Long-term monitoring ofLong-term monitoring of RRAT J1819-1458RRAT J1819-1458

HU HuiDongHU HuiDonghuhd@uao.ac.cnhuhd@uao.ac.cn

Urumqi Observatory, NAOCUrumqi Observatory, NAOC

July 27, 2009July 27, 2009

Rotating Radio Transients Observation

Introduction Rotating Radio Transients (RRATs)Rotating Radio Transients (RRATs)11 discovered and published on Nature11 discovered and published on Nature (M. A. McLaughlin et al. (M. A. McLaughlin et al. 20062006)) Characters of the 11 RRATsCharacters of the 11 RRATs• Bursts duration between 2 and 30 msBursts duration between 2 and 30 ms• Average time intervals between bursts range from 4 Average time intervals between bursts range from 4

minutes to 3 hoursminutes to 3 hours• Periodicities, 0.4-7sPeriodicities, 0.4-7s• Detectible flux duration <1s/dDetectible flux duration <1s/d• Brightest radio sources after the giant pulses from Brightest radio sources after the giant pulses from

the Crab pulsar and the pulsar B1937+21.the Crab pulsar and the pulsar B1937+21. The number of RRATs may exceed that of regular The number of RRATs may exceed that of regular

pulsarspulsars

Name P Pdot DM Ra Dec BurstRate Survey

  s 10-15 s/s pc/cm^3 hh:mm:ss.s dd:mm:ss.s 1/h  

J0054+66 1.39   15 00:54 +66 240 GBT350

J0557-15     43 05:57 -14:20 3.43 PH

J0755-44     115 07:55 -44:28 5.14 PH J0848-43 5.97   293 08:48 -43:16 1.42 PM1 J1047-58 1.23   69 10:47 -58:41 6.86 PM2 J1131-57     130 11:31 -57:11 1.71* PM2 J1317-5759 2.64 12.6 145 13:17:46.3 57:59:30.2 4.5 PM1 J1328-58     213 13:28 -58:54 1.71* PM2 J1423-56     31 14:23 -56:47 12.00 PM2 J1443-60 4.75   369 14:43 -60:32 0.78 PM1 J1623-08 0.50   60 16:23 -08:46 154 GBT350 J1739-25     181 17:39 -25:13 1.71* PM2 J1754-30 0.42   98 17:54 -30:11 0.60 PM1 J1819-1458 4.26 576 196 18:19:33.0 -14:58:16 17.62 PM1 J1826-14 0.77   159 18:26 -14:27 1.06 PM1 J1839-01 0.93   307 18:39 -01:36 0.62 PM1 J1840-06 1.59   773 18:40 -06:25 13.71 PM2 J1846-02 4.47   239 18:46 -02:56 1.10 PM1 J1848-12 6.79   88 18:48 -12:47 1.25 PM1 J1911+00     100 19:11 +00:37 0.31 PM1 J1913+133 0.92 7.87 175 19:13:17.6 +13:33:20.1 4.71 PM 1J1928+15 0.40     19:28 +15 90 PALFA

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

About RRAT J1819-1458

Mclaughlin et al. 2006, Nature ， 439, 817

Burst rate: 17 per hourBurst duration: 2 msPeak flux : ~3.6 Jy

Single pulses timingP: 4.26 sP-dot: 576 10-15 s/s DM: 196 (3) pc cm-3

Age: 117 KyrBsurf: 5 × 1013 Gauss

Radio observations X-ray observations

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)

So, what is it?

Observation system and de-dispersion method

128 channels, with bandwidth 2.5M Hz2 polarizations,Center frequency is 1540M Hz

22

3

DM4.148808ms

GHz GHz cm pchighlowff

t

Observations of RRATsGiant pulses of some pulsarsSearch of extremely strong pulses from pulsars PSR B0656+14 Weltevrede et al. 2006 ， ApJ ， 645 ， 147

Small-time-scale radio transients searchMonitoring of magnetars (AXP & SGRs)

Based on the Filter-Bank de-dispersion system, We developed software to search rare and strong single pulses.

Since March 2007:

Identifying the signal

Long Term monitoring of RRAT J1819-1458-- Timing results from 162 bursts

Updated to Mar. 2008

Esamdin et al. 2008 ， MNRAS, 389, 1399

DM=196.0(4)

Long Term monitoring of RRAT J1819-1458-- Timing results from 162 bursts

Single pulse timing ：

Updated to Mar. 2008

Esamdin et al. 2008 ， MNRAS, 389, 1399

Long Term monitoring of RRAT J1819-1458-- Timing results from 162 bursts

Timing positionTiming residuals and pulse phases

Bimodal distribution of pulse phase?In fact, there are even more…

Updated to Mar. 2008

Esamdin et al. 2008 ， MNRAS, 389, 1399

About 350 strong bursts detected updated to June 2009

Long-Term monitoring of RRAT J1819-1458

Timing irregularity: First glitch detected in RRAT ？ Epoch around MJD 54580

Long-Term monitoring of RRAT J1819-1458

Top left: Timing residuals with 1st glitch fitted.

Bottom right: Timing residuals with both glitches fitted

Long Term monitoring of RRAT J1819-1458

Glitch parameters got:Glitch parameters got: Epoch of Glitch 1: MJD 54572Epoch of Glitch 1: MJD 54572 ΔνΔν:: 1.989(8)×101.989(8)×10-09-09 Hz Hz νν (dot):(dot): 8.11(7)×108.11(7)×10-17-17 Hz s Hz s-1-1

Epoch of Glitch 2: MJD 54870Epoch of Glitch 2: MJD 54870 ΔνΔν:: 1.02(1) ×101.02(1) ×10-09-09 Hz Hz νν (dot):(dot): 1.8(2) ×101.8(2) ×10-17-17 Hz s Hz s-1-1

The second glitch is too small?

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.

Long Term monitoring of RRAT J1819-1458

Thanks!

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