t he Parkes 12 m Keith Bannister kbannisterphysicsusydeduau Sydney Institute for Astronomy SIfA University of Sydney CSIRO Astronomy and Space Science CAASTRO Supervised By Tara Murphy USyd ID: 221329
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Results of automatic, high time resolution GRB follow-up with the Parkes 12 m
Keith Bannisterk.bannister@physics.usyd.edu.auSydney Institute for Astronomy (SIfA) University of SydneyCSIRO Astronomy and Space ScienceCAASTRO
Supervised By:Tara Murphy (USyd)Bryan Gaensler (USyd)Tim Cornwell (CASS)
Thanks To:
CASS
: John Reynolds ,
Chris
Phillips,
Sarah Burke-
Spolaor
, Mike Keith
Swinburne
: Willem
van
Straten
,
Andrew Jameson,
Matthew
Bailes
HTRU TeamSlide2
Gamma ray burstsLong GRB (>2s) Collapse of massive star, orShort GRB (< 2s) Binary merger ?
Gamma rays
Gamma Ray Coordinate Network (GCN)
Coordinates
Parkes 12m
InternetSlide3
Robotic follow-upAutomatically slew the 12m to the GRB coordinateOn source within 2 minutes1.4 GHz, 250 MHz bandwidth64us time resolution, 600 channelsSearched for:
Single pulsesRepeating pulses (e.g. pulsars)Long time scale (>1s) variation
2Slide4
Bucket Feed3Slide5
Installation4Slide6
ResultsResponded to 15 GCN events9 GRBsRemainder where X-ray binaries or instrumental effectsTwo single pulse detectionsOne repeating candidate probable high latitude pulsarNothing in long time resolution
5Slide7
Single pulse detection
66.6 σ pulse (~7 Jy), 25 ms wide, 524s after GRB 101011A
GRB 101011ASlide8
7Slide9
Single pulse detection
86.2 σ pulse (~7 Jy), 6 ms wide, 1076
s after GRB 100704AGRB 100704ASlide10
Correspondence with X-ray break
9GRB 101011ASlide11
Correspondence with X-ray break - 210Slide12
Rates2/9 GRBs have a single pulse detection2/7 long GRBs have a single pulse detectionBlind rate = 3.5 x 105 sky-1 day-1
at ~7 JyGRB rate (2 sky-1 day-1) is compatible with ATA fly’s eye result (Simeon et. al. 2011) of < 24 sky-1 day-1at ~44 Jy
Keith Bannister11Slide13
Are they real?Could it be random chance?Statistical argument rules out with > 99.8% confidenceNull test rules out random pulse with 99% confidenceRate incompatible with chance detection of all other known astrophysical sources20% chance of random event falling on X-ray breakEquipment
bugJust an unlucky bit of RFIKeith Bannister12
junksbronews.comSlide14
ConclusionsGood things can be done with a small telescopeTypically on source within 2 minutesPossible high latitude pulsar detected serendipitously Next: confirm with coincidence or interferometer experiment
Delayed GRB radio pulsesDelayed formation of a black hole after magnetar spindown?Applications: direct detection of the intergalactic medium, distinguishing between reionisation modelsGRB physics
13Slide15
A shameless plugTwo new techniques for antenna-coherent detection of dispersed radio pulses: The Chirpolator & The Chimageator
142011 ApJS,196 16BSlide16
Chirpolator: de-disperse thyself15
y(t)=x
1(t) x2*(t)
time
frequency
y(t)
FFT(y(t))
frequency
Y(f)
time
frequency
Δt
x
1
(t)
B
T
x
2
(t)Slide17
Computational CostsPre integratorPost integrator
Keith Bannister16Slide18
Data RatesKeith Bannister
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