Search Publications
The young stellar content of the giant H II regions M 8, G333.6-0.2, and NGC 6357 with VLT/KMOS
Henning, T.; Kaper, L.; De Ridder, J. +14 more
Context. The identification and characterisation of populations of young massive stars in (giant) H II regions provides important constraints on (i) the formation process of massive stars and their early feedback on the environment, and (ii) the initial conditions for population synthesis models predicting the evolution of ensembles of stars.
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Electron-positron pair plasma in TXS 0506+056 and the 'neutrino flare' in 2014-2015
Fraija, N.; Aguilar-Ruiz, E.; Galván-Gámez, A.
The detection of a prolonged flaring activity from blazar TXS 0506+056 in temporal and spatial coincidence with the energetic neutrino IceCube-170922A provided evidence about the photohadronic interactions in this source. However, analysis of the archival neutrino and multiwavelength data from the direction of this blazar between 2014 September an…
Stellar activity with LAMOST. III. Temporal variability pattern in Pleiades, Praesepe, and Hyades
Zhao, Gang; Bharat Kumar, Yerra; Bidin, Christian Moni +2 more
We present the results from a systematic study of temporal variation of stellar activity in young late-type stars. We used multi-epoch LAMOST (Large sky Area Multi-Object fiber Spectroscopic Telescope) low-resolution spectra of over 300 member candidates in three young open clusters: Pleiades, Praesepe, and Hyades. The spectral measurements of TiO…
The OH Megamaser galaxy IRAS11506-3851: an AGN and star formation revealed by multiwavelength observations
Robinson, Andrew; Storchi-Bergmann, Thaisa; Riffel, Rogemar A. +4 more
We present Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Hubble Space Telescope (HST), and Very Large Array (VLA) observations of the OH Megamaser (OHM) galaxy IRAS 11506-3851. The HST images reveal an isolated spiral galaxy and the combination with the GMOS-IFU flux distributions and VLA data allow us to identify a partial ri…
Successful application of PSF-R techniques to the case of the globular cluster NGC 6121 (M 4)
Massari, D.; Fiorentino, G.; Milli, J. +4 more
Context. Precise photometric and astrometric measurements on astronomical images require an accurate knowledge of the point spread function (PSF). When the PSF cannot be modelled directly from the image, PSF-reconstruction techniques become the only viable solution. So far, however, their performance on real observations has rarely been quantified…
Performance of VERA in 10 micro-arcsecond astrometry
Hirota, Tomoya; Honma, Mareki; Nakagawa, Akiharu +9 more
Very Long Baseline Interferometry (VLBI) astrometry using the phase-referencing technique remains an open issue for the quantitative characterization of the observing conditions to achieve a feasible parallax precision of 10 micro-arcseconds (µas). To address this issue, we evaluated the astrometric performance of the VLBI Exploration of Rad…
Xenon Isotopes Identify Large-scale Nucleosynthetic Heterogeneities across the Solar System
Avice, G.; Moreira, M.; Gilmour, J. D.
Nucleosynthetic isotopic anomalies in meteorites and planetary objects contribute to our understanding of the formation of the solar system. Isotope systematics of chondrites demonstrate the existence of a physical separation between isotopic reservoirs in the solar system. The isotopic composition of atmospheric xenon (Xe) indicates that its prog…
Statistical Properties of Habitable Zones in Stellar Binary Systems
Sozzetti, Alessandro; Vladilo, Giovanni; Silva, Laura +1 more
Observations of exoplanets and protoplanetary disks show that binary stellar systems can host planets in stable orbits. Given the high binary fraction among stars, the contribution of binary systems to Galactic habitability should be quantified. Therefore, we have designed a suite of Monte Carlo experiments aimed at generating large (up to 10…
Energized Oxygen in the Magnetotail: Current Sheet Bifurcation From Speiser Motion
George, Don E.; Jahn, Jörg-Micha
Oxygen can be a major constituent of magnetospheric plasma, yet the role of oxygen in the magnetosphere is not sufficiently understood. Observations of bifurcated current sheets (BCS) attributed to O+ have been made, yet their origin is not well understood. We examine the case of a thinning current sheet prior to the onset of magnetic r…
Simulation of the Interplanetary Bz Using a Data-driven Heliospheric Solar Wind Model
Feng, Xueshang; Zuo, Pingbing; Wei, Fengsi +1 more
Aimed to be ready for the transition from research to operation, we have developed a solar wind model by coupling a data-driven empirical coronal model with a magnetohydrodynamics heliospheric model. We performed a data-driven simulation of the solar wind for a two-year period during the declining and minimum phases of solar cycle 23. Comparisons …