Search Publications
Exploring the origin of low-metallicity stars in Milky-Way-like galaxies with the NIHAO-UHD simulations
Buck, Tobias; Sestito, Federico; Navarro, Julio F. +6 more
The kinematics of the most metal-poor stars provide a window into the early formation and accretion history of the Milky Way (MW). Here, we use five high-resolution cosmological zoom-in simulations (∼ 5 × 106 star particles) of MW-like galaxies taken from the NIHAO-UHD project, to investigate the origin of low-metallicity stars ([Fe/H] …
The ASAS-SN catalogue of variable stars IX: The spectroscopic properties of Galactic variable stars
Kochanek, C. S.; Stanek, K. Z.; Dong, Subo +11 more
The All-Sky Automated Survey for Supernovae provides long baseline (~4 yr) V-band light curves for sources brighter than V≲ 17 mag across the whole sky. We produced V-band light curves for a total of ~61.5 million sources and systematically searched these sources for variability. We identified ~426 000 variables, including ~219 000 new discoveries…
VINTERGATAN III: how to reset the metallicity of the Milky Way
Feuillet, Diane K.; Ryde, Nils; Bensby, Thomas +5 more
Using the cosmological zoom simulation VINTERGATAN, we present a new scenario for the onset of star formation at the metal-poor end of the low-[α/Fe] sequence in a Milky Way-like galaxy. In this scenario, the galaxy is fuelled by two distinct gas flows. One is enriched by outflows from massive galaxies, but not the other. While the former feeds th…
Testing the effect of H0 on fσ8 tension using a Gaussian process method
Xu, Lixin; Li, En-Kun; Du, Minghui +2 more
Using the fσ8(z) redshift space distortion (RSD) data, the $\sigma _8^0\!-\!\Omega _\mathrm{ m}^0$ tension is studied utilizing a parametrization of growth rate f(z) = Ωm(z)γ. Here, f(z) is derived from the expansion history H(z) which is reconstructed from the observational Hubble data applying the Gaussian proces…
Exploring the Galaxy's halo and very metal-weak thick disc with SkyMapper and Gaia DR2
Schmidt, B. P.; Da Costa, G. S.; Milone, A. P. +16 more
In this work, we combine spectroscopic information from the SkyMapper survey for Extremely Metal-Poor stars and astrometry from Gaia DR2 to investigate the kinematics of a sample of 475 stars with a metallicity range of $-6.5 \le \rm [Fe/H] \le -2.05$ dex. Exploiting the action map, we identify 16 and 40 stars dynamically consistent with the Gaia …
Abundance measurements of H2O and carbon-bearing species in the atmosphere of WASP-127b confirm its supersolar metallicity
Deming, Drake; Nikolov, Nikolay; Carter, Aarynn L. +14 more
The chemical abundances of exoplanet atmospheres may provide valuable information about the bulk compositions, formation pathways, and evolutionary histories of planets. Exoplanets with large, relatively cloud-free atmospheres, and which orbit bright stars provide the best opportunities for accurate abundance measurements. For this reason, we meas…
A comprehensive reanalysis of Spitzer's 4.5 µm phase curves, and the phase variations of the ultra-hot Jupiters MASCARA-1b and KELT-16b
Fortney, Jonathan J.; Stevenson, Kevin B.; Désert, Jean-Michel +12 more
We have developed an open-source pipeline for the analysis of Spitzer/IRAC channel 1 and 2 time-series photometry, incorporating some of the most popular decorrelation methods. We applied this pipeline to new phase curve observations of ultra-hot Jupiters MASCARA-1b and KELT-16b, and we performed the first comprehensive reanalysis of 15 phase curv…
Measuring fundamental jet properties with multiwavelength fast timing of the black hole X-ray binary MAXI J1820+070
Maccarone, T. J.; Dhillon, V. S.; Gandhi, P. +9 more
We present multiwavelength fast timing observations of the black hole X-ray binary MAXI J1820+070 (ASASSN-18ey), taken with the Karl G. Jansky Very Large Array (VLA), Atacama Large Millimeter/Sub-Millimeter Array (ALMA), Very Large Telescope (VLT), New Technology Telescope (NTT), Neutron Star Interior Composition Explorer (NICER), and XMM-Newton. …
Einstein@Home discovery of the gamma-ray millisecond pulsar PSR J2039-5617 confirms its predicted redback nature
Dhillon, V. S.; Guillemot, L.; Harding, A. K. +19 more
The Fermi Large Area Telescope gamma-ray source 3FGL J2039.6-5618 contains a periodic optical and X-ray source that was predicted to be a 'redback' millisecond pulsar (MSP) binary system. However, the conclusive identification required the detection of pulsations from the putative MSP. To better constrain the orbital parameters for a directed sear…
Distances to Galactic X-ray binaries with Gaia DR2
Barmby, P.; Bahramian, A.; Arnason, R. M. +2 more
Precise and accurate measurements of distances to Galactic X-ray binaries (XRBs) reduce uncertainties in the determination of XRB physical parameters. We have cross-matched the XRB catalogues of Liu, van Paradijs & van den Heuvel to the results of Gaia Data Release 2. We identify 86 XRBs with a Gaia candidate counterpart, of which 32 are low-m…