...1,2,3

Address for correspondence: Krasin str. 19, ap. 81, Moscow 123056, Russia.

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... pulsar

The $3.2 ~ {\rm s}$ individual exposure time of the ACIS instrument makes the search for short pulsations impossible.

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... matter

The large dispersion measure variations inherent to this pulsar (Jacoby & Wolszczan 1999) could be considered as an indirect support of this suggestion.

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