We derive abundances and central star parameters for 15 planetary nebulae (PNe) in M31: 12 in the bulge and 3 in a disk field 14 kpc from the nucleus. No single abundance value characterizes the bulge stars: although the median abundances of the sample are similar to those seen for PNe in the LMC, the distribution of abundances is several times broader, spanning over 1 decade. None of the PNe i...

Published maps of red giant stars in the halo region of M31 exhibit a giant stellar stream to the south of this galaxy, as well as a giant “shelf” to the northeast of M31’s center. Using these maps, we find that there is a fainter shelf of comparable size on the western side as well. By choosing appropriate structural and orbital parameters for an accreting dwarf satellite within the accurate M...

Pixel lensing is the gravitational microlensing of light from unresolved stars contributing to the lumi-nosity flux collected by a single pixel. A star must be sufficiently magnified, that is, the lens impact parameter must be less than a threshold value uT if the excess photon flux in a pixel is to be detected over the background. Assuming the parameters of the Isaac Newton Telescope and typic...

Since Baade’s photographic study of M32 in the mid 1940s, it has been accepted as an established fact that M32 is a compact dwarf satellite of M31. The purpose of this paper is to report on the findings of our investigation into the nature of the existing evidence. We find that the case for M32 being a satellite of M31 rests upon Hubble Space Telescope (HST) based stellar population studies whi...

We have used Hubble Space Telescope Wide Field Planetary Camera 2 observations to construct a color-magnitude diagram (CMD) for the bulge of M31 at a location ∼1.6 kpc from the galaxy’s center. Using scaled-solar abundance theoretical red giant branches with a range of metallicities, we have translated the observed colors of the stars in the CMD to abundances and constructed a metallicity distr...

NGC 205 is the nearest example of a dwarf elliptical (dE) galaxy and the prototype of this enigmatic galaxy class. Photometric evidence suggests that NGC 205, a close satellite of the M31 galaxy, is tidally interacting with its parent galaxy. We present stellar radial velocity measurements out to a projected radius of 20 ′ (5 kpc) in NGC 205 based on Keck/DEIMOS multislit spectroscopic observat...

The gas content of the complete compilation Local Group dwarf galaxies (119 within 2 Mpc) is presented using HI survey data. Within virial radius Milky Way (224 kpc here), 53 55 are devoid to limits M$_{\rm HI}<10^4$ M$_\odot$. M31 (266 kpc), 27 30 (with typically $<10^5$ M$_\odot$). Beyond radii and M31, majority have detected masses higher than limits. When relationship between distance inves...