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
   

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2. FRATs : Fast Radio Transients
   ž  Millisecond radio pulses
   — 
   ○ 
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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 ??
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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, …
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5. ž  Detection
   —  FRATs Trigger during parallel LOFAR observations
   Sander ter Veen
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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
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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
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8. Pipelines
   ž  First stage pipeline:
   —  False positive
   detection
   —  Human learning
   ž  Second stage pipeline:
   —  TAB
   —  Imaging => Localization
   LOFAR
   locus013
   NIJMEGEN
   Coma Cluster
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9. Initial Classification
   ž  Good FRATS
   ž  Bad FRATS
   ž  Ugly FRATS
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10. Good FRATS
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    easy to identify
    

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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.
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12. Good FRATS
    Example 1
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13. PSR B0329+54
    Good FRATS
    Example 1
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14. Good FRATS - Jupiter
    S-Bursts
    L-Bursts
    Example 3
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15. Good FRATS - Jupiter S-burst
    Olaf Wucknitz
    Example 3
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16. Good FRATS - Jupiter S-burst
    Olaf Wucknitz
    Example 3
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17. The Good FRATS
    ž  Easy to identify
    —  Pulsars
    —  Jupiter bursts
    —  Solar flares
    —  …
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18. Bad FRATS
    Sander ter Veen
    Example 1
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    no useful data
    

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19. Bad FRATS
    Sander ter Veen
    Example 2
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20. Bad FRATS
    Example 2
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21. Bad FRATS
    Example 2
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22. Bad FRATS
    Example 2
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23. Bad FRATS
    Example 2
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24. Bad FRATS
    Example 2
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25. The Bad FRATS
    ž  Cannot be identified as astrophysical
    source since no data
    —  Out of time range
    —  Bad Antennas
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26. Ugly FRATS
    Sander ter Veen
    Example 1
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    challenging to identify
    

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27. Ugly FRATS
    Example 1
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28. Ugly FRATS
    Example 1
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29. Ugly FRATS
    Example 1
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30. Ugly FRATS Solar Flare!
    Example 1
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31. Ugly FRATS
    Example 2
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32. Ugly FRATS
    Example 2
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33. Ugly FRATS
    Example 2
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34. Ugly FRATS
    Example 2
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35. Example 2
    Ugly FRATS
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36. Example 2
    Ugly FRATS
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37. The Ugly FRATS
    ž  Hard to identify
    —  Bad antennas
    —  Side lobes
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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.
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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.
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