Kinematics, structure and environment of three dwarf spheroidal galaxies

We explore the environmental status of three low surface brightnessdwarf spheroidal galaxies (dSphs) KKH65, KK180 and KK227 using the results of our long slitspectroscopic observations at the 6m telescope of the Russian Academy of Sciences and surfacephotometry on the Sloan Digital Sky Survey (SDSS) images.The objects were selected by Karachentseva in 2010 as presumably isolated galaxies.The obtained surface brightness profiles demonstrate that our sample dSphs are lesscentrally concentrated than the objects of the same morphological type in the Virgo cluster (VC).Using the derived kinematic data we searched for possible neighbours of the dSphs withinthe projected distances from them R_proj > 500 kpc and with the differences in radial velocities |Δ V| > 500 kms^-1. We applied the group finding algorithm byMakarov and Karachentsev to the selected sample.Our analysis shows that the dwarf galaxies of our study are not isolated.KKH65 and KK227 belong to the groups NGC3414and NGC5371, respectively. KK180 is in the VC infall region. We conclude thatit is not possible at the moment to justify the existence of isolated dSphs outsidethe Local Volume. The searches are complicated due to the lack of the accuratedistances to the galaxies farther than 10 Mpc.