Search Publications
Magnetic helicity accumulation and tilt angle evolution of newly emerging active regions
Zhang, H.; Yang, S.; Büchner, J.
Context: It has been known for years that there is a general dominance of negative (positive) helicity of active regions (ARs) in the northern (southern) solar hemisphere. For a better understanding of the role of helicity in the evolution of active regions, it is necessary to know more about the accumulation of helicity during the emergence of ac…
A forming disk at z ~ 0.6: collapse of a gaseous disk or major merger remnant?
Yang, Y.; Neichel, B.; Flores, H. +2 more
Context: Local spiral galaxies contain roughly two-thirds of the present-day stellar mass density. However, the formation process of disks is still poorly understood.
Aims: We present and analyze observations of J033241.88-274853.9 at z = 0.6679 to understand how its stellar disk was formed.
Methods: We combine multi-wavelength EIS, HST/AC…
The architecture of the GJ 876 planetary system. Masses and orbital coplanarity for planets b and c
Bean, J. L.; Seifahrt, A.
We present a combined analysis of previously published high-precision radial velocities and astrometry for the GJ 876 planetary system using a self-consistent model that accounts for the planet-planet interactions. Assuming the three planets so far identified in the system are coplanar, we find that including the astrometry in the analysis does no…
XMM-Newton observation of the persistent Be/NS X-ray binary pulsar RX J1037.5-5647 in a low luminosity state
Tiengo, A.; Mereghetti, S.; Sidoli, L. +2 more
The spectra of several X-ray binary pulsars display a clear soft excess, which in most cases can be described with a blackbody model, above the main power-law component. While in the high-luminosity sources it is usually characterized by low temperature (kT < 0.5 keV) and a large emission radius (R > 100 km), in the two persistent and low-lu…
High-precision multi-band measurements of the angular clustering of X-ray sources
Ebrero, J.; Carrera, F. J.; Watson, M. G. +2 more
Aims: We aim to study the large-scale structure of an extragalactic serendipitous X-ray survey with unprecedented accuracy thanks to the large statistics involved, and provide insight into the environment of AGN at the epochs when their space density declines (z ∼ 1{-}2).
Methods: In this paper we present the two-point angular correlation func…
Phase-resolved XMM-Newton observations of the massive WR+O binary WR 22
Gosset, E.; Nazé, Y.; Rauw, G. +2 more
Aims. To better understand the phenomenon of colliding winds in massive binary stars, we study the X-ray lightcurve of a WR+O system of the Carina region, a system well known for the high mass of its primary.
Methods: Phase-resolved X-ray observations of the massive WR+O binary system WR 22 were performed with the XMM-Newton facility. We obser…
Probing variability patterns of the Fe K line complex in bright nearby AGNs
Cappi, M.; Ponti, G.; Iwasawa, K. +5 more
Context: The unprecedented sensitivity of current X-ray telescopes allows the issue of the Fe K line complex variability patterns in bright, nearby AGNs to be addressed for the first time. These kinds of studies have the potential to map the accretion flow in the strong gravity regime of supermassive black holes.
Aims: We examine XMM-Newton ob…
Pulsations in the late-type Be star HD 50 209 detected by CoRoT
Auvergne, M.; Poretti, E.; Michel, E. +22 more
Context: The presence of pulsations in late-type Be stars is still a matter of controversy. It constitutes an important issue to establish the relationship between non-radial pulsations and the mass-loss mechanism in Be stars.
Aims: To contribute to this discussion, we analyse the photometric time series of the B8IVe star HD 50 209 observed by…
Broad-band properties of the hard X-ray cataclysmic variables IGR J00234+6141 and 1RXS J213344.1+510725
Mukai, K.; de Martino, D.; Terada, Y. +5 more
Context: A significant number of cataclysmic variables have been detected as hard X-ray sources in the INTEGRAL survey, most of them of the magnetic intermediate polar type.
Aims: We present a detailed X-ray broad-band study of two new sources, IGR J00234+6141 and 1RXS J213344.1+510725, that allow us to classify them as secure members of the i…
Solar transition region above sunspots
Marsch, E.; Curdt, W.; Teriaca, L. +2 more
Aims: We study the transition region (TR) properties above sunspots and the surrounding plage regions, by analyzing several sunspot reference spectra obtained by the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) instrument in March 1999 and November 2006.
Methods: We compare the SUMER spectra observed in the umbra, penumbra, plag…