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© Galaxies in the Local Volume

Science Rationale

The `Local Volume' (ie, the sphere of radius 10 Mpc centered on the Local Group) is known to contain at least 500 known galaxies, many of which congregate in well-known groups like the Local Group, the relatively loose Sculptor Group, and the more compact Centaurus A group. Accurate distances are now available for the majority of these nearby galaxies, allowing us to visualise the Local Volume in 3D, study the local Hubble flow and its dispersion, the (baryonic) Tully-Fisher relation, the local star formation density, etc. Individual galaxies in the Local Volume can be studied in amazing detail across a large range of wavelengths (some stunning examples are compiled in the Multiwavelength Astronomy pages).

The first catalog of galaxies within 10 Mpc was compiled by Kraan-Korteweg & Tammann (1979); it contained 179 galaxies. Following numerous updates, the latest `Catalog of Neighboring Galaxies' was presented by Karachentsev et al. (2004); it contains 451 galaxies. They find that about 85% of the LV population are dwarf galaxies which contribute approx. 4% to the local optical luminosity density and roughly 10-15% to the local HI mass density. For the majority of galaxies within 8 Mpc we currently have quite reliable, independent distance estimates either from the luminosity of Cepheids, the tip of the red giant branch (TRGB), or surface brightness fluctuations (SBF).

Several large surveys of nearby galaxies have recently been carried out or are in progress. E.g., `The Westerbork observations of neutral Hydrogen in Irregular and SPiral galaxies' (WHISP, Swaters et al. 2002), which is based on the Uppsala General Catalogue of Galaxies (UGC; Nielson 1973), provides HI distributions and velocity fields of about 200 gas-rich galaxies with declinations larger than +20 degrees and velocities less than 2000 km/s. This is complemented by `The Hα Galaxy Survey' (HαGS; James et al. 2004), also based on the UGC, which provides star formation parameters for a large number of mostly northern galaxies. `The HI Nearby Galaxy Survey' (THINGS; Walter, Brinks, de Blok et al. 2004), which provides high-resolution HI imaging of initially 36 galaxies with declinations larger than -30 degrees, has just been completed at the Very Large Array (VLA). The THINGS sample is targeting galaxies from `The Spitzer Nearby Galaxies Survey' (SINGS, Kennicutt et al. 2003), a comprehensive infrared imaging and spectroscopic survey of 75 nearby galaxies with distances less than 30 Mpc, as well as key objects from the Spitzer GTO list. SINGS is supplemented by high-resolution studies at many other wavelengths covering the entire spectrum from X-ray to radio. Another multi-wavelength study is `The Survey for Ionization in Neutral Gas Galaxies' (SINGG, Meurer et al. 2006, Hanish et al. 2006), the largest star formation survey of an HI-selected sample (based on `The HI Parkes All-Sky Survey' , HIPASS) and its sister surveys SUNGG and SONGG, based on GALEX ultraviolet and Spitzer infrared observations, respectively. Surveys of nearby galaxies currently underway in Australia include `The Galactic All Sky Survey' (GASS), obtained with the Parkes 64-m telescope, `The Local Volume HI Survey' (LVHIS), obtained with the Australia Telescope Compact Array (ATCA), and the `Local Sphere of Influence H-band survey' (LSI), obtained with the Anglo-Australian Telescope (AAT).

Given the many recent advances in our understanding of the star formation and ISM composition of nearby galaxies and more generally in the field of `Near-Field Cosmology', which are mostly based on the large amounts and superb quality of new ground- and space-based multi-wavelength data, it is timely to hold a conference on the subject and review the Local Volume by combining observations, simulations and theoretical developments. We hope to provide a vibrant forum for presentations and discussions accross a broad range of astrophysical topics, including what may be possible with future facilities such as the Atacama Large Millimeter Array (ALMA), and the international Square Kilometre Array (SKA).

Recent meetings on related topics: