Search Publications
The shape of the Galactic halo with Gaia DR2 RR Lyrae. Anatomy of an ancient major merger
Belokurov, Vasily; Iorio, Giuliano
We use the Gaia DR2 RR Lyrae sample to gain an uninterrupted view of the Galactic stellar halo. We dissect the available volume in slices parallel to the Milky Way's disc to show that within ∼30 kpc from the Galactic centre the halo is triaxial, with the longest axis misaligned by ∼70° with respect to the Galactic x-axis. This anatomical procedure…
Potential kick velocity distribution of black hole X-ray binaries and implications for natal kicks
Maccarone, T. J.; Chaty, S.; Miller-Jones, J. C. A. +14 more
We use very long baseline interferometry to measure the proper motions of three black hole X-ray binaries (BHXBs). Using these results together with data from the literature and Gaia DR2 to collate the best available constraints on proper motion, parallax, distance, and systemic radial velocity of 16 BHXBs, we determined their three-dimensional Ga…
ACCESS: a featureless optical transmission spectrum for WASP-19b from Magellan/IMACS
Fortney, Jonathan J.; López-Morales, Mercedes; Jordán, Andrés +13 more
The short-period (0.94-d) transiting exoplanet WASP-19b is an exceptional target for transmission spectroscopy studies, due to its relatively large atmospheric scale height (∼500 km) and equilibrium temperature (∼2100 K). Here, we report on six precise spectroscopic Magellan/IMACS observations, five of which target the full optical window from 0.4…
The pattern speed of the Milky Way bar from transverse velocities
Evans, N. Wyn; Sanders, Jason L.; Smith, Leigh
We use the continuity equation to derive a method for measuring the pattern speed of the Milky Way's bar/bulge from proper motion data. The method has minimal assumptions but requires complete coverage of the non-axisymmetric component in two of the three Galactic coordinates. We apply our method to the proper motion data from a combination of Gai…
The GREATS H β + [O III] luminosity function and galaxy properties at z ∼ 8: walking the way of JWST
Oesch, P. A.; Bouwens, R. J.; Illingworth, G. D. +5 more
The James Webb Space Telescope will allow to spectroscopically study an unprecedented number of galaxies deep into the reionization era, notably by detecting [O III]λλ4959, 5007, and H β nebular emission lines. To efficiently prepare such observations, we photometrically select a large sample of galaxies at z ∼ 8 and study their rest-frame optical…
Ingredients for solar-like systems: protostar IRAS 16293-2422 B versus comet 67P/Churyumov-Gerasimenko
van Dishoeck, Ewine F.; Drozdovskaya, Maria N.; Jørgensen, Jes K. +2 more
Our modern day Solar System has 4.6 × 109 yr of evolution behind it with just a few relics of its birth conditions remaining. Comets are thought to be some of the most pristine tracers of the initial ingredients that were combined to produce the Earth and the other planets. Other low-mass protostars may be analogous to our proto-Sun and…
The origin of galactic metal-rich stellar halo components with highly eccentric orbits
Springel, Volker; Grand, Robert J. J.; Gómez, Facundo A. +6 more
Using the astrometry from the ESA's Gaia mission, previous works have shown that the Milky Way stellar halo is dominated by metal-rich stars on highly eccentric orbits. To shed light on the nature of this prominent halo component, we have analysed 28 Galaxy analogues in the Auriga suite of cosmological hydrodynamics zoom-in simulations. Some three…
Piercing the Milky Way: an all-sky view of the Orphan Stream
Li, T. S.; Evans, N. W.; Belokurov, V. +14 more
We use astrometry, broad-band photometry, and variability information from the Data Release 2 of ESA's Gaia mission (GDR2) to identify members of the Orphan Stream (OS) across the whole sky. The stream is traced above and below the celestial equator and in both Galactic hemispheres, thus increasing its visible length to ∼210° equivalent to ∼150 kp…
The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters - XIX. A chemical tagging of the multiple stellar populations over the chromosome maps
Anderson, J.; Milone, A. P.; Cordoni, G. +8 more
The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated GCs and their stellar populations. In previous papers of this series we have introduced a pseudo two-colour diagram, or `chromosome map' (ChM) that maximizes the separation between the multiple populations. We have identified two main classes of GCs: T…
Homogeneous photometry - VII. Globular clusters in the Gaia era
Pancino, E.; Sanna, N.; Stetson, P. B. +2 more
We present wide-field, ground-based Johnson-Cousins UBVRI photometry for 48 Galactic globular clusters based on about 90 000 public and proprietary images. The photometry is calibrated with the latest transformations obtained in the framework of our secondary standard project, with typical internal and external uncertainties of order a few millima…