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Astron. Astrophys. 324, 155-160 (1997)

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2. Summary of observations

The observations of BP Tau (for the properties of BP Tau; see Paper I and references therein) were performed during five nights between September 10 to September 14, 1993. One of the five nights was clouded out and thus no optical data were taken. The optical observations were made at the 1.2 m telescope at the Calar Alto Observatory, Spain, with a fiber-fed fifteen channels three-star high-speed photometer (see Barwig et al. 1987) simultaneously in the Kron-Cousins U, B, V, R and I colours and with a time resolution of 2 seconds. Unfortunately the U-band channel malfunctioned during the last two and a half clear nights. The X-ray observations were made with the ROSAT satellite, using the Position Sensitive Proportional Counter (PSPC; Pfeffermann et al. 1987) for a useful observing time of approximately 29 ksec. The source counts were measured within a circle of radius 45 [FORMULA] around the target which was positioned in the center of the field. No nearby X-ray sources were located in the field close to the object, and source counts were recorded only at energies above 0.5 keV. This coupled with the low counting statistics of our data prevents any more detailed spectral analysis of our observations. The X-ray data were typically binned into time intervals of 400 seconds duration, and because of the low count rate no useful information on variability on shorter time scales can be derived. Note that the background count above 0.5 keV in a nearby control area was very low with 0 to 1 counts per 400 seconds bin, emphasizing that our data are photon-limited.

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© European Southern Observatory (ESO) 1997

Online publication: May 26, 1998