Search Publications
Missions
Journals
Publication Years
VHE observations of binary systems performed with the MAGIC telescopes
Torres, Diego F.; Zanin, Roberta; Casares, Jorge +11 more
The improvement on the Imaging Air Cherenkov Technique (IACT) led to the discovery of a new type of sources that can emit at very high energies: the gamma-ray binaries. Only six systems are part of this exclusive class. We summarize the latest results from the observations performed with the MAGIC telescopes on different systems as the gamma-ray b…
DBSCAN Clustering Algorithm for Detection of Nearby Open Clusters Based on Gaia-DR2
Wang, C.; Xu, S. K.; Zhuang, L. H. +1 more
In this paper, we attempt to use the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering algorithm to detect nearby open clusters based on Gaia Data Release 2 (Gaia-DR2). We select 594284 stars (within a distance of 100 pc to the sun) from the Gaia-DR2 catalog, and construct a five dimensional phase space (three dimensi…
Pseudo-photometric distances of 30 open clusters
Duvert, G.; Chelli, A.
Aims: We demonstrate that reliable photometric distances of stellar clusters, and more generally of stars, can be obtained using pseudomagnitudes and rough spectral type without having to correct for visual absorption.
Methods: We determine the mean absolute pseudomagnitude of all spectral (sub)types between B and K. Distances are comput…
New Carbon Stars in the Catalina Catalog of Periodic Variables
Mauron, N.; Gigoyan, K. K.; Gigoyan, K. S. +5 more
This study is about carbon stars detected in a program of spectral type determinations for a large amount of optically faint periodic variables. These variables are taken from the Catalina Survey Data Release-1 (CSDR1) data set. As much as 967 objects were studied. Spectral classification uses the objective-prism scanned plates of the Hamburg Quas…
Special Section Guest Editorial: The Hitomi X-Ray Observatory, Part 2
Kelley, Richard L.; Nakazawa, Kazuhiro
This guest editorial summarizes the Special Section on the Hitomi X-Ray Observatory.
The first Charge Coupled Device photometry of the poorly studied clusters Teutsch 126 & Czernik 11
Hendy, Yasser; Tadross, Ashraf Latif; Bendary, Reda +1 more
In this study, we determined the astrophysical parameters of the poorly studied clusters Teutsch 126 and Czernik 11. We used the Visual Red Charge Coupled Device pass-bands that were carried down to a limiting magnitude of V = 20 mag. The stars of the clusters were observed utilizing the Newtonian focus of a 74-inch telescope at the Kottamia Astro…
Probing the nature of AX J0043-737: Not an 87 ms pulsar in the Small Magellanic Cloud
Haberl, F.; Tiengo, A.; Filipović, M. D. +4 more
Aims: AX J0043-737 is a source in the ASCA catalogue whose nature is uncertain. It is most commonly classified as a Crab-like pulsar in the Small Magellanic Cloud (SMC) following apparent detection of pulsations at 87 ms from a single ASCA observation. A follow-up ASCA observation was not able to confirm this, and the X-ray detection of the s…
A photometric study of the nonrelaxed cluster Mayer 3
Tadross, A. L.; Bendary, R.; Hasan, P.
The astrophysical parameters of the open star cluster Mayer 3 have been estimated using the Newtonian focus (f/4.84) of the 1.88 m Telescope of Kottamia Observatory in Egypt. The VRI observations have been carried out down to a limiting magnitude of V ~ 20 mag. To emphasize the main astrophysical parameters, Near-Infra Red, Two Micron All Sky Surv…
GT Ursae Majoris AB - a Possible Quadruple System
Kamiński, K.; Dimitrov, W.; Polińska, M. +3 more
We present the first spectroscopic study of an eclipsing system GT UMa. Our spectra show that the main visual component A is a triple-lined star, which consists of a close eclipsing pair and a farther third component. Radial velocity measurements show evidence of reflex motion. We used Hipparcos and our own R-band light curves for the analysis. Th…
Fast stars point to supernovae, black holes
Sokol, Joshua
On 25 April, the European Space Agency released a data set gathered by the Gaia satellite containing the motions, and much more, of 1.3 billion stars. Astronomers have immediately sifted the data for fast-moving stars. They are prized as forensic tools: When rewound, their trajectories point back to the violent events that launched them. Last week…