We present the results of a kinematic survey of the dwarf spheroidal satellite of M31, Andromeda IX, which appears to be the lowest surface brightness and also the faintest galaxy (MV = −8.3) found to date. Using Keck/DEIMOS spectroscopic data, we have measured its velocity relative to M31, its velocity dispersion, and its metallicity. It exhibits a significant velocity dispersion σv = 6.8 +3.0...

The High Resolution Echelle Spectrometer on the Keck I telescope has been used to measure nine radial velocities having a median precision of ' 2 km s−1 for seven red giants belonging to the isolated dwarf spheroidal galaxy Andromeda II (And II). We find a weighted mean radial velocity of vr = –188±3 km s−1 and a central velocity dispersion of σ0 = 9.3 −2.6 km s −1. There may be evidence for a ...

We have obtained spectra for 50 candidate red giants in Andromeda II, a dwarf spheroidal companion of M31, using the Low Resolution Imaging Spectrometer on the Keck II telescope. After eliminating background galaxies and Galactic foreground stars, we are left with a sample of 42 red giants for which membership in Andromeda II can be established unambiguously from radial velocities. Line indices...

We report on the discovery of three new dwarf galaxies in the Local Group. These galaxies are found in new CFHT/MegaPrime g, i imaging of the southwestern quadrant of M31, extending our extant survey area to include the majority of the southern hemisphere of M31’s halo out to 150 kpc. All these galaxies have stellar populations which appear typical of dwarf spheroidal (dSph) systems. The first ...

We have conducted an optical long-term monitoring survey of the majority of dwarf galaxies in the Local Group, with the Isaac Newton Telescope (INT), to identify the long period variable (LPV) stars. LPV stars vary on timescales of months to years, and reach the largest amplitudes of their brightness variations at optical wavelengths, due to the changing temperature. They trace stellar populati...

I analyze the properties of the first galaxies in cosmological simulations with radiative feedback. Preliminary results indicate similarities with the observed properties of the bulk of dwarf spheroidal galaxies (dSphs) in the Local Group and Andromeda. I briefly discuss observational tests that could help in understanding the impact of a population of small primordial objects on the cosmic evo...

We present a complete census of RR Lyrae stars in a halo field of the Andromeda galaxy. These deep observations, taken as part of a program to measure the star formation history in the halo, spanned a period of 41 days with sampling on a variety of time scales, enabling the identification of short and long period variables. Although the long period variables cannot be fully characterized within...

We present the discovery of two new dwarf galaxies, Andromeda XXI and Andromeda XXII, located in the surroundings of the Andromeda and Triangulum galaxies (M31 and M33). These discoveries stem from the first year data of the Pan-Andromeda Archaeological Survey (PAndAS), a photometric survey of the M31/M33 group conducted with the Megaprime/MegaCam wide-field camera mounted on the Canada-France-...

We have used Suprime-Cam on the Subaru Telescope to conduct a V and I-band imaging survey of fields sampling the spheroid of the Andromeda galaxy along its south-east minor axis. Our photometric data are deep enough to resolve stars down to the red clump. Based on a large and reliable sample of red giant stars available from this deep wide-field imager, we have derived metallicity distributions...

Lying at a projected distance of 40 or 9 kpc from the centre of M31, Andromeda IV is an enigmatic object first discovered during van den Bergh’s search for dwarf spheroidal companions to M31. Being bluer, more compact and higher surface brightness than other known dwarf spheroidals, it has been suggested that And IV is either a relatively old ‘star cloud’ in the outer disk of M31 or a backgroun...