Search Publications
Comparative study of photo-produced ionosphere in the close environment of comets
Galand, M.; Beth, A.; Heritier, K. L.
Context. The Giotto and Rosetta missions gave us the unique opportunity of probing the close environment of cometary ionospheres of 1P/Halley (1P) and 67P/Churyumov-Gerasimenko (67P). The plasma conditions encountered at these two comets were very different from each other, which mainly stem from the different heliocentric distances, which drive p…
Influence of inelastic collisions with hydrogen atoms on the non-local thermodynamic equilibrium line formation for Fe I and Fe II in the 1D model atmospheres of late-type stars
Yakovleva, S. A.; Belyaev, A. K.; Sitnova, T. +1 more
Context. Iron plays a crucial role in studies of late-type stars. In their atmospheres, neutral iron is the minority species, and lines of Fe I are subject to the departures from local thermodynamic equilibrium (LTE). In contrast, one believes that LTE is a realistic approximation for Fe II lines. The main source of the uncertainties in the non-LT…
ARGOS at the LBT. Binocular laser guided ground-layer adaptive optics
Genzel, R.; Quirrenbach, A.; Beckmann, U. +48 more
Having completed its commissioning phase, the Advanced Rayleigh guided Ground-layer adaptive Optics System (ARGOS) facility is coming online for scientific observations at the Large Binocular Telescope (LBT). With six Rayleigh laser guide stars in two constellations and the corresponding wavefront sensing, ARGOS corrects the ground-layer distortio…
The TeV-emitting radio galaxy 3C 264. VLBI kinematics and SED modeling
Vignali, C.; Grandi, P.; Boccardi, B. +5 more
Context. In March 2018, the detection by VERITAS of very-high-energy emission (VHE > 100 GeV) from 3C 264 was reported. This is the sixth, and second most distant, radio galaxy ever detected in the TeV regime.
Aims: In this article we present a radio and X-ray analysis of the jet in 3C 264. We determine the main physical parameters of the …
Constraints on positron annihilation kinematics in the inner Galaxy
Diehl, Roland; Siegert, Thomas; Panther, Fiona H. +4 more
Context. The annihilation of cosmic positrons with electrons in the interstellar medium results in the strongest persistent γ-ray line signal in the sky. For the past 50 yr, this 511 keV emission - predominantly from the galactic bulge region and from a low surface-brightness disk - has puzzled observers and theoreticians. A key issue for understa…
Molecular gas in radio galaxies in dense megaparsec-scale environments at z = 0.4-2.6
Castignani, G.; De Zotti, G.; Benoist, C. +4 more
Context. Low luminosity radio galaxies (LLRGs) typically reside in dense megaparsec-scale environments and are often associated with brightest cluster galaxies (BCGs). They are an excellent tool to study the evolution of molecular gas reservoirs in giant ellipticals, even close to the active galactic nucleus.
Aims: We investigate the role of …
Outgassing-induced acceleration of comet 67P/Churyumov-Gerasimenko
Kramer, T.; Läuter, M.
Context. Cometary activity affects the orbital motion and rotation state through sublimation-induced forces. The availability of precise rotation-axis orientation and position data from the Rosetta mission allows us to accurately determine the outgassing of comet Churyumov-Gerasimenko/67P (67P).
Aims: We derived the observed non-gravitational…
Interplay between pulsation, mass loss, and third dredge-up: More about Miras with and without technetium
Bernhard, K.; Cristallo, S.; McDonald, I. +2 more
Context. We follow-up on a previous finding that AGB Mira variables containing the third dredge-up indicator technetium (Tc) in their atmosphere form a different sequence of K - [22] colour as a function of pulsation period than Miras without Tc. A near- to mid-infrared colour such as K - [22] is a good probe for the dust mass-loss rate of the sta…
Herschel map of Saturn's stratospheric water, delivered by the plumes of Enceladus
Fletcher, L. N.; Hartogh, P.; Lellouch, E. +13 more
Context. The origin of water in the stratospheres of giant planets has been an outstanding question ever since its first detection by the Infrared Space Observatory some 20 years ago. Water can originate from interplanetary dust particles, icy rings and satellites, and large comet impacts. Analyses of Herschel Space Observatory observations have p…
Stellar population astrophysics (SPA) with the TNG. Characterization of the young open cluster ASCC 123
Vallenari, A.; Sordo, R.; Bragaglia, A. +10 more
Star clusters are crucial to understanding stellar and Galactic evolution. ASCC 123 is a little-studied, nearby, and very sparse open cluster. We performed the first high-resolution spectroscopic study of this cluster in the framework of the Stellar Population Astrophysics (SPA) project with GIARPS at the TNG. We observed 17 stars, 5 of which turn…