Search Publications
Search for gamma-ray emission from a galactic supernova with the anticoincidence system of SPI
Jean, P.; Isern, J.; Bravo, E. +1 more
The detection of the very early gamma-emission of a Type Ia supernova (SNIa) could provide a deep insight on the explosion mechanism and nature of the progenitor. However, this has not been yet possible as a consequence of the expected low luminosity and the distance at which all the events have occurred up to now. An SNIa occurring in our Galaxy …
Galactic component mapping of galaxy UGC 2885 by machine learning classification
Holwerda, Benne W.; Barmby, Pauline; Kwik, Robin J. +1 more
Automating classification of galaxy components is important for understanding the formation and evolution of galaxies. Traditionally, only the larger galaxy structures such as the spiral arms, bulge, and disc are classified. Here we use machine learning (ML) pixel-by-pixel classification to automatically classify all galaxy components within digit…
Rectilinear elements of visual optical double stars: With application to the 1829 southern double star catalogue of James Dunlop
Letchford, Roderick R.; White, Graeme L.; Brown, Carolyn J.
The relative Rectilinear motion of optical double stars provides an important clue to the relationship of the components. We provide an objective method of confirming the optical status of double stars, and of obtaining unbiased rectilinear elements solely on data obtained from the HIPPARCOS and Gaia DR2 space missions. We apply this technique to …
The OmegaWhite survey for short-period variable stars - VI. Open clusters
Groot, P. J.; Ramsay, G.; Jeffery, C. S. +3 more
Using light curves with ~3 min cadence and a duration of 2 h made using the OmegaWhite survey, we present the results of a search for short-period variable stars in the field of 20 open clusters. We identified 92 variable stars in these fields. Using a range of cluster member catalogues and Gaia EDR3 data, we have determined that 10 are cluster me…
Quasars' physical properties study based on the medium-band photometric survey
Kotov, Sergey; Dodonov, Sergey; Grokhovskaya, Aleksandra
The study is about the quasars' cosmological evolution. We used the medium-band photometric survey at the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory. The HS47-22 field with an area of 2.38 square degrees has been selected. We have classified objects and composed a sample of quasars using broadband photometric data and morpholo…
Kinematics and interplanetary characteristics of a halo Coronal Mass Ejection: a multi-wavelength analysis
Ebenezer, E.; Soni, Shirsh Lata
In this paper, we present the evolution and speed expansion of a shock driven by a Coronal Mass Ejection (CME) that triggered a type II radio. We combine radio analysis with a broad range of observations taken by other ground-based and space borne observatories to track the evolution of this CME/shock from Sun to 1 AU. The Halo CME studied here oc…
Dippers from TESS Full-frame Images. II. Spectroscopic Characterization of Four Young Dippers
Takita, Satoshi; Hattori, Kohei; Muto, Takayuki +9 more
Photometric monitoring by the Transiting Exoplanet Survey Satellite (TESS) has discovered not only periodic signals by transiting exoplanets but also episodic or quasiperiodic dimming around young stellar objects. The dimming mechanisms of these objects, the so-called "dippers," are thought to be related to either the accretion property or the str…
Chemical composition of a palomar 12 blue straggler
Pasquini, L.; Bonifacio, P.; Randich, S. +5 more
With the equivalent area of a 16-m telescope, ESPRESSO in 4UT mode allows to inaugurate high resolution spectroscopy for solar-type stars belonging to extragalactic globular clusters. We determine the chemical composition of an extragalactic blue straggler (BS). The star has a G magnitude of 19.01 and belongs to the globular cluster Pal12, that is…
A Gap at 1 au in the Disk of DI Cha A Revealed by Infrared Interferometry
Pál, András; Moór, Attila; Ábrahám, Péter +6 more
DI Cha A is K0-type pre-main-sequence star, the brightest component of a quadruple stellar system. Here we report on a detailed study of this star based on archival VLTI/MIDI and VLTI/PIONIER infrared interferometric observations, as well as optical-infrared photometric monitoring from ground-based and space-born instruments. We determined the str…
Cometocentric coordinates of the tail axis of comet 67P/Churyumov-Gerasimenko
Ibragimov, A. A.
In this paper, we consider errors in the measurement of cometocentric coordinates. The sequence of actions for determining the cometocentric coordinates by perspective projection of the image points of the comet onto the orbital plane is given on the example of comet 67P. Conditions are shown that increase the accuracy of determining the angle of …