We present a new deep 21-cm survey of the Andromeda galaxy, based on high resolution observations performed with the Synthesis Telescope and the 26-m antenna at DRAO. The Hi distribution and kinematics of the disc are analyzed and basic dynamical properties are given. The rotation curve is measured out to 38 kpc, showing a nuclear peak at 340 km s −1 , a dip at 202 km s −1 around 4 kpc, two distinct flat parts at 264 km s −1 and 230 km s −1 and an increase to 275 km s −1 in the outermost regions. Except for the innermost regions, the axisymmetry of the gas rotation is very good. A very strong warp of the Hi disc is evidenced. The central regions appear less inclined than the average disc inclination of 74 • , while the outer regions appear more inclined. Mass distribution models by ΛCDM Navarro-Frenk-White, Einasto or pseudo-isothermal dark matter halos with baryonic components are presented. They fail to reproduce the exact shape of the rotation curve. No significant differences are measured between the various shapes of halo. The dynamical mass of M31 enclosed within a radius of 38 kpc is (4.7 ± 0.5) × 10 11 M ⊙ . The dark matter component is almost 4 times more massive than the baryonic mass inside this radius. A total mass of 1.0 × 10 12 M ⊙ is derived inside the virial radius. New Hi structures are discovered in the datacube, like the detection of up to five Hi components per spectrum, which is very rarely seen in other galaxies. The most remarkable new Hi structures are thin Hi spurs and an external arm in the disc outskirts. A relationship between these spurs and outer stellar clumps is evidenced. The external arm is 32 kpc long, lies on the far side of the galaxy and has no obvious counterpart on the other side of the galaxy. Its kinematics clearly differs from the outer adjacent disc. Both these Hi perturbations could result from tidal interactions with galaxy companions.

We present a new catalogue containing all known Galactic supernova remnants observed in phase I and II of the Canadian Galactic Plane Survey (65. Stokes I images at 1420 MHz of 34 SNRs and at 408 MHz of 36 SNRs are displayed. From these 1 and 3 -resolution data (respectively) we determine accurate centre positions and angular dimensions. The flux densities at 1420 and 408 MHz are integrated and combined with values from the literature to define more accurate radio spectra. The CGPS polarization data at 1420 MHz were examined and significant linear polarization from 18 SNRs is found, with a modest signal from 6 others.

A new deep Hi survey of the galaxy Messier 33 is presented, based on observations obtained at the Dominion Radio Astrophysical Observatory. We observe a perturbed outer gas distribution and kinematics in M33, and confirm the disk warping as a significant kinematical twist of the major axis of the velocity field, though no strong tilt is measured, in agreement with previous work. Evidence for a new low brightness Hi component with anomalous velocity is reported. It harbours a large velocity scatter, as its kinematics both exceeds and lags the rotation of the disk, and leaks in the forbidden velocity zone of apparent counter-rotation. The observations also reveal wide and multiple peak Hi profiles which can be partly explained by crowded orbits in the framework of the warp model. Asymmetric motions are identified in the velocity field, as possible signatures of a lopsided potential and the warp. The mass distribution modeling of the hybrid Hα-Hi rotation curve favours a cuspy dark matter halo with a concentration in disagreement with the ΛCDM dark halo mass-concentration relationship. The total mass enclosed in 23 kpc is 8 10 10 M , of which 11% are stars and gas. At the virial radius of the cuspy halo, the resulting total mass is 5 10 11 M , but with a baryonic mass fraction of 2% only. This strongly suggests a more realistic radius encompassing the total mass of M33 well smaller than the virial radius of the halo, maybe comparable to the size of the Hi disk.

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The study of supernova remnants (SNRs) is fundamental to understanding the chemical enrichment and magnetism in galaxies, including our own Milky Way. In an effort to understand the connection between the morphology of SNRs and the Galactic magnetic field (GMF), we have examined the radio images of all known SNRs in our Galaxy and compiled a large sample that have an axisymmetric morphology, which we define to mean SNRs with a bilateral or barrel-shaped morphology, in addition to one-sided shells. We selected the cleanest examples and model each of these at their appropriate Galactic position using two GMF models, one of which includes a vertical halo component, and another that is oriented entirely parallel to the plane. Since the magnitude and relative orientation of the magnetic field changes with distance from the sun, we analyze a range of distances, from 0.5 to 10 kpc in each case. Using a physically motivated model of an SNR expanding into an ambient GMF that includes a vertical halo component, we find it is able to reproduce observed morphologies of many SNRs in our sample. These results strongly support the presence of an off-plane, vertical component to the GMF, and the importance of the Galactic field on SNR morphology. Our approach also provides a potentially new method for determining distances to SNRs, or conversely, distances to features in the large-scale GMF if SNR distances are known.

Two potential sites of H2 formation have been discovered in diffuse gas at high Galactic latitude through examining the far‐infrared (FIR) H i ratio and looking for an excess over that expected from an atomic medium. We call these the Spider and Ursa Major fields. New 12CO and 13CO Five College Radio Astronomical Observatory observations are presented for both regions (53 936 spectra in the Spider and 23 517 spectra in Ursa Major). Although there is a correlation between FIR excess and CO emission, we find that the FIR excess peaks do not coincide with the 12CO emission peaks, indicating that CO might be a poor tracer of H2 in diffuse regions. This implies (i) that the density is too small to allow CO excitation, (ii) that the CO self‐shielding is insufficient or (iii) local variations of the dust properties. The 12CO observations are compared with H i observations from the Dominion Radio Astrophysical Observatory. We decompose the 10 000 H i profiles of the Spider and the 20 302 H i profiles of Ursa Major into Gaussian components. We always find at most two narrow components and one broad component. CO always seems to appear where two H i velocity components merge or where there is a H i velocity‐shear.

A survey of the Milky Way disk and the Magellanic System at the wavelengths of the 21-cm atomic hydrogen (H i) line and three 18-cm lines of the OH molecule will be carried out with the Australian Square Kilometre Array Pathfinder * Hubble Fellow. telescope. The survey will study the distribution of H i emission and absorption with unprecedented angular and velocity resolution, as well as molecular line thermal emission, absorption, and maser lines. The area to be covered includes the Galactic plane (|b| < 10°) at all declinations south of δ = +40 • , spanning longitudes 167 • through 360 • to 79 • at b = 0 • , plus the entire area of the Magellanic Stream and Clouds, a total of 13 020 deg 2 . The brightness temperature sensitivity will be very good, typically σ T 1 K at resolution 30 arcsec and 1 km s −1 . The survey has a wide spectrum of scientific goals, from studies of galaxy evolution to star formation, with particular contributions to understanding stellar wind kinematics, the thermal phases of the interstellar medium, the interaction between gas in the disk and halo, and the dynamical and thermal states of gas at various positions along the Magellanic Stream.