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Pulsar surveys at Arecibo and Green Bank. David Champion Gravity Wave Meeting, Marsfield, Dec 2007. The PALFA survey. 7 beam receiver (ALFA) Gain is 11 K/Jy L-band 100 MHz bw (300 very soon) 256 channels (768 very soon) 64 µ s time resolution 1 Petabyte of data Pointings are 4.5 mins

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pulsar surveys at arecibo and green bank

Pulsar surveys at Arecibo and Green Bank

David Champion

Gravity Wave Meeting, Marsfield, Dec 2007

arecibo multibeam survey
7 beam receiver (ALFA)

Gain is 11 K/Jy

L-band

100 MHz bw (300 very soon)

256 channels (768 very soon)

64 µs time resolution

1 Petabyte of data

Pointings are 4.5 mins

Anti-centre only sparsely surveyed

Arecibo Multibeam Survey
quicklook processing results
Quicklook Processing Results
  • Uses SIGPROC processing pipeline
  • No acceleration search
  • Little RFI excision
  • Reduced resolution by 8 and 16 in frequency and time respectively
  • Good enough to find ‘normal’ pulsars
  • Runs in nearly real-time
  • Has found nearly 40 pulsars inc. 1 relativistic binary (all expected redections accounted for)
  • Capable of finding ~80% of the pulsars expected (RFI not accounted for)
full processing pipeline
Full Processing Pipeline
  • Each 4hr observing session produces 0.25TB of data (0.75 soon)
  • Full acceleration search
  • Processing is shared over many institutions using different clusters
  • Pipeline developed by Scott Ransom, Patrick Lazarus and myself
  • Each beam takes 22hrs to process
psr j1903 0327 discovery
PSR J1903+0327 Discovery
  • 2.15 ms
  • 5th fastest outside GCs
  • 11th including GCs
  • DM of 297 pc cm-3
  • Estimated distance of 6.4 kpc
  • Timing RMS of ~3 µs
high dm and short period
High DM and Short Period
  • Of the 4 faster pulsars, B1938+27 has the highest DM of 71 pc cm-3
  • Its DM/P, an estimate of detectability, is ~3x higher of any pulsar found in a blind survey
  • PALFA clearly has the potential to discover many MSPs
palfa summary
PALFA Summary
  • Has been slow to get to full processing
  • All data will be processed twice using different pipelines
  • Has the potential to find a large number of MSPs deep in the plane
  • Numbers of slow pulsars seems low but is likely RFI affected
  • Numbers of MSPs – too early to tell
  • RFI excision will be the key
other arecibo surveys
Other Arecibo Surveys

Paulo’s 327 MHz survey

  • 50 MHz Bandwidth
  • All sky
  • Found 2 pulsars (I think)
  • Most of the data has yet to be processed
gbt 350
GBT 350
  • 350 MHz
  • Bandwidth of 50 MHz
  • Beam is 0.6°
  • Gain of 2 K/Jy
  • Uses Pulsar Spigot backend
  • 1024 lags
  • 81.92 µs sample time
the survey
The Survey
  • North Galactic plane
  • 75° < l < 165°
  • |b| < 5.5°
  • Requires ~4000 pointings
  • Data can detect fastest MSPs up to DM = 100 pc cm-3
  • 120 seconds per pointing
  • Smin = 2 mJy for slow pulsars
  • Compared to previous surveys in the same sky:
    • > 4 times more sensitive to slow pulsars
    • > 10 times more sensitive to fast pulsars
  • The RFI environment is remarkably good
reduced resolution processing
Reduced Resolution Processing
  • Takes 10% of the full processing time
  • Sensitive to periods > 50 ms (the majority of pulsars expected)
  • Standard periodicity search
  • Single pulse search
results thus far
Results Thus Far
  • 33 pulsars discovered (nearly doubling the population in the survey area)
  • 5 discovered in single pulse search
  • Pulsars are being timed at GBT and WSRT
  • Timing solutions for 12
  • One pulsar discovered with a DM of only 4 pc cm-3
searching for msps
Searching For MSPs
  • The data is being reprocessed to search for MSPs
  • Increasing the population of MSPs in the north is a science driver for this survey
  • This survey is a pathfinder for a full sky survey at 350 MHz
other gbt surveys
Other GBT Surveys
  • A drift-scan at 350 MHz during track repair in summer 2007
    • 2048 lags
    • Requires 9700 DM trials
    • ‘pointings’ are 140 seconds
    • Each beam takes ~15 hrs to process
  • Potentially a full sky 350 MHz survey depending on the results of the current surveys
summary
Summary
  • Large scale surveys at both telescopes show potential to discover more northern MSPs
  • Processing for MSPs is computationally very expensive in these surveys
  • No survey has processed enough high resolution data to give an expected number of MSPs
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