Search Publications
Measurements of visual double stars with PISCO2 at the Nice 76-cm refractor in 2016-2017
Piccotti, Luca; Rivet, Jean-Pierre; Vakili, Farrokh +11 more
We present relative astrometric and photometric measurements of visual double stars made in 2016-2017, with PISCO2 installed at the 76-cm refractor of Côte d'Azur Observatory in Nice (France). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. Three different techniques were used for obtaining meas…
The deep eclipses of RW Aur revisited by long-term photometric and spectroscopic monitoring
Mugrauer, Markus; Lux, Oliver; Bischoff, Richard
RW Aurigae is a young stellar system containing a classical T Tauri star as the primary component. It shows deep, irregular dimmings, first detected in 2010. At the University Observatory Jena, we carried out optical follow-up observations. We performed multiband (BVRI) photometry of the system with the Cassegrain-Teleskop-Kamera II and the Schmid…
HX Velorum: Ellipsoidal/Rotational Binary With β Cep Type Component
Gürol, B.
We present the Transiting Exoplanet Survey Satellite (TESS) light curve analysis of HX Velorum, located in the Southern Hemisphere, where one of the components is found for the first time to be a β$$ \beta $$ Cep (BCEP) type pulsator. The TESS observations of HX Velorum were published in a total of 6 sectors. Fourier analysis of the observations r…
Photometry and astrometry with JWST‑II: NIRCam distortion correction
Bedin, L. R.; Nardiello, D.; Griggio, M.
In preparation to make the most of our own planned James Webb Space Telescope investigations, we take advantage of publicly available calibration and early‑science observations to independently derive and test a geometric‑distortion solution for NIRCam detectors. Our solution is able to correct the distortion to better than 0.2 mas. Current data i…
Winds in ultraluminous X‑ray sources: New challenges
Pinto, C.; Kosec, P.
Ultraluminous X‑ray sources (ULXs) are extreme X‑ray binaries shining above 1039 erg/s, in most cases as a consequence of super‑Eddington accretion onto neutron stars and stellar‑mass black holes accreting above their Eddington limit. This was understood after the discovery of coherent pulsations, cyclotron lines, and powerful winds. The latter wa…
Gaia search for stellar companions of TESS Objects of Interest IV
Mugrauer, M.; Rück, J.; Michel, K. -U.
We present the latest results of our ongoing multiplicity study of (Community) TESS Objects of Interest, using astrometric and photometric data from the ESA‑Gaia mission to detect stellar companions of these stars and characterize their properties. A total of 134 binary, 6 hierarchical triple, and two quadruple star systems are identified among 11…
XMM2ATHENA, the H2020 project to improve XMM‑Newton analysis software and prepare for Athena
Ballet, Jean; Pouliasis, Ektoras; Maggi, Pierre +31 more
XMM‑Newton, a European Space Agency observatory, has been observing the X‑ray, ultra‑violet, and optical sky for 23 years. During this time, astronomy has evolved from mainly studying single sources to populations and from a single wavelength, to multi‑wavelength/messenger data. We are also moving into an era of time domain astronomy. New software…
The hyperluminous X‑ray source population
Roberts, T. P.; Walton, D. J.; MacKenzie, A. D. A.
We have recently published a catalog of 1843 candidate ultraluminous X‑ray sources (ULXs). This is the largest catalog of ULXs to date and was built by cross‑correlating recent serendipitous source catalogs from the XMM‑Newton, Swift, and Chandra observatories with a large sample of galaxies, primarily from HyperLEDA. The catalog contains 71 hyper…
On the true nature of the contact binary CRTS J192848.7‑404555
Filipović, Miroslav; Wadhwa, Surjit S.; DeHorta, Ain Y. +1 more
CRTS J192848.7‑404555 was recognized as a potential contact binary merger candidate on the basis of survey photometry analysis. We have carried out follow‑up ground‑based photometry of the system and showed that at the recorded coordinates for the system, there are two stars approximately 3 s of arc apart. Our analysis shows that the fainter of th…
Kinematical and ellipsoidal properties of K dwarfs in the solar neighborhood of the Gaia era
Elsanhoury, W. H.; Al-Johani, Amnah S.
The study reports velocity ellipsoid parameters including the kinematical properties of K dwarf stars. Herein, two samples of K dwarf stars are presented with the solar neighborhood ( pc) for high (; 106 points) and low galactic latitudes (; 199 points). We calculated spatial velocities (, , and ; km s) along the galactic coordinates and the veloc…