1. Rotating Radio Transients and their place among pulsars Sarah Burke Spolaor Jet Propulsion Laboratory Sarah Burke Spolaor Jet Propulsion Laboratory IAU Symposium #291, August 21 2012 © 2012 California Institute of Technology, Government Sponsorship Acknowledged

2. Part I. What makes a RRAT?

3. Mclaughlin+06 PSR J1317–5759 DM = 145 pc/cm 3 P = 2.6421979742(3) s PSR J1443–60 DM = 369 pc/cm 3 P = 4.758565(5) s PSR J1826–14 DM = 159 pc/cm 3 P = 0.7706187(3) s

4. The discoveries continue…  >70 now identified!  Archival reprocessing, new surveys (PALFA, HTRU, GBT350) Hessels+08, Deneva+09, Burke-Spolaor+Bailes10, Keane+11, Burke-Spolaor+11, Chen Karako’s talk  “RRATalog” – search online  >70 now identified!  Archival reprocessing, new surveys (PALFA, HTRU, GBT350) Hessels+08, Deneva+09, Burke-Spolaor+Bailes10, Keane+11, Burke-Spolaor+11, Chen Karako’s talk  “RRATalog” – search online RRAT beaming angle = Pulsar beaming angle Keane+11 Normalised number Abs [ galactic latitude ] Pulsars RRATs Burke-Spolaor+Bailes10

5. So what is a RRAT?  Fourier vs. Single Pulse detection  RFI  Fourier vs. Single Pulse detection  RFI Extended from Mclaughlin+Cordes03/Keane10 Search thresholds

6. So what is a RRAT?  Fourier vs. Single Pulse detection  RFI  Important: the term “RRAT” describes a detection classification  Fourier vs. Single Pulse detection  RFI  Important: the term “RRAT” describes a detection classification Extended from Mclaughlin+Cordes03/Keane10 Search thresholds hmm…

7. No “RRAT Population”!  Pulse energy distribution analysis  1% “Just pulsars”  Pulse energy distribution analysis  1% “Just pulsars” Energy Npulses Keane+10, Miller+??

8. No “RRAT Population”!  Pulse energy distribution analysis  1% “Just pulsars”  5-15% Modulated pulsars  20% to be determined  65-75% Very-high-nulling-fraction pulsars (“extreme nullers”)  Pulse energy distribution analysis  1% “Just pulsars”  5-15% Modulated pulsars  20% to be determined  65-75% Very-high-nulling-fraction pulsars (“extreme nullers”) Energy Npulses Keane+10, Miller+?? S max /S avg (latitude resolved) Relative N pulsars (~70% of pulsars below noise limit) Burke-Spolaor+12 Archival Swin Surveys HTRU South |gb|<15 o Parkes Multibeam Survey

9. No “RRAT Population”!  Pulse energy distribution analysis  1% “Just pulsars”  5-15% Modulated pulsars  20% to be determined  Pulse energy distribution analysis  1% “Just pulsars”  5-15% Modulated pulsars  20% to be determined Energy Npulses Keane+10, Miller+??

10. No “RRAT Population”!  Pulse energy distribution analysis  1% “Just pulsars”  5-15% Modulated pulsars  20% to be determined  65-75% Very-high-nulling-fraction pulsars (“extreme nullers”)  Pulse energy distribution analysis  1% “Just pulsars”  5-15% Modulated pulsars  20% to be determined  65-75% Very-high-nulling-fraction pulsars (“extreme nullers”) Energy Npulses Keane+10, Miller+??

11. Part II. How extreme nulling pulsars fit in with their peers Other nullers – Magnetars – All pulsars

12. Smooth null distribution? Burke-Spolaor+Bailes09

13. Vela pulsar Smooth null distribution? J1646-6831 J1647-36 J1226-32 4 minute timeseries Burke-Spolaor+Bailes09

14. Quasi-periodic activities  Nulling:  Quasi-periodic/characteristic timescales (Ritchings76,Wang+07,Herfindal+Rankin07,Gajjar+12)  High-fraction-nulling RRAT discoveries:  Short-scale characteristic pulsation rates, long- timescale quasi-periodicities (Palliyaguru+11)  Intermittent pulsars:  Quasi-periodicities in activity and nulls (Kramer+06,Eatough-Thesis)  Nulling:  Quasi-periodic/characteristic timescales (Ritchings76,Wang+07,Herfindal+Rankin07,Gajjar+12)  High-fraction-nulling RRAT discoveries:  Short-scale characteristic pulsation rates, long- timescale quasi-periodicities (Palliyaguru+11)  Intermittent pulsars:  Quasi-periodicities in activity and nulls (Kramer+06,Eatough-Thesis)

15. Fraction of time in “on” state Average duration of “off” state (seconds) “On” duration shorter than period f null Characteristic activity cycles Burke-Spolaor+11 Pulsar search sensitivity falls rapidly Intermittent pulsars Red: Wang et al. nulling pulsars Green: Nulling RRAT detections

16. Characteristic timescales: Exciting!  Intrinsic cycle origins  Activity cycles  internal/plasma timescales spin parameters?  Closed/open field line switching Phinney “in prep”  vs. External cycle origins  Intrinsic cycle origins  Activity cycles  internal/plasma timescales spin parameters?  Closed/open field line switching Phinney “in prep”  vs. External cycle origins Cordes & Shannon (2008)

17.  Clue from birthrate analysis Nrrats = 1-4 times the population of pulsars Mclaughlin+06/Keane+Kramer08/Keane10 N pulsars > N supernovae ! RRAT nullers

18. Solutions to the Birthrate Problem?  Nullers are linked in evolution to other population(s)  CCSN rate is wrong (factor of 2-6)  Something else can create neutron stars  …?  Nullers are linked in evolution to other population(s)  CCSN rate is wrong (factor of 2-6)  Something else can create neutron stars  …?

19. Clues from timing RRATs XDINS Magnetars Intermittent pulsars

20. PSR J1819-1458: crossover object? Highest B-field RRAT Anomalous glitch: net decrease in P dot (Lyne+09) Burst rate increase with glitch Similar changes with magnetar glitches (Dib+09). Similar behavior in high-B pulsar J1846-0258 (Gavriil et al. 2008). Highest B-field RRAT Anomalous glitch: net decrease in P dot (Lyne+09) Burst rate increase with glitch Similar changes with magnetar glitches (Dib+09). Similar behavior in high-B pulsar J1846-0258 (Gavriil et al. 2008).

21. PSR J1819-1458: crossover object? Detected in X-rays Significant absorption: cyclotron @ B = 2e14 G, mor than double the timing McLaughlin+07,Miller+in prep Detected in X-rays Significant absorption: cyclotron @ B = 2e14 G, mor than double the timing McLaughlin+07,Miller+in prep Chandra: 30 ks (May 2008) X-ray Nebula tells us more about this pulsar: see talk by A. Camero on Thursday

22. Conclusions  “RRATs”  Detection definition  Mostly high-fraction nulling pulsars  4% of pulsar population and growing!  Nullers: open questions  Too many. Why?  Phenomenological links to low-NF nullers, magnetars, XDINS. Proof of links?  J1819: Hints of magnetar-pulsar connections?  “RRATs”  Detection definition  Mostly high-fraction nulling pulsars  4% of pulsar population and growing!  Nullers: open questions  Too many. Why?  Phenomenological links to low-NF nullers, magnetars, XDINS. Proof of links?  J1819: Hints of magnetar-pulsar connections?

23. Near-future possibilities  New galactic pulsar census  Can successful evolution + birthrate modelling with all neutron star populations suggest links?  More data:  Continued discovery, monitoring, timing  Timescale cycle measurements:  Testing cycle correlations with spin  High-energy follow-ups on other pulsars:  Esp. during burst rate changes/glitches  New galactic pulsar census  Can successful evolution + birthrate modelling with all neutron star populations suggest links?  More data:  Continued discovery, monitoring, timing  Timescale cycle measurements:  Testing cycle correlations with spin  High-energy follow-ups on other pulsars:  Esp. during burst rate changes/glitches

24. Pulsar Ages and Periods  Ritchings (1976):  Age  1/NF ?  Biggs (1992):  Inverse correlation between nulling fraction and period  Wang et al. (2007):  Nulling relationship to age  Higher tendency for “old” pulsars to null  Ritchings (1976):  Age  1/NF ?  Biggs (1992):  Inverse correlation between nulling fraction and period  Wang et al. (2007):  Nulling relationship to age  Higher tendency for “old” pulsars to null