Search Publications
A census of OBe stars in nearby metal-poor dwarf galaxies reveals a high fraction of extreme rotators
Lennon, D. J.; Schootemeijer, A.; Langer, N. +3 more
The early Universe, together with many nearby dwarf galaxies, is deficient in heavy elements. The evolution of massive stars in such environments is thought to be affected by rotation. Extreme rotators among them tend to form decretion disks and manifest themselves as OBe stars. We use a combination of UB, Gaia, Spitzer, and Hubble Space Telescope…
The eccentric millisecond pulsar, PSR J0955−6150. I. Pulse profile analysis, mass measurements, and constraints on binary evolution
Camilo, F.; Possenti, A.; Kramer, M. +17 more
Context. PSR J0955−6150 is a member of an enigmatic class of eccentric millisecond pulsar (MSP) and helium white dwarf (He WD) systems (eMSPs), whose binary evolution is poorly understood and believed to be strikingly different to that of traditional MSP+He WD systems in circular orbits.
Aims: Measuring the masses of the stars in this system …
Single-lens mass measurement in the high-magnification microlensing event Gaia19bld located in the Galactic disc
Harrison, D. L.; Bryden, G.; Soszyński, I. +66 more
Context. Microlensing provides a unique opportunity to detect non-luminous objects. In the rare cases that the Einstein radius θE and microlensing parallax πE can be measured, it is possible to determine the mass of the lens. With technological advances in both ground- and space-based observatories, astrometric and interferom…
Multiply eclipsing candidates from the TESS satellite
Mašek, M.; Zasche, P.; Henzl, Z.
We present a catalogue of the Transiting Exoplanet Survey Satellite (TESS) targets that show multiple eclipses. In all of these stars, we detected two sets of eclipses, for which their two distinctive periods can be derived. These multiple stellar systems could either be doubly eclipsing quadruples or triple-star coplanar systems showing eclipses …
Transient obscuration event captured in NGC 3227. II. Warm absorbers and obscuration events in archival XMM-Newton and NuSTAR observations
Kaspi, Shai; Kriss, Gerard A.; Mehdipour, Missagh +18 more
The relationship between warm absorber (WA) outflows of active galactic nuclei and nuclear obscuration activities caused by optically thick clouds (obscurers) crossing the line of sight is still unclear. NGC 3227 is a suitable target for studying the properties of both WAs and obscurers because it matches the following selection criteria: WAs in b…
A WISE view on extreme AGB stars
Groenewegen, M. A. T.
Context. Variability is a key property of stars on the asymptotic giant branch (AGB). Their pulsation period is related to the luminosity and mass-loss rate (MLR) of the star. Long-period variables (LPVs) and Mira variables are the most prominent of all types of variability of evolved stars. However, the reddest, most obscured AGB stars are too fa…
A blast from the infant Universe: The very high-z GRB 210905A
Covino, S.; D'Avanzo, P.; Campana, S. +52 more
We present a detailed follow-up of the very energetic GRB 210905A at a high redshift of z = 6.312 and its luminous X-ray and optical afterglow. Following the detection by Swift and Konus-Wind, we obtained a photometric and spectroscopic follow-up in the optical and near-infrared (NIR), covering both the prompt and afterglow emission from a few min…
Ca II triplet spectroscopy of Small Magellanic Cloud red giants. V. Abundances and velocities for 12 massive clusters
Grebel, E. K.; Da Costa, G.; Geisler, D. +4 more
Aims: We aim to analyze the chemical evolution of the Small Magellanic Cloud, adding 12 additional clusters to our existing sample, based on accurate and homogeneously derived metallicities. We are particularly interested in seeing if there is any correlation between age and metallicity for the different structural components to which the clu…
A quarter century of spectroscopic monitoring of the nearby M dwarf Gl 514. A super-Earth on an eccentric orbit moving in and out of the habitable zone
Amado, P. J.; Caballero, J. A.; Reiners, A. +31 more
Context. Statistical analyses based on Kepler data show that most of the early-type M dwarfs host multi-planet systems consisting of Earth- to sub-Neptune-sized planets with orbital periods of up to ~250 days, and that at least one such planet is likely located within the habitable zone. M dwarfs are therefore primary targets to search for potenti…
Modeling the 2020 November 29 solar energetic particle event using EUHFORIA and iPATH models
Li, Gang; Poedts, Stefaan; Ding, Zheyi +1 more
Aims: We present the implementation of a coupling between EUropean Heliospheric FORcasting Information Asset (EUHFORIA) and improved Particle Acceleration and Transport in the Heliosphere (iPATH) models. In this work, we simulate the widespread solar energetic particle (SEP) event of 2020 November 29 and compare the simulated time-intensity p…