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Pulsar Observations in Urumqi
Na Wang
Xinjiang Astronomical Observatory, CAS
FAN4, Hongkong University 1 Jul 8-12, 2013
Jul 8-12, 2013 FAN4, Hongkong University 2
• Pulsar Observations
– Pulsar timing
– Pulsar emission
• The Future
Jul 8-12, 2013 FAN4, Hongkong University 3
• Pulsar Observations
– Pulsar timing
– Pulsar emission
• The Future
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
5
A very large glitch in PSR B2334+61
• Minimal post glitch recovery
• Large ~15%, rapid decay (21d
+147d), and permanent jump
• Post-glitch oscillation period ~ 364(5) days
• Tkachenko oscillation of superfluid vortex
array (Ruderman 1970, Popov 2008)
Jul 8-12, 2013 FAN4, Hongkong University 5
52 10g
Cf. high-magnetic-field pulsar PSR J1718-3718:
• no exponential recovery
• increasing braking torque
• negative braking index(Manchester et al., 2011)
Yuan J. P. et al., 2010, ApJL
12
T 6~ 1.77 yr ~1 yrP R P
53.3 10g
Glitch in PSR J1835-1106
Zou et al. 2004, MNRAS
• Significant cubic terms in timing residual
• Little or no change in
• The jump in , reverse sign
Jul 8-12, 2013 FAN4, Hongkong University 6
7
Glitches in the Crab pulsar
• 1969-1999, 12 glitch events
• 2000-2010, 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.
2.51 by Lyne (1993) : varying particle wind
Wang J. B. et al. 2012, APSS Tong H. et al., 2013, ApJ
Jul 8-12, 2013 FAN4, Hongkong University 7
n for the Crab pulsar
8
Yuan, et al. 2010, MNRAS
Glitches in PSR B1737-30
• 22 glitches in 22 years.
• The amplitudes of the fractional
jump in rotation rate range from
10 – 9 to 10 – 6 .
• Inter-glitch intervals are also
variable.
• No relationship is observed
between interval and the size of
the preceding glitch.
Jul 8-12, 2013 FAN4, Hongkong University 8
Jul 8-12, 2013 FAN4, Hongkong University 9
• Vela like permanent change in frequency derivative: PSRs B1800-21, B1823-13, B1046-58, B1610-50, B1706-44, B1727-33, B2334+61
• Others have no permanent change: PSRs B1338-62, J1617-5055, B1737-30, J1708-4009, B1757-24, J2021+3651
Yuan, et al. 2010, MNRAS
Various glitch recoveries
Jul 8-12, 2013 FAN4, Hongkong University 10
Slow glitches
Also see Shabanova, 2000
Yuan, et al. 2010, MNRAS
Jul 8-12, 2013 FAN4, Hongkong University 11
Tiny glitches 11 910 10 ( )
PSRs B0144+59, B0402+61, B0525+21, J1705−3423, B1815−14, B1900+06, B1907+10 and B2224+65
Yuan, et al. 2010, MNRAS
Origin of timing noise
Jul 8-12, 2013 FAN4, Hongkong University 12
Jul 8-12, 2013 FAN4, Hongkong University 13
• Pulsar Observations
– Pulsar timing
– Pulsar emission
• The Future
Jul 8-12, 2013 FAN4, Hongkong University 14
Mode changing of PSR B0329+54
176 events Sep 2003 to Apr
2009.
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
85% normal
15% abnormal
Chen et al. 2011, ApJ
15 Jul 8-12, 2013 FAN4, Hongkong University
• Polarization Observations reveal previously unknown profile features
in many of the MSPs.
• For MSPs, there are little or no
significant long-term variation in RM
after ionospheric correction.
Significant Rotation Measure variations
for Vela pulsar (Hamilton et al. 1985,
MNRAS):
Yan et al. 2011,
MNRAS
Yan et al. 2011, Ap&SS
16
16 Jul 8-12, 2013 FAN4, Hongkong University
Hu et al. 2011, A&A
The emission mechanism of RRAT J1819-1458 is perhaps similar to that of pulsars with giant pulses.
RRAT J1819-1458
• Tri-band pattern of timing residuals
is observed: core and conal
components
• Flux intensity distribution of bursts
follow a power law: α=1.6
@1.5GHz
• This is similar to those pulsars
with giant pulses, e.g.
PSR B1927+21: α[email protected] GHz
PSR J1824-2452A: α[email protected] GHz
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 10-30 sec
9 integration ≥ 60 sec
Wang N. et al. 2007, MNRAS
Jul 8-12, 2013 FAN4, Hongkong University 17
Nullers
Jul 8-12, 2013 FAN4, Hongkong University 18
Nulls and mode change
Jul 8-12, 2013 FAN4, Hongkong University 19
Profiles of PSR B1326-6700
• Single pulse
• Trailing component nulls
• Interval 2-10 min (200-1000 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
• On 10-30 min
• NF 1.6%
• Short burst within a null
• Weak leading component
Jul 8-12, 2013 FAN4, Hongkong University 21
• Large NF pulsars: >1Myr, some >5Myr
• Nulling is related more to age than
period
PSR Name P(s) τc (Myr) NF
1820-0509 0.34 5.7 67%
0525+21 3.75 1.5 25%
1831-1223 2.86 8.3 4%
• 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
Statistics of NF
Jul 8-12, 2013 FAN4, Hongkong University 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 24
• Pulsar Observations
– Pulsar timing
– Pulsar emission
• The Future
Jul 8-12, 2013 FAN4, Hongkong University 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
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)
Primary Focus
100 cm Band
30 cm Band
15 cm Band (PAF)
Servo & Control System
Az / El Encoder
Az / El Servo
Active Surface Servo
Safeguard 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 26
Band 100cm 30cm 5cm 1cm 6mm 3mm
Efficiency
(Optimum El.) 60% 63% 63%
60%
~50%
54%
~30%
30%
~12%
System Noise
(K) 30 25 20 20 45 100
QTT Electric Performances
Jul 8-12, 2013 FAN4, Hongkong University 27
Type
Band
(cm)
RF Freq
(GHz) Focus Feed Poln Science Goals
Single
Pixel
100 0.15 – 0.6 Primary Kildal Linear Pulsar, RRT
30 0.6 – 4 Primary Horn Linear Pulsar, RRT, HI, OH,
Galaxies
5 2 – 12 Greg. Horn Linear Molecular spectrum,
Galaxies; VLBI
1 12 – 36 Greg. Horn Linear Pulsar, H2O, NH3, VLBI
0.6 36 – 50 Greg. Horn Linear Molecular spectrum,
High-z CO
0.3 72 – 115 Greg. Horn Linear Molecular spectrum,
Galaxies
Dual-
Band
13/3.6 2.2 – 2.5
8 – 9 Greg. Horn Circular
VLBI, space
exploration, System
measurement (3.6cm)
3.6/0.9 8 – 9
30 – 34 Greg. Horn Circular
VLBI, space exploration
Multi-
Pixel
15 1 – 2 Primary PAF Linear Pulsar, RRT, HI, OH,
Galaxies
0.3 80 – 115 Greg. Horn(7/13
Beam) Linear
Molecular spectrum,
Galaxies
Jul 8-12, 2013 FAN4, Hongkong University 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 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
18 10 13 9 30%
13 8 61 17 71%
6 10 14 12 16%
3.6 8 31 21 34%
1.3 6 149 101 33%
Jul 8-12, 2013 FAN4, Hongkong University 30
Shihezi Village
Qitai
Nanshan
Urumqi
Ulastai
Jul 8-12, 2013 FAN4, Hongkong University 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 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 -26.6 °
Temperature drifting Ratio
≤ 5 ℃/hr 99.0%
≤ 3 ℃/hr 92.7%
≤ 2 ℃/hr 82.7%
Jul 8-12, 2013 FAN4, Hongkong University 33
Roses diagram
• Frequency distribution of extreme wind speed:
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 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 35
• Evaluations organized by CAS & NAO
• Conferences: Key Tech., Rx, Science
• Support from local government and CAS
Jul 8-12, 2013 FAN4, Hongkong University 36
2012 Nov. 29—Dec. 1,QTT International Advisory Workshop
Jul 8-12, 2013 FAN4, Hongkong University 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
• ……
15°
ring1…… ring22
15°
5m2, 2856 12.5m2, 888
Receiver Monitoring Software
Receiver Selection Software
Antenna Monitor Software
Antenna Servo Software
Antenna Control Software
Telescope and Receiver Softwares
Antenna Measurement Softwares Astronomical Observation Softwares
Time Synchronization
Software
Weather Monitoring Software
Timing Reference Softwares
Environmental Monitoring Softwares
RFI Monitoring Software
Time Comparison
Software
Antenna Holography Measuring Software
Antenna Measuring Software
Active Surface Adjusting Software
Continuum Observation Software
VLBI Observation Software
Spectrum Observation Software
Pulsar Observation Software
Backends Control
Software
H-Maser Environment Monitoring
Software
Time Synchronization Signal
Data Stream Environmental Data
Time Comparison Signal
Jul 8-12, 2013 FAN4, Hongkong University 38
Jul 8-12, 2013 FAN4, Hongkong University 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 40
Collaboration are expected!