Search Publications
The color dependent morphology of the post-AGB star HD 161796
Waters, L. B. F. M.; Jeffers, S. V.; Min, M. +3 more
Context. Many protoplanetary nebulae show strong asymmetries in their surrounding shells, pointing to asymmetries during the mass loss phase. Questions concerning the origin and the onset of deviations from spherical symmetry are important for our understanding of the evolution of these objects. Here we focus on the circumstellar shell of the post…
Optical monitoring of extragalactic sources for linking the ICRF and the future Gaia celestial reference frame. I. Variability of ICRF sources
Bouquillon, S.; Lambert, S.; Souchay, J. +8 more
Context. The astrometric mission Gaia of the European Space Agency is scheduled to be launched in 2013. It will provide an astrometric catalog of 500 000 extragalactic sources that could be the basis of a new optical reference frame after the Hipparcos satellite one. On the other hand, the current International Celestial Reference Frame (ICRF) is …
Cold fronts and metal anisotropies in the X-ray cool core of the galaxy cluster Zw 1742+3306
Gastaldello, F.; Ettori, S.; Gaspari, M. +5 more
Context. In recent years, our understanding of the cool cores of galaxy clusters has changed. Once thought to be relatively simple places where gas cools and flows towards the centre, now they are believed to be very dynamic places where heating from the central active galactic nucleus (AGN) and cooling, as inferred from active star formation, mol…
The evolution of the jet from Herbig Ae star HD 163296 from 1999 to 2011
Günther, H. M.; Schneider, P. C.; Li, Z. -Y.
Young A and B stars, the so-called Herbig Ae/Be stars (HAeBe), are surrounded by active accretion disks and drive outflows. We study the jet HH 409, which is launched from the HAeBe star HD 163296, using new and archival observations from Chandra and HST/STIS. In X-rays we can show that the central source is not significantly extended. The approac…
High-precision CoRoT space photometry and fundamental parameter determination of the B2.5V star HD 48977
Auvergne, M.; Baudin, F.; Michel, E. +10 more
We present the CoRoT light curve of the bright B2.5V star HD 48977 observed during a short run of the mission in 2008, as well as a high-resolution spectrum gathered with the HERMES spectrograph at the Mercator telescope. We use several time series analysis tools to explore the nature of the variations in the light curve. We performed a detailed a…
X-ray observations of the Compton-thick Seyfert 2 galaxy, NGC 5643
Bianchi, S.; Guainazzi, M.; Matt, G. +3 more
We present results from a ~55 ks long XMM-Newton observation of the obscured AGN, NGC 5643, performed in July 2009. A previous, shorter (about 10 ks) XMM-Newton observation in February 2003 had left two major issues open, the nature of the hard X-ray emission (Compton-thin vs. Compton-thick) and of the soft X-ray excess (photoionized vs. collision…
Tully-Fisher analysis of the multiple cluster system Abell 901/902
Gray, M. E.; Wolf, C.; Barden, M. +7 more
Context.
Aims: We derive rotation curves from optical emission lines of 182 disc galaxies (96 in the cluster and 86 in the field) in the region of Abell 901/902 located at z ~ 0.165. We continue the kinematic analysis presented in a previous paper. Here, we focus on the analysis of B-band and stellar-mass Tully-Fisher relations. We examine po…
The twofold debris disk around HD 113766 A. Warm and cold dust as seen with VLTI/MIDI and Herschel/PACS
Absil, O.; Augereau, J. -C.; Henning, Th. +5 more
Context. Warm debris disks are a sub-sample of the large population of debris disks, and display excess emission in the mid-infrared. Around solar-type stars, very few objects (~2% of all debris disks) show emission features in mid-IR spectroscopic observations that are attributed to small, warm silicate dust grains. The origin of this warm dust c…
Herschel imaging and spectroscopy of the nebula around the luminous blue variable star WRAY 15-751
Magain, P.; Nazé, Y.; Groenewegen, M. A. T. +5 more
We have obtained far-infrared Herschel-PACS imaging and spectroscopic observations of the nebular environment of the luminous blue variable (LBV) WRAY 15-751. The far-infrared images clearly show that the main, dusty nebula is a shell of radius 0.5 pc and width 0.35 pc extending outside the Hα nebula. Furthermore, these images reveal a second, big…
A portrait of the extreme solar system object 2012 DR30
Pál, A.; Lellouch, E.; Müller, T. G. +15 more
2012 DR30 is a recently discovered solar system object on a unique orbit, with a high eccentricity of 0.9867, a perihelion distance of 14.54 AU, and a semi-major axis of 1109 AU, in this respect outscoring the vast majority of trans-Neptunian objects (TNOs). We performed Herschel/PACS and optical photometry to uncover the sizeand albedo…