Search Publications
A Multimass Velocity Dispersion Model of 47 Tucanae Indicates No Evidence for an Intermediate-mass Black Hole
Anderson, Jay; Caiazzo, Ilaria; Baumgardt, Holger +6 more
In this paper, we analyze stellar proper motions in the core of the globular cluster 47 Tucanae to explore the possibility of an intermediate-mass black hole (IMBH) influence on the stellar dynamics. Our use of short-wavelength photometry affords us an exceedingly clear view of stellar motions into the very center of the crowded core, yielding pro…
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…
High-resolution confirmation of an extended helium atmosphere around WASP-107b
Aceituno, J.; Ehrenreich, D.; Lovis, C. +7 more
Context. Probing the evaporation of exoplanet atmospheres is key to understanding the formation and evolution of exoplanetary systems. The main tracer of evaporation in the UV is the Lyman-α transition, which can reveal extended exospheres of neutral hydrogen. Recently, the near-infrared (NIR) metastable helium triplet (10 833 Å) revealed extended…
Disruption of the Orion molecular core 1 by wind from the massive star θ1 Orionis C
Teyssier, D.; Goicoechea, J. R.; Stutzki, J. +10 more
Massive stars inject mechanical and radiative energy into the surrounding environment, which stirs it up, heats the gas, produces cloud and intercloud phases in the interstellar medium, and disrupts molecular clouds (the birth sites of new stars1,2). Stellar winds, supernova explosions and ionization by ultraviolet photons control the l…
The Fall of a Giant. Chemical evolution of Enceladus, alias the Gaia Sausage
Silva Aguirre, Victor; Matteucci, Francesca; Miglio, Andrea +4 more
We present the first chemical evolution model for Enceladus, alias the Gaia Sausage, to investigate the star formation history of one of the most massive satellites accreted by the Milky Way during a major merger event. Our best chemical evolution model for Enceladus nicely fits the observed stellar [α/Fe]-[Fe/H] chemical abundance trends, and rep…
Observable tests of self-interacting dark matter in galaxy clusters: cosmological simulations with SIDM and baryons
Massey, Richard; Jauzac, Mathilde; Harvey, David +5 more
We present BAHAMAS-SIDM, the first large-volume, (400 h^{-1} Mpc)3, cosmological simulations including both self-interacting dark matter (SIDM) and baryonic physics. These simulations are important for two primary reasons: (1) they include the effects of baryons on the dark matter distribution and (2) the baryon particles can be used to…
The L 98-59 System: Three Transiting, Terrestrial-size Planets Orbiting a Nearby M Dwarf
Kostov, Veselin B.; Barclay, Thomas; Moran, Sarah E. +112 more
We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L 98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia-measured distance and broadband photometry, we find that the host star is an M3 dwarf. Combined with the TESS transits from three sectors, the c…
High Density Reflection Spectroscopy - II. The density of the inner black hole accretion disc in AGN
Fabian, Andrew C.; Reynolds, Christopher S.; Walton, Dominic J. +7 more
We present a high density disc reflection spectral analysis of a sample of 17 Seyfert 1 galaxies to study the inner disc densities at different black hole mass scales and accretion rates. All the available XMM-Newton observations in the archive are used. OM observations in the optical/UV band are used to estimate their accretion rates. We find tha…
Close Companions around Young Stars
Bizyaev, Dmitry; Oravetz, Daniel; Pan, Kaike +26 more
Multiplicity is a fundamental property that is set early during stellar lifetimes, and it is a stringent probe of the physics of star formation. The distribution of close companions around young stars is still poorly constrained by observations. We present an analysis of stellar multiplicity derived from Apache Point Observatory Galactic Evolution…
White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 14
Kepler, S. O.; Pelisoli, Ingrid; Romero, Alejandra D. +6 more
White dwarfs carry information on the structure and evolution of the Galaxy, especially through their luminosity function and initial-to-final mass relation. Very cool white dwarfs provide insight into the early ages of each population. Examining the spectra of all stars with 3σ proper motion in the Sloan Digital Sky Survey Data Release 14, we rep…