Search Publications
Constraints on dark radiation from cosmological probes
Palanque-Delabrouille, Nathalie; Yèche, Christophe; Rossi, Graziano +1 more
We present joint constraints on the number of effective neutrino species Neff and the sum of neutrino masses ∑mν, based on a technique which exploits the full information contained in the one-dimensional Lyman-α forest flux power spectrum, complemented by additional cosmological probes. In particular, we obtain Neff
The calculation of moment uncertainties from velocity distribution functions with random errors
Gershman, Daniel J.; Pollock, Craig J.; Dorelli, John C. +1 more
Instrumentation that detects individual plasma particles is susceptible to random counting errors. These errors propagate into the calculations of moments of measured particle velocity distribution functions. Although rules of thumb exist for the effects of random errors on the calculation of lower order moments (e.g., density, velocity, and tempe…
Hierarchical fragmentation and collapse signatures in a high-mass starless region
Henning, Th.; Beuther, H.; Kuiper, R. +6 more
Aims: We study the fragmentation and collapse properties of the dense gas during the onset of high-mass star formation.
Methods: We observed the massive (~800 M⊙) starless gas clump IRDC 18310-4 with the Plateau de Bure Interferometer (PdBI) at subarcsecond resolution in the 1.07 mm continuum and N2H+(3-2…
Internally driven large-scale changes in the size of Saturn's magnetosphere
Coates, A. J.; Dougherty, M. K.; Thomsen, M. F. +7 more
Saturn's magnetic field acts as an obstacle to solar wind flow, deflecting plasma around the planet and forming a cavity known as the magnetosphere. The magnetopause defines the boundary between the planetary and solar dominated regimes, and so is strongly influenced by the variable nature of pressure sources both outside and within. Following fro…
Galactic interstellar filaments as probed by LOFAR and Planck.
Boulanger, F.; Alves, M. I. R.; Ghosh, T. +13 more
Recent Low-Frequency Array (LOFAR) observations at 115-175 MHz of a field at medium Galactic latitudes (centred at the bright quasar 3C196) have shown striking filamentary structures in polarization that extend over more than 4° across the sky. In addition, the Planck satellite has released full sky maps of the dust emission in polarization at 353…
Aeolian processes as drivers of landform evolution at the South Pole of Mars
Spiga, Aymeric; Holt, John W.; Smith, Isaac B.
We combine observations of surface morphology, topography, subsurface stratigraphy, and near surface clouds with mesoscale simulations of south polar winds and temperature to investigate processes governing the evolution of spiral troughs on the South Pole of Mars. In general we find that the south polar troughs are cyclic steps that all formed du…
Super-solar metallicity at the position of the ultra-long GRB 130925A
Greiner, J.; Klose, S.; Schady, P. +18 more
Over the last decade there has been immense progress in the follow-up of short and long gamma-ray bursts (GRBs), resulting in a significant rise in the detection rate of X-ray and optical afterglows, in the determination of GRB redshifts, and of the identification of the underlying host galaxies. Nevertheless, our theoretical understanding of the …
Observed Variability of the Solar Mg II h Spectral Line
De Pontieu, B.; Schmit, D.; Leenaarts, J. +3 more
The Mg ii h&k doublet are two of the primary spectral lines observed by the Sun-pointing Interface Region Imaging Spectrograph (IRIS). These lines are tracers of the magnetic and thermal environment that spans from the photosphere to the upper chromosphere. We use a double-Gaussian model to fit the Mg ii h profile for a full-Sun mosaic data se…
The Binary Mass Transfer Origin of the Red Blue Straggler Sequence in M30
Dalessandro, E.; Beccari, G.; Ferraro, F. R. +4 more
Two separated sequences of blue straggler stars (BSSs) have been revealed by Ferraro et al. in the color-magnitude diagram (CMD) of the Milky Way globular cluster M30. Their presence has been suggested to be related to the two BSS formation channels (namely, collisions and mass transfer in close binaries) operating within the same stellar system. …
New 40Ar/39Ar dating of the Clearwater Lake impact structures (Québec, Canada) - Not the binary asteroid impact it seems?
Trieloff, Mario; Osinski, Gordon R.; Schmieder, Martin +4 more
The two Clearwater Lake impact structures (Québec, Canada) are generally interpreted as a crater doublet formed by the impact of a binary asteroid. Here, arguments are presented that raise important questions about the proposed double impact scenario. New 40Ar/39Ar dating of two virtually fresh impact melt rock samples from t…