The Proper Motion of the Large Magellanic Cloud using HST

Journal Article · Fri Aug 19 04:00:00 EDT 2005 · The Astrophysical Journal

OSTI ID:884769

Kallivayalil, N; der Marel, R; Alcock, C; Axelrod, T; Cook, K; Drake, A J; Geha, M

The authors present a measurement of the systemic proper motion of the Large Magellanic Cloud (LMC) from astrometry with the High Resolution Camera (HRC) of the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). They observed LMC fields centered on 21 background QSOs that were discovered from their optical variability in the MACHO database. The QSOs are distributed homogeneously behind the central few degrees of the LMC. With 2 epochs of HRC data and a {approx} 2 year baseline they determine the proper motion of the LMC to better than 5% accuracy: {mu}{sub W} = -2.03 {+-} 0.08 mas yr{sup -1}, {mu}{sub N} = 0.44 {+-} 0.05 mas yr{sup -1}. This is the most accurate proper motion measurement for any Milky Way satellite thus far. When combined with HI data from the Magellanic Stream this should provide new constraints on both the mass distribution of the Galactic Halo and models of the Stream.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 884769
• Report Number(s): UCRL-JRNL-214724
• Journal Information: The Astrophysical Journal, Journal Name: The Astrophysical Journal Journal Issue: 2 Vol. 638
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
99 GENERAL AND MISCELLANEOUS
ACCURACY
CAMERAS
MAGELLANIC CLOUDS
MASS DISTRIBUTION
MILKY WAY
PROPER MOTION
RESOLUTION
SATELLITES
TELESCOPES