Bibcode
DOI
Siegel, M. H.; Majewski, S. R.; Gallart, C.; Sohn, S. T.; Kunkel, W. E.; Braun, R.
Referencia bibliográfica
The Astrophysical Journal, Volume 623, Issue 1, pp. 181-195.
Fecha de publicación:
4
2005
Revista
Número de citas
15
Número de citas referidas
15
Descripción
We report the results of a photometric search for giant stars associated
with the cores of four high-velocity clouds (HVCs)-two of which are
compact HVCs-using the Las Campanas du Pont 2.5 m and Cerro Tololo
Blanco 4 m telescopes in combination with a system of filters
(Washington M, T2+DDO51) useful for identifying low surface
gravity, evolved stars. Identical observations of nearby control fields
provide a measure of the ``giant star'' background. Our data reach
M0=22 for three of the HVCs and M0=21.25 for the
fourth, depths that allow the detection of any giant stars within 600
kpc. Although we identify a number of faint late-type giant star
candidates, we find neither a coherent red giant branch structure nor a
clear excess of giant candidate counts in any HVC. This indicates that
the giant candidates are probably not related to the HVCs and are more
likely to be either random Milky Way giant stars or one of several
classes of potential survey contaminants. Echelle spectroscopy of the
brightest giant candidates in one HVC and its control field reveals
radial velocities representative of the canonical Galactic stellar
populations. In addition to these null results, no evidence of any young
HVC stellar populations (represented by blue main-sequence stars) is
found, a result consistent with previous searches. Our methodology,
specifically designed to find faint diffuse stellar populations, places
the tightest upper limit yet on the total stellar mass of HVCs of a few
times 105 Msolar.