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The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda I and Andromeda III
Barton J. Pritzl, Taft E. Armandroff, George H. Jacoby +1
(Abridged) We present the results of variable star searches of the M31 dwarf spheroidal companions Andromeda I and Andromeda III using the Hubble Space Telescope. A total of 100 va…
The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda II
Barton J. Pritzl, Taft E. Armandroff, George H. Jacoby +1
(abridged) We present the results of a variable star search in Andromeda II, a dwarf spheroidal galaxy companion to M31, using HST/WFPC2 observations. Seventy-three variables were…
The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda VI
Barton J. Pritzl, Taft E. Armandroff, George H. Jacoby +1
We have surveyed Andromeda VI, a dwarf spheroidal galaxy companion to M31, for variable stars using F450W and F555W observations obtained with the Hubble Space Telescope. A total o…
The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda III
G. S. Da Costa, T. E. Armandroff, Nelson Caldwell
The Hubble Space Telescope WFPC2 camera has been used to image Andromeda III, a dwarf spheroidal companion (dSph) to M31. The resulting color-magnitude (c-m) diagrams reveal the mo…
Structure of the Draco Dwarf Spheroidal Galaxy
Slawomir Piatek, Carlton Pryor, Taft E. Armandroff +1
This article studies the structure of the Draco dwarf spheroidal galaxy with an emphasis on the question of whether the spatial distribution of its stars has been affected by the t…
Surface Photometry of Star Clusters in the Dwarf Elliptical Galaxies NGC 185 and NGC 205
Sang Chul Kim, Myung Gyoon Lee, Doug Geisler +3
We present the surface photometry of star clusters in the nearby dwarf elliptical galaxies NGC 185 and NGC 205, obtained from deep HST WFPC2 F555W (V) and F814W (I) images. We have…
Stars of the Draco Dwarf Spheroidal Galaxy Beyond its Measured Tidal Boundary
Slawomir Piatek, Carlton Pryor, Taft E. Armandroff +1
We report R- and V-band photometry derived from CCD imaging for objects in nine fields in and around the Draco dwarf spheroidal galaxy. The most distant fields are about 1.3 degree…
The Age of the Inner Halo Globular Cluster NGC 6652
Brian Chaboyer, Ata Sarajedini, Taft E. Armandroff
HST (V,I) photometry has been obtained for the inner halo globular cluster NGC 6652. The photometry reaches approximately 4 mag below the turn-off and includes a well populated hor…
Neutron-Capture Elements in the Early Galaxy: Insights from a Large Sample of Metal-Poor Giants
Debra L. Burris, Catherine A. Pilachowski, Taft E. Armandroff +3
New abundances for neutron-capture (n-capture) elements in a large sample of metal-poor giants from the Bond survey are presented. The spectra were acquired with the KPNO 4-m echel…
The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda II
G. S. Da Costa, T. E. Armandroff, Nelson Caldwell +1
The HST WFPC2 camera has been used to image Andromeda II, a dwarf spheroidal (dSph) companion to M31. The resulting color-magnitude diagrams reveal the morphology of the horizontal…
A Survey for Low Surface Brightness Galaxies Around M31. II. The Newly Discovered Dwarf Andromeda VI
Taft E. Armandroff, George H. Jacoby, James E. Davies
We present B-, V-, and I-band images, as well as an H alpha image, of And VI. This is the second newly identified dwarf spheroidal (dSph) companion to M31 found using a digital fil…
The Andromeda Dwarf Spheroidal Galaxies
Taft E. Armandroff, Gary S. Da Costa
Our current knowledge of M31's dwarf spheroidal companions is reviewed. Two topics of recent interest constitute the bulk of this review. First, color-magnitude diagrams reaching b…
A Survey for Low Surface Brightness Dwarf Galaxies Around M31
Taft E. Armandroff, James E. Davies, George H. Jacoby
By applying a digital filtering technique to 1550 square degrees of the POSS-II in the vicinity of M31, we found two previously unidentified very low surface brightness dwarf galax…
A Survey for Low-Surface-Brightness Galaxies Around M31. I. The Newly Discovered Dwarf Andromeda V
Taft E. Armandroff, James E. Davies, George H. Jacoby
We present images and a color-magnitude diagram for And V, a new dwarf spheroidal companion to M31 that was found using a digital filtering technique applied to 1550 square degrees…
Dwarf Elliptical Galaxies in the M81 Group: The Structure and Stellar Populations of BK5N and F8D1
Nelson Caldwell, Taft E. Armandroff, G. S. Da Costa +1
We have obtained HST WFPC2 images through the F555W and F814W filters of two M81 group dE's: BK5N and a new system, designated F8D1. The resulting color-magnitude diagrams show the…
The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda I
G. S. Da Costa, T. E. Armandroff, Nelson Caldwell +1
Images have been obtained with the Hubble Space Telescope WFPC2 camera of Andromeda I, a dwarf spheroidal (dSph) galaxy that lies in the outer halo of M31. The resulting color-magn…
The Mass-to-Light Ratios of the Draco and Ursa Minor Dwarf Spheroidal Galaxies. II. The Binary Population and Its Effect in the Measured Velocity Dispersions of Dwarf Spheroidal Galaxies
E. Olszewski, C. Pryor, T. Armandroff
We use a large set of radial velocities in the Ursa Minor and Draco dwarf spheroidal galaxies to search for binary stars and to infer the binary frequency. Of the 118 stars in our…