Astron. Astrophys. 335, 991-994 (1998)

1. Introduction

PSR B1951+32 is a fast pulsar in the peculiar combination supernova remnant (SNR) CTB 80. The characteristic spin-down age of the pulsar and the dynamical age of the SNR (Koo et al. 1990) are both yrs. Its low surface magnetic field strength, of T, is unusual amongst the selection of young and middle-aged pulsars detected so far but it has been suggested that this is more representative of young pulsars in general (Lyne et al. 1983). It is clearly important to test pulsar models with as wide a variety of pulsar parameters as possible.

Steady emission from the pulsar has so far been detected at radio (Strom 1987; Kulkarni et al. 1988) and X-ray (Becker et al. 1982; Wang & Seward 1984) wavelengths. Two possible optical counterparts have been proposed by Blair & Schild (1985) and Fesen & Gull (1985). Since the initial discovery of the 39.5-ms pulsar (Kulkarni et al. 1988), evidence for pulsed emission has also been found in X-rays (Safi-Harb et al. 1995) and -rays (Ramanamurthy et al. 1995) with upper limits in the infrared (Clifton et al. 1988). To-date no upper limits on pulsed emission in the optical have been published.

Optical observations are essential in determining the relative contributions of thermal and magnetospheric processes to pulsar emission. The continuing improvements in optical-detector sensitivities means that pulsed emission from 6 isolated neutron stars has already been detected. In this paper we present time-resolved optical observations of the central region of the supernova remnant CTB 80 and, in particular, of the two proposed pulsar candidates.

© European Southern Observatory (ESO) 1998

Online publication: June 26, 1998
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