Search Publications
X-ray view of dissipative warm corona in active galactic nuclei
Bianchi, S.; Petrucci, P. O.; Belmont, R. +8 more
Context. Detections of the X-ray spectra of active galactic nuclei (AGNs) typically reveal a noticeable excess of soft X-rays beyond the extrapolation of the power-law trend observed between 2 and 10 keV. However, the cause of this surplus remains unclear. In the scenario of soft Comptonization, observations suggest a warm corona temperature, rang…
Examining the nature of the ultraluminous X-ray source Holmberg II X-1
Pinto, C.; Di Salvo, T.; Roberts, T. P. +4 more
We present a comprehensive spectral analysis of the ultraluminous X-ray source Holmberg II X-1 using broadband and high-resolution X-ray spectra taken with the XMM-Newton satellite over a period of 19 yr, taking advantage of data from a recent campaign. We tested several models for the broadband spectra, including a double thermal component provid…
Connecting remote and in situ observations of shock-accelerated electrons associated with a coronal mass ejection
Jebaraj, I. C.; Vainio, R.; Kilpua, E. K. J. +7 more
Context. One of the most prominent sources for energetic particles in our Solar System are huge eruptions of magnetised plasma from the Sun, known as coronal mass ejections (CMEs), which usually drive shocks that accelerate charged particles up to relativistic energies. In particular, energetic electron beams can generate radio bursts through the …
Secular change in the spin states of asteroids due to radiation and gravitation torques. New detections and updates of the YORP effect
Snodgrass, C.; Ehgamberdiev, Sh. A.; Kučáková, H. +21 more
Context. The rotation state of small asteroids is affected in the long term by perturbing torques of gravitational and radiative origin (the YORP effect). The former can be detected by a change in the spin-axis orientation in the inertial space; the latter manifests itself by a quadratic increase in the rotation phase.
Aims: Direct observatio…
Planets observed with CHEOPS. Two super-Earths orbiting the red dwarf star TOI-776
Alonso, R.; Deeg, H.; Deleuil, M. +86 more
Context. M-dwarf stars are the most common of potential exoplanet host stars in the Galaxy. It is therefore very important to understand planetary systems orbiting such stars and to determine the physical parameters of such planets with high precision. Also with the launch of the James Webb Space Telescope (JWST) the observation of atmospheric par…
X-shooter spectroscopy of Liller 1 giant stars
Dalessandro, E.; Rich, R. M.; Mucciarelli, A. +8 more
We present the first comprehensive chemical study of a representative sample of 27 luminous red giant branch (RGB) stars belonging to Liller 1, a complex stellar system in the Galactic bulge. This study is based on medium-resolution near-infrared spectra acquired with X-shooter at the Very Large Telescope. We found a subpopulation counting 22 star…
Mass and wind luminosity of young Galactic open clusters in Gaia DR2
Morlino, G.; Celli, S.; Specovius, A. +2 more
Context. Star clusters constitute a significant part of the stellar population in our Galaxy. The feedback processes they exert on the interstellar medium impact multiple physical processes from the chemical to the dynamical evolution of the Galaxy. In addition, young and massive stellar clusters might act as efficient particle accelerators and co…
CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side
Alonso, R.; Deleuil, M.; Erikson, A. +87 more
Context. Occultations are windows of opportunity to indirectly peek into the dayside atmosphere of exoplanets. High-precision transit events provide information on the spin-orbit alignment of exoplanets around fast-rotating hosts.
Aims: We aim to precisely measure the planetary radius and geometric albedo of the ultra-hot Jupiter (UHJ) KELT-2…
Spectroscopy of the binary TNO Mors-Somnus with the JWST and its relationship to the cold classical and plutino subpopulations observed in the DiSCo-TNO project
Stansberry, J.; Cruikshank, D.; Emery, J. P. +16 more
Context. Trans-Neptunian objects (TNOs) are remnants of small icy bodies from planetary formation that orbit in the region beyond Neptune. Within the population of TNOs, Trans-Neptunian binaries (TNBs) provide a valuable opportunity to test the models of the formation and evolution of planetesimals in the trans-Neptunian region. Various theories h…
Gaia's brightest very metal-poor (VMP) stars. Metallicity catalogue of a thousand VMP stars from Gaia's radial velocity spectrometer spectra
Sestito, Federico; Martin, Nicolas F.; Fabbro, Sébastien +10 more
Context. Gaia DR3 has offered the scientific community a remarkable dataset of approximately one million spectra acquired with the radial velocity spectrometer (RVS) in the calcium II triplet region, which is well suited to identify very metal-poor (VMP) stars. However, over 40% of these spectra have no released parameters by Gaia's GSP-Spec pipel…