Search Publications
Uncovering fossils of the distant Milky Way with UNIONS: NGC 5466 and its stellar stream
Jensen, Jaclyn; McConnachie, Alan W.; Cuillandre, Jean-Charles +9 more
We examine the spatial clustering of blue horizontal branch (BHB) stars from the u-band of the Canada-France Imaging Survey (CFIS, a component of the Ultraviolet Near-Infrared Optical Northern Survey, or UNIONS). All major groupings of stars are associated with previously known satellites, and among these is NGC 5466, a distant (16 kpc) globular c…
Clumpiness of observed and simulated cold circumgalactic gas
Hamanowicz, Aleksandra; Zanella, Anita; Péroux, Céline +3 more
Determining the clumpiness of matter around galaxies is pivotal to a full understanding of the spatially inhomogeneous, multiphase gas in the circumgalactic medium (CGM). We combine high spatially resolved 3D observations with hydrodynamical cosmological simulations to measure the cold circumgalactic gas clumpiness. We present new adaptive-optics-…
Relativistic viscous accretion flow model for ULX sources: a case study for IC 342 X-1
Agrawal, Vivek K.; Nandi, Anuj; Das, Santabrata +2 more
In this paper, we develop a model formalism to study the structure of a relativistic, viscous, optically thin, advective accretion flow around a rotating black hole in presence of radiative coolings. We use this model to examine the physical parameters of the ultra-luminous X-ray sources (ULXs), namely mass (MBH), spin (ak), …
Evolutionary map of the Universe (EMU): Compact radio sources in the SCORPIO field towards the galactic plane
Umana, G.; Filipović, M. D.; Michałowski, M. J. +26 more
We present observations of a region of the Galactic plane taken during the Early Science Program of the Australian Square Kilometre Array Pathfinder (ASKAP). In this context, we observed the SCORPIO field at 912 MHz with an uncompleted array consisting of 15 commissioned antennas. The resulting map covers a square region of ∼40 deg2, ce…
An X-ray and radio study of the Hubble Frontier Field cluster Abell S1063
Rapetti, David; Rahaman, Majidul; Raja, Ramij +3 more
We present results from Chandra X-ray observations and 325 MHz Giant Metrewave Radio Telescope (GMRT) observations of the massive and X-ray luminous cluster of galaxies Abell S1063. We report the detection of large-scale 'excess brightness' in the residual Chandra X-ray surface brightness map that extends at least 2.7 Mpc towards the north-east fr…
Progenitor mass distribution for 22 historic core-collapse supernovae
Dolphin, Andrew E.; Williams, Benjamin F.; Dalcanton, Julianne J. +2 more
We infer the progenitor mass distribution for 22 historic core-collapse supernovae (CCSNe) using a Bayesian hierarchical model. For this inference, we use the local star formation histories to estimate the age for each supernova (SN). These star formation histories often show multiple bursts of star formation; our model assumes that one burst is a…
The structure of the Milky Way based on unWISE 3.4 µm integrated photometry
Mosenkov, Aleksandr V.; Camps, Peter; Savchenko, Sergey S. +1 more
We present a detailed analysis of the Galaxy structure using an unWISE wide-field image at $3.4\,\mu$m. We perform a 3D photometric decomposition of the Milky Way taking into account (i) the projection of the Galaxy on the celestial sphere and (ii) that the observer is located within the Galaxy at the solar radius. We consider a large set of photo…
A panoramic view of the Local Group dwarf galaxy NGC 6822
Mackey, Dougal; Da Costa, Gary S.; Zhang, Shumeng
We present a panoramic survey of the isolated Local Group dwarf irregular galaxy NGC 6822. Our photometry reaches ~2-3 mag deeper than most previous studies and spans the widest area around the dwarf compared to any prior work. We observe no stellar overdensities in the outskirts of NGC 6822 to V ~ 30 mag arcsec-2 and a projected radius…
Exploring the hot gaseous halo around an extremely massive and relativistic jet launching spiral galaxy with XMM-Newton
Fabian, A. C.; Ho, L. C.; Combes, F. +6 more
We present a deep XMM-Newton observation of the extremely massive, rapidly rotating, relativistic-jet-launching spiral galaxy 2MASX J23453268-0449256. Diffuse X-ray emission from the hot gaseous halo around the galaxy is robustly detected out to a radius of 160 kpc, corresponding roughly to 35 per cent of the virial radius (≈450 kpc). We fit the X…
Observing and modelling the young solar analogue EK Draconis: starspot distribution, elemental abundances, and evolutionary status
Solanki, S. K.; Montes, D.; Hussain, G. A. J. +4 more
Observations and modelling of stars with near-solar masses in their early phases of evolution are critical for a better understanding of how dynamos of solar-type stars evolve. We examine the chemical composition and the spot distribution of the pre-main-sequence solar analogue EK Dra. Using spectra from the HERMES Spectrograph (La Palma), we obta…