Search Publications
Membership of stars in open clusters using random forest with gaia data
Hasan, S. N.; Hasan, Priya; Raja, Mudasir +1 more
Membership of stars in open clusters is one of the most crucial parameters in studies of star clusters. Gaia opened a new window in the estimation of membership because of its unprecedented 6-D data. In the present study, we used published membership data of nine open star clusters as a training set to find new members from Gaia DR2 data using a s…
Ubiquitous signs of interactions in early-type galaxies with prolate rotation
Duc, Pierre-Alain; Bílek, Michal; Ebrová, Ivana +2 more
Context. A small fraction of early-type galaxies (ETGs) show prolate rotation; that is, they rotate around their long photometric axis. In simulations, certain configurations of galaxy mergers are known to produce this type of rotation.
Aims: We investigate the association of prolate rotation and signs of galaxy interactions among the observe…
Dipper-like variability of the Gaia alerted young star V555 Ori
Pál, András; Moór, Attila; Ábrahám, Péter +26 more
V555 Ori is a T Tauri star, whose 1.5 mag brightening was published as a Gaia science alert in 2017. We carried out optical and near-infrared (NIR) photometric, and optical spectroscopic observations to understand the light variations. The light curves show that V555 Ori was faint before 2017, entered a high state for about a year, and returned to…
Surveying the Giant H II Regions of the Milky Way with SOFIA. III. W49A
Lim, Wanggi; Karnath, Nicole; De Buizer, James M. +2 more
We present our third set of results from our mid-infrared imaging survey of Milky Way Giant H II regions with our detailed analysis of W49A, one of the most distant, yet most luminous, GH II regions in the Galaxy. We used the FORCAST instrument on the Stratospheric Observatory For Infrared Astronomy (SOFIA) to obtain 20 and 37 µm images of t…
The Cosmic Large-Scale Structure in X-rays (CLASSIX) Cluster Survey. IV. Superclusters in the local Universe at z ≤ 0.03
Böhringer, Hans; Chon, Gayoung
It is important to map the large-scale matter distribution in the local Universe for cosmological studies, such as the tracing of the large-scale peculiar velocity flow, the characterisation of the environment for different astronomical objects, and for precision measurements of cosmological parameters. We used X-ray luminous clusters to map this …
Orbital pericentres and the inferred dark matter halo structure of satellite galaxies
Bullock, James S.; Robles, Victor H.
Using the phat-ELVIS suite of Milky Way-sized halo simulations, we show that subhalo orbital pericentres, rperi, correlate with their dark matter halo structural properties. Specifically, at fixed maximum circular velocity, Vmax, subhaloes with smaller rperi are more concentrated (have smaller rmax value…
Modeling irregular small bodies gravity field via extreme learning machines and Bayesian optimization
Reddy, Vishnu; Le Corre, Lucille; Furfaro, Roberto +4 more
Close proximity operations around small bodies are extremely challenging due to their uncertain dynamical environment. Autonomous guidance and navigation around small bodies require fast and accurate modeling of the gravitational field for potential on-board computation. In this paper, we investigate a model-based, data-driven approach to compute …
Study of the thermal and nonthermal emission components in M 31: the Sardinia Radio Telescope view at 6.6 GHz
de Bernardis, P.; Masi, S.; Paladini, R. +21 more
Context. The Andromeda galaxy is the best-known large galaxy besides our own Milky Way. Several images and studies exist at all wavelengths from radio to hard X-ray. Nevertheless, only a few observations are available in the microwave range where its average radio emission reaches the minimum.
Aims: In this paper, we want to study the radio m…
Flow directions of low-energy ions in and around the diamagnetic cavity of comet 67P
Nilsson, Hans; Stenberg Wieser, Gabriella; Wieser, Martin +5 more
The flow direction of low-energy ions around comet 67P/Churyumov-Gerasimenko has previously been difficult to constrain due to the influence of the spacecraft potential. The Ion Composition Analyzer of the Rosetta Plasma Consortium (RPC-ICA) on Rosetta measured the distribution function of positive ions with energies down to just a few eV/q throug…
Forward Modeling Helioseismic Signatures of One- and Two-cell Meridional Circulation
Kosovichev, Alexander G.; Pipin, Valery V.; Stejko, Andrey M.
Using a 3D global solver of the linearized Euler equations, we model acoustic oscillations over background velocity flow fields of single-cell meridional circulation with deep and shallow return flows as well as double-cell meridional circulation with strong and weak reversals. The velocities are generated using a mean-field hydrodynamic and dynam…