CCD photometry of Markarian 421 and 501

Abstract

A CCD detector at the prime focus of a 3.6 m telescope has been used to observe the BL Lacertae objects Markarian 501 and 421 in two bands of FWHM equaling approximately 700 A, centered at 5000 and 6500 A. The photometric profiles obtained for both objects are shown to be consistent with composite profiles from a point source and from an elliptical galaxy that obeys the de Vaucouleurs surface brightness law. The photometric parameters derived for the underlying galaxies show them to be apparently normal elliptical galaxies.