A SEARCH FOR A PULSAR IN THE REMNANT OF SN 1987A WITH THE HUBBLE-SPACE-TELESCOPE HIGH-SPEED PHOTOMETER

The High Speed Photometer (HSP) on the Hubble Space Telescope (HST) ob served the remnant of SN 1987A on four different epochs between 1992 J une 2 and 1993 November 4 in a 1600-7000 Angstrom bandpass. Each obser vation was similar to 40 minutes in duration and used a 100 mu s sampl ing time. Assuming a spectrum like PSR B0540-69 with similar reddening , the observed count rates imply a time-averaged magnitude V approxima te to 18.2. After correcting to the barycenter of the solar system, no periodic signal was found in any data set using autocorrelation funct ion (ACF) analyses with lags from 200 ps to 10 s and power spectral fu nction (PSF) analyses with a Nyquist frequency corresponding to a peri od of 200 mu s, or in trial pulse profiles obtained by binning the dat a module the frequencies of highest significance in the ACF and PSF an alyses. Searches for signals with large values of P also proved negati ve. We estimate an upper limit of V fainter than similar to 24 for pul sed radiation from any stellar remnant of SN 1987A.