Search Publications
Designing large pixelated CdTe detection planes for hard X-ray transients detection
Bouchet, Laurent; Mate, Sujay; Bajat, Armelle +10 more
In this paper, we discuss the need for very large detection planes for the detection of hard X-ray transients in the multi-messenger era, started with the quasi-simultaneous detection of GRB 170817A by Fermi/GBM and INTEGRAL/SPI and the gravitational waves event GW 170817, detected by the LVC collaboration. After pointing that current and future i…
A Bayesian model for inferring properties of the local white dwarf population in astrometric and photometric surveys
Peiris, Hiranya V.; Widmark, Axel; Mortlock, Daniel J.
The Gaia mission is providing precise astrometry for an unprecedented number of white dwarfs (WDs), encoding information on stellar evolution, Type Ia supernovae progenitor scenarios, and the star formation and dynamical history of the Milky Way. With such a large data set, it is possible to infer properties of the WD population using only astrome…
Numerical Simulation of the Long-Term Thermal Evolution of the Nuclei of Short-Period Comets Using the Nucleus of Comet 67P/Churyumov–Gerasimenko as an Example
Dorofeeva, V. A.; Marov, M. Ya.; Rusol, A. V.
Using numerical models, we have studied what depth of the outer layer the comet nuclei are degassed to when they are in orbits whose perihelion is close to the Sun for tens of years. The problem is topical, because it helps to understand how much the experimentally obtained results on the composition of comet comas depend on how long the comet is …
Features of the Residual Velocity Ellipsoid of Hot Subdwarfs from the Gaia DR2 Catalog
Bobylev, V. V.; Bajkova, A. T.
The evolution of the parameters of the residual velocity ellipsoid of hot subdwarfs (HSDs) with their position relative to the Galactic plane is traced, using the HSDs selected by Geier et al. from the Gaia DR2 catalog. Parameters of the Galactic rotation are determined for two ∣ z∣ zones. These are used to estimate the gradient of the circular ro…
Star clusters in the dwarf irregular galaxy Leo A
Vansevičius, V.; Stonkutė, R.; Čeponis, M. +2 more
Context. Leo A is an isolated gas-rich dwarf irregular galaxy of low stellar mass and metallicity residing at the outskirts of the Local Group. Ages of the stellar populations in Leo A range from ∼10 Myr to ∼10 Gyr. So far, only one star cluster has been discovered in this galaxy.
Aims: Our aim is to search for star cluster candidates in the …
Follow-up observations of X-ray emitting hot subdwarf stars: the compact He-poor sdO star Feige 34
Tiengo, A.; Mereghetti, S.; Esposito, P. +1 more
We report on results obtained with the XMM-Newton observation of Feige 34 carried out in April 2018. This is the first spectroscopic X-ray observation of a compact and helium-poor hot subdwarf star. The source was detected at a flux level fX = 3.4 × 10-14 erg cm-2 s-1 in the energy range 0.2-3 keV, which…
Observations of photospheric magnetic structure below a dark filament using the Hinode Spectro-Polarimeter
Shimojo, Masumi; Yokoyama, Takaaki; Katsukawa, Yukio
The structure of the photospheric vector magnetic field below a dark filament on the Sun is studied using the observations of the Spectro-Polarimeter attached to the Solar Optical Telescope onboard Hinode. Special attention is paid to discriminating between two suggested models, a flux rope or a bent arcade. "Inverse polarity" orientation is possi…
Distribution of visual binary stars over masses and separation between components
Tutukov, A. V.; Kovaleva, D. A.
We investigate initial ditributions of visual binary stars over semimajor axes of orbits, initial masses of main components, and mass ratios of components using complete data on wide stellar pairs from WDS catalogue and results of astrometric space missions Gaia and Hipparcos.
Automatic detection of tidal disruption events and other long‑duration transients in XMM‑Newton data
Webb, N. A.
XMM‑Newton's large field of view and excellent sensitivity have resulted in hundreds of thousands of serendipitous X‑ray detections. While their spectra have been widely exploited, their variable nature has been little studied. Part of this is due to the way XMM‑Newton currently operates, where observations generally have a 12‑month proprietary pe…
Influence of Digital Noise on Interpretation of a Transit Light Curve
Abubekerov, M. K.; Gostev, N. Yu.
The algorithms often used for the interpretation of light curves, such as the frequently applied JKTEBOP algorithm, have limited accuracy, which causes rounding errors, and hence a non-physical contribution to the residuals (digital noise). The transit light curve of the binary HD 209458 is used as an example to demonstrate the need to take into a…