We report our first microlensing candidate NMS-E1 towards M31 from the data accumulated during four years long Nainital Microlensing Survey. Cousin R and I band observations of ∼ 13 ′ × 13 ′ field in the direction of M31 were carried out since 1998 and data is analysed using pixel technique proposed by the AGAPE collaboration. The NMS-E1 lies in the disk of M31 at α = 04333.3 and δ = +41◦06 ′ 4...

We present the first results from our survey of stellar substructure in the outskirts of M31 using the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope. We discuss the stellar populations associated with five prominent stellar overdensities discovered during the course of our panoramic ground-based imaging survey with the Isaac Newton Telescope Wide-Field Camera (INT WFC); ...

We present a color-magnitude diagram (CMD) of the globular cluster SKHB-312 in the Andromeda galaxy (M31), obtained with the Advanced Camera for Surveys on the Hubble Space Telescope. The cluster was included in deep observations taken to measure the star formation history of the M31 halo. Overcoming a very crowded field, our photometry of SKHB-312 reaches mV ≈ 30.5 mag, more than 1 mag below t...

The autocorrelation function provides an objective test for the existence of special scales in the hierarchical clustering of young stars. We apply this measure to single-star photometry for the brightest main sequence stars in the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC), M33, and M31, using data from the Magellanic Clouds Photometric Survey and the Massey Local Group Sur...

We report the first detailed chemical abundances for 5 globular clusters (GCs) in M31 from highresolution (R ∼ 25,000) spectroscopy of their integrated light. These GCs are the first in a larger set of clusters observed as part of an ongoing project to study the formation history of M31 and its globular cluster population. The data presented here were obtained with the HIRES echelle spectrograp...

A search for variable stars is performed using two epochs of Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging data for a 9.28 square arcminute portion of M31. This data set reveals 254 sources that vary by at least 4σ between epochs. The positions and 2-epoch B-band (equivalent) photometry of these sources are presented. The photometry suggests that this catalog includes m...

Recent work by several groups has established the properties of the dwarf satellites to M31. We reexamine the reported kinematics of this group employing a fresh technique we have developed previously. By calculating the distribution of a χ statistic (which we define in the paper) for the M31 system, we conclude that the total mass (disk plus halo) of the primary is unlikely to be as great as t...

We present deep F606W, F814W ACS photometry of the recently discovered globular cluster B514, the outermost known globular in the M31 galaxy. The cluster appears quite extended and member stars are unequivocally identified out to ∼ 200 pc from the center. The Color Magnitude Diagram reveals a steep Red Giant Branch (RGB), and a Horizontal Branch (HB) extending blue ward of the instability strip...

ASTRONOMY AND ASTROPHYSICS 1.2.2008 " The globular cluster distributions in the Galaxy, M31 and M87: are many globulars disappeared to the galactic centres? " Abstract. The radial distribution of globular clusters in our Galaxy, M31 and M87 is studied and compared with that of halo stars. The globular cluster distributions seem significantly flatter than those of the stars bulge. Assuming this ...