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Zone of Avoidance (ZOA) P. Henning, UNM. Obscuration due to dust and high stellar density in our Galaxy blocks ~20% of optical extragalactic universe, less in the IR Need all-sky map of surrounding mass inhomogeneity to understand LG’s motion, dynamical evolution
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Zone of Avoidance (ZOA)P. Henning, UNM • Obscuration due to dust and high stellar density in our Galaxy blocks ~20% of optical extragalactic universe, less in the IR • Need all-sky map of surrounding mass inhomogeneity to understand LG’s motion, dynamical evolution • HI surveys can map galaxies, large-scale structure in regions of bad obscuration and stellar confusion
New New Part of Norma SC PKS1343 cluster New Puppis void Puppis Hydra wall and Monoceros extension
ZOA in the AO sky cuts some important (known) LSS: Pisces-Perseus SC; Local, Orion, Taurus, edge of Monoceros voids
ZOA with ALFA • Due to likely pressure on popular, low-b portions of AO sky, best bet is commensal observing • Option 1: GALFA • Single, or double-drift mapping of |b| < 5° • Uniform sky sensitivity • Nyquist sampling with double drift. Time needed is ~460 hours • Would look much like an E-ALFA survey, but would add much to Parkes info? Better positions, further north, but not much deeper
ZOA with ALFA, cont. • Option 2: PALFA • Galactic plane survey, |b| < 5°, 32° < l < 80°, “possibly also anticenter” • Intermediate latitude survey, to 10° or beyond (tbd) • 300 sec beam-1 oodles of time, but point and stare mode. Total time 2000 – 3000 hours • Enormously deep, but observing mode introduces complications from varying feed-sky geometry • Really want 200 MHz backend