Search Publications
Frequency drifts of 3-min oscillations in microwave and EUV emission above sunspots
Nakariakov, V. M.; Shibasaki, K.; Yan, Y. +3 more
Aims: We analysed 3-min oscillations of microwave and extreme ultraviolet (EUV) emission generated at different heights of a sunspot atmosphere, studied the amplitude and frequency modulation of the oscillations, and its relationship with the variation of the spatial structure of the oscillations.
Methods: High-resolution data obtained w…
X-ray variations in the inner accretion flow of dwarf novae
Revnivtsev, M.; Balman, Ş.
Aims: We study the inner disk structure of dwarf novae (DNe; i.e., nonmagnetic cataclysmic variables).
Methods: We performed power spectral analysis of the X-ray light curves obtained using the Rossi X-ray Timing Explorer (RXTE) and X-ray Multi-mirror Mission (XMM-Newton) data. We fit the power spectra with a simple model that describes …
The ultracool dwarf DENIS-P J104814.7-395606. Chromospheres and coronae at the low-mass end of the main-sequence
Schmitt, J. H. M. M.; Leone, F.; Cupani, G. +8 more
Context. Several diagnostics ranging from the radio to the X-ray band are suitable for investigating the magnetic activity of late-type stars. Empirical connections between the emission at different wavelengths place constraints on the nature and efficiency of the emission mechanism and the physical conditions in different atmospheric layers. The …
The Herschel Virgo Cluster Survey. XI. Environmental effects on molecular gas and dust in spiral disks
Ciesla, L.; Bianchi, S.; Fritz, J. +19 more
Aims: We investigate the dust-to-gas mass ratio and the environmental effects on the various components of the interstellar medium for a spatially resolved sample of Virgo spirals.
Methods: We have used the IRAM-30 m telescope to map over their full extent NGC 4189, NGC 4298, NGC 4388, and NGC 4299 in the 12CO(1-0) and the
Supernova remnants and candidates detected in the XMM-Newton M 31 large survey
Stiele, H.; Pietsch, W.; Haberl, F. +5 more
Context. We present the analysis of supernova remnants (SNRs) and candidates in M 31 identified in the XMM-Newton large programme survey of M 31. Supernova remnants are among the brightest X-ray sources in a galaxy. They are good indicators of the recent star-formation activities of galaxies and the interstellar environment in which they evolve. <…
A peculiar class of debris disks from Herschel/DUNES. A steep fall off in the far infrared
Krivov, A. V.; Eiroa, C.; Löhne, T. +21 more
Context. The existence of debris disks around old main sequence stars is usually explained by continuous replenishment of small dust grains through collisions from a reservoir of larger objects.
Aims: We present photometric data of debris disks around HIP 103389 (HD 199260), HIP 107350 (HN Peg, HD 206860), and HIP 114948 (HD 219482), obtained…
A journey from the outskirts to the cores of groups. I. Color- and mass-segregation in 20K-zCOSMOS groups
Finoguenov, A.; Kneib, J. -P.; Cimatti, A. +49 more
Context. Studying theevolution of galaxies located within groups may have important implications for our understanding of the global evolution of the galaxy population as a whole. The fraction of galaxies bound in groups at z ~ 0 is as high as 60% and therefore any mechanism (among the many suggested) that could quench star formation when a galaxy…
Searching for heavily obscured post-AGB stars and planetary nebulae. II. Near-IR observations of IRAS sources
Guerrero, M. A.; Ramos-Larios, G.; Gómez, J. F. +2 more
The most massive AGB stars are expected to result in heavily obscured post-AGB stars, proto-PNe and PNe with highly axisymmetric morphologies. To investigate this evolutionary connection, we have selected a sample of 165 presumably obscured IRAS post-AGB star and PN candidates and obtained near-IR JHK images for 164 of them. These images, in conju…
Quasi full-disk maps of solar horizontal velocities using SDO/HMI data
Roudier, Th.; Malherbe, J. M.; Gizon, L. +6 more
Aims: For the first time, the motion of granules (solar plasma on the surface on scales larger than 2.5 Mm) has been followed over the entire visible surface of the Sun, using SDO/HMI white-light data.
Methods: Horizontal velocity fields are derived from image correlation tracking using a new version of the coherent structure tracking al…
BD-22°3467, a DAO-type star exciting the nebula Abell 35
Rauch, T.; Werner, K.; Kruk, J. W. +2 more
Context. Spectral analyses of hot, compact stars with non-local thermodynamical equilibrium (NLTE) model-atmosphere techniques allow the precise determination of photospheric parameters such as the effective temperature (Teff), the surface gravity (log g), and the chemical composition. The derived photospheric metal abundances are cruci…