Search Publications
Precession from Hipparcos and FK5 proper motions compared with current values: Reasons for discrepancies
Walter, H. G.; Hering, R.
The comparison of Hipparcos and FK5 proper motions points to an inconsistency with the correction, Δ p, of the luni-solar precession derived from VLBI and LLR observations with unprecedented accuracy. An attempt is made to explain this inconsistency of approximately -1.3 mas/yr by rotational offsets of the Hipparcos and FK5 proper motion systems. …
Large-scale dynamics and polarities of magnetic structures
Meunier, N.
A large data set of MDI magnetograms is studied in order to analyse the dependence of the global dynamics of magnetic structures on their polarity. Two complementary techniques (feature tracking and correlation tracking) are used to determine the differential rotation and meridional circulation. A faster rotation of leading polarity structures is …
Accurate photometric light curves of the lensed components of Q2237+0305 derived with an optimal image subtraction technique: Evidence for microlensing in image A
Surdej, J.; Libbrecht, C.; Moreau, O. +1 more
Using an optimal image subtraction technique, we have derived the V and R light curves of the four lensed QSO components of Q2237+0305 from the monitoring CCD frames obtained by the GLITP collaboration with the 2.6 m NOT telescope in 1999/2000 (Alcalde et al. 2002). We give here a detailed account of the data reduction and analysis and of the erro…
Outbursts on normal stars. FH Leo misclassified as a novalike variable
Santos, N. C.; Schmidtobreick, L.; Israelian, G. +1 more
We present high resolution spectroscopy of the common proper motion system FH Leo (components HD 96273 and BD+07 2411B), which has been classified as a novalike variable due to an outburst observed by Hipparcos, and we present and review the available photometry. We show from our spectra that neither star can possibly be a cataclysmic variable, in…
Systematic motions in the galactic plane found in the Hipparcos catalogue using Herschel's Method
Vieira, K.; Abad, C.
Two motions in the galactic plane have been detected and characterized, based on the determination of a common systematic component in Hipparcos catalogue proper motions. The procedure is based only on positions, proper motions and parallaxes, plus a special algorithm which is able to reveal systematic trends. Our results come from two stellar sam…
Cosmic Shear from STIS pure parallels. III. Analysis of Cycle 9 pure parallels
Fosbury, R. A. E.; Schneider, P.; Erben, T. +4 more
Following the detection of a cosmic shear signal at the 30'' scale using archival parallel data from the STIS CCD camera onboard HST in the previous paper of this series, we analyzed a larger data set obtained from an HST GO pure parallel program. Although this data set is considerably larger than the one analyzed previously, we do not obtain a si…
The X-ray activity of the slowly rotating G giant δ CrB
Gondoin, P.
δ CrB is a single G giant whose distinctive characteristics include an X-ray luminosity exceptionally high for a slowly rotating star. δ CrB was observed in March 2003 by the {XMM{-}Newton} observatory. The X-ray spectra of δ CrB are described by a MEKAL plasma model with two components at 6.5 ×106 K and 107 K. Series of line…
The peculiar galaxy Mkn 298 revisited with integral field spectroscopy
Ciroi, S.; Rafanelli, P.; Radovich, M. +3 more
Spectroscopic and imaging data of the peculiar galaxy Mkn 298 are presented. Narrow-band Hα and broad-band R images are used to study the star formation rate in the galaxy and its morphology, which is typical of a merging system. Long-slit and integral field spectra are used to assess the kinematics of gas and stars, and the nature of the ionizing…
Discovery of multiple ultra-luminous X-ray sources in the galaxy KUG 0214-057
Akiyama, M.; Watson, M. G.; Roberts, T. P. +1 more
We report the serendipitous discovery of several unresolved X-ray sources lying in the prominent spiral arms of the galaxy
XMM-Newton observation of 4U 1543-475: The X-ray spectrum of a stellar-mass black-hole at low luminosity
Mereghetti, S.; La Palombara, N.
We report the results of an observation of the galactic black-hole binary 4U 1543-475 performed by XMM-Newton on 2002 August 18, about two months after the start of an outburst detected by RXTE. Despite the relatively low flux of the source, corresponding to a luminosity LX∼ 4× 1034 erg s-1∼ 10-5 LE…