IERS TDC NEWS No.6 TR5

4. Technical Reports

4.2 Other IERS Related Technical Development Activities

Pulsar VLBI (Yuko Hanado)

Pulsar observation study at CRL

  Timing measurement: Application of millisecond pulsars to 
                      frequency reference.
  Pulsar VLBI       : Measure the pulsars' positions and 
                      proper motions, and comparison 
                      of reference frames. 
  Survey            : Search for the new observation targets.

Pulsar VLBI

Significance:

Information concerning the pulsar's position, proper motion and distance are required.
By comparing the position defined from VLBI and the position defined from timing analysis, different reference frames and connected.

Attention points in observation:

Pulsars' intensities are weak.
Dispersion effect causes pulse-smearing.
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Large antenna is required.
Observation bandwidth and integration time must be considered.
Signal processing is required for improvement of S/N ratio.

Observation at CRL up to now:

 '91 34m(Kashima)-25m(Shanghai) PSR0329+54 L-band  K-3 correlator X 
 '92 26m(Kashima)-64m(Usuda)    PSR0329+54 S-band  K-3 correlator O(gating) 
 '94 34m(Kashima)-64m(Usuda)    PSR1937+21 L-band  K-3 correlator X

Japan - Russia pulsar VLBI
Pulsar VLBI is planned between Kashima 34m antenna (Japan) and Kalyazin 64m antenna (Russia). This project is carried out based on the international cooperation between CRL and Puchino Radio Astronomy Station Astro Space Center of P. N. Lebedev Physical Insitute. Observation frequency is L-band. The K-4 VLBI system is transported from CRL and used in Russia. The correlation processing will be

Experiments in 1995 (preliminary experiments):

  '95. 3. 4    Fringe test (= system check) 
  '95. 3.15    1st pulsar VLBI (for rather strong pulsars) 
  '95. 3.27    2nd pulsar VLBI (for rather weak pulsars)

Future plan:
Based on the preliminary results in 1995, observations will be carried out during 2 or 3 years. They may be expanded to the Japan-Russia-Australia pulsar VLBI network.

Q&A

Q:　 Why were fringes not obtained for the 1994 experiments?
A: 　Because the elevations of selected sources were low and S/N ratios were not high enough.

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