Search Publications
Gaia Data Release 2. Specific characterisation and validation of all-sky Cepheids and RR Lyrae stars
Szabados, L.; Audard, M.; Rimoldini, L. +21 more
Context. The Gaia second Data Release (DR2) presents a first mapping of full-sky RR Lyrae stars and Cepheids observed by the spacecraft during the initial 22 months of science operations.
Aims: The Specific Objects Study (SOS) pipeline, developed to validate and fully characterise Cepheids and RR Lyrae stars (SOS Cep&RRL) observed by Gaia…
Gaia Data Release 2. Properties and validation of the radial velocities
Smith, M.; Gosset, E.; Allende Prieto, C. +52 more
Context. For Gaia DR2, 280 million spectra collected by the Radial Velocity Spectrometer instrument on board Gaia were processed, and median radial velocities were derived for 9.8 million sources brighter than GRVS = 12 mag.
Aims: This paper describes the validation and properties of the median radial velocities published in Gaia D…
Age determination for 269 Gaia DR2 open clusters
Jordi, C.; Casamiquela, L.; Cantat-Gaudin, T. +9 more
Context. The Gaia Second Data Release provides precise astrometry and photometry for more than 1.3 billion sources. This catalog opens a new era concerning the characterization of open clusters and test stellar models, paving the way for better understanding of the disk properties.
Aims: The aim of the paper is to improve the knowledge of clu…
Mass and shape of the Milky Way's dark matter halo with globular clusters from Gaia and Hubble
Helmi, Amina; Posti, Lorenzo
Aims: We estimate the mass of the inner (< 20 kpc) Milky Way and the axis ratio of its inner dark matter halo using globular clusters as tracers. At the same time, we constrain the distribution in phase-space of the globular cluster system around the Galaxy.
Methods: We use the Gaia Data Release 2 catalogue of 75 globular clusters' pr…
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…