Search Publications
Effect of galaxy mergers on star-formation rates
Wang, L.; van der Tak, F. F. S.; Holwerda, B. W. +8 more
Context. Galaxy mergers and interactions are an integral part of our basic understanding of how galaxies grow and evolve over time. However, the effect that galaxy mergers have on star-formation rates (SFRs) is contested, with observations of galaxy mergers showing reduced, enhanced, and highly enhanced star formation.
Aims: We aim to determi…
Characterization and history of the Helmi streams with Gaia DR2
Helmi, Amina; Koppelman, Helmer H.; Massari, Davide +2 more
Context. The halo of the Milky Way has long been hypothesized to harbour significant amounts of merger debris. For more than a decade this view has been supported by wide-field photometric surveys which have revealed the outer halo to be lumpy.
Aims: The recent release of Gaia DR2 is allowing us to establish that mergers also have been import…
Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization
Tamura, M.; Nagel, E.; Amado, P. J. +73 more
We report the detection of a transiting Earth-size planet around GJ 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). GJ 357 b (TOI-562.01) is a transiting, hot, Earth-sized planet (Teq = 525 ± 11 K) with a radius of Rb = 1.217 ± 0.084 R⊕ and an orbital period of Pb
Carbon, oxygen, and iron abundances in disk and halo stars. Implications of 3D non-LTE spectral line formation
Skúladóttir, Á.; Amarsi, A. M.; Nissen, P. E.
The abundances of carbon, oxygen, and iron in late-type stars are important parameters in exoplanetary and stellar physics, as well as key tracers of stellar populations and Galactic chemical evolution. However, standard spectroscopic abundance analyses can be prone to severe systematic errors, based on the assumption that the stellar atmosphere i…
Hyades tidal tails revealed by Gaia DR2
Goldman, Bertrand; Röser, Siegfried; Schilbach, Elena
Aims: Within a 200 pc sphere around the Sun, we search for the Hyades tidal tails in the Gaia DR2 dataset.
Methods: We used a modified convergent-point method to search for stars with space velocities close to the space velocity of the Hyades cluster.
Results: We find a clear indication for the existence of the Hyades tidal tails, a…
The GALAH survey: An abundance, age, and kinematic inventory of the solar neighbourhood made with TGAS
Freeman, K. C.; Skúladóttir, Á.; Rix, H. -W. +32 more
The overlap between the spectroscopic Galactic Archaeology with HERMES (GALAH) survey and Gaia provides a high-dimensional chemodynamical space of unprecedented size. We present a first analysis of a subset of this overlap, of 7066 dwarf, turn-off, and sub-giant stars. These stars have spectra from the GALAH survey and high parallax precision from…
YBC: a stellar bolometric corrections database with variable extinction coefficients. Application to PARSEC isochrones
Fu, Xiaoting; Girardi, Léo; Marigo, Paola +7 more
We present the YBC database of stellar bolometric corrections, in which we homogenise widely used theoretical stellar spectral libraries and provide BCs for many popular photometric systems, including Gaia filters. The database can easily be extended to additional photometric systems and stellar spectral libraries. The web interface allows users t…
Structure and kinematics of the Taurus star-forming region from Gaia-DR2 and VLBI astrometry
Bouy, H.; Covey, K.; Sarro, L. M. +9 more
Aims: We take advantage of the second data release of the Gaia space mission and the state-of-the-art astrometry delivered from very long baseline interferometry observations to revisit the structure and kinematics of the nearby Taurus star-forming region.
Methods: We apply a hierarchical clustering algorithm for partitioning the stars i…
The MUSE-Wide Survey: survey description and first data release
Steinmetz, M.; Diener, C.; Enke, H. +17 more
We present the MUSE-Wide survey, a blind, 3D spectroscopic survey in the CANDELS/GOODS-S and CANDELS/COSMOS regions. The final survey will cover 100 × 1 arcmin2 MUSE fields. Each MUSE-Wide pointing has a depth of one hour and hence targets more extreme and more luminous objects over ten times the area of the MUSE-Deep fields. The legacy…
The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters
Hamann, W. -R.; Oskinova, L. M.; Sander, A. A. C. +6 more
Comprehensive spectral analyses of the Galactic Wolf-Rayet stars of the nitrogen sequence (i.e. the WN subclass) have been performed in a previous paper. However, the distances of these objects were poorly known. Distances have a direct impact on the "absolute" parameters, such as luminosities and mass-loss rates. The recent Gaia Data Release (DR2…