Search Publications
The Outer spiral arm of the Milky Way using red clump stars. Tracing the asymmetry across the disc
Ganesh, Shashikiran; Schultheis, Mathias; Uppal, Namita
Aims: Our aim is to provide an observational view of the old disc structure of the Milky Way galaxy using the distribution of red clump (RC) stars. The spiral arms, warp structure, and other asymmetries present in the disc are revisited using a systematic study of RC star counts over the disc of the Galaxy.
Methods: We developed a method…
Gaia view of primitive inner-belt asteroid families. Searching for the origins of asteroids Bennu and Ryugu
Delbo, M.; Avdellidou, C.; Walsh, K. J.
Aims: The near-Earth asteroids Ryugu and Bennu were visited, characterised, and sampled by the Hayabusa2 and OSIRIS-REx missions, where remote sensing data and sample return analysis showed that both asteroids have primitive, hydrated, and organic-rich compositions. The dark families of the inner main belt that belong to the spectroscopic C-c…
Asteroids' reflectance from Gaia DR3: Artificial reddening at near-UV wavelengths
Tatsumi, E.; Tanga, P.; De Angeli, F. +6 more
Context. Observational and instrumental difficulties observing small bodies below 0.5 µm make this wavelength range poorly studied compared with the visible and near-infrared. Furthermore, the suitability of many commonly used solar analogues, essential in the computation of asteroid reflectances, is usually assessed only in visible waveleng…
Enhancing the alignment of the optically bright Gaia reference frame with respect to the International Celestial Reference System
Xu, Ming H.; Anderson, James M.; Lunz, Susanne +4 more
Context. The link of the Gaia frame in terms of non-rotation with respect to the International Celestial Reference System (ICRS), which is realized via very long baseline interferometry (VLBI) at radio wavelengths, has to be conducted for the wide range of optical magnitudes in which the spacecraft observes. There is a sufficient number of suitabl…
The Yarkovsky effect and bulk density of near-Earth asteroids from Gaia DR3
Oszkiewicz, Dagmara; Tanga, Paolo; Carry, Benoit +3 more
Aims: The primary objective of this study is to utilize Gaia DR3 asteroid astrometry to detect the Yarkovsky effect, a non-gravitational acceleration that affects the orbits of small asteroids. We then computed the bulk densities for the sample of objects for which we obtained an estimation of the Yarkovsky effect.
Methods: We used the v…
Multiwavelength observations of PSR J2021+4026 across a mode change reveal a phase shift in its X-ray emission
Harding, A. K.; Kerr, M.; Marelli, M. +6 more
Context. We have investigated the multiwavelength emission of PSR J2021+4026, the only isolated γ-ray pulsar known to be variable, which in October 2011 underwent a simultaneous change in γ-ray flux and spin-down rate, followed by a second mode change in February 2018. Multiwavelength monitoring is crucial to understand the physics behind these ev…
An imaged 15 MJup companion within a hierarchical quadruple system
Henning, T.; Janson, M.; Langlois, M. +20 more
Context. Since 2019, the direct imaging B-star Exoplanet Abundance STudy (BEAST) at SPHERE@VLT has been scanning the surroundings of young B-type stars in order to ascertain the ultimate frontiers of giant planet formation. Recently, the 17−4+3 Myr HIP 81208 was found to host a close-in (∼50 au) brown dwarf and a wider (∼230 …
Near-infrared evolution of the equatorial ring of SN 1987A
Larsson, J.; Lundqvist, P.; Fransson, C. +4 more
We used adaptive optics imaging and integral field spectroscopy from the Very Large Telescope, together with images from the Hubble Space Telescope, to study the near-infrared (NIR) evolution of the equatorial ring (ER) of SN 1987A. We studied the NIR flux and morphology over time in order to lay the groundwork for James Webb Space Telescope obser…
CO enhancement by magnetohydrodynamic waves. Striations in the Polaris Flare
Panopoulou, G. V.; Goldsmith, P. F.; Pelgrims, V. +4 more
Context. The formation of molecular gas in interstellar clouds is a slow process, but can be enhanced by gas compression. Magneto-hydrodynamic (MHD) waves can create compressed quasi-periodic linear structures, referred to as striations. Striations are observed at the column densities at which the transition from atomic to molecular gas takes plac…
CHEX-MATE: Pressure profiles of six galaxy clusters as seen by SPT and Planck
Pointecouteau, E.; Pratt, G. W.; Rossetti, M. +11 more
Context. Pressure profiles are sensitive probes of the thermodynamic conditions and the internal structure of galaxy clusters. The intra-cluster gas resides in hydrostatic equilibrium within the dark-matter gravitational potential. However, this equilibrium may be perturbed; for example, as a consequence of thermal energy losses, feedback, and non…