Search Publications
Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code - II. The Southern clusters and overview
Cohen, Roger E.; Bizyaev, Dmitry; Ebelke, Garrett +33 more
We investigate the Fe, C, N, O, Mg, Al, Si, K, Ca, Ce, and Nd abundances of 2283 red giant stars in 31 globular clusters from high-resolution spectra observed in both the Northern and Southern hemisphere by the SDSS-IV APOGEE-2 survey. This unprecedented homogeneous data set, largest to date, allows us to discuss the intrinsic Fe spread, the shape…
Chemodynamics of barred galaxies in cosmological simulations: On the Milky Way's quiescent merger history and in-situ bulge
White, S. D. M.; Fragkoudi, F.; Monachesi, A. +9 more
We explore the chemodynamical properties of a sample of barred galaxies in the Auriga magnetohydrodynamical cosmological zoom-in simulations, which form boxy/peanut (b/p) bulges, and compare these to the Milky Way (MW). We show that the Auriga galaxies which best reproduce the chemodynamical properties of stellar populations in the MW bulge have q…
H0LiCOW XII. Lens mass model of WFI2033-4723 and blind measurement of its time-delay distance and H0
Treu, Tommaso; Marshall, Philip J.; Sonnenfeld, Alessandro +15 more
We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033 - 4723, and perform a blind cosmographical analysis based on this system. Our analysis combines (1) time-delay measurements from 14 yr of data obtained by the COSmological MOnitoring of GRAvItational Lenses (COSMOGRAIL) collaboration, (2) high-resolution H…
The dual origin of the Galactic thick disc and halo from the gas-rich Gaia-Enceladus Sausage merger
Grand, Robert J. J.; Gómez, Facundo A.; Fattahi, Azadeh +6 more
We analyse a set of cosmological magnetohydrodynamic simulations of the formation of Milky Way-mass galaxies identified to have a prominent radially anisotropic stellar halo component similar to the so-called 'Gaia Sausage' found in the Gaia data. We examine the effects of the progenitor of the Sausage (the Gaia-Enceladus Sausage, GES) on the form…
An outflow powers the optical rise of the nearby, fast-evolving tidal disruption event AT2019qiz
Campana, S.; Berger, E.; Gromadzki, M. +42 more
At 66 Mpc, AT2019qiz is the closest optical tidal disruption event (TDE) to date, with a luminosity intermediate between the bulk of the population and the faint-and-fast event iPTF16fnl. Its proximity allowed a very early detection and triggering of multiwavelength and spectroscopic follow-up well before maximum light. The velocity dispersion of …
Observing the tail of reionization: neutral islands in the z = 5.5 Lyman-α forest
Nasir, Fahad; D'Aloisio, Anson
Previous studies have noted difficulties in modelling the highest opacities of the z > 5.5 Ly α forest, epitomized by the extreme Lyα trough observed towards quasar ULAS J0148 + 0600. One possibility is that the most opaque regions at these redshifts contain significant amounts of neutral hydrogen. This explanation, which abandons the common as…
Limit on the LMC mass from a census of its satellites
Belokurov, Vasily A.; Erkal, Denis
We study the orbits of dwarf galaxies in the combined presence of the Milky Way and Large Magellanic Cloud (LMC) and find six dwarfs that were likely accreted with the LMC (Car 2, Car 3, Hor 1, Hyi 1, Phe 2, and Ret 2), in addition to the Small Magellanic Cloud (SMC), representing strong evidence of dwarf galaxy group infall. This procedure depend…
A radio parallax to the black hole X-ray binary MAXI J1820+070
Maccarone, T. J.; Altamirano, D.; Belloni, T. +18 more
Using the Very Long Baseline Array and the European Very Long Baseline Interferometry Network, we have made a precise measurement of the radio parallax of the black hole X-ray binary MAXI J1820+070, providing a model-independent distance to the source. Our parallax measurement of (0.348 ± 0.033) mas for MAXI J1820+070 translates to a distance of (…
Ionizing the intergalactic medium by star clusters: the first empirical evidence
Giavalisco, M.; Castellano, M.; Gilli, R. +14 more
We present a VLT/X-Shooter spectroscopy of the Lyman continuum (LyC) emitting galaxy Ion2 at z = 3.2121 and compare it to that of the recently discovered strongly lensed LyC emitter at z = 2.37, known as the Sunburst arc. Three main results emerge from the X-Shooter spectrum: (a) the Ly α has three distinct peaks with the central one at the system…
The Milky Way's disc of classical satellite galaxies in light of Gaia DR2
Kroupa, Pavel; Pawlowski, Marcel S.
We study the correlation of orbital poles of the 11 classical satellite galaxies of the Milky Way, comparing results from previous proper motions with the independent data by Gaia DR2. Previous results on the degree of correlation and its significance are confirmed by the new data. A majority of the satellites co-orbit along the Vast Polar Structu…