Search Publications
Weighing the stellar constituents of the galactic halo with APOGEE red giant stars
Bovy, Jo; Mackereth, J. Ted
The stellar mass in the halo of the Milky Way is notoriously difficult to determine, owing to the paucity of its stars in the solar neighbourhood. With tentative evidence from Gaia that the nearby stellar halo is dominated by a massive accretion event - referred to as Gaia-Enceladus or Sausage - these constraints are now increasingly urgent. We me…
Gaia white dwarfs within 40 pc II: the volume-limited Northern hemisphere sample
Toonen, Silvia; Rebassa-Mansergas, Alberto; Gänsicke, Boris T. +6 more
We present an overview of the sample of Northern hemisphere white dwarfs within 40 pc of the Sun detected from Gaia Data Release 2 (DR2). We find that 521 sources are spectroscopically confirmed degenerate stars, 111 of which were first identified as white dwarf candidates from Gaia DR2 and followed up recently with the William Herschel Telescope …
NIHAO-UHD: the properties of MW-like stellar discs in high-resolution cosmological simulations
Ostriker, Jeremiah P.; Buck, Tobias; Minchev, Ivan +3 more
Simulating thin and extended galactic discs has long been a challenge in computational astrophysics. We introduce the NIHAO-UHD suite of cosmological hydrodynamical simulations of Milky Way (MW) mass galaxies and study stellar disc properties such as stellar mass, size, and rotation velocity which agree well with observations of the MW and local g…
Discovery of a nearby 1700 km s-1 star ejected from the Milky Way by Sgr A*
Lewis, Geraint F.; Boubert, Douglas; Erkal, Denis +18 more
We present the serendipitous discovery of the fastest main-sequence hyper-velocity star (HVS) by the Southern Stellar Stream Spectroscopic Survey (S5). The star S5-HVS1 is a ∼2.35 M⊙ A-type star located at a distance of ∼9 kpc from the Sun and has a heliocentric radial velocity of 1017 ± 2.7 km s^{-1} without any signature of…
The diversity and variability of star formation histories in models of galaxy evolution
Somerville, Rachel S.; Genel, Shy; Hernquist, Lars +10 more
Understanding the variability of galaxy star formation histories (SFHs) across a range of time-scales provides insight into the underlying physical processes that regulate star formation within galaxies. We compile the SFHs of galaxies at z = 0 from an extensive set of models, ranging from cosmological hydrodynamical simulations (Illustris, Illust…
Driving classical Wolf-Rayet winds: a Γ- and Z-dependent mass-loss
Hamann, W. -R.; Vink, J. S.; Sander, Andreas A. C.
Classical Wolf-Rayet (cWR) stars are at a crucial evolutionary stage for constraining the fates of massive stars. The feedback of these hot, hydrogen-depleted stars dominates their surrounding by tremendous injections of ionizing radiation and kinetic energy. The strength of a Wolf-Rayet (WR) wind decides the eventual mass of its remnant, likely a…
Thermal luminosities of cooling neutron stars
Zyuzin, D. A.; Shibanov, Yu A.; Potekhin, A. Y. +2 more
Ages and thermal luminosities of neutron stars, inferred from observations, can be interpreted with the aid of the neutron star cooling theory to gain information on the properties of superdense matter in neutron-star interiors. We present a survey of estimated ages, surface temperatures, and thermal luminosities of middle-aged neutron stars with …
The SkyMapper-Gaia RVS view of the Gaia-Enceladus-Sausage - an investigation of the metallicity and mass of the Milky Way's last major merger
Feuillet, Diane K.; Casagrande, Luca; Feltzing, Sofia +1 more
We characterize the Gaia-Enceladus-Sausage kinematic structure recently discovered in the Galactic halo using photometric metallicities from the SkyMapper survey, and kinematics from Gaia radial velocities measurements. By examining the metallicity distribution functions (MDFs) of stars binned in kinematic/action spaces, we find that the $\sqrt{J_…
Missing [C II] emission from early galaxies
Maiolino, R.; Castellano, M.; Pentericci, L. +9 more
ALMA observations have revealed that [C II] 158 µm line emission in high-z galaxies is ≈2-3 × more extended than the UV continuum emission. Here we explore whether surface brightness dimming (SBD) of the [C II] line is responsible for the reported [C II] deficit, and the large $L_{\rm [O\, \small {III}]}/L_{\rm [C\, \small {II}]}$ luminosity…
The last breath of the Sagittarius dSph
Vasiliev, Eugene; Belokurov, Vasily
We use the astrometric and photometric data from Gaia Data Release 2 and line-of-sight velocities from various other surveys to study the 3D structure and kinematics of the Sagittarius dwarf galaxy. The combination of photometric and astrometric data makes it possible to obtain a very clean separation of Sgr member stars from the Milky Way foregro…