Search Publications
2D radiative-magnetohydrostatic model of a prominence observed by Hinode, SoHO/SUMER and Meudon/MSDP
Heinzel, P.; Schmieder, B.; Schwartz, P. +2 more
Aims: Prominences observed by Hinode show very dynamical and intriguing structures. To understand the mechanisms that are responsible for these moving structures, it is important to know the physical conditions that prevail in fine-structure threads. In the present work we analyse a quiescent prominence with fine structures, which exhibits dy…
Mid-infrared interferometric monitoring of evolved stars. The dust shell around the Mira variable RR Aquilae at 13 epochs
Wittkowski, M.; Ohnaka, K.; Karovicova, I. +3 more
Aims: We present a unique multi-epoch infrared interferometric study of the oxygen-rich Mira variable RR Aql in comparison to radiative transfer models of the dust shell. We investigate flux and visibility spectra at 8-13 µm with the aim of better understanding the pulsation mechanism and its connection to the dust condensation sequence…
Evolution of microflares associated with bright points in coronal holes and in quiet regions
Curdt, W.; Innes, D. E.; Teriaca, L. +1 more
Aims: We aim to find similarities and differences between microflares at coronal bright points found in quiet regions and coronal holes, and to study their relationship with large scale flares.
Methods: Coronal bright points in quiet regions and in coronal holes were observed with Hinode/EIS using the same sequence. Microflares associate…
The X-ray spectral signatures from the complex circumnuclear regions in the Compton thick AGN NGC 424
Bianchi, S.; Piconcelli, E.; Iwasawa, K. +4 more
Aims: Most of our knowledge of the circumnuclear matter in Seyfert galaxies is based on the X-ray spectra of the brightest Compton-thick Seyfert 2 galaxies. The complete obscuration of the nuclear radiation in these sources allows us to study all the components arising from reprocessing of the primary continuum in the circumnuclear matter in …
Detailed study of the X-ray and optical/UV orbital ephemeris of X1822-371
Robba, N. R.; Papitto, A.; Burderi, L. +4 more
Aims: Recent studies of the optical/UV and X-ray ephemerides of X1822-371 have found some discrepancies in the value of the orbital period derivative. Because of the importance of this value in constraining the system evolution, we comprehensively analyse all the available optical/UV/X eclipse times of this source to investigate the origin of…
X-ray detected infrared excess AGN in the Chandra deep fields: a moderate fraction of Compton-thick sources
Comastri, A.; Georgantopoulos, I.; Rovilos, E. +2 more
We examine the properties of the X-ray-detected infrared excess AGN or dust obscured galaxies (DOGs) in the Chandra deep fields (CDFs). We find 26 X-ray-detected sources that obey the 24 µm to R-band flux ratio criterion f24/fR > 1000. These are at a median redshift of 2.3, while their IR luminosities are above 10
The two components of the evolved massive binary LZ Cephei. Testing the effects of binarity on stellar evolution
Bouret, J. -C.; Martins, F.; Donati, J. -F. +2 more
Aims: We present an in-depth study of the two components of the binary system LZ Cep to constrain the effects of binarity on the evolution of massive stars.
Methods: We analyzed a set of high-resolution, high signal-to-noise ratio optical spectra obtained over the orbital period of the system to perform a spectroscopic disentangling and …
HST/ACS color-magnitude diagrams of candidate intermediate-age M 31 globular clusters. The role of blue horizontal branches
Bellazzini, M.; Galleti, S.; Federici, L. +3 more
We present deep (V ≃ 28.0) BV photometry obtained with the wide field channel of the Advanced Camera for Surveys on board HST for four M 31 globular clusters that were identified as candidate intermediate-age (age ~ 1-9 Gyr) by various authors, based on their integrated spectra and/or broad/intermediate-band colors. Two of them (B292 and B350) dis…
A multi-epoch XMM-Newton campaign on the core of the massive Cygnus OB2 association
Rauw, G.
Context. Cyg OB2 is one of the most massive associations of O-type stars in our Galaxy. Despite the large interstellar reddening towards Cyg OB2, many studies, spanning a wide range of wavelengths, have been conducted to more clearly understand this association. X-ray observations provide a powerful tool to overcome the effect of interstellar abso…
Solar total irradiance in cycle 23
Solanki, S. K.; Schmutz, W.; Krivova, N. A.
Context. The most recent minimum of solar activity was deeper and longer than the previous two minima as indicated by different proxies of solar activity. This is also true for the total solar irradiance (TSI) according to the PMOD composite.
Aims: The apparently unusual behaviour of the TSI has been interpreted as evidence against solar surf…