Search Publications
XMM-Newton observations of the symbiotic recurrent nova T CrB: evolution of X-ray emission during the active phase
Zhekov, Svetozar A.; Tomov, Toma V.
We present an analysis of the XMM-Newton observations of the symbiotic recurrent nova T CrB, obtained during its active phase which started in 2014-2015. The XMM-Newton spectra of T CrB have two prominent components: a soft one (0.2-0.6 keV), well represented by blackbody emission, and a heavily absorbed hard component (2-10 keV), well matched by …
What information can we derive from historical Far Eastern guest stars for modern research on novae and cataclysmic variables?
Hoffmann, Susanne M.
Recently, there have been several studies on the evolution of binary systems using historical data that are treated as facts in the chain of argument. This paper discusses six case studies of modern dwarf novae with suggested historical counterparts from the historical point of view, as well as the derived consequences for the physics of close bin…
The study of unclassified B[e] stars and candidates in the Galaxy and Magellanic Clouds†
Borges Fernandes, M.; Condori, C. A. H.; Kraus, M. +2 more
We investigated 12 unclassified B[e] stars or candidates, 8 from the Galaxy, 2 from the Large Magellanic Cloud (LMC), and 2 from the Small Magellanic Cloud (SMC). Based on the analysis of high-resolution spectroscopic (FEROS) and photometric data, we confirmed the presence of the B[e] phenomenon for all objects of our sample, except for one (IRAS …
A DECam view of the diffuse dwarf galaxy Crater II: the colour-magnitude diagram
Walker, A. R.; Stetson, P. B.; Bono, G. +12 more
We present a deep Blanco/DECam colour-magnitude diagram (CMD) for the large but very diffuse Milky Way satellite dwarf galaxy Crater II. The CMD shows only old stars with a clearly bifurcated subgiant branch (SGB) that feeds a narrow red giant branch. The horizontal branch (HB) shows many RR Lyrae and red HB stars. Comparing the CMD with [Fe/H] = …
Galaxy structural analysis with the curvature of the brightness profile
Ferrari, Fabricio; Lucatelli, Geferson
In this work, we introduce the curvature of a galaxy brightness profile to identify its structural subcomponents in a non-parametrically fashion. Bulges, bars, discs, lens, rings, and spiral arms are key to understand the formation and evolution path the galaxy undertook. Identifying them is also crucial for morphological classification of galaxie…
The kinematics of Galactic disc white dwarfs in Gaia DR2
Kilic, Mukremin; Rowell, Nicholas
We present an analysis of the kinematics of Galactic disc white dwarf (WD) stars in the solar neighbourhood using data from Gaia Data Release 2. Selection of WDs based on parallax provides the first large, kinematically unbiased sample of solar neighbourhood WDs to date. Various classical properties of the solar neighbourhood kinematics have been …
Sub-millimetre non-contaminated detection of the disc around TWA 7 by ALMA
de Gregorio-Monsalvo, I.; Bayo, A.; Schreiber, M. R. +9 more
Debris discs can be seen as the leftovers of giant planet formation and the possible nurseries of rocky planets. While M-type stars outnumber more massive stars we know very little about the time evolution of their circumstellar discs at ages older than ∼10 Myr. Sub-millimetre observations are best to provide first order estimates of the available…
Volume uncertainty assessment method of asteroid models from disc-integrated visual photometry
Bartczak, P.; Dudziński, G.
The need for more accurate asteroid models is perhaps secondary to the need to measure their quality. The uncertainties of models' parameters propagate to quantities like volume or density - the most important and informative properties of asteroids - affecting conclusions about their physical nature. Our knowledge on shapes and spins of small Sol…
Ground-based observation of ZZ Ceti stars and the discovery of four new variables
Kepler, S. O.; Romero, Alejandra D.; Koester, D. +7 more
We perform ground-based photometric observations of 22 DA white dwarf stars, 10 already known ZZ Cetis and 12 candidates with atmospheric parameters inside the classical instability strip. We report on the discovery of four new variable DA white dwarf stars. Two objects are near the middle of the instability strip, SDSS J082804.63+094956.6 and SDS…
A hyper-runaway white dwarf in Gaia DR2 as a Type Iax supernova primary remnant candidate
Ruffini, Nicholas J.; Casey, Andrew R.
Observations of stellar remnants linked to Type Ia and Type Iax supernovae are necessary to fully understand their progenitors. Multiple progenitor scenarios predict a population of kicked donor remnants and partially burnt primary remnants, both moving with relatively high velocity. But only a handful of examples consistent with these two predict…