Search Publications
Dissecting galaxies: spatial and spectral separation of emission excited by star formation and AGN activity
Kewley, Lisa J.; Juneau, Stéphanie; Davies, Rebecca L. +13 more
The optical spectra of Seyfert galaxies are often dominated by emission lines excited by both star formation and active galactic nucleus (AGN) activity. Standard calibrations (such as for the star formation rate) are not applicable to such composite (mixed) spectra. In this paper, we describe how integral field data can be used to spectrally and s…
A first assessment of the strength of cometary particles collected in-situ by the COSIMA instrument onboard ROSETTA
Langevin, Yves; Della Corte, Vincenzo; Hornung, Klaus +9 more
Soon after the arrival of the ROSETTA spacecraft at Comet 67/P Churyumov-Gerasimenko the onboard instrument COSIMA ("Cometary Secondary Ion Mass Analyzer") collected a large number of cometary dust particles on targets from gold black of thickness between 10 and 30 µm. Inspection by its camera subsystem revealed that many of them consist of …
An observational study of dust nucleation in Mira (o Ceti). I. Variable features of AlO and other Al-bearing species
Menten, K. M.; Müller, H. S. P.; Patel, N. A. +8 more
Context. Dust is efficiently produced by cool giant stars, but the condensation of inorganic dust is poorly understood. Observations of key aluminum bearing molecules around evolved stars has enabled us to investigate the nucleation of alumina (Al2O3) dust in the gas.
Aims: We aim to identify and characterize aluminum be…
A hard X-ray view of the soft excess in AGN
Ricci, Claudio; Paltani, Stéphane; Boissay, Rozenn
An excess of X-ray emission below 1 keV, called soft excess, is detected in a large fraction of Seyfert 1-1.5s. The origin of this feature remains debated, as several models have been suggested to explain it, including warm Comptonization and blurred ionized reflection. In order to constrain the origin of this component, we exploit the different b…
Spectral analysis of the XMM-Newton data of GX 339-4 in the low/hard state: disc truncation and reflection
Zdziarski, Andrzej A.; Basak, Rupal
We analyse all available observations of GX 339-4 by XMM-Newton in the hard spectral state. We jointly fit the spectral data by Comptonization and the currently best reflection code, relxill. We consider in detail a contribution from a standard blackbody accretion disc, testing whether its inner radius can be set equal to that of the reflector. Ho…
Globules and pillars in Cygnus X. I. Herschel far-infrared imaging of the Cygnus OB2 environment
Hill, T.; White, G. J.; André, Ph. +21 more
The radiative feedback of massive stars on molecular clouds creates pillars, globules and other features at the interface between the H II region and molecular cloud. Optical and near-infrared observations from the ground as well as with the Hubble or Spitzer satellites have revealed numerous examples of such cloud structures. We present here Hers…
An Enhanced Rate of Tidal Disruptions in the Centrally Overdense E+A Galaxy NGC 3156
Stone, Nicholas C.; van Velzen, Sjoert
Time domain optical surveys have discovered roughly a dozen candidate stellar tidal disruption flares in the last five years, and future surveys like the Large Synoptic Survey Telescope will likely find hundreds to thousands more. These tidal disruption events (TDEs) present an interesting puzzle: a majority of the current TDE sample is hosted by …
RPC observation of the development and evolution of plasma interaction boundaries at 67P/Churyumov-Gerasimenko
Coates, A. J.; Kallio, E.; Glassmeier, K. -H. +32 more
One of the primary objectives of the Rosetta Plasma Consortium, a suite of five plasma instruments on-board the Rosetta spacecraft, is to observe the formation and evolution of plasma interaction regions at the comet 67P/Churyumov-Gerasimenko (67P/CG). Observations made between 2015 April and 2016 February show that solar wind-cometary plasma inte…
The X-ray emission of the γ Cassiopeiae stars
Smith, Myron A.; Motch, C.; Lopes de Oliveira, R.
Long considered as the ;odd man out; among X-ray emitting Be stars, γ Cas (B0.5e IV) is now recognized as the prototype of a class of stars that emit hard thermal X-rays. Our classification differs from the historical use of the term ; γ Cas stars; defined from optical properties alone. The luminosity output of this class contributes significantly…
Water and carbon dioxide distribution in the 67P/Churyumov-Gerasimenko coma from VIRTIS-M infrared observations
Erard, S.; Crovisier, J.; Piccioni, G. +14 more
Context. Studying the coma environment of comet 67P/Churyumov-Gerasimenko (67P) is one of the primary scientific goals of the VIRTIS experiment on the ESA Rosetta mission.
Aims: The distribution and variability of water vapour and carbon dioxide in the comet's coma are needed to estimate their production rate, abundances in the nucleus, and t…