The very local Hubble flow

We present Hubble Space Telescope/WFPC2 images of eighteen galaxies situated in the vicinity of the Local Group (LG) as part of an ongoing snapshot survey of nearby galaxies. Their distances derived from the magnitude of the tip of the red giant branch are $1.92\pm0.10$ Mpc (ESO 294-010), $3.06\pm0.37$ (NGC 404), $3.15\pm0.32$ (UGCA 105), $1.36\pm0.07$ (Sex B), $1.33\pm0.08$ (NGC 3109), $2.64\pm0.21$ (UGC 6817), $2.86\pm0.14$ (KDG 90), $2.27\pm0.19$ (IC 3104), $2.54\pm0.17$ (UGC 7577), $2.56\pm0.15$ (UGC 8508), $3.01\pm0.29$ (UGC 8651), $2.61\pm0.16$ (KKH 86), $2.79\pm0.26$ (UGC 9240), $1.11\pm0.07$ (SagDIG), $0.94\pm0.04$ (DDO 210), $2.07\pm0.18$ (IC 5152), $2.23\pm0.15$ (UGCA 438), and $2.45\pm0.13$ (KKH 98). Based on the velocity-distance data for 36 nearest galaxies around the LG, we find the radius of the zero-velocity surface of the LG to be $R_0 = (0.94\pm0.10)$ Mpc, which yields a total mass $M_{\rm LG} = (1.3\pm0.3)\times 10^{12}~M_{\odot}$. The galaxy distribution around the LG reveals a Local Minivoid which does not contain any galaxy brighter than M V =-11 mag within a volume of ~100 Mpc 3 . The local Hubble flow seems to be very cold, having a one-dimensional mean random motion of ~30 km s -1 . The best-fit value of the local Hubble parameter is $73\pm15$ km s -1 Mpc -1 . The luminosity function for the nearby field galaxies is far less steep than one for members of the nearest groups.