Local galaxy flows within 5 Mpc

Karachentsev, ID; Makarov, DI; Sharina, ME; Dolphin, AE; Grebel, EK; Geisler, D; Guhathakurta P.; HODGE, PW; Karachentseva, VE; Sarajedini, A; Seitzer, P

Abstract

We present Hubble Space Telescope/WFPC2 images of sixteen dwarf galaxies as part of our snapshot survey of nearby galaxy candidates. We derive their distances from the luminosity of the tip of the red giant branch stars with a typical accuracy of ?12%. The resulting distances are 4.26 Mpc (KKH 5), 4.74 Mpc (KK 16), 4.72 Mpc (KK 17), 4.66 Mpc (ESO 115021), 4.43 Mpc (KKH 18), 3.98 Mpc (KK 27), 4.61 Mpc (KKH 34), 4.99 Mpc (KK 54), 4.23 Mpc (ESO 490-017), 4.90 Mpc (FG 202), 5.22 Mpc (UGC 3755), 5.18 Mpc (UGC 3974), 4.51 Mpc (KK 65), 5.49 Mpc (UGC 4115), 3.78 Mpc (NGC 2915), and 5.27 Mpc (NGC 6503). Based on distances and radial velocities of 156 nearby galaxies, we plot the local velocity-distance relation, which has a slope of H0 = 73 km s-1 Mpc-1 and a radial velocity dispersion of 85 km s-1. When members of the M81 and Cen A groups are removed, and distance errors are taken into account, the radial velocity dispersion drops to ?v = 41 km s-1. The local Hubble flow within 5 Mpc exhibits a significant anisotropy, with two infall peculiar velocity regions directed towards the Supergalactic poles. However, two observed regions of outflow peculiar velocity, situated on the Supergalactic equator, are far away (?50°) from the Virgo/anti-Virgo direction, which disagrees with a spherically symmetric Virgo-centric flow. About 63% of galaxies within 5 Mpc belong to known compact and loose groups. Apart from them, we found six new probable groups, consisting entirely of dwarf galaxies.

Más información

Título según WOS: Local galaxy flows within 5 Mpc
Título según SCOPUS: Local galaxy flows within 5 Mpc
Título de la Revista: ASTRONOMY & ASTROPHYSICS
Volumen: 398
Número: 2
Editorial: EDP SCIENCES S A
Fecha de publicación: 2003
Página de inicio: 479
Página final: 491
Idioma: English
URL: http://www.edpsciences.org/10.1051/0004-6361:20021566
DOI:

10.1051/0004-6361:20021566

Notas: ISI, SCOPUS