Chromospheric activity on the RS Canum Venaticorum binary SZ Piscium

Aims. We present the new high-resolution echelle spectra of SZ Psc, obtained in Nov. 2004 and Sep.-Dec. 2006, and study its chromospheric activity. Methods. By means of the spectral subtraction technique, we analyze our spectroscopic observations including several optical chromospheric activity indicators (the $\mbox{He~{\sc i}}$ D3, $\mbox{Na~{\sc i}}$ D1, D2, Hα, and $\mbox{Ca~{\sc ii}}$ infrared triplet lines). Results. All indicators show that the chromospheric activity of the system is associated with the cooler component. We find that the values of $EW_{8542}/EW_{8498}$ are in the range 1-3, which indicates optically thick emission in plage-like regions. The 2006 data suggest the presence of active longitude phenomena. For the $\mbox{Ca~{\sc ii}}$ 8542 and 8662 and the Hα lines, it seems that the excess emission is stronger near the two quadratures of system. This may be anti-correlated with the behavior of the $\mbox{Na~{\sc i}}$ D1 line. The absorption features are detected in the subtracted Hα lines, which could be explained by prominence-like extended material seen on the stellar disk or by mass transfer from the cooler component to the hotter one