Trigger Code (Sander’s Talk) by parallel observations during LOTAAS (Cycle 0 & 1) and MSSS (tests before Cycle 0) so far. ○  During Cycle 1 we are expanding to other regular observations (beamform and imaging). —  Future?: ○  LOFAR related : ARTEMIS, AARTFAAC ○  Multiwavelength: SWIFT/BAT, Fermi, … 2014-01-09 4 

ž  Detection —  FRATs Trigger during parallel LOFAR observations Sander ter Veen 2014-01-09 5 

FRATs : Fast Radio Transients Detection and Verification ž  Verification: Transient Buffer Boards (TBBs) —  Parallel System in LOFAR —  Ring buffer of raw data from each antenna —  Look back in time (5sec) —  Offline processing 2014-01-09 6 

FRATs : Fast Radio Transients FRATs TBB Goals ž  Pulse characterization of bright millisecond pulses —  High SNR by coherent addition of antennas/ stations. ž  Accurate position —  Multi-station Imaging 2014-01-09 7 

Pipelines ž  First stage pipeline: —  False positive detection —  Human learning ž  Second stage pipeline: —  TAB —  Imaging => Localization LOFAR locus013 NIJMEGEN Coma Cluster 2014-01-09 8 

Initial Classification ž  Good FRATS ž  Bad FRATS ž  Ugly FRATS 2014-01-09 9 

Good FRATS 2014-01-09 10 easy to identify 

Dispersion Measure (DM) ž  Dispersive nature of interstellar plasma: radio wave interaction with free electrons makes for slower group velocities for lower frequencies. ž  Time delay is calculated by: ž  DM Total column density of free electrons, or a distance estimate with ne models of the ISM. 2014-01-09 11 

Good FRATS Example 1 2014-01-09 12 

PSR B0329+54 Good FRATS Example 1 2014-01-09 13 

Good FRATS - Jupiter S-Bursts L-Bursts Example 3 2014-01-09 14 

Good FRATS - Jupiter S-burst Olaf Wucknitz Example 3 2014-01-09 15 

Good FRATS - Jupiter S-burst Olaf Wucknitz Example 3 2014-01-09 16 

The Good FRATS ž  Easy to identify —  Pulsars —  Jupiter bursts —  Solar flares —  … 2014-01-09 17 

Bad FRATS Sander ter Veen Example 1 2014-01-09 18 no useful data 

Bad FRATS Sander ter Veen Example 2 2014-01-09 19 

Bad FRATS Example 2 2014-01-09 20 

Bad FRATS Example 2 2014-01-09 21 

Bad FRATS Example 2 2014-01-09 22 

Bad FRATS Example 2 2014-01-09 23 

Bad FRATS Example 2 2014-01-09 24 

The Bad FRATS ž  Cannot be identified as astrophysical source since no data —  Out of time range —  Bad Antennas 2014-01-09 25 

Ugly FRATS Sander ter Veen Example 1 2014-01-09 26 challenging to identify 

Ugly FRATS Example 1 2014-01-09 27 

Ugly FRATS Example 1 2014-01-09 28 

Ugly FRATS Example 1 2014-01-09 29 

Ugly FRATS Solar Flare! Example 1 2014-01-09 30 

Ugly FRATS Example 2 2014-01-09 31 

Ugly FRATS Example 2 2014-01-09 32 

Ugly FRATS Example 2 2014-01-09 33 

Ugly FRATS Example 2 2014-01-09 34 

Example 2 Ugly FRATS 2014-01-09 35 

Example 2 Ugly FRATS 2014-01-09 36 

The Ugly FRATS ž  Hard to identify —  Bad antennas —  Side lobes 2014-01-09 37 

The Ugly FRATS ž  Hard to identify —  Bad antennas —  Side lobes ž  But with use of TBB data we can prettify the ugly FRATS. 2014-01-09 38 

Conclusion ž  With the use of TBBs to identify false positives. —  We can verify good FRATS candidates —  We can quickly identify bad candidates —  We can flag misbehaving antennas ž  We can also: —  We can localize triggers with better angular precision than the incoherent beam. —  Can study the pulses with higher SNR than the incoherent stokes since can add raw data coherently. —  Determine if the FRBs are astrophysical. 2014-01-09 39 

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