Search Publications
Planetary surface dating from crater size-frequency distribution measurements: Poisson timing analysis
Michael, G. G.; Kneissl, T.; Neesemann, A.
The predictions of crater chronology models have customarily been evaluated by dividing a crater population into discrete diameter intervals, plotting the crater density for each, and finding a best-fit model isochron, with the uncertainty in the procedure being assessed using 1/√n estimates, where n is the number of craters in an interval. This a…
The discovery, monitoring and environment of SGR J1935+2154
Campana, S.; Tiengo, A.; Götz, D. +13 more
We report on the discovery of a new member of the magnetar class, SGR J1935+2154, and on its timing and spectral properties measured by an extensive observational campaign carried out between 2014 July and 2015 March with Chandra and XMM-Newton (11 pointings). We discovered the spin period of SGR J1935+2154 through the detection of coherent pulsat…
An evaporating planet in the wind: stellar wind interactions with the radiatively braked exosphere of GJ 436 b
Vidotto, A. A.; Ehrenreich, D.; Lecavelier des Etangs, A. +2 more
Observations of the warm Neptune GJ 436 b were performed with HST/STIS at three different epochs (2012, 2013, 2014) in the stellar Lyman-α line. They showed deep, repeated transits that were attributed to a giant exosphere of neutral hydrogen. The low radiation pressure from the M-dwarf host star was shown to play a major role in the dynamics of t…
Enceladus's internal ocean and ice shell constrained from Cassini gravity, shape, and libration data
Bourgeois, Olivier; Massé, Marion; Čadek, Ondřej +8 more
The intense plume activity at the South Pole of Enceladus together with the recent detection of libration hints at an internal water ocean underneath the outer ice shell. However, the interpretation of gravity, shape, and libration data leads to contradicting results regarding the depth of ocean/ice interface and the total volume of the ocean. Her…
Estimating Distances from Parallaxes. III. Distances of Two Million Stars in the Gaia DR1 Catalogue
Bailer-Jones, Coryn A. L.; Astraatmadja, Tri L.
We infer distances and their asymmetric uncertainties for two million stars using the parallaxes published in the Gaia DR1 (GDR1) catalogue. We do this with two distance priors: A minimalist, isotropic prior assuming an exponentially decreasing space density with increasing distance, and an anisotropic prior derived from the observability of stars…
Gamma-ray spectroscopy of positron annihilation in the Milky Way
Diehl, Roland; Greiner, Jochen; Siegert, Thomas +5 more
Context. The annihilation of positrons in the Galaxy's interstellar medium produces characteristic gamma-rays with a line at 511 keV. This gamma-ray emission has been observed with the spectrometer SPI on ESA's INTEGRAL observatory, confirming a puzzling morphology with bright emission from an extended bulge-like region, while emission from the di…
The XXL Survey. II. The bright cluster sample: catalogue and luminosity function
Smith, G. P.; Chiappetti, L.; Altieri, B. +40 more
Context. The XXL Survey is the largest survey carried out by the XMM-Newton satellite and covers a total area of 50 square degrees distributed over two fields. It primarily aims at investigating the large-scale structures of the Universe using the distribution of galaxy clusters and active galactic nuclei as tracers of the matter distribution. The…
Exposed water ice on the nucleus of comet 67P/Churyumov-Gerasimenko
Langevin, Y.; Bellucci, G.; Jaumann, R. +77 more
Although water vapour is the main species observed in the coma of comet 67P/Churyumov-Gerasimenko and water is the major constituent of cometary nuclei, limited evidence for exposed water-ice regions on the surface of the nucleus has been found so far. The absence of large regions of exposed water ice seems a common finding on the surfaces of many…
L‧CO/LFIR Relations with CO Rotational Ladders of Galaxies Across the Herschel SPIRE Archive
Conley, A.; Glenn, J.; Kamenetzky, J. +2 more
We present a catalog of all CO (J = 4-3 through J = 13-12), [C I], and [N II] lines available from extragalactic spectra from the Herschel SPIRE Fourier Transform Spectrometer (FTS) archive combined with observations of the low-J CO lines from the literature and from the Arizona Radio Observatory. This work examines the relationships between L
The central parsecs of M87: jet emission and an elusive accretion disc
Espada, D.; Prieto, M. A.; González-Martín, O. +2 more
We present the first simultaneous spectral energy distribution (SED) of M87 core at a scale of 0.4 arcsec ( ∼ 32 pc) across the electromagnetic spectrum. Two separate, quiescent, and active states are sampled that are characterized by a similar featureless SED of power-law form, and that are thus remarkably different from that of a canonical activ…