2 Observations

 

2.1 Near-IR observations

Observations in the $K^{\prime}$-band were performed with the 3.5-m telescope (+OMEGA) of the Calar Alto Observatory on 1997 June 21.18, 25.17 and 26.18 UT. Also J-band images were taken with the 2.2-m Telescope (+MAGIC) on June 25.14. The frames were centered on the candidate proposed by Galama et al. (1997). Additional $K^{\prime}$-band observations were performed on 1998 Oct. 5.125 with the 3.5-m telescope.

2.2 Optical observations

Optical observations were mainly taken at La Silla with the Danish 1.54-m telescope equipped with DFOSC, whose field of view ($13^{\prime}.6 \times 13^{\prime}.6$) enabled us to cover the four ASCA sources (see Fig. 1). Table 1 displays the observing log.

 

Table1:   Observing log of the optical observations performed with the 1.54-m Danish telescope

Additional R-band imaging was obtained on 1997 July 20.199, 20.207 and 20.257 with the 0.8-m IAC80 telescope at the Observatorio del Teide. A 1020 $\times$ 1024 pixels CCD provides a $7\hbox{$.\mkern-4mu^\prime$}4 \times 7\hbox{$.\mkern-4mu^\prime$}4$field of view. Limiting magnitude was $R \sim 20$ on the 360-s exposures.