Search Publications
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…
Precise dynamical masses of new directly imaged companions from combining relative astrometry, radial velocities, and HIPPARCOS-Gaia eDR3 accelerations
Zhang, H.; Ségransan, D.; Udry, S. +7 more
Aims: With an observing time span of more than 20 yr, the CORALIE radial-velocity survey is able to detect long-term trends in data corresponding to companions with masses and separations accessible to direct imaging. Combining exoplanet detection techniques, such as radial velocities from the CORALIE survey, astrometric accelerations from HI…
Transit least-squares survey. IV. Earth-like transiting planets expected from the PLATO mission
Heller, René; Samadi, Réza; Harre, Jan-Vincent
In its long-duration observation phase, the PLATO satellite (scheduled for launch in 2026) will observe two independent, non-overlapping fields, nominally one in the northern hemisphere and one in the southern hemisphere, for a total of four years. The exact duration of each pointing will be determined two years before launch. Previous estimates o…
The molecular gas properties in local Seyfert 2 galaxies
Andreani, P.; Pozzi, F.; Hatziminaoglou, E. +8 more
Aims: We present a multiwavelength study of the molecular gas properties of a sample of local Seyfert 2 galaxies to assess if, and to what extent, the presence of an active galactic nucleus (AGN) can affect the interstellar medium (ISM) properties in a sample of 33 local Seyfert 2 galaxies.
Methods: We compare the molecular gas content (…
Substructures, resonances, and debris streams. A new constraint on the inner shape of the Galactic dark halo
Helmi, Amina; Koppelman, Helmer H.; Dodd, Emma
Context. The local stellar halo of the Milky Way contains the debris from several past accretion events.
Aims: Here we study in detail the structure and properties of nearby debris associated with the Helmi streams, which was originally identified as an overdensity in integrals of motion space.
Methods: We use 6D phase-space information …