Title of article :
Local galaxy flows within 5 Mpc
Author/Authors :
Grebel، E. K. نويسنده , , Karachentsev، I. D. نويسنده , , Sharina، M. E. نويسنده , , Dolphin، A. E. نويسنده , , Geisler، D. نويسنده , , Guhathakurta، P. نويسنده , , Hodge، P. W. نويسنده , , Karachentseva، V. E. نويسنده , , Sarajedini، A. نويسنده , , Seitzer، P. نويسنده , , Makarov، D. I. نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2003
Pages :
-478
From page :
479
To page :
0
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 (sigma)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.
Keywords :
galaxies , dwarf , distances , redshifts , Kinematics , Dynamics
Journal title :
Astronomy and Astrophysics
Serial Year :
2003
Journal title :
Astronomy and Astrophysics
Record number :
77274
Link To Document :
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