Search Publications
Investigation into the origin of the soft excess in Ark 564 using principal component analysis
Yang, X. J.; Zhang, G. B.; Lyu, M. +1 more
We combined a principal component analysis (PCA) and spectroscopy to investigate the origin of the soft excess in narrow-line Seyfert 1 galaxy Ark 564 with XMM-Newton observations over a period of ten years. We find that the principal components in different epochs are very similar, suggesting stable variability patterns in this source. More impor…
Forgotten treasures in the HST/FOC UV imaging polarimetric archives of active galactic nuclei: III. Five years monitoring of M87
Lopez-Rodriguez, E.; Marin, F.; Wu, K. +1 more
Context. The active galactic nucleus within M87, a giant elliptical galaxy, is responsible for one of the closest kiloparsec-scale relativistic jets to Earth. It is thus a perfect target for spatially resolved observations. Aims. This one-sided jet has been extensively observed at almost all wavelengths, with almost all techniques. Among many othe…
Determining stellar properties of massive stars in NGC346 in the SMC with a Bayesian statistic technique
Hamann, W. -R.; Prinja, R. K.; Oskinova, L. M. +8 more
Context. NGC 346 is a young cluster with numerous hot OB stars. It is part of the Small Magellanic Cloud (SMC), and has an average metallicity that is one-seventh of the Milky Way's. A detailed study of its stellar content provides a unique opportunity to understand the stellar and wind properties of massive stars in low-metallicity environments, …
Spatially resolving the AGB star V3 in the metal-poor globular cluster 47 Tuc with VLTI/GRAVITY
Weigelt, G.; Hofmann, K. -H.; Schertl, D. +1 more
Context. Mass loss at the asymptotic giant branch (AGB) plays an important role not only in the final fates of stars, but also in the chemical evolution of galaxies. Nevertheless, the metallicity effects on AGB mass loss are not yet fully understood.
Aims: We present spatially resolved observations of an AGB star, V3, in the metal-poor globul…
Revisiting the warm sub-Saturn TOI-1710b. The impact of stellar activity on the mass measurement
Pallé, E.; Nowak, G.; Winn, J. N. +37 more
The Transiting Exoplanet Survey Satellite (TESS) provides a continuous suite of new planet candidates that need confirmation and precise mass determination from ground-based observatories. This is the case for the G-type star TOI-1710, which is known to host a transiting sub-Saturn planet (Mp = 28.3 ± 4.7 M⊕) in a long-period…
Abundances of iron-peak elements in 58 bulge spheroid stars from APOGEE
Schultheis, M.; Minniti, D.; Valentini, M. +22 more
Context. Stars presently identified in the bulge spheroid are probably very old, and their abundances can be interpreted as due to the fast chemical enrichment of the early Galactic bulge. The abundances of the iron-peak elements are important tracers of nucleosynthesis processes, in particular oxygen burning, silicon burning, the weak s-process, …
Description of turbulent dynamics in the interstellar medium: Multifractal microcanonical analysis. II. Sparse filtering of Herschel observation maps and visualization of filamentary structures at different length scales
Schneider, N.; Bontemps, S.; Simon, R. +15 more
We present significant improvements to our previous work on noise reduction in Herschel observation maps by defining sparse filtering tools capable of handling, in a unified formalism, a significantly improved noise reduction as well as a deconvolution in order to reduce effects introduced by the limited instrumental response (beam). We implement …
The HST Large Programme on ω Centauri: VII. The white dwarf cooling sequence
Salaris, M.; Apai, D.; Anderson, J. +9 more
We present a study of the white dwarf (WD) cooling sequence (CS) in the globular cluster (GC) Omega Centauri (or NGC 5139; hereafter, ω Cen), the primary goal of a dedicated Hubble Space Telescope (HST) programme. We find that the peak at the termination of the WD CS is located at mF606W = 30.1 ± 0.2 (equivalent to V ∼ 31). The brighter…
Distinguishing exoplanet companions from field stars in direct imaging using Gaia astrometry
Bailer-Jones, Coryn A. L.; Samland, Matthias; Herz, Philipp
Direct imaging searches for exoplanets around stars detect many spurious candidates that are in fact background field stars. To help distinguish these from genuine companions, multi-epoch astrometry can be used to identify a common proper motion with the host star. Although this is frequently done, many approaches lack an appropriate model for the…
Bidirectional propagating brightenings in arch filament systems observed by Solar Orbiter/EUI
Chen, Yajie; Peter, Hardi; Chitta, Lakshmi Pradeep +1 more
Arch filament systems (AFSs) are chromospheric and coronal manifestations of emerging magnetic flux. Using high spatial resolution observations taken at a high cadence by the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter, we identified small-scale elongated brightenings within the AFSs. These brightenings appear as bidirectional flows al…