Search Publications
Star cluster survival in dark matter haloes: an old cluster in Eridanus II?
Alzate, Jairo A.; Bruzual, Gustavo; Lomelí-Núñez, Luis +2 more
The star formation history and the internal dynamics of Milky Way satellite galaxies are often complicated. In the last years, a substantial fraction of the known faint dwarf satellites have been studied. Some of them show embedded stellar substructures, such as star clusters and even globular star clusters. In this work, we study Eridanus II, a d…
Are we observing an NSC in course of formation in the NGC 4654 galaxy?
Mastrobuono-Battisti, A.; Georgiev, I. Y.; Capuzzo-Dolcetta, R. +2 more
We use direct N-body simulations to explore some possible scenarios for the future evolution of two massive clusters observed towards the centre of NGC 4654, a spiral galaxy with mass similar to that of the Milky Way. Using archival HST data, we obtain the photometric masses of the two clusters, M = 3 × 105 M⊙ and M = 1.7 × 1…
V680 Mon - a young mercury-manganese star in an eclipsing heartbeat system
Vaňko, Martin; Paunzen, Ernst; Hümmerich, Stefan +3 more
Chemically peculiar stars in eclipsing binary systems are rare objects that allow the derivation of fundamental stellar parameters and important information on evolutionary status and the origin of the observed chemical peculiarities. Here we present an investigation of the known eclipsing binary system BD+09 1467 = V680 Mon. Using spectra from th…
Point spread function reconstruction of adaptive-optics imaging: meeting the astrometric requirements for time-delay cosmography
Treu, Tommaso; Fassnacht, Christopher D.; Chen, Geoff C. -F. +3 more
Astrometric precision and knowledge of the point spread function are key ingredients for a wide range of astrophysical studies including time-delay cosmography in which strongly lensed quasar systems are used to determine the Hubble constant and other cosmological parameters. Astrometric uncertainty on the positions of the multiply-imaged point so…
Confirming known planetary trends using a photometrically selected Kepler sample
Lin, Jane; Casagrande, Luca; Ireland, Michael J. +1 more
Statistical studies of exoplanets and the properties of their host stars have been critical to informing models of planet formation. Numerous trends have arisen in particular from the rich Kepler data set, including that exoplanets are more likely to be found around stars with a high metallicity and the presence of a 'gap' in the distribution of p…
An infrared study of Galactic OH/IR stars - III. Variability properties of the Arecibo sample
García-Lario, P.; Engels, D.; Jiménez-Esteban, F. M. +2 more
We present the results of a near-infrared (NIR) monitoring programme carried out between 1999 and 2005 to determine the variability properties of the 'Arecibo sample of OH/IR stars'. The sample consists of 385 IRAS-selected Asymptotic Giant Branch (AGB) candidates, for which their O-rich chemistry has been proven by the detection of 1612 MHz OH ma…
HD 183579b: a warm sub-Neptune transiting a solar twin detected by TESS
Torres, Guillermo; Barclay, Thomas; Hellier, Coel +48 more
We report the discovery and characterization of a transiting warm sub-Neptune planet around the nearby bright (V = 8.75 mag, K = 7.15 mag) solar twin HD 183579, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located 56.8 ± 0.1 pc away with a radius of R* = 0.97 ± 0.02 R⊙ and a mass of M*<…
Dynamical modelling of CXOGBS J175553.2-281633: a 10 h long orbital period cataclysmic variable
Strader, Jay; Maccarone, Thomas J.; Jonker, Peter G. +8 more
We present modelling of the long-term optical light and radial velocity curves of the binary stellar system CXOGBS J175553.2-281633, first detected in X-rays in the Chandra Galactic Bulge Survey. We analysed 7 yr of optical I-band photometry from Optical Gravitational Lensing Experiment and found long-term variations from year to year. These long-…
First high-resolution optical spectra of the distant emission-line star VES 723 (IRAS 02110+6212)
Miroshnichenko, A. S.; Manset, N.; Klochkova, V. G. +3 more
The first high-resolution spectra (resolving powers of R ≥ 60 000) of the emission-line star VES 723, which has an unknown evolutionary status, were taken at the 6-m Big Telescope Alt-Azimuthal and the 3.6-m Canada-France-Hawaii Telescope. The spectrum is dominated with powerful emission lines of neutral hydrogen and helium, and forbidden singly i…
Probing the physical properties of the intergalactic medium using blazars
Morris, Simon L.; Fumagalli, Michele; Gatuzz, Efrain +1 more
We use Swift blazar spectra to estimate the key intergalactic medium (IGM) properties of hydrogen column density ($\mathit {N}\small {\rm HXIGM}$), metallicity, and temperature over a redshift range of 0.03 ≤ z ≤ 4.7, using a collisional ionization equilibrium model for the ionized plasma. We adopted a conservative approach to the blazar continuum…