Pulsar VLBI Experiment with Kashima (Japan) - Kalyazin (Russia) Baseline

M. Sekido, Y.Takahashi, Y.Koyama
Kashima Space Research Center
Communications Research Laboratory
893-1 Hirai, Kashima, Ibaraki 314, Japan

M.Imae, Y. Hanado
Communications Research Laboratory
4-2-1 Nukui-kita, Koganei, Tokyo 184, Japan

Y.P. Ilyasov, A.E.Rodin, A.E. Avramenko, V.V. Oreshko
Astro Space Center P.N. Lebedev Physical Institute, Russia

B.A. Poperchenko
Special Research Bureau of the Moscow Power Engineering Institute, Russia

1. Introduction

Interferometric measurement of a pulsar is one of the most effective techniques to measure accurate source positions. Precise measurement of a pulsar position will give us information concerning proper motion and parallax. Interferometric measurements on pulsars have been carried out, but the number of pulsars whose positions were measured is still smaller than the total number of known pulsars because newly discovered pulsars are rapidly increasing due to recent intensive systematic surveys. We have started measuring their positions by using VLBI between Kashima and Kalyazin. This report shows the results of the first experiment.

2. Observations

This Pulsar VLBI observation program is based on collaboration between the Communications Research Laboratory (CRL) and the Lebedev Physical Institute. Our first VLBI observation was performed on 14 March 1995. We used a 34m antenna at Kashima and 64m antenna at Kalyazin, which is about 150 km north of Moscow. The baseline length is about 7000 km and minimum fringe spacing is 7 mas at 1.4 GHz. The system temperature and efficiency of the 34m antenna and the 64m antenna are about 40 K and 0.6 respectively for both antennas. The employed VLBI data acquisition system is Japanese K4 system which is compatible with the Mark -III mode C.

3. Correlation and Analysis

Correlation processing was performed by a K3 correlator, which was developed by CRL. A gating function was available on the correlator, but we couldn't use it due to some problems in data processing of gated data. After ordinal cross correlation processing, the result was stored in the Mk-III database and analyzed with software SOLVE. The SOLVE is a program developed by NASA for baseline and source position analysis with group delay. The estimated position of PSR0329+54 is
     PSR0329+54      Alpha:  3h32m59.369s+/-0.01
                     Delta: 54d34'43.627"+/-0.08
Now we are developing a new correlator with gating function to improve the signal to noise ratio. Our observations will be continued for a few years to detect the proper motion.

Figure 1. Estimated position of PSR0329+54. Our result is "O(circle)" and others are as follows: A: Taylor et al.(1993), B: VLBI by Bartel et al. (1985), C: 35 km-Interferometer by Backer and Sramek (1981), D: VLA by Formalont et al. (1984), E: Pulse-Time-of-Arrival (PTA) measurement by Downs and Reichely(1983), F: PTA measurement by Helfand et al.(1980). Transformation between the deferent coordinate system is not applied in this figure.


We thank the staff of Kalyazin 64m antenna operation team, especially V.A.Agafonov, A.N.Fatiev, and M.A.Dolgov. Also V.V.Oreshko, V.Sternenko, and A.V.Serov, who helped us with the receiver and atomic standard. Many thanks to members of CRL Radio astronomy applications section for their support of this experiment.


Backer,D. C., Sramek, R. A., 1981, In Pulsars, IAU Symposium No. 95, edited by W. Sieber and R. Wielebinski (Reidel, Derdriecht), 205.
Bartel,N., Ratner, M. I., Shapiro,I. I., Cappallo, R. J. Rogers, A. E. E., Whitney, A. R., 1985. Astrophys.J., 90, 318
Downs,G. S., Reichley, P. E. 1983, Astrophys. Suppl. Ser., 53, 169.
Formalont, E. B., Gross, W. M., Lyne, A. G., and Manchester, R. N. 1984, M.N.R.A.S., 210, 113.
Helfand,D. J., Taylor, J. H., Backus, P. R., and Cordes, J. M. 1980, Astrophys.J., 237, 206
Taylor,J. H., Manchester, and R. N., Lyne, A. G. 1993, Astrophys. Suppl. Ser., 88, 529

Updated on June 25, 1995. Return to CONTENTS