Search Publications
A CHEOPS white dwarf transit search
Lendl, Monika; Brandeker, Alexis; Heng, Kevin +2 more
White dwarf spectroscopy shows that nearly half of white dwarf atmospheres contain metals that must have been accreted from planetary material that survived the red giant phases of stellar evolution. We can use metal pollution in white dwarf atmospheres as flags, signalling recent accretion, in order to prioritize an efficient sample of white dwar…
The first coronal mass ejection observed in both visible-light and UV H I Ly-α channels of the Metis coronagraph on board Solar Orbiter
Heinzel, P.; Vial, J. -C.; Woch, J. +68 more
Context. The Metis coronagraph on board Solar Orbiter offers a new view of coronal mass ejections (CMEs), observing them for the first time with simultaneous images acquired with a broad-band filter in the visible-light interval and with a narrow-band filter around the H I Ly-α line at 121.567 nm, the so-called Metis UV channel.
Aims: We show…
A random forest-based selection of optically variable AGN in the VST-COSMOS field
Bauer, F. E.; Brandt, W. N.; Vaccari, M. +6 more
Context. The survey of the COSMOS field by the VLT Survey Telescope is an appealing testing ground for variability studies of active galactic nuclei (AGN). With 54 r-band visits over 3.3 yr and a single-visit depth of 24.6 r-band mag, the dataset is also particularly interesting in the context of performance forecasting for the Vera C. Rubin Obser…
Recurrence of galactic cosmic-ray intensity and anisotropy in solar minima 23/24 and 24/25 observed by ACE/CRIS, STEREO, SOHO/EPHIN and neutron monitors. Fourier and wavelet analysis
Modzelewska, R.; Gil, A.
Aims: We studied the 27-day variations of galactic cosmic rays (GCRs) based on neutron monitor (NM), ACE/CRIS, STEREO, and SOHO/EPHIN measurements in the solar minima 23/24 and 24/25, which are characterized by the opposite polarities of solar magnetic cycle. We used the opportunity to reanalyze the polarity dependence of the amplitudes of th…
Nebular Hα emission in Type Ia supernova 2016jae
Cappellaro, E.; Benetti, S.; Morrell, N. +7 more
There is a wide consensus that Type Ia supernovae (SNe Ia) originate from the thermonuclear explosion of CO white dwarfs (WDs), with the lack of hydrogen in the observed spectra as a distinctive feature. Here, we present supernova (SN) 2016jae, which was classified as an SN Ia from a spectrum obtained soon after its discovery. The SN reached a B-b…
Constraining stellar rotation and planetary atmospheric evolution of a dozen systems hosting sub-Neptunes and super-Earths
Fossati, L.; Kubyshkina, D.; Bonfanti, A. +1 more
Context. Planetary atmospheric evolution modelling is a prime tool for understanding the observed exoplanet population and constraining formation and migration mechanisms, but it can also be used to study the evolution of the activity level of planet hosts.
Aims: We constrain the planetary atmospheric mass fraction at the time of the dispersa…
Mysterious, variable, and extremely hot: White dwarfs showing ultra-high excitation lines. I. Photometric variability
Pelisoli, Ingrid; Reindl, Nicole; Schaffenroth, Veronika +3 more
Context. About 10% of all stars exhibit absorption lines of ultra-highly excited (UHE) metals (e.g., O VIII) in their optical spectra when entering the white dwarf cooling sequence. This is something that has never been observed in any other astrophysical object, and poses a decades-long mystery in our understanding of the late stages of stellar e…
Balmer continuum enhancement detected in a mini flare observed with IRIS
Heinzel, Petr; Schmieder, Brigitte; Joshi, Reetika +3 more
Context. Optical and near-UV continuum emissions in flares contribute substantially to the flare energy budget. Two mechanisms play an important role for continuum emission in flares: hydrogen recombination after sudden ionization at chromospheric layers, and transportation of the energy radiatively from the chromosphere to lower layers in the atm…
The AMBRE Project: Solar neighbourhood chemodynamical constraints on Galactic disc evolution
Recio-Blanco, A.; de Laverny, P.; Kordopatis, G. +2 more
Context. The abundance of α-elements relative to iron ([α/Fe]) is an important fossil signature in Galactic archaeology for tracing the chemical evolution of disc stellar populations. High-precision chemical abundances, together with accurate stellar ages, distances, and dynamical data, are crucial to infer the Milky Way formation history.
Ai…
Molecular gas kinematics in the nuclear region of nearby Seyfert galaxies with ALMA
Andreani, P.; Hatziminaoglou, E.; Spinoglio, L. +11 more
Context. The study of the distribution, morphology, and kinematics of cold molecular gas in the nuclear and circumnuclear regions of active galactic nuclei (AGNs) helps to characterise and hence to quantify the impact of the AGNs on the host galaxy over its lifetime.
Aims: We present the analysis of the molecular gas in the nuclear regions of…