• DOI:10.1086/510125
• Corpus ID: 120584

The Hubble Flow around the Centaurus A/M83 Galaxy Complex

@article{Karachentsev2006TheHF,
  title={The Hubble Flow around the Centaurus A/M83 Galaxy Complex},
  author={Igor D. Karachentsev and R. Brent Tully and Andrew E. Dolphin and Margarita E. Sharina and Lidia Makarova and Dmitry I. Makarov and Olga Kashibadze and Valentina E. Karachentseva and Shoko Sakai and Edward J. Shaya and Luca Rizzi},
  journal={The Astronomical Journal},
  year={2006},
  volume={133},
  pages={504-517}
}

• I. Karachentsev, R. Tully, +8 authors L. Rizzi
• Published 3 March 2006
• Physics
• The Astronomical Journal

We present Hubble Space Telescope ACS images and color-magnitude diagrams for 24 nearby galaxies in and near the constellation of Centaurus with radial velocities VLG < 550 km s-1. Distances are determined based on the luminosities of stars at the tip of the red giant branch that range from 3.0 to 6.5 Mpc. The galaxies are concentrated in two spatially separated groups around Cen A (NGC 5128) and M83 (NGC 5236). The Cen A group itself has a mean distance of 3.76 ± 0.05 Mpc, a velocity dispersion of 136 km s-1, a mean harmonic radius of 192 kpc, and an estimated orbital/virial mass of (6.4-8.1) × 1012 M⊙. This elliptical-dominated group is found to have a relatively high mass-to-light ratio: M/LB = 125 M⊙/L⊙. For the M83 group we derived a mean distance of 4.79 ± 0.10 Mpc, a velocity dispersion of 61 km s-1, a mean harmonic radius of 89 kpc, and an estimated orbital/virial mass of (0.8-0.9) × 1012 M⊙. This spiral-dominated group is found to have a relatively low M/LB = 34 M⊙/L⊙. The radius of the zero-velocity surface around Cen A lies at R0 = 1.40 ± 0.11 Mpc, implying a total mass within R0 of MT = (6.0 ± 1.4) × 1012 M⊙. This value is in good agreement with the Cen A orbital/virial mass estimates and provides confirmation of the relatively high M/LB of this elliptical-dominated group. The centroids of both groups, as well as surrounding field galaxies, have very small peculiar velocities, <25 km s-1, with respect to the local Hubble flow with H0 = 68 km s-1 Mpc-1.