Related papers: Mapping the Stellar Dynamics of M31
The kinematic and dynamical properties of galaxy stellar halos are difficult to measure because of the faint surface brightness that characterizes these regions. Spiral galaxies can be probed using the radio HI emission; on the contrary,…
Using an [OIII]5007 on-band/off-band filter technique, we identify 109 planetary nebulae (PNe) candidates in M 82, using the FOCAS instrument at the 8.2m Subaru Telescope. The use of ancillary high-resolution HST ACS H-alpha imaging aided…
Detailed studies of stellar populations in the halos of the Milky Way and the Andromeda (M 31) galaxies have shown increasing numbers of tidal streams and dwarf galaxies, attesting to a complicated and on-going process of hierarchical…
With the exceptional sensitivity of the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we conducted observations of the neutral hydrogen (HI) in the circumgalactic medium of Andromeda's (M31) satellite galaxies, specifically…
We present the first comprehensive spectroscopic study of the Andromeda galaxy's Eastern Extent. This ~4 degree long filamentary structure. located 70-90 kpc from the centre of M31, lies perpendicular to Andromeda's minor axis and the Giant…
We present a color-magnitude diagram (CMD) for a field in the giant tidal stream of the Andromeda galaxy (M31). These observations, taken with the Advanced Camera for Surveys on the Hubble Space Telescope, are 50% complete at V~30 mag,…
We present new planetary nebulae (PNe) positions, radial velocities, and magnitudes for 6 early-type galaxies obtained with the Planetary Nebulae Spectrograph, their two-dimensional velocity and velocity dispersion fields. We extend this…
A large, faint nebula was unexpectedly discovered near M31 using narrowband [O III] images. Its apparent size and the lack of a clear counterpart at other wavelengths make it unique and challenging to explain. We aim to determine whether…
The Andromeda Galaxy (M31) is one of a few galaxies that has sufficient angular size on the sky to be resolved by the Planck satellite. Planck has detected M31 in all of its frequency bands, and has mapped out the dust emission with the…
We investigate the evolution of a population of 100 dark matter satellites orbiting in the gravitational potential of a realistic model of M31. We find that after 10 Gyr, seven subhalos are completely disrupted by the tidal field of the…
We examine the nature of the progenitor of the giant stellar stream in M31 using as constraints new radial velocity measurements of stream red giant stars (presented in the companion paper by Guhathakurta et al. 2005, astro-ph/0406145)…
We analyse the M31 halo and its substructure within a projected radius of 120 kpc using a combination of Subaru/HSC $\textit{NB515}$ and CFHT/MegaCam $\textit{g}$- \& $\textit{i}$-bands. We succeed in separating M31's halo stars from…
We present the velocity dispersion of red giant branch (RGB) stars in M31's halo, derived by modeling the line of sight velocity distribution of over 5000 stars in 50 fields spread throughout M31's stellar halo. The dataset was obtained as…
New high resolution, high sensitivity WSRT HI synthesis observations of the spiral galaxy NGC 3631 are presented. In the total atomic hydrogen map, the spiral arms are well distinguished from the interarm regions, while the sensitivity…
Gas response to the underlying stellar spirals is explored for M81 using unmagnetized hydrodynamic simulations. Constrained within the uncertainty of observations, 18 simulations are carried out to study the effects of selfgravity and to…
Using the 100-m radio telescope at Effelsberg, we mapped a large area around the Andromeda Galaxy in the 21-cm line emission of neutral hydrogen to search for high-velocity clouds (HVCs) out to large projected distances in excess of 100…
This review attempts to place the observations of extragalactic planetary nebulae in the context of galactic dynamics. From this point of view only the radial velocities of the PNe are important. We have built a specialised instrument to…
Recent observations of our neighbouring galaxy M31 have revealed that its disk was shaped by widespread events. The evidence for this includes the high dispersion ($V/\sigma$ $\le$ 3) of stars older than 2 Gyr, and a global star formation…
We observed 21 polarized background radio sources in the field of M31 at 1.365 GHz and 1.652 GHz, and determined their rotation measures (RMs). The RM data show that the regular magnetic field of the disk probably extends from about 5 kpc…
Much of our understanding of dark matter halos comes from the assumption that the mass-to-light ratio (M/L) of spiral disks is constant. The best way to test this hypothesis is to measure the disk surface mass density directly via the…