Pulsar Observations in Urumqi

Transcription

1 Pulsar Observations in Urumqi Na Wang Xinjiang Astronomical Observatory, CAS Jul 8-12, 2013 FAN4, Hongkong University 1

2 Pulsar Observations Pulsar timing Pulsar emission The Future Jul 8-12, 2013 FAN4, Hongkong University 2

3 Pulsar Observations Pulsar timing Pulsar emission The Future Jul 8-12, 2013 FAN4, Hongkong University 3

4 25 m radio telescope 18cm cryogenic Rx Analog FilterBank + DFB 0.4 mjy ~300 pulsars, including 38 Fermi pulsars and 9 MSPs Allowing to investigate the instability of pulsar rotation, electron distribution of ISM, proper motion and velocity of pulsars. Jul 8-12, 2013 FAN4, Hongkong University 4 4

5 A very large glitch in PSR B Minimal post glitch recovery Large ~15%, rapid decay (21d +147d), and permanent jump g Post-glitch oscillation period ~ 364(5) days Tkachenko oscillation of superfluid vortex array (Ruderman 1970, Popov 2008) P T ~ 1.77 R P yr ~1 yr g Cf. high-magnetic-field pulsar PSR J : no exponential recovery increasing braking torque negative braking index(manchester et al., 2011) Yuan J. P. et al., 2010, ApJL Jul 8-12, 2013 FAN4, Hongkong University 5 5

6 Glitch in PSR J Significant cubic terms in timing residual Little or no change in The jump in, reverse sign Zou et al. 2004, MNRAS Jul 8-12, 2013 FAN4, Hongkong University 6

7 Glitches in the Crab pulsar , 12 glitch events , 9 glitches (Wang et al. 2012) Glitch interval: Poisson distribution, 419 d. Trigger of glitch not relevant to the slowdown Braking index: 2.454(7) and 2.571(3), cf by Lyne (1993) : varying particle wind n for the Crab pulsar Wang J. B. et al. 2012, APSS Tong H. et al., 2013, ApJ Jul 8-12, 2013 FAN4, Hongkong University 7 7

8 Glitches in PSR B glitches in 22 years. The amplitudes of the fractional jump in rotation rate range from 10 9 to Inter-glitch intervals are also variable. No relationship is observed between interval and the size of the preceding glitch. Yuan, et al. 2010, MNRAS Jul 8-12, 2013 FAN4, Hongkong University 8 8

9 Various glitch recoveries Vela like permanent change in frequency derivative: PSRs B , B , B , B , B , B , B Others have no permanent change: PSRs B , J , B , J , B , J Yuan, et al. 2010, MNRAS Jul 8-12, 2013 FAN4, Hongkong University 9

10 Slow glitches Also see Shabanova, 2000 Yuan, et al. 2010, MNRAS Jul 8-12, 2013 FAN4, Hongkong University 10

11 ( ) Tiny glitches 11 9 PSRs B , B , B , J , B , B , B and B Yuan, et al. 2010, MNRAS Jul 8-12, 2013 FAN4, Hongkong University 11

12 Origin of timing noise Jul 8-12, 2013 FAN4, Hongkong University 12

13 Pulsar Observations Pulsar timing Pulsar emission The Future Jul 8-12, 2013 FAN4, Hongkong University 13

14 15% abnormal 85% normal Mode changing of PSR B events Sep 2003 to Apr R=I/III, R~0.56 for normal, R~1.17 for abnormal mode R: normal distribution, wider for abnormal mode: less stable timescales: gamma distribution, t_normal~154.2 min t_abnormal~31.5 min Chen et al. 2011, ApJ Jul 8-12, 2013 FAN4, Hongkong University 14

15 Polarization Observations reveal previously unknown profile features in many of the MSPs. Yan et al. 2011, MNRAS For MSPs, there are little or no significant long-term variation in RM after ionospheric correction. Yan et al. 2011, Ap&SS Significant Rotation Measure variations for Vela pulsar (Hamilton et al. 1985, MNRAS): Jul 8-12, 2013 FAN4, Hongkong University 15

16 RRAT J Tri-band pattern of timing residuals is observed: core and conal components Flux intensity distribution of bursts follow a power law: This is similar to those pulsars with giant pulses, e.g. PSR B : α=1.8@1.4 GHz PSR J A: α=1.6@1.4 GHz Hu et al. 2011, A&A The emission mechanism of RRAT J is perhaps similar to that of pulsars with giant pulses. Jul 8-12, 2013 FAN4, Hongkong University 16 16

17 Observations: Observed at Parkes, 2004 March & June HOH + Filterbank (576 MHz, 192 channels) 50cm + Filterbank (64 MHz, 256 channels) 35 pulsars observed, 2 hours each mostly 18 single pulse 8 integration sec 9 integration 60 sec Wang N. et al. 2007, MNRAS Jul 8-12, 2013 FAN4, Hongkong University 17

18 Nullers Jul 8-12, 2013 FAN4, Hongkong University 18

19 Nulls and mode change Jul 8-12, 2013 FAN4, Hongkong University 19

20 Profiles of PSR B Single pulse Trailing component nulls Interval 2-10 min ( pulses) Two main components cease for ~1min The fourth component appears Frequent short intervals during B mode Jul 8-12, 2013 FAN4, Hongkong University 20

21 On min NF 1.6% Short burst within a null Weak leading component Jul 8-12, 2013 FAN4, Hongkong University 21

22 Large NF pulsars: >1Myr, some >5Myr Nulling is related more to age than period PSR Name P(s) τ c (Myr) NF % % % Statistics of NF Pulsar period vs period derivative. Nulling pulsars: circle Circle area: proportional to the NF, with a lower bound of 5%. Pulsars in this work: cross. Jul 8-12, 2013 FAN4, Hongkong University 22

23 Both nulling and mode changing result from large-scale and persistent changes in the magnetospheric current distribution. Mode changes must be a manifestation of a redistribution of current flow in the magnetosphere, resulting in changes in the radio beam emission pattern and hence in the observed pulse profile. Nulls may result from a cessation of (or at least a large reduction in) the current,but may also result from a current redistribution which leads to a beam pattern with little or no power in our direction. Jul 8-12, 2013 FAN4, Hongkong University 23

24 Pulsar Observations Pulsar timing Pulsar emission The Future Jul 8-12, 2013 FAN4, Hongkong University 24

25 Proposed to build 110m radio telescope: QTT: QiTai radio Telescope General purpose telescope Fully Steerable Active Surface Freq Range 150 MHz 115 GHz Prime/Gregorian paraboloid, Az/El Wide-band, Multi-beam & PAF Rx Digital backend Secondary Servo Az / El Encoder Az / El Servo Active Surface Servo Safeguard System Primary Focus 100 cm Band 30 cm Band 15 cm Band (PAF) Secondary Focus 5 cm Band 1 cm Band 6 mm Band 3 mm Band 13 / 3.6 cm Band 3.6 / 0.9 cm Band 3 mm Band (MB) Servo & Control System Back End Multi-Function Digital Backend VLBI Backend Continuum Total Power Backend Time & Frequency Hydrogen Maser Time & Frequency System GPS Receiver Jul 8-12, 2013 FAN4, Hongkong University 25

26 QTT Electric Performances Band 100cm 30cm 5cm 1cm 6mm 3mm Efficiency (Optimum El.) 60% 63% 63% 60% ~50% 54% ~30% 30% ~12% System Noise (K) Jul 8-12, 2013 FAN4, Hongkong University 26

27 Type Single Pixel Dual- Band Multi- Pixel Band (cm) RF Freq (GHz) Focus Feed Poln Science Goals Primary Kildal Linear Primary Horn Linear Greg. Horn Linear Greg. Horn Linear Greg. Horn Linear Greg. Horn Linear 13/ / Greg. Horn Circular Greg. Horn Circular Primary PAF Linear Greg. Horn(7/13 Beam) Linear Pulsar, RRT Pulsar, RRT, HI, OH, Galaxies Molecular spectrum, Galaxies; VLBI Pulsar, H2O, NH3, VLBI Molecular spectrum, High-z CO Molecular spectrum, Galaxies VLBI, space exploration, System measurement (3.6cm) VLBI, space exploration Pulsar, RRT, HI, OH, Galaxies Molecular spectrum, Galaxies Jul 8-12, 2013 FAN4, Hongkong University 27

28 Astronomy High precision pulsar timing Molecular spectra observations Active galactic nuclei Dark matter VLBI astrometry, astro-dynamics and space VLBI Sky survey: detecting organic molecule and sulphur chain molecule Application VLBI orbit measurement for space exploration Pulsar time standard Deep space pulsar autonomous navigation NASA/GSFC Jul 8-12, 2013 FAN4, Hongkong University 28

29 China VLBI (CVN): astrometry, space exploration CVN+QTT: sensitivity increase 1.8 times CVN+QTT+65m: sensitivity increase 3 times EVN Band (cm) EVN Available Tele SEFD (Jy) (NS 25m) SEFD (Jy) (QTT) Ratio improvement % % % % % Jul 8-12, 2013 FAN4, Hongkong University 29

30 Qitai Urumqi Shihezi Village Nanshan Ulastai Jul 8-12, 2013 FAN4, Hongkong University 30

31 1.5 kilometers long and 2 kilometers wide rectangle basin Altitude range from 1730 m to 2250 m Surrounding ridges form an isolated layer with outside region Jul 8-12, 2013 FAN4, Hongkong University 31

32 Average annual rainfall of area: 180 mm to 200 mm (cf. average evaporation capacity of Xinjiang area is ~2000mm) Precipitable water vapor: Summer: ~19 mm Spring and Autumn: ~8 mm to 9.5 mm Winter: ~3 mm Temperature range: maximum +29.3, minimum Temperature drifting Ratio 5 /hr 99.0% 3 /hr 92.7% 2 /hr 82.7% Jul 8-12, 2013 FAN4, Hongkong University 32

33 Frequency distribution of extreme wind speed: Roses diagram Wind speed Ratio Qitai_Average Qitai_Day Qitai_Night GBT 4m/s (3 beaufort scale) 65.9% 48.9% 83.0% 45.9% 6m/s (4 beaufort scale) 83.6% 74.3% 92.9% 64.5% 8m/s (5 beaufort scale) 93.7% 91.0% 96.6% 79.2% 10m/s (6 beaufort scale) 97.5% 96.7% 98.3% 88.9% 17m/s (8 beaufort scale) 0.14% 0.21% 0.06% 0.5% Jul 8-12, 2013 FAN4, Hongkong University 33

34 RFI Most interference are recognizable: Measured 150 MHz - 13 GHz 2 or 3-G mobile wireless communication (UHF, L, S band) broadcast television (analog digital, VHF, UHF band) differential rotation system of wireless satellite television (UHF, C band) satellite navigations Jul 8-12, 2013 FAN4, Hongkong University 34

35 Evaluations organized by CAS & NAO Conferences: Key Tech., Rx, Science Support from local government and CAS Jul 8-12, 2013 FAN4, Hongkong University 35

36 2012 Nov. 29 Dec. 1,QTT International Advisory Workshop Jul 8-12, 2013 FAN4, Hongkong University 36

37 Servo control and very accurate pointing Active surface: measurement and adjust: OOF, holography Reflector: parabolic dish vs. shaped design Dividing the main reflector and number of actuators Track and wheels: monolithic track & heavy load Structure and electronics: environment under -30 Rx: wide band feed, Multi-beam, PAF 5m 2, m 2, ring1 ring22 Jul 8-12, 2013 FAN4, Hongkong University 37

38 Telescope and Receiver Softwares Receiver Monitoring Software Receiver Selection Software Antenna Monitor Software Timing Reference Softwares Time Synchronization Software Time Comparison Software H-Maser Environment Monitoring Software Environmental Monitoring Softwares Antenna Servo Software Antenna Control Software RFI Monitoring Software Weather Monitoring Software Antenna Holography Measuring Software Antenna Measuring Software Active Surface Adjusting Software Backends Control Software Pulsar Observation Software Spectrum Observation Software Continuum Observation Software Antenna Measurement Softwares VLBI Observation Software Astronomical Observation Softwares Time Synchronization Signal Data Stream Time Comparison Signal Environmental Data Jul 8-12, 2013 FAN4, Hongkong University 38

39 Land acquisition: approved Herdsman relocate: 130 families, move in 3 years Road flattening: done Power: satisfy the infrastructure requirement Water supply plan: assessed Fiber connection: done for construction period Jul 8-12, 2013 FAN4, Hongkong University 39

40 Collaboration are expected! Jul 8-12, 2013 FAN4, Hongkong University 40