The very local Hubble flow
Abstract
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+-0.10 Mpc (ESO 294-010), 3.06+-0.37 (NGC404), 3.15+-0.32 (UGCA105), 1.36+-0.07 (SexB), 1.33+-0.08 (NGC3109), 2.64+-0.21 (UGC6817), 2.86+-0.15 (UGC8508), 3.01+-0.29 (UGC8651), 2.61+-0.16 (KKH86), 2.79+-0.18 (IC5152), 2.23+-0.15 (UGCA438), and 2.45+-0.13 (KKH98). 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+-0.10) Mpc, which yields a total mass M_{LG} = (1.3+-0.3)*10^{12} M_{\sun}. The galaxy distribution around the LG reveals a Local Minivoid which does not contain any galaxy brighter than M_V=-10 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. The best-fit value of the local Hubble parameter is 73+-15 km/s Mpc^{-1}. The luminosity function for the nearby field galaxies is far less steep than one for members of the nearest groups.
Keywords
Cite
@article{arxiv.astro-ph/0204507,
title = {The very local Hubble flow},
author = {I. D. Karachentsev and M. E. Sharina and D. I. Makarov and A. E. Dolphin and E. K. Grebel and D. Geisler and P. Guhathakurta and P. W. Hodge and V. E. Karachentseva and A. Sarajedini and P. Seitzer},
journal= {arXiv preprint arXiv:astro-ph/0204507},
year = {2009}
}
Comments
13 pages, 6 figures, accepted for publication in the A&A. Version has low resolution figures and does not include Figure 2. All high resolution figures (8366k) are available at http://luna.sao.ru/~sme/figures.tar.gz