Distances to Dwarf Galaxies of the Canes Venatici I Cloud

Abstract

We determined the spatial structure of the scattered concentration of galaxies in the Canes Venatici constellation. We redefined the distances for 30 galaxies of this region using the deep images from the Hubble Space Telescope archive with the WFPC2 and ACS cameras. We carried out a high-precision stellar photometry of the resolved stars in these galaxies, and determined the photometric distances by the tip of the red giant branch (TRGB) using an advanced technique and modern calibrations. High accuracy of the results allows us to distinguish the zone of chaotic motions around the center of the system. A group of galaxies around M94 is characterized by the median velocity VLG=287 km/s, distance D=4.28 Mpc, internal velocity dispersion sigma=51 km/s and total luminosity LB=1.61x10^10 Lo. The projection mass of the system amounts to Mp=2.56x10^12 Mo, which corresponds to the mass-luminosity ratio of (M/L)p=159 (M/L)o. The estimate of the mass-luminosity ratio is significantly higher than the typical ratio M/LB ~30 for the nearby groups of galaxies. The CVnI cloud of galaxies contains 4-5 times less luminous matter compared with the well-known nearby groups, like the Local Group, M81 and Centaurus A. The central galaxy M94 is at least 1 mag fainter than any other central galaxy of these groups. However, the concentration of galaxies in the Canes Venatici may have a comparable total mass.

18 pages, 7 figures, 2 tables; published in Astrophysical Bulletin, Volume 68, Issue 2, p.131 (2013)

References in corpus (8)

• The ACS Nearby Galaxy Survey Treasury
• Updated Nearby Galaxy Catalog
• FIGGS: Faint Irregular Galaxies GMRT Survey - Overview, observations and first results
• Galaxy groups and clouds in the Local (z~0.01) universe
• Tip of the Red Giant Branch Distances. I. Optimization of a Maximum Likelihood Algorithm
• Associations of Dwarf Galaxies
• The Hubble flow around the Local Group
• Canes Venatici I cloud of galaxies seen in the H-alpha line

Cited by in corpus (8)

• HyperLEDA. III. The catalogue of extragalactic distances
• The M101 group complex: new dwarf galaxy candidates and spatial structure
• Dynamical History Of The Local Group In $\Lambda$CDM $\mathrm{II}$ $-$ Including External Perturbers In 3D
• Study of galaxies in the Lynx-Cancer void. VI. HI-observations with the Nancay Radio Telescope
• The Tully-Fisher relation for flat galaxies
• Unveiling the nitrogen-rich massive star in the metal-poor galaxy NGC 4068
• The Smallest Scale of Hierarchy Survey (SSH). I. Survey Description
• UGC 7639: a Dwarf Galaxy in the Canes Venatici I Cloud