Pulsar Studies at Urumqi

Na Wang

Urumqi Observatory, NAOC

History of Urumqi Observatory

Nov 1957: Founded, Urumqi Satellite Observation Station, Chinese Academy Of Sciences (CAS)

Oct 1987: Urumqi Observatory, CAS

Apr 2001: Urumqi Observatory, National Astronomical Observatories of CAS

The Nanshan Station of Urumqi Observatory

• Built in 1993 as a VLBI station• 76 km to the south Urumqi• Altitude: 2080 m• On Tianshan Mountain, called

Nanshan

0.001s 0.01s 0.1s 1s 10s

~1750 known, Galaxy, period ～ 1s

MSPs(~ 0.003 s): Binary, recycled, stable

NASA/GSFC; Walt Feimer/Allied Signal

Pulsars in brief

Pulsar timing systemat Urumqi

PCI-DIO-32HS:Data card

PCI-DIO-96:Control card

GPIB: Start time

Center Frequency:1540 MHzTotal Bandwidth: 320 MHzFilterbank: 2x128x2.5 MHz

• Glitch & Timing noise• Proper motion • Scintillation: DISS & RISS• Emission & single pulse• Transient source• Searching

• New backend• 80m• Application: GW, navigation & time keeper

Future

Work done at Urumqi

Glitch & Timing Noise Study

• For the slow glitch, there was a continuous increase in frequency for about 300~d followed by a return to the initial state for the next 500~d.

• Associated with the spin-up process is a decreasing slow-down rate (increasing ) which lasted 120~d with maximum

. The slow-down rate then decayed to approximately the pre-glitch level within 220~d.

• The fractional changes in frequency and frequency derivative before and after the slow glitch are and

respectively.

Urumqi: Detected a slow glitch in PSR B1822-09 (J1825-0935)

9/ 31.2(2) 10

15 2~ 3 10 s

3/ 1.9(1) 10

Similar glitches were also observed in PSR B1822-09 by Shabanova & Urama (2000)

Unusual glitch behaviours of two young pulsars

• Significant cubic terms with opposite signal are present in the pre- and post-glitch data, suggesting a sign change in at the time of the glitch.

• The jump in at MJD 52220 has the reversed sign of before and after the glitch. There was little or no change in at the time of the glitch.

Detected one glitch in PSR J1835-1106

Zou, W. Z.; Wang, N.; Wang, H. X.; Manchester R. N. et al. 2004, MNRAS, 354, 811

Observations of Six Glitches in PSR B1737-30

Zou, W. Z.; Wang, N.; Manchester, R. N.; Urama, J. O.; Hobbs, G.; Liu, Z. Y.; Yuan, J. P.: MNRAS, accepted.

Observations of Six Glitches in PSR B1737-30

n= -3(1)

Observations of Six Glitches in PSR B1737-30

Updated rotational parameters

Residual: few hundred usPeriod accuracy: 0.1ns or better

Pulsar timing at Urumqi Astronomical Observatory:

observing system and results

Wang, N.; Manchester, R. N.; Zhang, J.; Wu, X. J. et al.: 2001, MNRAS, 328, 855

Glitch Model:

ttQtt pdg )]/exp(1(1[)()( 0

pdd tt )/exp()(

Fractional decay Q = △νd/ △νg

Size △ν/ν=10-6

time constant τd=400 d

◇ Amplitude in ΔP and

agree with our observation◇ In agreement with the Crab pulsar glitch:

◇ Correlation in sign

0P 0pP

pP

0pP

Zou, W. Z.; Hobbs, G.; Wang, N. ; Manchester R. N. et al.: 2005, MNRAS, 362, 1189

Timing measurements and proper motions of

74 pulsars using the Nanshan radio telescope

Projected directions of the proper motions for the 74 pulsars in our sample relative to the Galactic Plane

20/25

Analyzed timing noise for 100 pulsars, to study the effect of timing noise to the accuracy of pulsar position measurement

White noise Red noise

拟投MNRAS Long term monitoring of RRAT 1819 － 1458• RRATs are discovered in 2006• 11 known, 3pdot • Our observations started from 2007, 174pulses

（ a ）宽爆信号 （ b ）窄爆信号 （ c ）双峰脉冲 （ d ） RRAT 脉冲和地面干扰。

RRAT1819 － 1458: timing residual of the observed 174 pulses.

Zhao, C. S.; Esamdin et al, 2009, MNRAS, in preparing

Long-term scintillation observations of five pulsars

at 1540 MHz Observe every 9 d, 2001 Jan – 2002 Jun

2 － 6hr ， 2 － 4min sub-integration

Pulsars ： PSR B0329+54

PSR B1823+26

PSR B1929+10

PSR B2020+28

PSR B2021+51

Wang, N.; Manchester, R. N.; Johnston, S.; Rickett, Bet al.: 2005, MNRAS, 358, 270

Dynamic spectra of PSR B0329+54

DM ＝ 26.8 pc cm-3

Dist = 1.06 kpc

3 hr obs.

Δtd ～ 10-30 min

Δνd ～ 5-15 MHz

Secondary Spectra,Two dimensional FFT of dynamic spectrum

3

s

r

V

D

d

dt

2222

t

s

fVc

Df

Observing the structure of central image !

Modulation indices

Observed > prediction !!

Frequency dependence of DISS parameters

a. Bhat, Rao & Gupta 1999b. Gupta, Rickett & Lyne 1994c. Stinebring, Fainon & Mckinnon 1996d. Our results

Kolmogorov Spectrum β=3.67

Daily Observations of Interstellar Scintillation in PSR B0329+54

Obs: Mar 12—31, 2004

Daily Observations of Interstellar Scintillation in PSR B0329+54

Structure Function

Cross correlation

Wang, N.; Yan, Z.; Manchester, R. N. et al.: 2008, MNRAS, 385, 1393

Other projects

• Searching for Radio Pulsars in 3EG Sources at Urumqi Observatory

Dong, J.; Wang, N.: 2006, ChJAS, 6b, 294

• Monitoring of Pulse Intensity and Mode Changing for PSR B0329+54

Liu, Z. Y.; Wang, N.; Urama, J. O. et al: 2006, ChJAS, 6b, 64

Timing Noise

Yuan J. P. et al, 2009, MNRAS, in preparing

Threads: • setting the digitizer

parameters• data sampling• data unpacking & checking

time synchronization, folding of channel data

• de-dispersion, display• save data to disk• communicating with

telescope computer

Block Diagram for Online Program

V1: Pulsar Timing Data Acquisition—PTDA ， written in Visual C++, by N. WangV2:Pulsar Observing —POP ， Linux version, fits, written in C, by Z. Y. Liu

Timing modeSingle pulse modeSearch mode

Future

New back-end system• Digital filter-bank• Coherent de-disperse

• 80m

• Freq ： up to 22 GHz

• digital filter-bank

• Multi-beam

ABC Collaboration for Global Pulsar Monitoring (Australia ， Britain ， China)

A plan for 80m radio telescope

Gravitation wavePulsars as clock Deep space navigationPulsar monitoring

49°10′

34°20′

73°33′

96°22′