Astronomy and Astrophysics – Astronomy
Scientific paper
Jul 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009hst..prop12270s&link_type=abstract
HST Proposal ID #12270. Cycle 18
Astronomy and Astrophysics
Astronomy
Scientific paper
The mass of the Milky Way is one of the most poorly established Galactic parameters. One important reason for this problem stems from the uncertainty about the bound/unbound status of one particular object, Leo I, which has an unusually large radial velocity {v_hel = 283 km/s} at extreme distance {261 kpc}. We propose to resolve this issue by measuring at high-precision the absolute proper motion of Leo I with HST. ACS/WFC F814W data that can be used as first epoch already exist in the archive. For the second epoch data, we request to obtain 6 more orbits with the same instrument and filter, yielding a 5 year time baseline. With proven techniques that use many compact background galaxies as astrometric reference sources, the predicted transverse velocity accuracy is only 26 km/s at the distance of Leo I. Our results will be accurate enough to address whether or not Leo I is bound. We will then perform new equilibrium modeling of the Milky Way satellite system to obtain an improved estimate of the Milky Way mass. We will also perform new N-body simulations of Leo I, constrained by the measured velocity, to fit simultaneously the orbit, extra-tidal features, and unusual star formation history. This will independently constrain the Milky Way mass. Only HST can achieve the required accuracy, and considerable progress can be made on these important issues with only a small investment of HST time.;
No associations
LandOfFree
Proper Motion of Leo I: Constraining the Milky Way Mass does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Proper Motion of Leo I: Constraining the Milky Way Mass, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Proper Motion of Leo I: Constraining the Milky Way Mass will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1786051