Search Publications
Spatially resolved evolution of the local H2O production rates of comet 67P/Churyumov-Gerasimenko from the MIRO instrument on Rosetta
Ip, W. -H.; Hartogh, P.; Lellouch, E. +11 more
Aims: Using spectroscopic and continuum data measured by the MIRO instrument on board Rosetta of comet 67P/Churyumov-Gerasimenko, it is possible to derive and track the change in the water production rate, to learn how the outgassing evolves with heliocentric distance. The MIRO data are well suited to investigate the evolution of 67P, in unpr…
Isotopic composition of CO2 in the coma of 67P/Churyumov-Gerasimenko measured with ROSINA/DFMS
Wurz, P.; Altwegg, K.; Balsiger, H. +15 more
Context. Measurements of isotopic abundances in cometary ices are key to understanding and reconstructing the history and origin of material in the solar system. Comets are considered the most pristine material in the solar system. Isotopic fractionation (enrichment of an isotope in a molecule compared to the initial abundance) is sensitive to env…
Galactic bulge population II Cepheids in the VVV survey: period-luminosity relations and a distance to the Galactic centre
Minniti, D.; Rejkuba, M.; Zoccali, M. +7 more
Context. Multiple stellar populations of different ages and metallicities reside in the Galactic bulge that trace its structure and provide clues to its formation and evolution.
Aims: We present the near-infrared observations of population II Cepheids in the Galactic bulge from VISTA Variables in the Vía Láctea (VVV) survey. The JHKs
Resolving galaxy cluster gas properties at z 1 with XMM-Newton and Chandra
Arnaud, M.; Pratt, G. W.; Bartalucci, I. +3 more
Massive, high-redshift, galaxy clusters are useful laboratories to test cosmological models and to probe structure formation and evolution, but observations are challenging due to cosmological dimming and angular distance effects. Here we present a pilot X-ray study of the five most massive (M500 > 5 × 1014M⊙), …
The Ca II infrared triplet's performance as an activity indicator compared to Ca II H and K. Empirical relations to convert Ca II infrared triplet measurements to common activity indices
Schmitt, J. H. M. M.; Schmidt, T. O. B.; Martin, J. +4 more
Aims: A large number of Calcium infrared triplet (IRT) spectra are expected from the Gaia and CARMENES missions. Conversion of these spectra into known activity indicators will allow analysis of their temporal evolution to a better degree. We set out to find such a conversion formula and to determine its robustness.
Methods: We have comp…
Very low-mass stellar content of the young supermassive Galactic star cluster Westerlund 1
Brandner, W.; Zinnecker, H.; de Marchi, G. +4 more
We present deep near-infrared HST/WFC3 observations of the young supermassive Galactic star cluster Westerlund 1 and an adjacent control field. The depth of the data is sufficient to derive the mass function for the cluster as a function of radius down to 0.15 M⊙ in the outer parts of the cluster. We identify for the first time a flatte…
3D shape of asteroid (6) Hebe from VLT/SPHERE imaging: Implications for the origin of ordinary H chondrites
Berthier, J.; Carry, B.; Delbo, M. +15 more
Context. The high-angular-resolution capability of the new-generation ground-based adaptive-optics camera SPHERE at ESO VLT allows us to assess, for the very first time, the cratering record of medium-sized (D 100-200 km) asteroids from the ground, opening the prospect of a new era of investigation of the asteroid belt's collisional history.
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37 GHz observations of narrow-line Seyfert 1 galaxies
Harrison, D. L.; Lähteenmäki, A.; López-Caniego, M. +12 more
Observations performed at Metsähovi Radio Observatory at 37 GHz are presented for a sample of 78 radio-loud and radio-quiet narrow-line Seyfert 1 (NLS1) galaxies, together with additional lower and higher frequency radio data from RATAN-600, Owens Valley Radio Observatory, and the Planck satellite. Most of the data have been gathered between Febru…
Characterization of star-forming dwarf galaxies at 0.1 ≲z ≲ 0.9 in VUDS: probing the low-mass end of the mass-metallicity relation
Maccagni, D.; Schaerer, D.; Castellano, M. +19 more
Context. The study of statistically significant samples of star-forming dwarf galaxies (SFDGs) at different cosmic epochs is essential for the detailed understanding of galaxy assembly and chemical evolution. However, the main properties of this large population of galaxies at intermediate redshift are still poorly known.
Aims: We present the…
Observational calibration of the projection factor of Cepheids. III. The long-period Galactic Cepheid RS Puppis
Mérand, Antoine; Bond, Howard E.; Anderson, Richard I. +10 more
The projection factor (p-factor) is an essential component of the classical Baade-Wesselink (BW) technique, which is commonly used to determine the distances to pulsating stars. It is a multiplicative parameter used to convert radial velocities into pulsational velocities. As the BW distances are linearly proportional to the p-factor, its accurate…