Search Publications
High-resolution spectroscopy of detached eclipsing binaries during total eclipses
Hełminiak, K. G.; Olszewska, J. M.; Pawar, T. +1 more
Context. We present results of high-resolution spectroscopic observations of detached eclipsing binaries (DEBs) with total eclipses, for which UVES spectra were obtained during the phase of totality. These observations serve as a key way to determine the age and initial metallicity of the systems and to verify evolutionary phases of their componen…
The Blanco DECam Bulge Survey (BDBS). VIII. Chemo-kinematics in the southern Galactic bulge from 2.3 million red clump stars with Gaia DR3 proper motions
Rich, R. Michael; Kunder, Andrea; Johnson, Christian I. +5 more
Context. The inner Galaxy is a complex environment, and the relative contributions of different formation scenarios to its observed morphology and stellar properties are still debated. The different components are expected to have different spatial, kinematic, and metallicity distributions, and a combination of photometric, spectroscopic, and astr…
MeerKAT reveals a ghostly thermal radio ring towards the Galactic Centre
Lundqvist, P.; Umana, G.; Filipović, M. D. +26 more
We present the serendipitous discovery of a new radio-continuum ring-like object nicknamed Kýklos (J1802–3353), with MeerKAT UHF and L-band observations. The radio ring, which resembles the recently discovered odd radio circles (ORCs), has a diameter of ∼80″ and is located just ∼6° from the Galactic plane. However, Kýklos exhibits an atypical ther…
Multi-wavelength spectroscopic analysis of the ULX Holmberg II X-1 and its nebula suggests the presence of a heavy black hole accreting from a B-type donor
Hamann, W. -R.; Bozzo, E.; Soria, R. +11 more
Context. Ultra-luminous X-ray sources (ULXs) are high-mass X-ray binaries with an X-ray luminosity above 1039 erg s‑1. These ULXs can be powered by black holes that are more massive than 20 M⊙, accreting in a standard regime, or lighter compact objects accreting supercritically. There are only a few ULXs with known…
Accretion versus core-filament collision: Implications for streamer formation in Per-emb-2
Nakamura, Fumitaka; Nguyen-Luong, Quang; Ishihara, Kousuke +1 more
Context. Recent millimetre and sub-millimetre observations have unveiled elongated and asymmetric structures around protostars. These structures, referred to as streamers, often exhibit coherent velocity gradients, seemingly indicating a directed gas flow towards the protostars. However, their origin and role in star formation remain uncertain. Ai…
Under the magnifying glass: A combined 3D model applied to cloudy warm Saturn-type exoplanets around M dwarfs
Decin, L.; Helling, Ch.; Jørgensen, U. G. +8 more
Context. Warm Saturn-type exoplanets orbiting M dwarfs are particularly suitable for an in-depth cloud characterisation through transmission spectroscopy because the contrast of their stellar to planetary radius is favourable. The global temperatures of warm Saturns suggest efficient cloud formation in their atmospheres which in return affects the…
Redshifts of candidate host galaxies of four fast X-ray transients using VLT/MUSE
Jonker, Peter G.; Bauer, Franz E.; Levan, Andrew J. +3 more
Context. Fast X-ray transients (FXTs) are X-ray flares that last from minutes to hours. Multi-wavelength counterparts to these FXTs have proven hard to find. As a result, distance measurements are made through indirect methods such as a host galaxy identification. Of the three main models proposed for FXTs, that is, supernova shock breakout emissi…
Slim-disk modeling reveals an accreting intermediate-mass black hole in the luminous fast blue optical transient AT2018cow
Wen, Sixiang; Jonker, Peter G.; Zabludoff, Ann I. +1 more
The origin of the most luminous subclass of the fast blue optical transients (LFBOTs) is still unknown. We present an X-ray spectral analysis of AT2018cow – the LFBOT archetype – using NuSTAR, Swift, and XMM-Newton data. The source spectrum can be explained by the presence of a slim accretion disk, and we find that the mass accretion rate decrease…
Lithium Cepheid V708 Car with an unusual chemical composition
Werner, K.; Korotin, S. A.; Andrievsky, S. M. +2 more
Aims: The purpose of this work is to spectroscopically analyse the classical Cepheid V708 Car. A preliminary check of the spectrum of V708 Car showed that this is a lithium-rich supergiant. We also found that V708 Car has an unusual chemical composition in that the abundances of various elements correlate with their condensation temperatures.…
A kinematical study of the launching region of the blueshifted HH 46/47 outflow with SINFONI K-band observations
Dougados, C.; Zhang, Y.; Nisini, B. +3 more
Context. Studying outflows is important, as they may significantly contribute to angular momentum removal from a star-disc system and thus affect disc evolution and planet formation. Aims. To investigate the different outflow components, including the collimated jet, wide-angled molecular outflow, and outflow cavity, of the Class I HH 46/47 outflo…