Dust properties of NGC 4753

Abstract

We report on BVR surface photometry of a lenticular galaxy, NGC 4753, with prominent dust lanes. We have used the multicolor broadband photometry to study dust extinction as a function of wavelength and derived the extinction curve. We find the extinction curve of NGC 4753 to be similar to the Galactic extinction curve in the visible region, which implies that the sizes of dust grains responsible for optical extinction are similar to those in our Galaxy. We derive the dust mass from optical extinction as well as from the far-infrared fluxes observed with IRAS. The ratio of the two dust masses, M_d,IRAS/M_d,optical, is 2.28 for NGC 4753, which is significantly lower than the value of 8.4±1.3 found previously for a large sample of elliptical galaxies. The total mass of the observed dust within NGC 4753 is about a factor of 10 higher than the mass of dust expected from loss of mass from red giant stars and destruction by sputtering and grain-grain collisions in low-velocity shocks and sputtering in supernova-driven blast waves. We find evidence for the coexistence of dust and Hα-emitting gas within NGC 4753. The current star formation rate of NGC 4753, averaged over the past 2×10⁶ yr, is estimated to be less than 0.21 M_⊙ yr⁻¹. A substantial amount of dust within NGC 4753 exists in the form of cirrus.