Search Publications
Imprints of white dwarf recoil in the separation distribution of Gaia wide binaries
Rix, Hans-Walter; El-Badry, Kareem
We construct from Gaia DR2 an extensive and very pure ({≲ } 0.2{{ per cent}} contamination) catalogue of wide binaries containing main-sequence (MS) and white dwarf (WD) components within 200 pc of the Sun. The public catalogue contains, after removal of clusters and resolved higher order multiples, > 50 000 MS/MS, > 3000 WD/MS, and nearly 4…
Systematic study of magnetar outbursts
Esposito, Paolo; Rea, Nanda; Coti Zelati, Francesco +2 more
We present the results of the systematic study of all magnetar outbursts observed to date, through a reanalysis of data acquired in about 1100 X-ray observations. We track the temporal evolution of the outbursts' soft X-ray spectral properties and the luminosities of the single spectral components as well as of the total emission. We model empiric…
VIRAC: the VVV Infrared Astrometric Catalogue
Minniti, D.; Gromadzki, M.; Marocco, F. +12 more
We present VIRAC version 1, a near-infrared proper motion and parallax catalogue of the VISTA Variables in the Via Lactea (VVV) survey for 312 587 642 unique sources averaged across all overlapping pawprint and tile images covering 560 deg2 of the bulge of the Milky Way and southern disc. The catalogue includes 119 million high-quality …
No evidence for a significant AGN contribution to cosmic hydrogen reionization
Dunlop, James S.; McLure, Ross J.; Parsa, Shaghayegh
We reinvestigate a claimed sample of 22 X-ray detected active galactic nuclei (AGN) at redshifts z > 4, which has reignited the debate as to whether young galaxies or AGN reionized the Universe. These sources lie within the Great Observatories Origins Deep Survey-South (GOODS-S)/Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CA…
LOFAR/H-ATLAS: the low-frequency radio luminosity-star formation rate relation
Prandoni, I.; Tasse, C.; Hardcastle, M. J. +11 more
Radio emission is a key indicator of star formation activity in galaxies, but the radio luminosity-star formation relation has to date been studied almost exclusively at frequencies of 1.4 GHz or above. At lower radio frequencies, the effects of thermal radio emission are greatly reduced, and so we would expect the radio emission observed to be co…
Weak lensing shear calibration with simulations of the HSC survey
Miyatake, Hironao; Leauthaud, Alexie; Mandelbaum, Rachel +8 more
We present results from a set of simulations designed to constrain the weak lensing shear calibration for the Hyper Suprime-Cam (HSC) survey. These simulations include HSC observing conditions and galaxy images from the Hubble Space Telescope (HST), with fully realistic galaxy morphologies and the impact of nearby galaxies included. We find that t…
RR Lyrae stars as standard candles in the Gaia Data Release 2 Era
Garofalo, Alessia; Clementini, Gisella; Muraveva, Tatiana +2 more
We present results from the analysis of 401 RR Lyrae stars (RRLs) belonging to the field of the Milky Way (MW). For a fraction of them multiband (V, Ks, W1) photometry, metal abundances, extinction values, and pulsation periods are available in the literature and accurate trigonometric parallaxes measured by the Gaia mission alongside G…
Isochrone ages for ∼3 million stars with the second Gaia data release
Sanders, Jason L.; Das, Payel
We present a catalogue of distances, masses, and ages for ∼3 million stars in the second Gaia data release with spectroscopic parameters available from the large spectroscopic surveys: APOGEE, Gaia-ESO, GALAH, LAMOST, RAVE, and SEGUE. We use a Bayesian framework to characterize the probability density functions of distance, mass, and age using pho…
The temporal evolution of neutron-capture elements in the Galactic discs
Dreizler, Stefan; Bedell, Megan; Meléndez, Jorge +8 more
Important insights into the formation and evolution of the Galactic disc(s) are contained in the chemical compositions of stars. We analysed high-resolution and high signal-to-noise HARPS spectra of 79 solar twin stars in order to obtain precise determinations of their atmospheric parameters, ages (σ ∼0.4 Gyr) and chemical abundances (σ <0.01 d…
The initial masses of the red supergiant progenitors to Type II supernovae
Beasor, Emma R.; Davies, Ben
There are a growing number of nearby supernovae (SNe) for which the progenitor star is detected in archival pre-explosion imaging. From these images it is possible to measure the progenitor's brightness a few years before explosion, and ultimately estimate its initial mass. Previous work has shown that II-P and II-L SNe have red supergiant (RSG) p…