Pulsar surveys at Arecibo and Green Bank

1. Pulsar surveys at Arecibo and Green Bank David Champion Gravity Wave Meeting, Marsfield, Dec 2007

2. The PALFA survey

3. 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

4. The Survey Begins!

5. Quick Processing

6. 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)

7. 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

8. 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

9. 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

10. 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

11. 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

12. The GBT 350 Survey

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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