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Up: A statistical study

4. Spectroscopic observations

The spectroscopic observations were made between Apr. 15, 1994 and Feb. 15, 1996. We obtained a total of 123 galaxy spectra. All of the observations were made with 2.16 m telescope at the Xinglong Station of Beijing Astronomical Observatory using Zeiss universal spectrograph with a grating of tex2html_wrap_inline1095 dispersion.

Before Nov. 5, 1994, a Tek tex2html_wrap_inline1097 CCD which covered a tex2html_wrap_inline1099 range from tex2html_wrap_inline993 to 7100 at a resolution of tex2html_wrap_inline1001 (2 pixels) was used. After that, a Tek tex2html_wrap_inline1107 CCD which covered a tex2html_wrap_inline1109 range from tex2html_wrap_inline997 to tex2html_wrap_inline999 at a resolution of tex2html_wrap_inline1003 (2 pixels) was employed.

In most cases, slit width of about 3'' was chosen to match the typical seeing disc at Xinglong Station, but occasionally, the seeing disc was smaller than 2'' or larger than 5'' . Thus may affect the spectral classification. Slit position angles of tex2html_wrap_inline1123 were generally used. For objects with two close nuclei (separation tex2html_wrap_inline1125), the slit was rotated such that two spectra could be obtained simultaneously.

The seeing was about 3'' to 4'' on most of the observation nights. In order to perform a relative flux calibration, KPNO standard stars were also observed on each night.

Table 2 lists the observations by target objects. The standard IRAS name, together with one upper case letters representing the individual components (See Fig. 9 for identifications) are listed in Col. 1. Column 2 to Col. 10 give for each source: coordinates, observation date (Beijing Time), exposure time, airmass, slit width and position angle respectively. The sources flagged with ticks in Col. 11 were observed during good weather condition.



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