Search Publications
RR Lyrae stars in the southern globular cluster NGC 362
Derekas, A.; Kiss, L. L.; Csák, B. +3 more
Aims:NGC 362 is a bright southern globular cluster in the foreground of the Small Magellanic Cloud (SMC), for which no extensive variability survey has ever been done. Finding regularly pulsating RR Lyrae stars in the cluster can lead to improved metallicity and distance estimates of the system, while other types of variable objects may be used to…
Structure detection in the D1 CFHTLS deep field using accurate photometric redshifts: a benchmark
Valtchanov, I.; Ilbert, O.; Pierre, M. +9 more
Aims:We investigate structures in the D1 CFHTLS deep field to test the method that will be applied to generate homogeneous samples of clusters and groups of galaxies in order to constrain the cosmology and detailed physics of groups and clusters.
Methods: An adaptive kernel technique was applied to galaxy catalogues. This technique needs none …
2003-2005 INTEGRAL and XMM-Newton observations of 3C 273
Walter, R.; Page, K. L.; Staubert, R. +9 more
Aims:The aim of this paper is to study the evolution of the broadband spectrum of one of the brightest and nearest quasars 3C 273.
Methods: We analyze the data obtained during quasi-simultaneous INTEGRAL and XMM-Newton monitoring of the blazar 3C 273 in 2003-2005 in the UV, X-ray and soft γ-ray bands and study the results in the context of the…
Water vapor and silicon monoxide maser observations in the protoplanetary nebula OH 231.8+4.2
Sánchez Contreras, C.; Alcolea, J.; Bujarrabal, V. +2 more
Context: OH 231.8+4.2 is a well studied preplanetary nebula (pPN) around a binary stellar system that shows a remarkable bipolar outflow.
Aims: To study the structure and kinematics of the inner 10-80 AU nebular regions probed by SiO and H2O maser emission, where the agents of wind collimation are expected to operate, in order to gain insights…
XMM-Newton observations of the Lockman Hole. V. Time variability of the brightest AGN
Page, M. J.; Barcons, X.; Fabian, A. C. +4 more
This paper presents the results of a study of X-ray spectral and flux variability on time scales from months to years, of the 123 brightest objects (including 46 type-1 AGN and 28 type-2 AGN) detected with XMM-Newton in the Lockman Hole field. We detected flux variability with a significance ≥3σ in ~50% of the objects, including 68 ± 11% and 48 ± …
Five years of SGR 1900+14 observations with BeppoSAX
Tiengo, A.; Mereghetti, S.; Sidoli, L. +3 more
We present a systematic analysis of all the BeppoSAX data of the soft gamma-ray repeater SGR 1900+14: these observations allowed us to study the long term properties of the source quiescent emission. In the observation carried out before the 1998 giant flare the spectrum in the 0.8-10 keV energy range was harder and there was evidence for a 20-150…
XMM-Newton observation of the deep minimum state of PG 2112+059. A spectrum dominated by reflection from the accretion disk?
Clavel, J.; Guainazzi, M.; Schartel, N. +5 more
Context: Highly ionised absorbers and the frequent occurrence of relativistically broad iron fluorescence lines characterize the 0.2-10 keV spectra of (soft) X-ray weak quasars.
Aims: We constrain the physical conditions of the absorber and the broad iron line of the X-ray weak quasar
Photospheric flows around a quiescent filament
Bommier, V.; Schmieder, B.; Rondi, S. +7 more
Context: The horizontal photospheric flows below and around a filament are one of the components in the formation and evolution of filaments. Few studies exist because they require multiwalength time sequences at high spatial resolution.
Aims: Our objective is to measure the horizontal photospheric flows associated with the evolution and erupt…
Interaction of magnetic field systems leading to an X1.7 flare due to large-scale flux tube emergence
Bommier, V.; Schmieder, B.; Li, H. +1 more
Aims:The aim of this paper is to understand the magnetic configuration and evolution of an active region, which permitted an X1.7 flare to be observed during the decaying phase of a long-duration X1.5 flare on 2005 September 13.
Methods: We performed a multi-wavelength analysis using data from space-borne (Solar and Heliospheric Observatory (S…
The velocity structure of moving magnetic feature pairs around sunspots: support for the U-loop model
Woch, J.; Solanki, S. K.; Zhang, J. +1 more
Context: Moving magnetic feature (MMF) pairs are among the most significant fine-scale structures around sunspots. Several models have been proposed to interpret the origin and evolution of MMF pairs. These models provide important clues to understanding MMF pairs.
Aims: We present an analysis of the velocity structure of MMF pairs in order to…