Search Publications
Slitless spectrophotometry with forward modelling: Principles and application to measuring atmospheric transmission
Copin, Y.; Le Guillou, L.; Moniez, M. +9 more
Context. In the next decade, many optical surveys will aim to answer the question of the nature of dark energy by measuring its equation-of-state parameter at the per mill level. This requires trusting the photometric calibration of the survey with a precision never reached so far on many sources of systematic uncertainties. The measurement of the…
Revisiting empirical solar energetic particle scaling relations: II. Coronal mass ejections
Veronig, Astrid M.; Papaioannou, Athanasios; Herbst, Konstantin +2 more
Aims. The space radiation environment conditions and the maximum expected coronal mass ejection (CME) speed are assessed by investigating scaling laws between the peak proton flux and fluence of solar energetic particle (SEP) events with the speed of the CMEs. Methods. We used a complete catalog of SEP events, covering the last ∼25 years of CME ob…
Stellar model tests and age determination for RGB stars from the APO-K2 catalogue
Valle, G.; Dell'Omodarme, M.; Prada Moroni, P. G. +1 more
Aims. By adopting the recently empirically derived dependence of α-elements on [α/Fe] instead of the conventionally applied uniform one, we tested the agreement between stellar model predictions and observations for red giant branch (RGB) stars in the APO-K2 catalogue. We particularly focused on the biases in effective temperature scales and on th…
A long-term study of the magnetic field and activity in the M giant RZ Ari. Magnetism and planet engulfment in a fairly evolved star?
Mathias, P.; Zamanov, R.; Baron, F. +12 more
Aims: We present a detailed long-term study of the single M6 III giant RZ Ari to obtain direct and simultaneous measurements of the magnetic field, activity indicators, and radial velocity in order to infer the origin of its activity. We study its magnetic activity in the context of stellar evolution, and for this purpose, we also refined its…
XMM-Newton - NuSTAR monitoring campaign of the Seyfert 1 galaxy IC 4329A
Paltani, S.; Tombesi, F.; Privon, G. C. +13 more
We present the results of a joint XMM-Newton and NuSTAR campaign on the active galactic nucleus (AGN) IC 4329A, consisting of 9 × 20 ks XMM-Newton observations, and 5 × 20 ks NuSTAR observations within nine days, performed in August 2021. Within each observation, the AGN is not very variable, and the fractional variability never exceeds 5%. Flux v…
Eight new 2+2 doubly eclipsing quadruple systems detected
Merc, J.; Kučáková, H.; Zasche, P. +2 more
We studied eight new doubly eclipsing stellar systems. We found that they are all rare examples of quadruple systems of 2 + 2 architecture, where both inner pairs are eclipsing binaries. Until now, such a configuration had only been proven for dozens of systems on the whole sky. We enlarged this rare group of systems with four stars in the Small M…
The Smallest Scale of Hierarchy Survey (SSH): III. Dwarf-dwarf satellite merging phenomena in the low-mass regime
de Jong, Roelof S.; Cannon, John M.; Cignoni, Michele +13 more
We present new deep, wide-field imaging data from the Large Binocular Telescope (LBT) in g and r bands from the Smallest Scale of Hierarchy Survey (SSH) that reveal previously undetected tidal features and stellar streams in the outskirts of six dwarf irregular galaxies (NGC 5238, UGC 6456, UGC 6541, UGC 7605, UGC 8638, and UGC 8760) with stellar …
Dust mass in protoplanetary disks with porous dust opacities
Fang, Min; Flock, Mario; Henning, Thomas +8 more
Atacama Large Millimeter/submillimeter Array surveys have suggested that protoplanetary disks are not massive enough to form the known exoplanet population, based on the assumption that the millimeter continuum emission is optically thin. In this work, we investigate how the mass determination is influenced when the porosity of dust grains is cons…
Multi-wavelength observations of the luminous fast blue optical transient AT 2023fhn: Up to ∼200 days post-explosion
Groot, P. J.; Levan, A. J.; Chrimes, A. A. +4 more
Context. Luminous fast blue optical transients (LFBOTs) are a class of extragalactic transients notable for their rapid rise and fade times, blue colour, and accompanying luminous X-ray and radio emission. Only a handful have been studied in detail since the prototypical example AT 2018cow. Their origins are currently unknown, but ongoing observat…
Jet formation in post-AGB binaries: Confronting cold magnetohydrodynamic disc wind models with observations
Ferreira, J.; Verhamme, O.; Van Winckel, H. +4 more
Context. Jets are launched from many classes of astrophysical objects, including post-asymptotic giant branch (post-AGB) binaries with a circumbinary disc. Despite dozens of detections, the formation of these post-AGB binary jets and their connection to the inter-component interactions in their host systems remains poorly understood. Aims. Buildin…