Search Publications
Optical constants of refractory oxides at high temperatures. Mid-infrared properties of corundum, spinel, and α-quartz, potential carriers of the 13 µm feature
Mutschke, H.; Zeidler, S.; Posch, Th.
Context. Many cosmic dust species, among them refractory oxides, form at temperatures higher than 300 K. Nevertheless, most astrophysical studies are based on the room-temperature optical constants of solids, such as corundum and spinel. A more realistic approach is needed for these materials, especially in the context of modeling late-type stars.…
Kinematics of massive star ejecta in the Milky Way as traced by 26Al
Wang, Wei; Gerhard, Ortwin; Diehl, Roland +5 more
Context. Massive stars form in groups and their winds and supernova explosions create superbubbles up to kpc in size. The fate of their ejecta is of vital importance for the dynamics of the interstellar medium, for chemical evolution models, and the chemical enrichment of galactic halos and the intergalactic medium. However, ejecta kinematics and …
The shape of broad-line profiles in active galactic nuclei
Kollatschny, W.; Zetzl, M.
Aims: We present a study of the broad optical/UV emission line profiles in active galactic nuclei (AGN) to get information on the dominant velocity components (turbulence, rotation, etc.) in the central broad-line region (BLR).
Methods: We introduce line broadening simulations of emission line profiles and compare these results with the …
The spectroscopic evolution of the γ-ray emitting classical nova Nova Mon 2012. I. Implications for the ONe subclass of classical novae
Cheung, C. C.; Shore, S. N.; Starrfield, S. +4 more
Aims: Among the classical novae, the ONe subgroup, distinguished by their large overabundance of neon, are thought to occur on the most massive white dwarfs. Nova Mon 2012 was the first classical nova to be detected as a high energy γ-ray transient, by Fermi-LAT, before its optical discovery. The first optical spectra obtained about 55 days a…
Beginning of activity in 67P/Churyumov-Gerasimenko and predictions for 2014-2015
Tubiana, C.; Snodgrass, C.; Bramich, D. M. +3 more
Context. Comet 67P/Churyumov-Gerasimenko was selected in 2003 as the new target of the Rosetta mission. It has since been the subject of a detailed campaign of observations to characterise its nucleus and activity.
Aims: We present previously unpublished data taken around the start of activity of the comet in 2007/8, before its last perihelio…
Spectroscopic FIR mapping of the disk and galactic wind of M 82 with Herschel-PACS
Lutz, D.; Genzel, R.; Poglitsch, A. +11 more
Context. We present maps of the main cooling lines of the neutral atomic gas ([OI] at 63 and 145 µm and [CII] at 158 µm) and in the [OIII] 88 µm line of the starburst galaxy M 82, carried out with the PACS spectrometer on board the Herschel satellite.
Aims: Our aim is to study the nature of the neutral atomic gas of M 82 and…
ALMA observations of the Red Rectangle, a preliminary analysis
Sánchez Contreras, C.; Alcolea, J.; Santander-García, M. +5 more
Aims: We aim to study equatorial disks in rotation and axial outflows in post-AGB objects so as to disclose the formation and shaping mechanisms in planetary nebulae. So far, both disks and outflows have not been observed simultaneously.
Methods: We obtained high-quality ALMA observations of 12CO and 13CO J = 3-2 an…
Waterfalls around protostars. Infall motions towards Class 0/I envelopes as probed by water
van Dishoeck, E. F.; Bruderer, S.; Kristensen, L. E. +4 more
Context. For stars to form, material must fall inwards from core scales through the envelope towards the central protostar. While theories of how this takes place have been around for some time, the velocity profile around protostars is poorly constrained. The combination of observations in multiple transitions of a tracer which is sensitive to ki…
The CORALIE survey for southern extrasolar planets. XVII. New and updated long period and massive planets
Alonso, R.; Queloz, D.; Sahlmann, J. +24 more
Context. Since 1998, a planet-search program around main sequence stars within 50 pc in the southern hemisphere has been carried out with the CORALIE echelle spectrograph at La Silla Observatory.
Aims: With an observing time span of more than 14 years, the CORALIE survey is now able to unveil Jovian planets on Jupiter's period domain. This gr…
Returning magnetic flux in sunspot penumbrae
Ruiz Cobo, B.; Asensio Ramos, A.
Aims: We study the presence of reversed polarity magnetic flux in sunspot penumbra.
Methods: We applied a new regularized method to deconvolve spectropolarimetric data observed with the spectropolarimeter SP onboard Hinode. The new regularization is based on a principal component decomposition of the Stokes profiles. The resulting Stokes…