Search Publications
Deriving star cluster parameters with convolutional neural networks. II. Extinction and cluster-background classification
Narbutis, D.; Bialopetravičius, J.
Context. Convolutional neural networks (CNNs) have been established as the go-to method for fast object detection and classification of natural images. This opens the door for astrophysical parameter inference on the exponentially increasing amount of sky survey data. Until now, star cluster analysis was based on integral or resolved stellar photo…
The proper motion of sub-populations in ω Centauri
Pancino, E.; Sanna, N.; Stetson, P. B. +2 more
The galactic globular cluster ω Centauri is the most massive of its kind, with a complex mix of multiple stellar populations and several kinematic and dynamical peculiarities. Different mean proper motions have been detected among the three main sub-populations, implying that the most metal-rich one is of accreted origin. This particular piece of …
A wide angle view of the Sagittarius dwarf spheroidal galaxy. II. A CEMP-r/s star in the Sagittarius dwarf spheroidal galaxy
Hansen, C. J.; Bonifacio, P.; Caffau, E. +5 more
We report on the discovery and chemical abundance analysis of the first CEMP-r/s star detected in the Sagittarius dwarf spheroidal galaxy (Sgr dSph) by means of UVES high-resolution spectra. The star, found in the outskirts of Sgr dSph, along the major axis of the main body, is a moderately metal-poor giant (Teff = 4753 K, log g = 1.75,…
Magnetically coupled atmosphere, fast sausage MHD waves, and forced magnetic field reconnection during the SOL2014-09-10T17:45 flare
Gömöry, P.; Mészárosová, H.
Aims: We study the physical properties and behaviour of the solar atmosphere during the GOES X1.6 solar flare on 2014 September 10.
Methods: The steady plasma flows and the fast sausage MHD waves were analysed with the wavelet separation method. The magnetically coupled atmosphere and the forced magnetic field reconnection were studied w…
Hybrid star HD 81817 accompanied by brown dwarf or substellar companion
Lee, Byeong-Cheol; Park, Myeong-Gu; Bang, Tae-Yang +4 more
HD 81817 is known as a hybrid star. Hybrid stars have both cool stellar wind properties and Ultraviolet (UV) or even X-ray emission features of highly ionized atoms in their spectra. A white dwarf companion has been suggested as the source of UV or X-ray features. HD 81817 has been observed since 2004 as a part of a radial velocity (RV) survey pro…
Differences in radio emission from similar M dwarfs in the binary system Ross 867-8
Callingham, J. R.; Shimwell, T. W.; Intema, H. T. +5 more
Serendipitously, we rediscovered radio emission from the binary system Ross 867 (M4.5V) and Ross 868 (M3.5V) while inspecting archival Giant Metrewave Radio Telescope (GMRT) observations. The binary system consists of two M-dwarf stars that share common characteristics such as spectral type, astrometric parameters, age, and emission at infrared, o…
Long photometric cycle and disk evolution in the β Lyrae-type binary OGLE-BLG-ECL-157529
Soszyński, I.; Poleski, R.; Iwanek, P. +4 more
Context. The subtype of hot algol semidetached binaries dubbed double periodic variables (DPVs) are characterized by a photometric cycle longer than the orbital one, whose nature has been related to a magnetic dynamo in the donor component controlling the mass transfer rate.
Aims: We aim to understand the morphologic changes observed in the l…
Searching for obscured AGN in z ∼ 2 submillimetre galaxies
Guidetti, D.; Bondi, M.; Prandoni, I. +13 more
Aims: Submillimetre-selected galaxies (SMGs) at high redshift (z ∼ 2) are potential host galaxies of active galactic nuclei (AGN). If the local Universe is a good guide, ∼50% of the obscured AGN amongst the SMG population could be missed even in the deepest X-ray surveys. Radio observations are insensitive to obscuration; therefore, very long…
The flux-weighted gravity-luminosity relation of Galactic classical Cepheids
Groenewegen, M. A. T.
The flux-weighted gravity-luminosity relation (FWGLR) is investigated for a sample of 477 classical Cepheids (CCs), including stars that have been classified in the literature as such but are probably not. The luminosities are taken from the literature, based on the fitting of the spectral energy distributions (SEDs) assuming a certain distance an…
Search for non-thermal X-ray emission in the colliding wind binary Cygnus OB2 #8A
Nazé, Y.; Rauw, G.; Pittard, J. M. +1 more
Aims: Cyg OB2 #8A is a massive O-type binary displaying strong non-thermal radio emission. Owing to the compactness of this binary, emission of non-thermal X-ray photons via inverse Compton scattering is expected.
Methods: We first revised the orbital solution for Cyg OB2 #8A using new optical spectra. We then reduced and analysed X-ray …