A Survey of Dwarfs and Tidal Debris around Nearby Massive Galaxies–Deep Imaging with Medium-Sized Telescopes

Abstract

The goal of this thesis was to search for interaction signatures among massive galaxies and to quantify the properties of their satellites. We performed deep wide-field imaging on nearby massive spiral galaxies in a distance range of 8 to 35 Mpc. The spirals cover a variety of morphologies and are located in environments of different densities and richness. We studied the surroundings of 47 massive galaxies. 29 targets were studied in detail. For all of them, we were able to detect dwarf companions. In total we found 55 mostly new candidate dwarf galaxies (CDG), on average about two CDGs per target. Based on their structural parameters and colors, we classified the majority of the CDGs as dwarf spheroidal galaxies, but also dwarf elliptical and dwarf irregular galaxies are included in the sample. The satellites’ observed surface brightness in the B-band falls in the range 22 < μ_B < 26 mag arcsec^−2, the colors vary from 0.8 < (B − R)_0 < 1.5 mag, and the measured range of luminosities is −8 < M_B,0 < −17. The number of CDGs observed is quantitatively in agreement with the expected number compared to the Milky Way or M31 within our sensitivity limits. Furthermore, about 54% of our host galaxies show signs of tidal interactions. These range from prominent tidal tails, plumes and clouds to thin and faint stellar streams. 35% of the massive galaxies exhibit signs of tidal tails or bridges, 11% show plumes or clouds, and only 8% show stellar streams. We discuss possible progenitors of these features based on their colors.