6 Concluding remarks

As was noted above, the CVn I cloud is a scattered system elongated towards the Local Group. Together with the LG and the loose group in Sculptor, aligned along the line of sight, the CVn I cloud consists of an amorphous filament of $\sim$10 Mpc in length. We estimated the excess of the number of galaxies in the CVn I cloud to be $(N- \langle N \rangle)/ \langle N \rangle \sim 7$. Because the complex is populated predominantly by dwarf galaxies, the overdensity of the CVn I in its luminosity turns out to be lower, $(\rho_{\rm lum} - \langle \rho_{\rm lum} \rangle)/ \langle \rho_{\rm lum} \rangle \sim 4$. Here we adopted that the space volume of the CVn I is 21 Mpc³, and the mean luminosity of 1 Mpc³is $2\times 10^8~ L_{\odot}$ (Bahcall et al. 1995).

Remarkably, the mass estimates for the cloud, derived via orbital and virial motions and being distributed over the 21 Mpc³ volume, yield an average density of dark matter $0.62 \rho_{\rm c}$ and $1.17 \rho_{\rm c}$, respectively, where $\rho_{\rm c} = 1.0\times 10^{-29}$ g/cm³ is the critical density with $H_{\rm o} = 70$ km s^-1 Mpc^-1.

The large crossing time for the CVn I cloud (15 Gyr), the low content of dSphs, the almost primordial shape of the LF indicate that the CVn I complex is in a transient state not so far from the pure Hubble flow. We hope that future accurate distance measurements of about 20-30 members of the cloud in a fast snapshot survey with the Advanced Camera will give a complete and reliable basis of studying the dynamical evolution of the Canes Venatici complex.

Acknowledgements

Support for this work was provided by NASA through grant GO-08601.01-A from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. This work was partially supported by RFBR grant 01-02-16001 and DFG-RFBR grant 02-02-04012. D.G. gratefully acknowledges support from the Chile Centro de Astrofísica FONDAP No. 15010003. D.G. kindly acknowledges support from ESO as a Visiting Astronomer which allowed him to work on this paper.

The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on the Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with permission of these institutions.

This project made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, Caltech, under contract with the National Aeronautics and Space Administration.