Search Publications
Probing the Lambda-DGP Braneworld model
Ravanpak, Arvin; Farajollahi, Hossein; Fadakar, Golnaz
We study cosmic dynamics in the context of the normal branch of the DGP braneworld model. Using current Planck data, we find the best fitting model and associated cosmological parameters in non-flat ΛDGP. With the transition redshift as a basic variable and statefinder parameters, our result shows that the Universe starts its accelerated expansion…
Spectroscopy from the Hubble Space Telescope Cosmic Origins Spectrograph of the Southern Nova-like BB Doradus in an Intermediate State
Szkody, Paula; Sion, Edward M.; Godon, Patrick +6 more
We present a spectral analysis of the spectrum from the Hubble Space Telescope Cosmic Origins Spectrograph (HST/COS) of the southern VY Scl nova-like variable BB Doradus, obtained as part of a Cycle 20 HST/COS survey of accreting white dwarfs (WDs) in cataclysmic variables. BB Dor was observed with COS during an intermediate state with a low mass …
94 Ceti: a triple star with a planet and dust disc
Faramaz, V.; Wiegert, J.; Cruz-Saenz de Miera, F.
94 Ceti is a triple star system with a circumprimary gas giant planet and far-infrared excess. Such excesses around main sequence stars are likely due to debris discs, and are considered as signposts of planetary systems and, therefore, provide important insights into the configuration and evolution of the planetary system. Consequently, to learn …
The Clusters AgeS Experiment (CASE). Variable stars in the field of the globular cluster NGC 362
Thompson, I. B.; Schwarzenberg-Czerny, A.; Rozyczka, M. +2 more
The field of the globular cluster NGC 362 was monitored between 1997 and 2015 in a search for variable stars. BV light curves were obtained for 151 periodic or likely periodic variable stars, over a hundred of which are new detections. Twelve newly detected variable stars are proper-motion members of the cluster: two SX Phe and two RR Lyr pulsator…
Nonlinear Waves in the Terrestrial Quasiparallel Foreshock
Nakariakov, V. M.; Hnat, B.; Kolotkov, D. Y. +2 more
We provide strongly conclusive evidence that the cubic nonlinearity plays an important part in the evolution of the large amplitude magnetic structures in the terrestrial foreshock. Large amplitude nonlinear wave trains at frequencies above the proton cyclotron frequency are identified after nonharmonic slow variations are filtered out by applying…
LOTUS: a low-cost, ultraviolet spectrograph
Marchant, J. M.; Steele, I. A.; Snodgrass, C. +10 more
We describe the design, construction and commissioning of a simple, low-cost long-slit spectrograph for the Liverpool Telescope. The design is optimized for near-UV and visible wavelengths and uses all transmitting optics. It exploits the instrument focal plane field curvature to partially correct axial chromatic aberration. A stepped slit provide…
POLYCOMP: Efficient and configurable compression of astronomical timelines
Tomasi, M.
This paper describes the implementation of polycomp, a open-sourced, publicly available program for compressing one-dimensional data series in tabular format. The program is particularly suited for compressing smooth, noiseless streams of data like pointing information, as one of the algorithms it implements applies a combination of least squares …
Analogue Simulation and Orbital Solving Algorithm of Astrometric Exoplanet Detection
Ji, J. H.; Huang, P. H.
Astrometry is an effective method to detect exoplanets. It has many advantages that other detection methods do not bear, such as providing three dimensional planetary orbit and determining the planetary mass. Astrometry will enrich the sample of exoplanets. As the high-precision astrometric satellite Gaia (Global Astrometry interferometer for Astr…
The far-infrared emission of the radio-loud quasar 3C 318
Peletier, R. F.; Barthel, P. D.; Podigachoski, P. +1 more
3C 318, a radio-loud quasar at z = 1.574, is a subgalactic-sized radio source, and a good test-bed for the interplay between black hole and galaxy growth in the high-z Universe. Based on its IRAS, ISO, and SCUBA detections, it has long been considered as one of the most intrinsically luminous (LIR > 1013 L⊙) inf…
The peculiar optical-UV X-ray spectra of the X-ray weak quasar PG 0043+039
Talavera, A.; Schartel, N.; Rodríguez-Pascual, P. M. +4 more
Context. The object PG 0043+039 has been identified as a broad absorption line (BAL) quasar based on its UV spectra. However, this optical luminous quasar has not been detected before in deep X-ray observations, making it the most extreme X-ray weak quasar known today.
Aims: This study aims to detect PG 0043+039 in a deep X-ray exposure. The …