1 Introduction

During the ROSAT All-Sky Survey (RASS) about 80 000 X-ray sources with a detection likelihood $\geq 10$ were found (Voges 1992; Voges et al. 1994; Voges et al. 1996b, 1997), from which 18 811 sources were compiled in the ROSAT Bright Source Catalogue (RASS-BSC) (Voges et al. 1996a,b; Voges et al. 1997). Most of them are newly discovered X-ray sources and more than $65\%$ of the objects were previously unknown (Brinkmann et al. 1995; Bade et al. 1998). The optical spectroscopic studies of these RASS sources are essential for understanding them more clearly. We are performing a program to identify unknown RASS sources at high galactic latitude ($\vert b\vert \geq 20\hbox{$^\circ$}$) in the northern hemisphere ($\delta \geq 3\hbox{$^\circ$}$) and whose likely optical counterparts have R magnitudes between 13.5 and 16.5. About 60 quasars were identified independently through low dispersion spectroscopic observations in 1996 and 1997 (Wei et al. 1996, 1997). In this paper we report on the discovery of 9 bright low-redshift quasars (hereafter BLRQs) with B magnitude equal to or less than 17.0.

In Sect. 2, the sample selection is introduced. The observations and results are presented in Sect. 3.