Advanced Techniques in Pulsar Discovery and Timing from the Parkes HITRUN Project
This update delves into the latest methodologies employed in pulsar surveys utilizing the HITRUN team’s advanced equipment and techniques at Parkes Observatory. Focusing on multi-system pointing, we discuss the improved detection of millisecond pulsars (MSPs) alongside the discovery of new rotating radio transients (RRATs). The study emphasizes precision timing techniques for observing pulsar profiles and addressing radio frequency interference (RFI). With groundbreaking GPU-accelerated processing and innovative survey strategies, the HITRUN effort promises to significantly enhance our understanding of pulsar astrophysics.
Advanced Techniques in Pulsar Discovery and Timing from the Parkes HITRUN Project
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Presentation Transcript
CASPER Update from Parkes Matthew Bailes Willem van Straten, Andrew Jameson Jonathon Kocz, Ben Barsdell, Paul Coster + HITRUN team
Crab pulsar Pulsars go this way Magnetic Field - Period Diagram “Noisy” “Smooth”
HITRUN Pulsar Surveys(Keith et al. 2010) • Digital Versions of the Parkes MB Surveys • 13 x 1024 x 64 us • Medium-Latitude Survey (540s) • Ultra-deep Survey (4000s) • All-sky Survey (260s) • Better for high-DM MSPs • Better for Radio bursts
Berkeley-Parkes-Swinburne-Recorder“BPSR” Dedicated fibre 5 TB/day
BPSR Hardware Set-up 13 iBOBs - 3K USD each 13 PCs with 10 Gb ethernet 1 Server Produces 1024 x 2bits every 64 us 10x better time resolution 5 TB/day! <100K
MSPs • HITRUN: 21 MSPs • P-ALFA: 9 MSPs? • MSP with a main sequence companion • (PSR J1903+0327)? • FERMI-Related: ~20-30 MSPs • Mostly short-period and many close • GBT Drift 350 MHz: 6 MSPs?? • MSP occasionally super-bright
1 “Magnetar” 120 20 “RRATs” 21 “MSPs”
Classic Eclipsing Pulsar (Bates et al 2010) PSR J1731-1845 P=2.3 ms Porb=8h Companion=0.03Mo Disappears for weeks at a time.
A Jupiter-mass “Planet” Pulsar Mc~ 0.001 Mo Porb~ 0.0907d D ~ 1.2 kpc?
RRATs • 20 new “RRATs” found from single pulses • RRAT definition waning. • Many RRATs pulse in groups • Classic RRAT definition/new class in doubt. • One RRAT became a pulsar! (Burke-Spoloar & Bailes) • New RFI removal techniques (Kocz et al.)
RAW Cleaned
Lorimer Burst • Found other “examples” • In all beams. • With new RFI excision • Another ~6 • Startling distribution in the human second • RFI probable origin, not lightening
Future: • Acceleration searching • Better RFI excision
Barsdell et al. • Dedispersion: • C/fortran, single threaded, generic • Sigproc (Lorimer) 16 hours, 40 minutes • Dedisperse_all: • C++/OpenMP • HTRU software (Bailes) 80 minutes • GPUdedisperse: • CUDA/C++ • 300 seconds (C1060) ~200s on Fermi
GPUseek (Coster, Bailes, Barsdell) • Builds on GPUdedisperse • Can do 10 x 8 Mpt FFTs + search per second per GPU. • Dedisperse->RAM • Foreach DM • Xfer to GPU • Unpack • FFT • Form power spectrum • Harmonic Sum • Seek spikes
HITRUN medlat Survey • 95,472 beams of 2 GB each • ~200 TB. • 95,472 x 1196 DMs x 200 accelerations • 24 billion FFTs • Time for 1 GPU = 77 years. • “Smarter” FFT lengths/acc = 30 years.
G star Supercomputer (SGI/Nvidia)~130 Tflops 1800 TB Stage 2: 2012 +100 Dual CPU/GPUs? 5 GB s-1 QDR Infiniband 51 x Dual GPU + 48 GB + 2 CPU 2 x Seven GPU + 48 GB + 2 CPU 2 x 512 GB + 4 CPU
Do complete Acc Search 30 / 116 GPUs = 3 months! Find pulsars useful for tests of relativistic gravity
Real-time Processing? • GPU benchmarks indicate: • Can dedisperse and RFI mask and FFT in real time. • Can have an RFI “weather station” • Confirm pulsars while still scintillating
Final PKS Set-up HIPSR 2 x 400 MHz (8 bit) ROACH Dual CPU Dual GPU RFI MASK X 13 X 7 X 8 Ring buffers Dual CPU Dual GPU CASPSR InfiniBand Switch Demux X 4 A/D +TerriBoB 2 x 400 MHz (8 bit) Demux Dual CPU 96 TB disk 12.8 Gb s-1
HITRUN Ultra-deep Survey • Ng et al. • 70 minute pointings: • Finding 5 pulsars/24h day of observing • On track for 500 new pulsars • HITRUN total: • ~650 pulsars (cf 1950 known)
Pulsar Timing Count the Pulses!
PSR J1600-3053 Form a Profile Cross Correlate Get time of arrival
Coherent vs Incoherent Dedispersion • Worthwhile if: • Narrowest feature is < dispersion smear time • Not worthwhile in: • Pulsar searches for “standard” pulse widths • High frequency/low DM timing
The Information Flood: 13 years, factor of 100 in information. Factor of better than 1000 in $/byte/sec • # bits?, 2 pols, Nyquist sampling • 1997, S2 VLBI recorder, 16 MB/s, 700K • 1999, CPSR1, 20 MB/s, 600K • 2002, CPSR2, 128 MB/s, 400K • 2009, APSR, 1 GB/s, 250K • 2010, CASPSR, 1.6 GB/s, 60K
Other Benefits 13 years, factor of 100 in information. Factor of better than 1000 in $/byte/sec • Time to “market” • 1997, S2 VLBI recorder, 16 MB/s, 700K, 1 month • 1999, CPSR1, 20 MB/s, 600K, 2 weeks • 2002, CPSR2, 128 MB/s, 400K, 5 minutes • 2009, APSR, 1 GB/s, 250K, 30 seconds • 2010, CASPSR, 1.6 GB/s, 60K, 40 seconds
Verbiest et al. (2008) CPSR1 Incoherent S2 CPSR2
CABB A/D DFB3 (Manchester/Hampson/Brown)APSR (+Bailes/van Straten/Jameson) 2 x 16 x 64 MHz PFB PFB-1 Switch Processors APSR 8096 Mb s-1 DFB3 8 Gb s-1
Artifacts Artifacts Separation is interchannel dispersion delay
