IAU00764
Presentation type requested: ORAL
LARGE-SCALE STRUCTURES BEHIND THE SOUTHERN MILKY WAY
Patrick A Woudt
Department of Astronomy, University of Cape Town, RSA
Extensive spectroscopy has been used to follow up optical searches for partially obscured galaxies behind the southern Milky Way (270 < l < 355 degrees, |b| < 10 degrees). This region encompasses the Great Attractor (GA), held responsible for a large part of the peculiar motion of the Galaxy. Our search has mapped nearby structures (cz < 20000 km/s) in detail and identified clusters and overdensities that clearly contribute to the GA, in particular the rich Norma cluster (ACO 3627). Recent work has focussed on deep J,H,Ks photometry (taken with SIRIUS on the Japanese InfraRed Survey Facility in South Africa) of the central part of the Norma cluster and PKS1343-601, a suspected cluster in the GA region at (l,b,v) = (309.7,+1.7, 3872 km/s). The latter is invisible in the optical (A(B) ~ 9 mag), but a clear overdensity of galaxies is seen in the near-infrared. Systematic uncertainties in low-latitude surface photometry, e.g. the effect of star-crowding, variations in the Galactic extinction law, are discussed. The photometry of the Norma cluster, in combination with velocity dispersions for ~50 elliptical galaxies obtained with the 2dF, will allow an accurate distance determination to the Norma cluster, and clarify its role within the GA.
Nagayama Takahiro , Fairall Anthony P, Kraan-korteweg Renee C, Lucey John
IAU XXV General Assembly | IAU216 HOME PAGE | IAU216 Speaker Program | IAU216 Poster Program