3 research outputs found
Draco, a flawless dwarf galaxy
The Draco dwarf spheroidal galaxy (dSph), with its apparent immense mass to
light ratio and compact size, holds many clues to the nature of the enigmatic
dark matter. Here we present deep photometric studies of this dwarf galaxy,
undertaken with the MegaCam Camera at the Canada-France-hawaii Telescope, the
Wide Field Camera at the Isaac Newton Telescope and the Wide-Field and
Planetary Camera on board the Hubble Space Telescope. The new photometric data
cover the entirety of the galaxy, and reach i=24.5 at 50% completeness,
significantly deeper than previous panoramic studies, allowing searches for
tidal disturbances of much lower surface brightness than has been possible
before. With these improved statistics, we find no evidence for asymmetric
disturbances or tidal tails that possess more than 3% of the stars found within
the centre of the galaxy. We find that the central stellar density, as probed
by the HST data, rises into the central 0.5'. Uncertainties in the position of
the centroid of the galaxy do not allow us to determine whether the apparent
flattening of the profile interior to 0.5' is reliable or not. Draco is
therefore a flawless dwarf galaxy, featureless and apparently unaffected by
Galactic tides.Comment: 13 pages, 16 figures, accepted for publication in MNRA