Search Publications
Clocking the assembly of double-barred galaxies with the MUSE TIMER project
Leaman, Ryan; Fragkoudi, Francesca; van de Ven, Glenn +11 more
The formation of two stellar bars within a galaxy has proved challenging for numerical studies. It is not yet clear whether the inner bar is born via a star formation process promoted by gas inflow along the outer bar or whether it is dynamically assembled from instabilities in a small-scale stellar disc. Observational constraints to these scenari…
Search for extra-tidal RR Lyrae stars in Milky Way globular clusters from Gaia DR2
Minniti, Dante; Singh, Harinder P.; Kundu, Richa
We used extra-tidal RR Lyrae stars to study the dynamics of Galactic globular clusters and know how effects like dynamical friction and tidal disruption affect these clusters. The Gaia DR2 catalogue for RR Lyrae stars (Clementini et al. 2018) is used along with the proper motions and tidal radii data for the globular clusters compiled from literat…
Dynamical evolution of star-forming regions: III. Unbound stars and predictions for Gaia
Parker, Richard J.; Schoettler, Christina; Wright, Nicholas J. +3 more
We use N-body simulations to probe the early phases of the dynamical evolution of star-forming regions and focus on mass and velocity distributions of unbound stars. In this parameter space study, we vary the initial virial ratio and degree of spatial and kinematic substructure and analyse the fraction of stars that become unbound in two different…
On measuring the Galactic dark matter halo with hypervelocity stars
Rossi, E. M.; Marchetti, T.; Contigiani, O.
Hypervelocity stars (HVSs) travel from the Galactic Centre across the dark matter halo of the Milky Way, where they are observed with velocities in excess of the Galactic escape speed. Because of their quasi-radial trajectories, they represent a unique probe of the still poorly constrained dark matter component of the Galactic potential. In this p…
A relativistic disc reflection model for 1H0419-577: Multi-epoch spectral analysis with XMM-Newton and NuSTAR
Fabian, Andrew C.; Walton, Dominic J.; Jiang, Jiachen +1 more
We present a detailed analysis of the spectral properties of the Seyfert 1 galaxy 1H0419-577, based on the archival XMM-Newton, NuSTAR, and simultaneous Swift observations taken between 2002 and 2015. All the observations show a broad emission line feature at the iron band. We demonstrate that the broad-band spectral variability at different level…
The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548
Starkey, D. A.; Pott, J. -U.; Peterson, B. M. +16 more
We have recently initiated the first spectroscopic dust reverberation programme on active galactic nuclei in the near-infrared. Spectroscopy enables measurement of dust properties, such as flux, temperature, and covering factor, with higher precision than photometry. In particular, it enables measurement of both luminosity-based dust radii and dus…
Analysis of colour and polarimetric variability of RW Aur A in 2010-2018
Grankin, K.; Shenavrin, V.; Safonov, B. +6 more
The results of UBVRIJHKLM photometry and VRI polarimetry of a young star RW Aur A observed during unprecedented long and deep (up to ΔV ≈ 5 mag) dimming events in 2010-11 and 2014-18 are presented. The polarization degree p of RW Aur A at this period has reached 30 per cent in the I band. As in the case of UX Ori-type stars (UXORs), the so-called …
L1495 revisited: a PPMAP view of a star-forming filament
Griffin, M. J.; Smith, M. W. L.; Marsh, K. A. +4 more
We have analysed the Herschel and SCUBA-2 dust continuum observations of the main filament in the Taurus L1495 star-forming region, using the Bayesian fitting procedure PPMAP. (i) If we construct an average profile along the whole length of the filament, it has FWHM ∼eq 0.087± 0.003 pc; but the closeness to previous estimates is coincidental. (ii)…
Through thick or thin: multiple components of the magneto-ionic medium towards the nearby H II region Sharpless 2-27 revealed by Faraday tomography
Federrath, Christoph; Gaensler, B. M.; McClure-Griffiths, N. M. +12 more
Sharpless 2-27 (Sh2-27) is a nearby H II region excited by ζOph. We present observations of polarized radio emission from 300 to 480 MHz towards Sh2-27, made with the Parkes 64 m Radio Telescope as part of the Global Magneto-Ionic Medium Survey. These observations have an angular resolution of 1.35°, and the data are uniquely sensitive to magneto-…
Galaxy cluster mergers as triggers for the formation of jellyfish galaxies: case study of the A901/2 system
Chies-Santos, Ana L.; Lima Neto, Gastão B.; Roman-Oliveira, Fernanda V. +4 more
The A901/2 system is a rare case of galaxy cluster interaction, in which two galaxy clusters and two smaller groups are seen in route of collision with each other simultaneously. Within each of the four substructures, several galaxies with features indicative of jellyfish morphologies have been observed. In this paper, we propose a hydrodynamic mo…