Search Publications
The K2 Galactic Caps Project - going beyond the Kepler field and ageing the Galactic disc
Khan, S.; Valentini, M.; García, R. A. +21 more
Analyses of data from spectroscopic and astrometric surveys have led to conflicting results concerning the vertical characteristics of the Milky Way. Ages are often used to provide clarity, but typical uncertainties of >40 per cent from photometry restrict the validity of the inferences made. Using the Kepler APOKASC sample for context, we expl…
The VMC survey - XXXIV. Morphology of stellar populations in the Magellanic Clouds
Girardi, Léo; de Grijs, Richard; Ripepi, Vincenzo +11 more
The Magellanic Clouds are nearby dwarf irregular galaxies whose morphologies show different properties when traced by different stellar populations, making them an important laboratory for studying galaxy morphologies. We study the morphology of the Magellanic Clouds using data from the Visible and Infrared Survey Telescope for Astronomy survey of…
Revealing the cosmic evolution of boxy/peanut-shaped bulges from HST COSMOS and SDSS
Debattista, Victor P.; Erwin, Peter; Lintott, Chris +1 more
Vertically thickened bars, observed in the form of boxy/peanut (B/P) bulges, are found in the majority of massive barred disc galaxies in the local Universe, including our own. B/P bulges indicate that their host bars have suffered violent bending instabilities driven by anisotropic velocity distributions. We investigate for the first time how the…
K2-264: a transiting multiplanet system in the Praesepe open cluster
Cochran, William D.; Endl, Michael; Tamura, Motohide +31 more
Planet host stars with well-constrained ages provide a rare window to the time domain of planet formation and evolution. The NASA K2 mission has enabled the discovery of the vast majority of known planets transiting stars in clusters, providing a valuable sample of planets with known ages and radii. We present the discovery of two planets transiti…
On the usefulness of existing solar wind models for pulsar timing corrections
Dettmar, R. -J.; Kramer, M.; Zucca, P. +15 more
Dispersive delays due to the solar wind introduce excess noise in high-precision pulsar timing experiments, and must be removed in order to achieve the accuracy needed to detect, e.g., low-frequency gravitational waves. In current pulsar timing experiments, this delay is usually removed by approximating the electron density distribution in the sol…
The solar wind in time - II. 3D stellar wind structure and radio emission
Petit, P.; Vidotto, A. A.; Jeffers, S. V. +6 more
In this work, we simulate the evolution of the solar wind along its main-sequence lifetime and compute its thermal radio emission. To study the evolution of the solar wind, we use a sample of solar mass stars at different ages. All these stars have observationally reconstructed magnetic maps, which are incorporated in our 3D magnetohydrodynamic si…
The redshift evolution of X-ray and Sunyaev-Zel'dovich scaling relations in the FABLE simulations
Sijacki, Debora; Puchwein, Ewald; Henden, Nicholas A.
We study the redshift evolution of the X-ray and Sunyaev-Zel'dovich (SZ) scaling relations for galaxy groups and clusters in the FABLE suite of cosmological hydrodynamical simulations. Using an expanded sample of 27 high-resolution zoom-in simulations, together with a uniformly sampled cosmological volume to sample low-mass systems, we find very g…
Distances and ages from isochrone fits of 150 open clusters using Gaia DR2 data
Dias, W. S.; Monteiro, H.
We investigate a sample of open cluster candidates with no previous age determination using astrometric and photometric data from the Gaia DR2 catalogue. Using proper motions and parallaxes and the full co-variance matrix we determined the astrometric membership probability of the stars in the field of each candidate. The memberships were used as …
AGN feedback and multiphase gas in giant elliptical galaxies
Ruszkowski, Mateusz; Li, Yuan; Wang, Chaoran
Recent observations have found extended multiphase gas in a significant fraction of massive elliptical galaxies. We perform high-resolution three-dimensional hydrodynamical simulations of two idealized elliptical galaxies - one representing a typical galaxy characterized by initial conditions conducive to the development of thermal instability and…
Evidence for spots on hot stars suggests major revision of stellar physics
Balona, L. A.
It has long been thought that starspots are not present in the A and B stars because magnetic fields cannot be generated in stars with radiative envelopes. Space observations show that a considerable fraction of these stars varies in light with periods consistent with the expected rotation periods. Here we show that the photometric periods are the…