1. Polarization Properties of an Eclipsing Pulsar
Xiaopeng YOU (游霄鹏)
2015 FPS Meeting, Mingantu, Inner-Mongolia

2. Outline Introduction of J1748-2446A Observation and Data processing
Results and discussion
Conclusions

3. Basic properties of J1748-2446A
Discovered in 1990, Parkes telescope, 20-cm (Lyne et al., 1990)
Locating in the globular cluster Terzan 5
Period : ms
Dispersion Measure: 242.0
Circular orbital period: 1.8 hours
Projected semi-major axis: light second
Companion: White drawf, Mʘ
Eclipsing time: variable, depending on frequency, greater than Roche lobe, 0.2 Rʘ
Sometimes disappearing

4. Observations Parkes 64 m telescope
3 frequencies, 1369 MHz (20 cm), 3100 MHz (10 cm), 728 MHz (50 cm),
1369 MHz, Bandwidth: 256 MHz,1024 Channels
3100 MHz, Bandwidth: 1024 MHz,1024 Channels
728 MHz, Bandwidth: 64 MHz,128 Channels
Full polarization recording
3 observations at 20cm
2 observations at 10/50 cm.
Almost all observations cover whole orbital phase.

5. Eclipsing : 20 cm

6. Eclipsing : 50 cm

7. Eclipsing : 10 cm

8. Rotation Measure (RM)
Faraday rotation of linearly polarized radio sources
Pulsars as high linearly polarized sources
Position Angle (PA) rotate as it pass through the magnetic intersteller medium
Incorrect RM: depolarization

9. Depolarization Phenomenon
3-min sub-integration
Searching for RM and showing polarization profiles.
RM: rad m-2
found PSR-WD system with depolarization phenomenon

13. Polarization profiles
10 cm: no linear polarization, because of weak signal and low linear polarization

14. Polarization properties VS orbital phase

15. Turbulence of Pulsar wind
Depolarization due to turbulence of Faraday Rotation (Burn 1996)
Lower frequency, easier depolarized
Assume significant depolarization when
Orbital Phase
[0.7,0.8]
< 4
[0.55, 0.7] [0.8,0.9]
others

16. Conclusions
Obtain polarization profiles for 3 bands for the eclipsing pulsar PSR J A
Found no eclipse at 10 cm
Found PSR-WD system with depolarization phenomenon
Duration of both total eclipse and depolarization depend on frequency
Depolarization because of turbulence of Faraday rotation of pulsar wind
Help understanding the eclipse mechanism

17. Timing results: 20 cm

18. Timing results: 50 cm

19. Timing results: 10 cm

20. Timing result Eclipsing duration:
50 cm: 54 mins, 20 cm : 36 mins, 10 cm: 0
20 cm: 400μs, DM, 0.18 cm-3 pc, ne: 8.0e6 cm-3