Search Publications
Multiple retrograde substructures in the Galactic halo: A shattered view of Galactic history
Price-Whelan, Adrian M.; Helmi, Amina; Koppelman, Helmer H. +2 more
Aims: Several kinematic and chemical substructures have been recently found amongst Milky Way halo stars with retrograde motions. It is currently unclear how these various structures are related to each other. This Letter aims to shed light on this issue.
Methods: We explore the retrograde halo with an augmented version of the Gaia DR2 R…
Massive runaway and walkaway stars. A study of the kinematical imprints of the physical processes governing the evolution and explosion of their binary progenitors
Renzo, M.; Zapartas, E.; de Mink, S. E. +6 more
We perform an extensive numerical study of the evolution of massive binary systems to predict the peculiar velocities that stars obtain when their companion collapses and disrupts the system. Our aim is to (i) identify which predictions are robust against model uncertainties and assess their implications, (ii) investigate which physical processes …
The Milky Way has no in-situ halo other than the heated thick disc. Composition of the stellar halo and age-dating the last significant merger with Gaia DR2 and APOGEE
Katz, D.; Haywood, M.; Robichon, N. +5 more
Previous studies based on the analysis of Gaia DR2 data have revealed that accreted stars, possibly originating from a single progenitor satellite, are a significant component of the halo of our Galaxy, potentially constituting most of the halo stars at [Fe/H] < -1 within a few kpc from the Sun and beyond. In this paper, we couple astrometric d…
Cyclotron lines in highly magnetized neutron stars
Haberl, F.; Klochkov, D.; Santangelo, A. +10 more
Cyclotron lines, also called cyclotron resonant scattering features are spectral features, generally appearing in absorption, in the X-ray spectra of objects containing highly magnetized neutron stars, allowing the direct measurement of the magnetic field strength in these objects. Cyclotron features are thought to be due to resonant scattering of…
Universal thermodynamic properties of the intracluster medium over two decades in radius in the X-COP sample
Pointecouteau, E.; Rossetti, M.; Rasia, E. +10 more
Context. The hot plasma in a galaxy cluster is expected to be heated to high temperatures through shocks and adiabatic compression. The thermodynamical properties of the gas encode information on the processes leading to the thermalization of the gas in the cluster's potential well and on non-gravitational processes such as gas cooling, AGN feedba…
ALMA observations of molecular tori around massive black holes
Krips, M.; van der Werf, P.; Combes, F. +12 more
We report Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO(3-2) emission in a sample of seven Seyfert/LINER galaxies at the unprecedented spatial resolution of 0.″1 = 4-8 pc. Our aim is to explore the close environment of active galactic nuclei (AGN), and the dynamical structures leading to their fueling…
Characterizing the properties of nearby molecular filaments observed with Herschel
André, Ph.; Arzoumanian, D.; Könyves, V. +8 more
Context. Molecular filaments have received special attention recently thanks to new observational results on their properties. In particular, our early analysis of filament properties from Herschel imaging data in three nearby molecular clouds revealed a narrow distribution of median inner widths centered at a characteristic value of about 0.1 pc.…
The CARMENES search for exoplanets around M dwarfs. Different roads to radii and masses of the target stars
Schmitt, J. H. M. M.; del Burgo, C.; Amado, P. J. +28 more
Aims: We determine the radii and masses of 293 nearby, bright M dwarfs of the CARMENES survey. This is the first time that such a large and homogeneous high-resolution (R > 80 000) spectroscopic survey has been used to derive these fundamental stellar parameters.
Methods: We derived the radii using Stefan-Boltzmann's law. We obtained …
A stellar census in globular clusters with MUSE: Binaries in NGC 3201
Brinchmann, Jarle; Weilbacher, Peter M.; Kamann, Sebastian +8 more
We utilise multi-epoch MUSE spectroscopy to study binary stars in the core of the Galactic globular cluster NGC 3201. Our sample consists of 3553 stars with 54 883 spectra in total comprising 3200 main-sequence stars up to 4 magnitudes below the turn-off. Each star in our sample has between 3 and 63 (with a median of 14) reliable radial velocity m…
Non-thermal pressure support in X-COP galaxy clusters
Pointecouteau, E.; Rossetti, M.; Rasia, E. +13 more
Galaxy clusters are the endpoints of structure formation and are continuously growing through the merging and accretion of smaller structures. Numerical simulations predict that a fraction of their energy content is not yet thermalized, mainly in the form of kinetic motions (turbulence, bulk motions). Measuring the level of non-thermal pressure su…