Pulsar surveys at arecibo and green bank
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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

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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


The palfa survey

The PALFA survey


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


The survey begins

The Survey Begins!


Quick processing

Quick Processing


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


The gbt 350 survey

The GBT 350 Survey


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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