Measurement of radial velocities and velocity dispersion of stars in circumnuclear regions of galaxies using the 2D spectrosopy technique

Abstract

A procedure is described of construction of velocity fields and velocity dispersion of the stellar component in the central regions of galaxies on the basis of data obtained with the integral field spectrograph MPFS. Cross-correlation and Fourier quotients techniques adapted for 2D spectra reduction are used. A detailed discussion is given of the problems of providing for the instrumental profile in measuring the velocity dispersion. Using the existing version of the spectrograph, one can measure radial velocities and the dispersion of velocities to an accuracy of 5-10 km/s and 10-15 km/s, respectively. As an example the double-barred galaxy NGC2950 is considered.