Search Publications
The deeply obscured AGN of NGC 4945. I. Spitzer-IRS maps of [Ne V], [Ne II], H2 0-0 S(1), S(2), and other tracers
Smith, J. D.; Spaans, M.; Spoon, H. W. W. +1 more
Context. The nearly edge-on galaxy NGC 4945 is one of the closest galaxies where an AGN and starburst coexist, and is one of the brightest sources at 100 keV. Near and mid-infrared spectroscopy have shown very strong obscuration of its central region, rivaled only in strength by some of the most deeply obscured ULIRGs.
Aims: We determine the …
The metal contents of two groups of galaxies
Kaastra, J. S.; de Plaa, J.; de Vries, C. P. +4 more
Context. The hot gas in clusters and groups of galaxies is continuously being enriched with metals from supernovae and stars. It is well established that the enrichment of the gas with elements from oxygen to iron is mainly caused by supernova explosions. The origins of nitrogen and carbon are still being debated. Possible candidates include massi…
Near-IR search for lensed supernovae behind galaxy clusters. III. Implications for cluster modeling and cosmology
Amanullah, R.; Goobar, A.; Mörtsell, E. +6 more
Context. Massive galaxy clusters at intermediate redshifts act as gravitational lenses that can magnify supernovae (SNe) occurring in background galaxies.
Aims: We assess the possibility of using lensed SNe to constraint the mass models of galaxy clusters and the Hubble parameter at high redshift.
Methods: Owing to the standard candle na…
Solar winds along curved magnetic field lines
Chen, Y.; Li, B.; Xia, L. D.
Context. Both remote-sensing measurements using the interplanetary scintillation (IPS) technique and in-situ measurements by the Ulysses spacecraft show a bimodal structure for the solar wind at solar minimum conditions. At present it still remains to address why the fast wind is fast and the slow wind is slow. While a robust empirical correlation…
Synthetic differential emission measure curves of prominence fine structures. II. The SoHO/SUMER prominence of 8 June 2004
Heinzel, P.; Vial, J. -C.; Anzer, U. +2 more
Aims: This study is the first attempt to combine the prominence observations in Lyman, UV, and EUV lines with the determination of the prominence differential emission measure derived using two different techniques, one based on the inversion of the observed UV and EUV lines and the other employing 2D non-LTE prominence fine-structure modelin…
Extended dust shell of the carbon star U Hydrae observed with AKARI
Izumiura, H.; Matsunaga, N.; Tanabé, T. +8 more
Context. Low- to intermediate-mass stars lose a significant fraction of their mass while they are on the asymptotic giant branch (AGB). This mass loss is considered to determine the final stages of their evolution. The material ejected from the stellar photosphere forms a circumstellar envelope in its surroundings. Layers of circumstellar envelope…
Astrometry with the MCAO instrument MAD. An analysis of single-epoch data obtained in the layer-oriented mode
Kürster, M.; Rix, H. -W.; Arcidiacono, C. +2 more
Context. Current instrument developments at the largest telescopes worldwide involve the installation of multi-conjugated adaptive optics (MCAO) modules. The large field of view and more uniform correction provided by these systems is not only highly beneficial for photometric studies but also for astrometric analysis of, e.g., large dense cluster…
Structure of the outer layers of cool standard stars
Blommaert, J. A. D. L.; Eriksson, K.; Dowell, C. D. +6 more
Context. Among late-type red giants, an interesting change occurs in the structure of the outer atmospheric layers as one moves to later spectral types in the Hertzsprung-Russell diagram: a chromosphere is always present, but the coronal emission diminishes and a cool massive wind steps in.
Aims: Where most studies have focussed on short-wave…
CoRoT light curves of Blazhko RR Lyrae stars. Evidence of a strong correlation between phase and amplitude modulations of CoRoT ID 0105288363
Auvergne, M.; Baglin, A.; Bono, G. +4 more
Context. The CoRoT - Convection Rotation and planetary Transits - space mission provides a unique opportunity to monitor RR Lyrae stars with excellent time-sampling, unprecedented photometric precision, and a long time base of 150 days.
Aims: The pulsation characteristics of RR Lyrae stars rely on robust physics, but we still lack a firm quan…
Long-period oscillations of millimeter emission above sunspots
Riehokainen, A.; Kallunki, J.; Smirnova, V. +2 more
Aims: The investigation of long quasi-periodic oscillations in sunspots/active regions based on millimeter radio data was the main goal of this work.
Methods: Data from simultaneous monitoring observations of solar active regions at 37 GHz and 93 GHz at two different ground-based radio telescopes were obtained. We analyzed them with the …