Search Publications
Yet another galaxy identification for an ultraluminous X-ray source
Palazzi, E.; Masetti, N.; Foschini, L. +4 more
We report on the identification of the optical and infrared counterparts of the ultraluminous X-ray source (ULX) XMMU J121214.5+131248 (NGC4168-ULX1). The optical spectrum yields a redshift of z=0.217, which implies that the ULX is not associated with the nearby galaxy NGC 4168, but rather with a background object. Optical spectral line ratios and…
INTEGRAL timing and localization performance
Walter, R.; Schmidt, M.; Kuiper, L. +10 more
In this letter we report on the accuracy of the attitude, misalignment, orbit and time correlation which are used to perform scientific analyses of the INTEGRAL data. The boresight attitude during science pointings has an accuracy of 3 arcsec. At the center of the field, the misalignments have been calibrated leading to a location accuracy of 4 to…
Line emission from circumstellar disks around A stars
Kamp, I.; van Dishoeck, E. F.; Stark, R. +1 more
The nature of the tenuous disks around A stars has raised considerable controversy in the literature during the past decade. The debate whether or not the disk around beta Pictoris contains gaseous molecular hydrogen is only the most recent example. Since CO is in general a poor tracer for the gas content of these low mass disks, we discuss here d…
A submillimetre selected quasar in the field of Abell 478
Jaffe, W.; Knudsen, K. K.; van der Werf, P. P.
We present the discovery of a dusty quasar, SMM J04135+10277, located behind the galaxy cluster
Metallicities of the SPB stars from the IUE ultraviolet spectra
Niemczura, E.
We derived the stellar parameters (angular diameters, effective temperatures, metallicities) and interstellar reddenings for 20 SPB and 34 reference stars observed during the IUE satellite mission. The parameters were derived by means of an algorithmic procedure of fitting theoretical flux distributions to the low-resolution IUE spectra and optica…
Tracing a Z-track in the M 31 X-ray binary RX J0042.6+4115
Kolb, U.; Osborne, J. P.; Barnard, R.
Four XMM-Newton observations of the core of M 31, spaced at 6 month intervals, show that the brightest point X-ray source, RX J0042.6+4115, has a 0.4-10 keV luminosity of ~ 5x 1038 erg s-1, and exhibits significant variability in intensity and X-ray spectrum over a time scale of ~ 100 s including hard flares; such behaviour i…
The detection of diffuse emission in HCG 16 with XMM-Newton
Bourdin, H.; Ponman, T. J.; Sauvageot, J. -L. +1 more
We report results obtained from analysis of the XMM-Newton observation of the compact group of galaxies HCG 16. It is a peculiar system composed of 7 spirals, 6 of which are active, and its nature as a bound system has been much debated. The EPIC camera observations give new insights into the X-ray parameters describing the physical status of the …
Deep XMM-Newton observation of a northern LMC field I. Selected X-ray sources
Pietsch, W.; Haberl, F.; Dennerl, K.
First results from a deep XMM-Newton observation of a field in the Large Magellanic Cloud (LMC) near the northern rim of the supergiant shell LMC 4 are presented. Spectral and temporal analyses of a sample of selected X-ray sources yielded two new candidates for supernova remnants, a supersoft X-ray source and a likely high mass X-ray binary (HMXB…
The mineralogy, geometry and mass-loss history of IRAS 16342-3814
Waters, L. B. F. M.; Dominik, C.; de Koter, A. +5 more
We present the 2-200 mu m Infrared Space Observatory (ISO) spectrum and 3.8-20 mu m ISAAC and TIMMI2 images of the extreme OH/IR star IRAS 16342-3814. Amorphous silicate absorption features are seen at 10 and 20 mu m, together with crystalline silicate absorption features up to almost 45 mu m. No other OH/IR star is known to have crystalline silic…
An HST study of three very faint GRB host galaxies
Fynbo, J. P. U.; Schaefer, B. E.; Gorosabel, J. +8 more
As part of the HST/STIS GRB host survey program we present the detection of three faint gamma-ray burst (GRB) host galaxies based on an accurate localisation using ground-based data of the optical afterglows (OAs). A common property of these three hosts is their extreme faintness. The location at which GRBs occur with respect to their host galaxie…