The Good, the Bad and the Ugly: identifying FRATs triggers with TBB data

J. Emilio Enriquez

Transcript

1. 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
2. FRATs : Fast Radio Transients ž  Millisecond radio pulses —  ◦  —  —  —  —  —  —  2014-01-09 2
3. 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
4. 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
5. ž  Detection —  FRATs Trigger during parallel LOFAR observations Sander ter Veen 2014-01-09 5
6. 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
7. 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
8. 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
9. Initial Classification ž  Good FRATS ž  Bad FRATS ž  Ugly FRATS 2014-01-09 9
10. Good FRATS 2014-01-09 10 easy to identify
11. 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
12. Good FRATS Example 1 2014-01-09 12
13. PSR B0329+54 Good FRATS Example 1 2014-01-09 13
14. Good FRATS - Jupiter S-Bursts L-Bursts Example 3 2014-01-09 14
15. Good FRATS - Jupiter S-burst Olaf Wucknitz Example 3 2014-01-09 15
16. Good FRATS - Jupiter S-burst Olaf Wucknitz Example 3 2014-01-09 16
17. The Good FRATS ž  Easy to identify —  Pulsars —  Jupiter bursts —  Solar flares —  … 2014-01-09 17
18. Bad FRATS Sander ter Veen Example 1 2014-01-09 18 no useful data
19. Bad FRATS Sander ter Veen Example 2 2014-01-09 19
20. Bad FRATS Example 2 2014-01-09 20
21. Bad FRATS Example 2 2014-01-09 21
22. Bad FRATS Example 2 2014-01-09 22
23. Bad FRATS Example 2 2014-01-09 23
24. Bad FRATS Example 2 2014-01-09 24
25. The Bad FRATS ž  Cannot be identified as astrophysical source since no data —  Out of time range —  Bad Antennas 2014-01-09 25
26. Ugly FRATS Sander ter Veen Example 1 2014-01-09 26 challenging to identify
27. Ugly FRATS Example 1 2014-01-09 27
28. Ugly FRATS Example 1 2014-01-09 28
29. Ugly FRATS Example 1 2014-01-09 29
30. Ugly FRATS Solar Flare! Example 1 2014-01-09 30
31. Ugly FRATS Example 2 2014-01-09 31
32. Ugly FRATS Example 2 2014-01-09 32
33. Ugly FRATS Example 2 2014-01-09 33
34. Ugly FRATS Example 2 2014-01-09 34
35. Example 2 Ugly FRATS 2014-01-09 35
36. Example 2 Ugly FRATS 2014-01-09 36
37. The Ugly FRATS ž  Hard to identify —  Bad antennas —  Side lobes 2014-01-09 37
38. 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
39. 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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