Long-term monitoring of RRAT J1819-1458

1. Rotating Radio Transients Observation Long-term monitoring ofRRAT J1819-1458 HU HuiDong huhd@uao.ac.cn Urumqi Observatory, NAOC July 27, 2009

2. Introduction • Rotating Radio Transients (RRATs) 11 discovered and published on Nature (M. A. McLaughlin et al. 2006) • Characters of the 11 RRATs • Bursts duration between 2 and 30 ms • Average time intervals between bursts range from 4 minutes to 3 hours • Periodicities, 0.4-7s • Detectible flux duration <1s/d • Brightest radio sources after the giant pulses from the Crab pulsar and the pulsar B1937+21. • The number of RRATs may exceed that of regular pulsars

3. http://www.as.wvu.edu/~pulsar/rratalog/

4. About RRAT J1819-1458 Radio observations X-ray observations Burst rate: 17 per hour Burst duration: 2 ms Peak flux : ~3.6 Jy Single pulses timing P: 4.26 s P-dot: 576 10-15 s/s DM: 196 (3) pc cm-3 Age: 117 Kyr Bsurf: 5 × 1013 Gauss The Chandra observation detected the X-ray counterpart (Reynolds et al. 2006). XMM–Newton, discovered the X-ray pulsations with the period predicted by the timing of radio bursts. Mclaughlin et al. (2007) Mclaughlin et al. 2006, Nature， 439, 817 So, what is it?

5. Observation system and de-dispersion method 128 channels, with bandwidth 2.5M Hz 2 polarizations, Center frequency is 1540M Hz

6. Identifying the signal Based on the Filter-Bank de-dispersion system, We developed software to search rare and strong single pulses. Since March 2007: Observations of RRATs Giant pulses of some pulsars Search of extremely strong pulses from pulsars PSR B0656+14 Weltevrede et al. 2006， ApJ，645， 147 Small-time-scale radio transients search Monitoring of magnetars (AXP & SGRs)

7. Long Termmonitoring of RRAT J1819-1458 -- Timing results from 162 bursts Updated to Mar. 2008 DM=196.0(4) Esamdin et al. 2008，MNRAS, 389, 1399

8. Long Term monitoring of RRAT J1819-1458 -- Timing results from 162 bursts Updated to Mar. 2008 Single pulse timing： Esamdin et al. 2008，MNRAS, 389, 1399

9. Long Term monitoring of RRAT J1819-1458 -- Timing results from 162 bursts Updated to Mar. 2008 Timing position Timing residuals and pulse phases Bimodal distribution of pulse phase? In fact, there are even more… Esamdin et al. 2008，MNRAS, 389, 1399

10. Long-Term monitoring of RRAT J1819-1458 About 350 strong bursts detected updated to June 2009 Timing irregularity: First glitch detected in RRAT？ Epoch around MJD 54580

11. Long-Term monitoring of RRAT J1819-1458 Top left: Timing residuals with 1st glitch fitted. Bottom right: Timing residuals with both glitches fitted

12. Long Term monitoring of RRAT J1819-1458 • Glitch parameters got: • Epoch of Glitch 1: MJD 54572 • Δν:1.989(8)×10-09 Hz • ν(dot): 8.11(7)×10-17 Hz s-1 • Epoch of Glitch 2: MJD 54870 • Δν: 1.02(1) ×10-09 Hz • ν(dot): 1.8(2) ×10-17 Hz s-1 The second glitch is too small?

13. Long Term monitoring of RRAT J1819-1458

14. Long Term monitoring of RRAT J1819-1458 Summary: • In observation of hundreds of hours, we detected about 350 dispersed bursts of RRAT J1819−1458 with the signal-to-noise ratios (S/Ns) above 5 σ threshold. The S/N of the strongest burst is 13.3. • The source’s DM measured through our data is 196.0 ± 0.4 pc cm−3. • Our timing position with 2σ error is consistent with the position of its X-ray counterpart CXOU J181934.1−145804. • 2 glitches detected in observation during 800 days, with first one at MJD 54572, the other one at MJD 54870. • The distribution of the timing residuals is bimodal before the first glitch, but has only one main component between the 2 glitches, and becomes bimodal again after the second glitch. • Careful study of the radio bursts properties is necessary to get a more accurate parameter of the second glitch.

15. Thanks! And, Thanks to YUAN J.P. ZHAO C.S. and A. Esamdin