Related papers: Advanced Classification of Hot Subdwarf Binaries U…
We present the analysis of a high-resolution, high-quality sample of optical spectra for 76 subdwarf B (sdB) stars from the ESO Supernova Ia Progenitor Survey (SPY). Effective temperature, surface gravity, and photospheric helium abundance…
Low mass (sub)stellar objects represent the low end of the initial mass function, the transition to free-floating planets and a prominent interloper population in the search for high-redshift galaxies. Without proper motions or…
The third Gaia Data Release has provided the astronomical community with astrometric data of more than 1.8 billion sources, and low resolution spectra for 220 million. Such a large amount of data is difficult to handle by means of visual…
With the advent of large-scale photometric surveys of the sky, modern science witnesses the dawn of big data astronomy, where automatic handling and discovery are paramount. In this context, classification tasks are among the key…
Hydrogen-deficient stars form sequences across the HR diagram from cool R CrB stars to helium-rich hot subdwarfs and PG1159 stars, tracing multiple evolution pathways. The Southern African Large Telescope (SALT) has been used to conduct a…
We present results of a search for objects with H-alpha excess, such as cataclysmic variables (CVs) and chromospherically active binaries (ABs), as counterparts to X-ray sources detected with Chandra satellite observatory in six Galactic…
We present a wavelet-based algorithm to identify dwarf galaxies in the Milky Way in ${\it Gaia}$ DR2 data. Our algorithm detects overdensities in 4D position--proper motion space, making it the first search to explicitly use velocity…
White dwarfs (WDs) polluted by exoplanetary material provide the unprecedented opportunity to directly observe the interiors of exoplanets. However, spectroscopic surveys are often limited by brightness constraints, and WDs tend to be very…
The Gaia Data Release 3 (DR3), published in June 2022, delivers a diverse set of astrometric, photometric, and spectroscopic measurements for more than a billion stars. The wealth and complexity of the data makes traditional approaches for…
Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Strikingly, the distribution in the Hertzsprung-Russell diagram of He-rich vs.…
With nearly two billion stars observed and their corresponding astrometric parameters evaluated in the recent Gaia mission, the number of astrometric binary candidates have risen significantly. Due to the surplus of astrometric data, the…
We report on the detection of a hot subdwarf component in the Be binary system, 59 Cygni. The spectral signature is found in cross-correlation functions of photospheric model spectra with far-ultraviolet spectra obtained by the…
The information contained in the Gaia Second Data Release (DR2) allows to search for the unusual objects with the pre-selected properties, literally constructing the stars with the desired characteristics. This work describes the idea of…
We have measured the orbital parameters of seven close binaries, including six new objects, in a radial velocity survey of 38 objects comprising a hot subdwarf star with orbital periods ranging from ~0.17 to 3 d. One new system, GALEX…
Multiplicity is a key statistic for understanding the formation of very low mass (VLM) stars and brown dwarfs. Currently, the separation distribution of VLM binaries remains poorly constrained at small separations (<1 AU), leading to…
Multiple radial velocity observations have been obtained for a large sample of local field subdwarf B (sdB) stars over a period of two years. SdB stars appear to fall into three distinct groups based on their kinematic and spectroscopic…
The ROSAT WFC survey has provided us with evidence for the existence of a previously unidentified sample of hot white dwarfs (WD) in non-interacting binary systems, through the detection of EUV and soft X-ray emission. These stars are…
A complete and pure sample of quasars with accurate redshifts is crucial for quasar studies and cosmology. In this paper, we present CatNorth, an improved Gaia DR3 quasar candidate catalog with more than 1.5 million sources in the 3$\pi$…
Utilizing the Two Micron All Sky Survey (2MASS) All-Sky Data Release Catalog, we have retrieved useful near-IR J, H, and Ks magnitudes for more than 800 hot subdwarfs (sdO and sdB stars) drawn from the "Catalogue of Spectroscopically…
Aims. Compact white-dwarf binaries are selected from spectra obtained in the early SDSS-V plate program. A dedicated set of SDSS plate observations were carried out in the eFEDS field, providing spectroscopic classifications for a…