Related papers: Tracing the Star Stream Through M31 Using Planetar…

We report the kinematic discovery of the Pisces Stellar Stream (PSS), at Galactic longitude of roughly l=135 degrees and longitude between -39 < b < -36 deg. We originally identified this halo substructure from velocities of red giant…

A revival over the past two decades in planetary nebula (PN) morphological studies springs from a combination of factors, including the advent of wide-area, high dynamic range detectors; the growing archives of high resolution images from…

I review some open questions and other aspects concerning the shaping of planetary nebulae (PNs) and related objects. I attribute the non-spherical structures of PNs to binary companions, stellar or substellar. I emphasize the role of jets…

In this paper we describe the results of the first optical kinematic study of the planetary nebula BD+30 3639. This system has a central star of the Wolf-Rayet type and is believed to be fairly young. Emission line spectra were obtained at…

We present a 3D dynamical model of the orbital induced curvature of the wind-wind collision region in binary star systems. Momentum balance equations are used to determine the position and shape of the contact discontinuity between the…

Over the course of the past two decades, observational surveys have unveiled the intricate orbital structure of the Kuiper Belt, a field of icy bodies orbiting the Sun beyond Neptune. In addition to a host of readily-predictable orbital…

We present high resolution spectroscopy in the [\ion{O}{3}]$\lambda$5007 and H$\alpha$ lines of bright planetary nebulae in the Milky Way bulge and the dwarf galaxies M32, Fornax, Sagittarius, and NGC 6822 obtained at the Observatorio…

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…

One of the possible mechanisms responsible for the panoply of shapes in planetary nebulae is the presence of magnetic fields that drive the ejection of ionized material during the proto-planetary nebula phase. Therefore, detecting magnetic…

We report results of an HST "snapshot" survey aimed at finding resolved binary companions of the central stars of Galactic planetary nebulae (PNe). Using WF/PC and WFPC2, we searched the fields of 113 PNe for stars whose close proximity to…

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…

The combination of large size, high stellar density, high metallicity, and Sersic surface brightness profile of the spheroidal component of the Andromeda galaxy (M31) within R_proj ~ 20 kpc suggest that it is unlike any subcomponent of the…

We obtained Keck/DEIMOS spectra of 556 individual red giant branch stars in 4 spectroscopic fields spanning $13-31$ projected kpc along the Northeast (NE) shelf of M31. We present the first detection of a complete wedge pattern in the space…

During the past 20 years, the idea that non-spherical planetary nebulae (PN) may need a binary or planetary interaction to be shaped was discussed by various authors. It is now generally agreed that the varied morphologies of PN cannot be…

Most fully developed galaxies have a vivid spiral structure, but the formation and evolution of the spiral structure are still an enigma in astrophysics. In this paper, according to the standard Newtonian gravitational theory and some…

Planetary nebulae are now well established as probes of galaxy dynamics and as standard candles in distance determinations. Motivated by the need to improve the efficiency of planetary nebulae searches and the speed with which their radial…

The 3D velocities of M31 and M33 are important for understanding the evolution and cosmological context of the Local Group. Their most massive stars are detected by Gaia, and we use Data Release 2 (DR2) to determine the galaxy proper…

We study the bending of jets in binary stellar systems. A compact companion accretes mass from the slow wind of the mass-losing primary star, forms an accretion disk, and blows two opposite jets. These fast jets are bent by the slow wind.…

We report on preliminary results from a new deep 21-cm survey of the Andromeda galaxy, based on observations performed with the Synthesis Telescope and the 26-m antenna at DRAO. The HI distribution and kinematics of the disc are analyzed…

Context: Planetary nebulae (PNe) are excellent tracers of stellar populations with low surface brightness, and therefore provide a powerful method to detect and explore the rich system of substructures discovered around the main spiral…