Search Publications
H0LiCOW - V. New COSMOGRAIL time delays of HE 0435-1223: H0 to 3.8 per cent precision from strong lensing in a flat ΛCDM model
Treu, T.; Auger, M. W.; Koopmans, L. V. E. +15 more
We present a new measurement of the Hubble Constant H0 and other cosmological parameters based on the joint analysis of three multiply imaged quasar systems with measured gravitational time delays. First, we measure the time delay of HE 0435-1223 from 13-yr light curves obtained as part of the COSMOGRAIL project. Companion papers detail…
The Hubble Space Telescope UV Legacy Survey of Galactic globular clusters - IX. The Atlas of multiple stellar populations
Salaris, M.; Anderson, J.; Milone, A. P. +17 more
We use high-precision photometry of red-giant-branch (RGB) stars in 57 Galactic globular clusters (GCs), mostly from the `Hubble Space Telescope (HST) UV Legacy Survey of Galactic GCs', to identify and characterize their multiple stellar populations. For each cluster the pseudo-two-colour diagram (or `chromosome map') is presented, built with a su…
An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907
Wolter, Anna; Esposito, Paolo; Turolla, Roberto +20 more
Ultraluminous x-ray sources (ULXs) in nearby galaxies shine brighter than any x-ray source in our Galaxy. ULXs are usually modeled as stellar-mass black holes (BHs) accreting at very high rates or intermediate-mass BHs. We present observations showing that NGC 5907 ULX is instead an x-ray accreting neutron star (NS) with a spin period evolving fro…
The Sloan Digital Sky Survey Quasar Catalog: Twelfth data release
Nandra, Kirpal; Pâris, Isabelle; Petitjean, Patrick +43 more
We present the Data Release 12 Quasar catalog (DR12Q) from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey III. This catalog includes all SDSS-III/BOSS objects that were spectroscopically targeted as quasar candidates during the full survey and that are confirmed as quasars via visual inspection of the spectra, h…
Can interacting dark energy solve the H0 tension?
Di Valentino, Eleonora; Melchiorri, Alessandro; Mena, Olga
The answer is yes. We indeed find that interacting dark energy can alleviate the current tension on the value of the Hubble constant H0 between the cosmic microwave background anisotropies constraints obtained from the Planck satellite and the recent direct measurements reported by Riess et al. 2016. The combination of these two data se…
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
Berger, E.; Rest, A.; Annis, J. +31 more
We present optical and ultraviolet spectra of the first electromagnetic counterpart to a gravitational-wave (GW) source, the binary neutron star merger GW170817. Spectra were obtained nightly between 1.5 and 9.5 days post-merger, using the Southern Astrophysical Research and Magellan telescopes; the UV spectrum was obtained with the Hubble Space T…
Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes
Stassun, Keivan G.; Collins, Karen A.; Gaudi, B. Scott
We present empirical measurements of the radii of 116 stars that host transiting planets. These radii are determined using only direct observables—the bolometric flux at Earth, the effective temperature, and the parallax provided by the Gaia first data release—and thus are virtually model independent, with extinction being the only free parameter.…
Unveiling ν secrets with cosmological data: Neutrino masses and mass hierarchy
Ho, Shirley; Mena, Olga; Gerbino, Martina +4 more
Using some of the latest cosmological data sets publicly available, we derive the strongest bounds in the literature on the sum of the three active neutrino masses, Mν, within the assumption of a background flat Λ CDM cosmology. In the most conservative scheme, combining Planck cosmic microwave background temperature anisotropies and ba…
Directly Observing the Galaxies Likely Responsible for Reionization
Finkelstein, S. L.; Lotz, J. M.; Livermore, R. C.
We report a new analysis of the Hubble Frontier Fields clusters Abell 2744 and MACS 0416 using wavelet decomposition to remove the cluster light, enabling the detection of highly magnified (>50×) galaxies a factor of 10× fainter in luminosity than previous studies. We find 167 galaxies at z≳ 6, and with this sample we are able to characterize t…
A deep ALMA image of the Hubble Ultra Deep Field
Ivison, R. J.; Scott, D.; van Kampen, E. +36 more
We present the results of the first, deep Atacama Large Millimeter Array (ALMA) imaging covering the full ≃4.5 arcmin2 of the Hubble Ultra Deep Field (HUDF) imaged with Wide Field Camera 3/IR on HST. Using a 45-pointing mosaic, we have obtained a homogeneous 1.3-mm image reaching σ1.3 ≃ 35 µJy, at a resolution of ≃0.7 a…