Search Publications
Evidence for Galactic disc RR Lyrae stars in the solar neighbourhood
Grebel, E. K.; Prudil, Z.; Kunder, A. +1 more
We present a kinematical study of 314 RR Lyrae stars in the solar neighbourhood using the publicly available photometric, spectroscopic, and Gaia DR2 astrometric data to explore their distribution in the Milky Way. We report an overdensity of 22 RR Lyrae stars in the solar neighbourhood at a pericentre distance of between 5 and 9 kpc from the Gala…
K2-111: an old system with two planets in near-resonance
Bouchy, F.; Rebolo, R.; Zapatero Osorio, M. R. +64 more
This paper reports on the detailed characterization of the K2-111 planetary system with K2, WASP, and ASAS-SN photometry, as well as high-resolution spectroscopic data from HARPS-N and ESPRESSO. The host, K2-111, is confirmed to be a mildly evolved (log g = 4.17), iron-poor ([Fe/H] = -0.46), but alpha-enhanced ([α/Fe]=0.27), chromospherically quie…
Connecting the metallicity dependence and redshift evolution of high-mass X-ray binaries
Fornasini, Francesca M.; Civano, Francesca; Suh, Hyewon
The integrated X-ray luminosity (LX) of high-mass X-ray binaries (HMXBs) in a galaxy is correlated with its star formation rate (SFR), and the normalization of this correlation increases with redshift. Population synthesis models suggest that the redshift evolution of LX/SFR is driven by the metallicity (Z) dependence of HMXB…
Reobserving the NLS1 galaxy RE J1034+396 - I. The long-term, recurrent X-ray QPO with a high significance
Done, Chris; Ward, Martin; Jin, Chichuan
RE J1034+396 is a narrow-line Seyfert 1 galaxy (NLS1) in which the first significant X-ray quasi-periodic oscillation (QPO) in an active galactic nucleus (AGN) was observed in 2007. We report the detection of this QPO in a recent XMM-Newton observation in 2018 with an even higher significance. The quality factor of this QPO is 20, and its period i…
Completeness of the Gaia-verse - I. When and where were Gaia's eyes on the sky during DR2?
Everall, Andrew; Boubert, Douglas; Holl, Berry
The Gaia space mission is crafting revolutionary astrometric, photometric, and spectroscopic catalogues that will allow us to map our Galaxy, but only if we know the completeness of this Gaia-verse of catalogues: what stars does it contain and what stars is it missing? We argue that the completeness is driven by Gaia's spinning-and-precessing scan…
The Milky Way's stellar streams and globular clusters do not align in a Vast Polar Structure
Riley, Alexander H.; Strigari, Louis E.
There is increasing evidence that a substantial fraction of Milky Way satellite galaxies align in a rotationally supported plane of satellites, a rare configuration in cosmological simulations of galaxy formation. It has been suggested that other Milky Way substructures (namely young halo globular clusters and stellar/gaseous streams) similarly te…
Testing dark energy models with a new sample of strong-lensing systems
Motta, V.; Amante, Mario H.; García-Aspeitia, Miguel A. +2 more
Inspired by a new compilation of strong-lensing systems, which consist of 204 points in the redshift range 0.0625 < zl < 0.958 for the lens and 0.196 < zs < 3.595 for the source, we constrain three models that generate a late cosmic acceleration: the ω-cold dark matter model, the Chevallier-Polarski-Linder, and th…
Photometry and performance of SPECULOOS-South
Queloz, D.; Delrez, L.; Gillon, M. +16 more
SPECULOOS-South, an observatory composed of four independent 1-m robotic telescopes, located at ESO Paranal, Chile, started scientific operation in 2019 January. This Southern hemisphere facility operates as part of the Search for Habitable Planets EClipsing ULtra-cOOl Stars (SPECULOOS), an international network of 1-m-class telescopes surveying f…
X-ray properties of z ≳ 6.5 quasars
Banerji, M.; McMahon, R. G.; Pons, E. +1 more
We present XMM-Newton X-ray observations and analysis of three Dark Energy Survey z > 6.5 quasars (VDES J0020-3653 at z = 6.824, VDES J0244-5008 at z = 6.724, and VDES J0224-4711 at z = 6.526) and six other quasars with 6.438 < z < 6.747 from the XMM-Newton public archive. Two of the nine quasars are detected at a high (>4σ) significan…
An obscured AGN population hidden in the VIPERS galaxies: identification through spectral energy distribution decomposition
Georgantopoulos, I.; Mountrichas, G.; Bonanos, A. Z. +3 more
The detection of X-ray emission constitutes a reliable and efficient tool for the selection of active galactic nuclei (AGNs), although it may be biased against the most heavily absorbed AGNs. Simple mid-infrared (IR) broad-band selection criteria identify a large number of luminous and absorbed AGNs, yet again host contamination could lead to non-…