NOAO >   Observing Info >   Approved Programs >   2009A-0407

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Proposal Information for 2009A-0407


PI: Carlton Pryor, Rutgers, the State University of New Jersey, pryor@physics.rutgers.edu
Address: Physics Department, 136 Frelinghuysen Road, Piscataway, NJ 08854-8016, USA

CoI: Slawomir Piatek, New Jersey Institute of Technology
CoI: Edward Olszewski, Steward Observatory

Title: Search for QSOs and AGNs behind dwarf galaxies of the Milky Way

Abstract: We propose to search for faint QSOs and AGN behind seven dwarf satellite galaxies of the Milky Way using the Mosaic Imager on the KPNO 4-m telescope. These objects are needed to provide reference frames in our continuing program to measure precise proper motions for these companion galaxies in short periods of time using Hubble Space Telescope imaging. Our goal is to more than double the current sample of nine proper motions (six published and three in preparation). Our program has achieved uncertainties in the tangential velocity of 30-50 km s^- 1 with 2-3 fields per galaxy and time baselines of 2-4 yrs. All seven galaxies that we propose to observe were recently discovered in Sloan Digital Sky Survey data and they have much lower surface brightnesses and luminosities than the previously-known companions. Are these differences due to different orbits around the Milky Way? An orbit with a small perigalacticon would let the Galactic tidal force strip these galaxies of stars and eventually cause them to merge into the Galactic halo. Such tidal stripping is needed for the most popular solution of the ``missing satellite'' problem in the Local Group. Measuring proper motions can test this model. The critical first step toward this goal is new deep photometry to identify fainter, hence more numerous, AGN and QSOs behind these small galaxies than are present in existing surveys for these regions.


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NOAO >   Observing Info >   Approved Programs >   2009A-0407

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