Search Publications
Detection of photometric variability in the very low-mass binary VHS J1256-1257AB using TESS and Spitzer
Miles-Páez, P. A.
Aims: We investigate the photometric properties of the M7.5 equal-mass binary VHS J1256-1257AB, which, combined with the late-L dwarf VHS J1256-1257 b, forms one of the few young triple systems of ultra-cool dwarfs currently known.
Methods: We analyzed two-minute TESS and two-second Spitzer archival data with total durations of about 25 …
The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XXII. Relative ages of multiple populations in five globular clusters
Piotto, G.; Nardiello, D.; Lucertini, F.
Aims: We present a new technique to estimate the relative ages of multiple stellar populations hosted by the following five globular clusters: NGC 104 (47 Tuc), NGC 6121 (M 4), NGC 6352, NGC 6362, and NGC 6723.
Methods: We used the catalogs of the database HST UV Globular Cluster Survey to create color-magnitude and two-color diagrams of…
Gas and stellar dynamics in Stephan's Quintet. Mapping the kinematics in a closely interacting compact galaxy group
Eckart, A.; Sánchez-Monge, Á.; Yttergren, M. +4 more
In nearby compact galaxy groups we can study the complex processes of galaxy interactions at high resolution and obtain a window into a time in the history of the Universe when the galaxies were closely spaced and the intergalactic medium was awash with gas. Stephan's Quintet is a nearby compact galaxy group and a perfect laboratory for studying t…
Electric field measurements at the plasma frequency around comet 67P by RPC-MIP on board Rosetta
Palmerio, E.; Nilsson, H.; Henri, P. +7 more
Context. The Mutual Impedance Probe (RPC-MIP) carried by the Rosetta spacecraft monitored both the plasma density and the electric field in the close environment of comet 67P/Churyumov-Gerasimenko (67P), as the instrument was operating alternatively in two main modes: active and passive. The active mode is used primarily to perform plasma density …
Gas terminal velocity from MIRO/Rosetta data using neural network approach
Hartogh, P.; Crovisier, J.; Ip, W. H. +8 more
Context. The Microwave Instrument on the Rosetta Orbiter (MIRO) on board the Rosetta spacecraft was designed to investigate the surface and gas activity of the comet 67P/Churyumov-Gerasimenko. The MIRO spectroscopic measurements carry information about the velocity of gas emanating from the nucleus surface. Knowledge of the terminal velocity of th…
Similarities of magnetoconvection in the umbra and in the penumbra of sunspots
Solanki, S. K.; Lagg, A.; Löptien, B. +1 more
Context. It is unclear why there is a rather sharp boundary in sunspots between the umbra and the penumbra. Both regions exhibit magnetoconvection, which manifests in penumbral filaments in the penumbra and in umbral dots in the umbra.
Aims: Here we compare the physical properties of umbral dots and penumbral filaments. Our goal is to underst…
Ancient and present surface evolution processes in the Ash region of comet 67P/Churyumov-Gerasimenko
Jorda, L.; Groussin, O.; Bouley, S. +3 more
Aims: The Rosetta mission provided us with detailed data of the surface of the nucleus of comet 67P/Churyumov-Gerasimenko. In order to better understand the physical processes associated with the comet activity and the surface evolution of its nucleus, we performed a detailed comparative morphometrical analysis of two depressions located in t…
X-ray emission of Seyfert 2 galaxy MCG-01-24-12
Bianchi, S.; Dadina, M.; Braito, V. +7 more
We present a detailed X-ray spectral analysis of the nearby Seyfert 2 galaxy MCG-01-24-12 based on a multi-epoch data set. Data were obtained with different X-ray satellites, namely XMM-Newton, NuSTAR, Swift, and Chandra, and cover different time intervals, from a few days to years. From 2006 to 2013 the source had a 2-10 keV flux of ∼1.5 × 10
Stellar X-rays and magnetic activity in 3D MHD coronal models
Peter, H.; Zhuleku, J.; Warnecke, J.
Context. Observations suggest a power-law relation between the coronal emission in X-rays, LX, and the total (unsigned) magnetic flux at the stellar surface, Φ. The physics basis for this relation is poorly understood.
Aims: We use three-dimensional (3D) magnetohydrodynamics (MHD) numerical models of the coronae above active region…
New precise positions in 2013-2019 and a catalog of ground-based astrometric observations of 11 Neptunian satellites (1847-2019) based on Gaia-DR2
Ren, Shulin; Fu, Yanning; Yuan, Ye +1 more
Context. Developing high-precision ephemerides for Neptunian satellites requires not only the continuation of observing campaigns but also the collection and improvement of existing observations. So far, no complete catalogs of observations of Neptunian satellites are available.
Aims: We aim to provide new, precise positions, and to compile a…