Search Publications
Discovering strongly lensed quasar candidates with catalogue-based methods from DESI Legacy Surveys
Zou, Hu; Li, Nan; He, Zizhao +3 more
Context. The Hubble tension, revealed by a ~5σ discrepancy between measurements of the Hubble-Lemaitre constant among observations of the early and local Universe, is one of the most significant problems in modern cosmology. In order to better understand the origin of this mismatch, independent techniques to measure H0, such as strong l…
Still alive and kicking: A significant outburst in changing-look AGN Mrk 1018
Granzer, T.; Gaspari, M.; Combes, F. +13 more
Context. Changing-look active galactic nuclei (AGN) have been observed to change their optical spectral type. Mrk 1018 is particularly unique: first classified as a type 1.9 Seyfert galaxy, it transitioned to being a type 1 Seyfert galaxy a few years later before returning to its initial classification as a type 1.9 Seyfert galaxy after ∼30 years.…
Red horizontal branch stars: An asteroseismic perspective
Tailo, Marco; Stokholm, Amalie; Valentini, Marica +7 more
Robust age estimates of red giant stars are now possible thanks to the precise inference of their mass based on asteroseismic constraints. However, there are cases where such age estimates can be highly precise yet very inaccurate. An example is giants that have undergone mass loss or mass transfer events that have significantly altered their mass…
Exploring the chemodynamics of metal-poor stellar populations
Smiljanic, R.; da Silva, A. R.
Context. Metal-poor stars are key for studying the formation and evolution of the Galaxy. Evidence of the early mergers that built up the Galaxy remains in the distributions of abundances, kinematics, and orbital parameters of its stars. Several substructures resulting from these mergers have been tentatively identified in the literature.
Aim…
Precise masses and ages of 1 million RGB and RC stars observed by LAMOST
Huang, Yang; Zhang, Huawei; Wang, Chun +1 more
We construct a catalogue of stellar masses and ages for 696 680 red giant branch (RGB) stars, 180 436 primary red clump (RC) stars, and 120 907 secondary RC stars selected from the LAMOSTDR8. The RGBs, primary RCs, and secondary RCs are identified with the large frequency spacing (∆ν) and period spacing (∆P) estimated from the LAMOST spectra with …
The outburst of the changing-look AGN IRAS 23226-3843 in 2019
Schartel, N.; Komossa, S.; Kollatschny, W. +8 more
Aims: IRAS 23226-3843 has previously been classified as a changing-look active galactic nucleus (AGN) based on observations taken in the 1990s in comparison to X-ray data (Swift, XMM-Newton, and NuSTAR) and optical spectra taken after a very strong X-ray decline in 2017. In 2019, Swift observations revealed a strong rebrightening in X-ray and…
Backstreaming ions at a high Mach number interplanetary shock. Solar Orbiter measurements during the nominal mission phase
Vainio, R.; Owen, C. J.; Wimmer-Schweingruber, R. F. +9 more
Context. Solar Orbiter, a mission developed by the European Space Agency, explores in situ plasma across the inner heliosphere while providing remote-sensing observations of the Sun. The mission aims to study the solar wind, but also transient structures such as interplanetary coronal mass ejections and stream interaction regions. These structures…
Combining HIPPARCOS and Gaia data for the study of binaries: The BINARYS tool
Arenou, F.; Babusiaux, C.; van Leeuwen, F. +6 more
Context. Orbital motion in binary and planetary systems is the main source of precise stellar and planetary mass measurements, and the joint analysis of data obtained using multiple observational methods can both lift degeneracies and improve precision.
Aims: We set out to measure the masses of individual stars in binary systems using all the…
Photometric metallicity for 694 233 Galactic giant stars from Gaia DR3 synthetic Strömgren photometry. Metallicity distribution functions of halo substructures
Massari, D.; De Angeli, F.; Riello, M. +4 more
We used two previous calibrations and the standardised synthetic photometry in the v, b, and y Strömgren passbands from Gaia DR3 BP/RP spectra to obtain photometric metallicities for a selected sample of 694 233 old Galactic giant stars having |b|> 20.0° and parallax uncertainties lower than 10%. The zero point of both sets of photometric metal…
Calibrating angular momentum transport in intermediate-mass stars from gravity-mode asteroseismology
Mombarg, J. S. G.
Context. The physical mechanisms driving the transport of angular momentum in stars are not fully understood, as current models cannot explain the observed stellar rotation profiles across all stages of evolution.
Aims: By making use of pulsating F-type dwarfs, we aim to (i) observationally calibrate the efficiency of angular momentum transpo…