Search Publications
Masses and ages for metal-poor stars. A pilot programme combining asteroseismology and high-resolution spectroscopic follow-up of RAVE halo stars
Valentini, M.; García, R. A.; Chiappini, C. +10 more
Context. Very metal-poor halo stars are the best candidates for being among the oldest objects in our Galaxy. Samples of halo stars with age determination and detailed chemical composition measurements provide key information for constraining the nature of the first stellar generations and the nucleosynthesis in the metal-poor regime.
Aims: A…
Six new supermassive black hole mass determinations from adaptive-optics assisted SINFONI observations
Krajnović, Davor; Sarzi, Marc; Cappellari, Michele +4 more
Different massive black hole mass - host galaxy scaling relations suggest that the growth of massive black holes is entangled with the evolution of their host galaxies. The number of measured black hole masses is still limited and additional measurements are necessary to understand the underlying physics of this apparent coevolution. We add six ne…
Exoplanet characterisation in the longest known resonant chain: the K2-138 system seen by HARPS
Bouchy, F.; Deleuil, M.; Kirk, J. +36 more
The detection of low-mass transiting exoplanets in multiple systems brings new constraints to planetary formation and evolution processes and challenges the current planet formation theories. Nevertheless, only a mere fraction of the small planets detected by Kepler and K2 have precise mass measurements, which are mandatory to constrain their comp…
Feedback from OB stars on their parent cloud: gas exhaustion rather than gas ejection
Peretto, N.; Marsh, K.; Fuller, G. A. +1 more
Context. Stellar feedback from high-mass stars shapes the interstellar medium, and thereby impacts gas that will form future generations of stars. However, due to our inability to track the time evolution of individual molecular clouds, quantifying the exact role of stellar feedback on their star formation history is an observationally challenging…
A UV and optical study of 18 old novae with Gaia DR2 distances: mass accretion rates, physical parameters, and MMRD
Selvelli, Pierluigi; Gilmozzi, Roberto
We combine the results of our earlier study of the UV characteristics of 18 classical novae (CNe) with data from the literature and with the recent precise distance determinations from the Gaia satellite to investigate the statistical properties of old novae. All final parameters for the sample include a detailed treatment of the errors and their …
Contrast sensitivities in the Gaia Data Release 2
Cataldi, Gianni; Brandeker, Alexis
The source detection sensitivity of Gaia is reduced near sources. To characterise this contrast sensitivity is important for understanding the completeness of the Gaia data products, in particular when evaluating source confusion in lower resolution surveys such as photometric monitoring for transits. Here, we statistically evaluate the catalogue …
Revisiting the 16 Cygni planet host at unprecedented precision and exploring automated tools for precise abundances
Spina, L.; Jofré, P.; Meléndez, J. +2 more
The binary system 16 Cygni is key in studies of the planet-star chemical composition connection, as only one of the stars is known to host a planet. This allows us to better assess the possible influence of planet interactions on the chemical composition of stars that are born from the same cloud and thus should have a similar abundance pattern. I…
Detecting shocked intergalactic gas with X-ray and radio observations
Ettori, S.; Roncarelli, M.; Vazza, F. +3 more
Detecting the thermal and non-thermal emission from the shocked cosmic gas surrounding large-scale structures represents a challenge for observations, as well as a unique window into the physics of the warm-hot intergalactic medium. In this work, we present synthetic radio and X-ray surveys of large cosmological simulations in order to assess the …
KiDS-SQuaD. II. Machine learning selection of bright extragalactic objects to search for new gravitationally lensed quasars
Agnello, Adriano; Kuijken, Konrad; Spiniello, Chiara +9 more
Context. The KiDS Strongly lensed QUAsar Detection project (KiDS-SQuaD) is aimed at finding as many previously undiscovered gravitational lensed quasars as possible in the Kilo Degree Survey. This is the second paper of this series where we present a new, automatic object-classification method based on the machine learning technique.
Aims: Th…
The survey of planetary nebulae in Andromeda (M 31). I. Imaging the disc and halo with MegaCam at the CFHT
Caldwell, Nelson; Gerhard, Ortwin; Arnaboldi, Magda +4 more
Context. The Andromeda (M 31) galaxy subtends nearly 100 square degrees on the sky. Any study of its halo must therefore account for the severe contamination from the Milky Way halo stars whose surface density displays a steep gradient across the entire M 31 field of view.
Aims: Our goal is to identify a population of stars firmly associated …