Title:
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Deep optical observations at the position of PSR1706-44 with the VLT-UT1

(Stockholm Observatory Supernova preprint No. STOCK_SN_010)


Authors:
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Peter Lundqvist, Jesper Sollerman, Alak Ray, Bruno Leibundgut, Firoza Sutaria


Abstract:
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We present optical data gathered by the VLT Test Camera in the V-band at the 
radio (interferometric) position of PSR1706-44. We find no optical counterpart
to the pulsar in the VLT image. At a distance of 2.7 arcsec from a nearby 
bright star, the 3-sigma upper limit to the pulsar magnitude above the 
background is V = 25.5. Within an error circle of 1.0 arcsec the upper limit 
is degraded in the direction towards the star. At a distance < 2 arcsec from 
the star we can with confidence only claim an upper limit of V = 24.5. This is
still several magnitudes fainter than previous estimates. The implications of
the optical upper limit taken together with the high energy pulsed gamma-ray 
radiation for theoretical models of pulsar emission are discussed.

Submitted to:
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Astronomy & Astrophysics, accepted for publication in the VLT special issue,
March 1, 1999