Search Publications

Strange magnification pattern in the large separation lens SDSS J1004+4112 from optical to X-rays

Christensen, L.; Schwope, A.; Wisotzki, L. +1 more

We present simultaneous XMM-Newton UV and X-ray observations of the quadruply lensed quasar SDSS J1004+4112 (RBS 825). Simultaneously with the XMM-Newton observations we also performed integral field spectroscopy on the two closest lens images A and B using the Calar Alto PMAS spectrograph. In X-rays the widel…

Globular cluster systems of six shell galaxies

Peletier, R. F.; Balcells, M.; Valentijn, E. A. +2 more

Context: .Shells in Elliptical Galaxies are faint, sharp-edged features, believed to provide evidence of a recent (∼ 0.5 - 2 × 10⁹ years ago) merger event. We analyse the Globular Cluster (GC) systems of six shell elliptical galaxies, to examine the effects of mergers upon the GC formation history.
Aims: .We examine the colour dist…

Magnetoacoustic wave propagation in off-limb polar regions

Doyle, J. G.; Banerjee, D.; O'Shea, E.

Aims.To find evidence of magnetoacoustic waves in off-limb polar regions.
Methods: .Using temporal series data from the Coronal Diagnostic Spectrometer (CDS) on SOHO, we study oscillations found in radiant flux and velocity measurements from transition region and coronal spectral lines. We use Fourier techniques to measure phase delays between…

Why is the mass function of NGC 6218 flat?

Pulone, L.; Paresce, F.; de Marchi, G.

We have used the FORS-1 camera on the VLT to study the main sequence (MS) of the globular cluster NGC 6218 in the V and R bands. The observations cover an area of 3.4 arcmin × 3.4 arcmin around the cluster centre and probe the stellar population out to the cluster's half-mass radius (r_h ≃ 2.2 arcmin). The colour-magnitude diagram (CMD) …

The super-soft source XMMU J052016.0-692505 in the LMC. A likely white dwarf Be/X-ray binary

Haberl, F.; Kahabka, P.; Filipović, M. D. +1 more

Aims.We report the discovery of the super-soft X-ray source XMMU J052016.0-692505 in the LMC with XMM-Newton.
Methods: .We analyse the EPIC spectra of XMMU J052016.0-692505 and study the likely optical counterpart LMCV2135.
Results: .Using an absorbed blackbody spectrum we derive a bolometric luminosity of ⪆ 10³⁴ erg s^-1

New insights on the complex planetary nebula Hen 2-113

Lopez, B.; Chesneau, O.; Zijlstra, A. A. +6 more

We report on infrared observations of the planetary nebula Hen 2-113 obtained with VLT/NACO, VLTI/MIDI, VLT/ISAAC and TIMMI at the ESO 3.6 m. Hen 2-113 exhibits a clear ring-like structure superimposed to a more diffuse environment visible in the L' (3.8 µm), M' (4.78 µm) and 8.7 µm bands. No clear core at 8.7 µm and no fri…

Orbits of new Hipparcos binaries. II

Weigelt, G.; Hofmann, K. -H.; Schertl, D. +4 more

We continue the presentation of new orbits for Hipparcos binaries determined from regular speckle interferometric observations. Most of the data were collected in the period between 1998.77 and 2004.82 using the 6 m BTA telescope

of the Special Astrophysical Observatory in Zelenchuk. New orbits are presented for six pairs: HIP 4809, HIP 4849,…

The X-ray properties of the magnetic cataclysmic variable UU Columbae

Mukai, K.; Haberl, F.; Burwitz, V. +5 more

Aims.XMM-Newton observations to determine for the first time the broad-band X-ray properties of the faint, high galactic latitude intermediate polar UU Col are presented.
Methods: .We performed X-ray timing analysis in different energy ranges of the EPIC cameras, which reveals the dominance of the 863 s white dwarf rotational period. The spin …

Multi-wavelength study of the gravitational lens system RXS J113155.4-123155. I. Multi-epoch optical and near infrared imaging

Altieri, B.; Jean, C.; Surdej, J. +6 more

Aims.RXS J113155.4-123155 (z=0.66) is a quadruply imaged lensed quasar with a resolved Einstein Ring. The goal of this paper is to provide a full characterization of this system, and more particularly accurate astrometry and photometry. These observational constraints constitute a mandatory ingredient for the precise determination of the lens mass…

A multi-wavelength census of star formation activity in the young embedded cluster around Serpens/G3-G6

Olofsson, G.; André, Ph.; Bontemps, S. +4 more

Aims.The aim of this paper is to characterise the star formation activity in the poorly studied embedded cluster Serpens/G3-G6, located ~45 arcmin (3 pc) to the south of the Serpens Cloud Core, and to determine the luminosity and mass functions of its population of Young Stellar Objects (YSOs).
Methods: .Multi-wavelength broadband photometry …