Search Publications
Probing deep photospheric layers of the quiet Sun with high magnetic sensitivity
Franz, M.; Schmidt, W.; Solanki, S. K. +31 more
Context. Investigations of the magnetism of the quiet Sun are hindered by extremely weak polarization signals in Fraunhofer spectral lines. Photon noise, straylight, and the systematically different sensitivity of the Zeeman effect to longitudinal and transversal magnetic fields result in controversial results in terms of the strength and angular …
Multiwavelength study of the flaring activity of Sagittarius A in 2014 February-April
Grosso, N.; Porquet, D.; Eckart, A. +8 more
Context. The supermassive black hole named Sgr A* is located at the dynamical center of the Milky Way. This closest supermassive black hole is known to have a luminosity several orders of magnitude lower than the Eddington luminosity. Flares coming from the Sgr A* environment can be observed in infrared, X-ray, and submillimeter wavelengths, but t…
Observations and analysis of a curved jet in the coma of comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lamy, P. L.; Lara, L. M. +48 more
Aims: We analyze the physical properties and dynamical origin of a curved jet of comet 67P/Churyumov-Gerasimenko that was observed repeatedly in several nucleus rotations starting on May 30 and persisting until early August, 2015.
Methods: We simulated the motion of dust grains ejected from the nucleus surface under the influence of the …
Multi-band morpho-Spectral Component Analysis Deblending Tool (MuSCADeT): Deblending colourful objects
Starck, J. -L.; Courbin, F.; Joseph, R.
We introduce a new algorithm for colour separation and deblending of multi-band astronomical images called MuSCADeT which is based on Morpho-spectral Component Analysis of multi-band images. The MuSCADeT algorithm takes advantage of the sparsity of astronomical objects in morphological dictionaries such as wavelets and their differences in spectra…
Hot prominence detected in the core of a coronal mass ejection: Analysis of SOHO/UVCS Lα and SOHO/LASCO visible-light observations
Heinzel, P.; Anzer, U.; Jejčič, S. +2 more
Context. The paper deals with the physics of erupting prominences in the core of coronal mass ejections (CME).
Aims: We determine the physical parameters of an erupting prominence embedded in the core of a CME using SOHO/UVCS hydrogen Lα and Lβ lines and SOHO/LASCO visible light observations. In particular we analyze the CME event observed on…
Firedec: a two-channel finite-resolution image deconvolution algorithm
Jablonka, P.; Meylan, G.; Courbin, F. +2 more
We present a two-channel deconvolution method that decomposes images into a parametric point-source channel and a pixelized extended-source channel. Based on the central idea of the deconvolution algorithm proposed by Magain et al. (1998, ApJ, 494, 472), the method aims at improving the resolution of the data rather than at completely removing the…
The rotation-metallicity relation for the Galactic disk as measured in the Gaia DR1 TGAS and APOGEE data
Cropper, Mark; Kawata, Daisuke; Allende Prieto, Carlos
Aims: Previous studies have found that the Galactic rotation velocity-metallicity (V-[Fe/H]) relations for the thin and thick disk populations show negative and positive slopes, respectively. The first Gaia data release includes the Tycho-Gaia Astrometric Solution (TGAS) information, which we use to analyze the V-[Fe/H] relation for a strictl…
HERschel Observations of Edge-on Spirals (HEROES). III. Dust energy balance study of IC 2531
Mosenkov, Aleksandr V.; De Looze, Ilse; Baes, Maarten +11 more
We investigate the dust energy balance for the edge-on galaxy IC 2531, one of the seven galaxies in the HEROES sample. We perform a state-of-the-art radiative transfer modelling based, for the first time, on a set of optical and near-infrared galaxy images. We show that by taking into account near-infrared imaging in the modelling significantly im…
Disentangling star formation and AGN activity in powerful infrared luminous radio galaxies at 1 < z < 4
Stern, D.; Seymour, N.; De Breuck, C. +5 more
High-redshift radio galaxies present signs of both star formation and AGN activity, making them ideal candidates to investigate the connection and coevolution of AGN and star formation in the progenitors of present-day massive galaxies. We make use of a sample of 11 powerful radio galaxies spanning 1 <z< 4 which have complete coverage of the…
The southern hemisphere of 67P/Churyumov-Gerasimenko: Analysis of the preperihelion size-frequency distribution of boulders ≥7 m
Bertaux, Jean-Loup; Da Deppo, Vania; Naletto, Giampiero +52 more
Aims: We calculate the size-frequency distribution of the boulders on the southern hemisphere of comet 67P Churyumov-Gerasimenko (67P), which was in shadow before the end of April 2015. We compare the new results with those derived from the northern hemisphere and equatorial regions of 67P, highlighting the possible physical processes that le…