Search Publications
Three cases of optical periodic modulation in Active Galactic Nuclei
Wang, Zhongxiang; Li, Jie; Zheng, Dong
We report on the case of optical periodic modulation discovered in two Active Galactic Nuclei (AGN) and one candidate AGN. Analysing the archival optical data obtained from large transient surveys, namely the Catalina Real-Transient Survey (CRTS) and the Zwicky Transient Facility (ZTF), we find periodicities of 2169.7, 2103.1, and 1462.6 d in sour…
BD +30°549: a young helium-weak silicon star in the NGC 1333 star-forming region
Potravnov, I.; Ryabchikova, T.; Mashonkina, L.
We present results of the spectroscopic study of the chemically peculiar star BD +30°549, which is a bona fide member of the young NGC 1333 star-forming region. We found that the star possesses negligible rotation and a helium-weak spectroscopic pattern with strongly enhanced Si II and Si III lines. The fundamental parameters of the star, Tef…
Spectral analysis of the AMXP IGR J17591-2342 during its 2018 outburst
Sanna, A.; Di Salvo, T.; Burderi, L. +9 more
The Accreting Millisecond X-ray Pulsar IGR J17591-2342 is a Low Mass X-ray Binary (LMXB) system that went in outburst on 2018 August and it was monitored by the NICER observatory and partially by other facilities. We aim to study how the spectral emission of this source evolved during the outburst by exploiting the whole X-ray data repository of s…
Projected spin-orbit alignments from Kepler asteroseismology and Gaia astrometry
Triaud, Amaury H. M. J.; Chaplin, William J.; Nielsen, Martin B. +2 more
The angle between the rotation and orbital axes of stars in binary systems - the obliquity - is an important indicator of how these systems form and evolve, but few such measurements exist. We combine the sample of astrometric orbital inclinations from Gaia Data Release 3 with a sample of solar-like oscillators in which rotational inclinations hav…
Precise near-infrared photometry, accounting for precipitable water vapour at SPECULOOS Southern Observatory
Queloz, D.; Delrez, L.; Gillon, M. +20 more
The variability induced by precipitable water vapour (PWV) can heavily affect the accuracy of time-series photometric measurements gathered from the ground, especially in the near-infrared. We present here a novel method of modelling and mitigating this variability, as well as open-sourcing the developed tool - Umbrella. In this study, we evaluate…
Classifying IGR J15038-6021 as a magnetic CV with a massive white dwarf
Hare, Jeremy; Mukai, Koji; Fornasini, Francesca M. +8 more
Cataclysmic variables (CVs) are binary systems consisting of a white dwarf (WD) accreting matter from a companion star. Observations of CVs provide an opportunity to learn about accretion discs, the physics of compact objects, classical novae, and the evolution of the binary and the WD that may ultimately end in a Type Ia supernova (SN). As Type I…
Predicting convective blueshift and radial-velocity dispersion due to granulation for FGK stars
Chaplin, W. J.; Meunier, N.; Dalal, S. +2 more
To detect Earth-mass planets using the Doppler method, a major obstacle is to differentiate the planetary signal from intrinsic stellar variability (e.g. pulsations, granulation, spots, and plages). Convective blueshift, which results from small-scale convection at the surface of Sun-like stars, is relevant for Earth-twin detections as it exhibits…
Discovery of δ Sct components in eclipsing binary systems IQ CMa, AW men and W Vol
Ulaş, Burak; Ulusoy, Ceren
We present the first evidence on the δ Sct type pulsations of the primary components of three eclipsing binaries IQ CMa, AW Men, and W Vol in the Transiting Exoplanet Survey Satellite (TESS) field. A comprehensive investigation of the binary properties is conducted. The light curves of the systems are analysed and the frequency analyses are perfor…
Multiband optical variability of a newly discovered 12 blazars sample from 2013 - 2019
Gupta, Alok C.; Damljanović, Goran; Bhatta, Gopal +2 more
Here we present the first optical photometric monitoring results of a sample of 12 newly discovered blazars from the ICRF - Gaia CRF astrometric link. The observations were performed from April 2013 to August 2019 using eight telescopes located in Europe. For a robust test for the brightness and colour variability, we use Abbé criterion and F-test…
Stellar clustering and the kinematics of stars around Collinder 121 using Gaia DR3
Ward-Thompson, Derek; Fleming, Graham D.; Kirk, Jason M.
We study the region around Collinder 121 (Cr 121) using newly available 6D data from the Gaia DR3 catalogue. Situated in the third quadrant, near the Galactic plane, Collinder 121 lies in the region of Canis Major centred around (l, b) ≈(236°, -10°). Previous studies have suggested that the stellar associations in this region comprise an OB associ…