Search Publications
High velocity structures in, and the X-ray emission from the LBV nebula around η Carinae
Weis, K.; Bomans, D. J.; Duschl, W. J.
The Luminous Blue Variable star eta Carinae is one of the most massive stars known. It underwent a giant eruption in 1843 in which the Homunculus nebula was created. ROSAT and ASCA data indicate the existence of a hard and a soft X-ray component which appear to be spatially distinct: a softer diffuse shell of the nebula around eta Carinae and a ha…
Evidence for micrometeoroid damage in the pn-CCD camera system aboard XMM-Newton
Aschenbach, B.; Trümper, J.; Kemmer, J. +9 more
The mirror systems of the X-ray observatory XMM-Newton were designed to image X-rays up to 15 keV by grazing incidence reflection onto a focal plane, equipped with Charge Coupled Devices (CCDs). In orbit # 156 we have observed a sudden increase of about 35 ``bright'' pixels spread over 15 cm2 in the pn-CCD camera system. The amount of l…
VLT spectroscopy of galaxies lensed by the AC 114 cluster:. Implications for the mass model and the study of low-luminosity galaxies at high-redshift
Smail, I.; Kneib, J. -P.; Pelló, R. +5 more
We present the first results of a spectroscopic survey of faint lensed galaxies in the core of the galaxy cluster AC 114 (z=0.312) obtained from observations with the FORS1 spectrograph mounted on the VLT-Antu (Unit Telescope 1). The galaxies were chosen according to both lensing and photometric redshift criteria in areas close to the high-z criti…
An active binary XY UMa revisited
Chochol, D.; Vittone, A. A.; Errico, L. +4 more
New extensive multicolour photoelectric photometry, performed since 1994, is presented. 17 more-or-less complete light curves were obtained and analyzed. The Wilson-Devinney code applied to the BVRI light curves without the maculation effect together with published spectroscopic mass ratio and semi-major axis yielded new absolute parameters of the…
The composition of circumstellar gas and dust in 51 Oph
Waters, L. B. F. M.; van den Ancker, M. E.; Meeus, G. +2 more
We analyze ISO archive data of the nearby bright emission-line star 51 Oph, previously classified as a proto-planetary system similar to beta Pic. The infrared spectrum reveals the presence of gas-phase emission bands of hot ( ~ 850 K) CO, CO_2, H_2O and NO. In addition to this, partially crystalline silicate dust is present. The solid-state bands…
Sky confusion noise in the far-infrared: Cirrus, galaxies and the cosmic far-infrared background
Juvela, M.; Ábrahám, P.; Lemke, D. +2 more
We examined the sky confusion noise in 40 sky regions by analysing 175 far-infrared (90-200 mu m) maps obtained with ISOPHOT, the photometer on-board the Infrared Space Observatory. For cirrus fields with < B > > 5 MJy sr-1 the formula based on IRAS data (Helou & Beichman \cite{Helou+Beichman_90}) predicts confusion noise v…
Large Magellanic Cloud stellar clusters. I. 21 HST colour magnitude diagrams
Brocato, E.; Di Carlo, E.; Menna, G.
We present WFPC2 photometry of 21 stellar clusters of the Large Magellanic Cloud obtained on images retrieved from the Hubble Space Telescope archive. The derived colour magnitude diagrams (CMDs) are presented and discussed. This database provides a sample of CMDs representing, with reliable statistics, simple stellar populations with a large spre…
The first broad-band X-ray images and spectra of the 30 Doradus region in the LMC
Pietsch, W.; Haberl, F.; Hasinger, G. +25 more
We present the XMM-Newton first light image, taken in January 2000 with the EPIC pn camera during the instrument's commissioning phase, when XMM-Newton was pointing towards the Large Magellanic Cloud (
A new galaxy near the Local Group in Draco
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +7 more
We present HST WFPC2 and ground-based images of the low surface brightness dwarf Irr/Sph galaxy KKR 25 in Draco. Its colour-magnitude diagram shows red giant branch stars with the tip at I= 22fm32 , and the presence of some blue stars. The derived true distance modulus, 26fm35 +/- 0fm14 , corresponds to linear distances of KKR 25 from the Milky Wa…
The infrared continuum radiation of NGC 1808. A PAH and polarisation study
Siebenmorgen, R.; Laureijs, R. J.; Krügel, E.
The paper is devoted to the understanding of the infrared emission of nuclear regions in galaxies. a) ISO data of NGC 1808 are presented: spectro-photometry from 5.1 to 16.4 mu m; a 25''x 25'' map at 6 mu m and 170 mu m photometry. b) The data are complemented by a polarisation measurement at 170 mu m (2.5+/-0.4% at position angle 94degr +/-5degr …