Search Publications
The INES system. IV. The IUE absolute flux scale
Wamsteker, W.; González-Riestra, R.; Cassatella, A
This paper deals with the definition of the input fluxes used for the calibration of the IUE Final Archive. The method adopted consists in the determination of the shape of the detector's sensitivity curves using IUE low resolution observations with model fluxes of the DA white dwarf G191-B2B. A scale factor was then determined so that the IUE obs…
The distance scale of planetary nebulae
Bensby, T.; Lundström, I.
By collecting distances from the literature, a set of 73 planetary nebulae with mean distances of high accuracy is derived. This sample is used for recalibration of the mass-radius relationship, used by many statistical distance methods. An attempt to correct for a statistical peculiarity, where errors in the distances influences the mass-radius r…
Modelling the orbital modulation of ultraviolet resonance lines in high-mass X-ray binaries
van Loon, J. Th.; Hammerschlag-Hensberge, G.; Kaper, L.
The stellar-wind structure in high-mass X-ray binaries (HMXBs) is investigated through modelling of their ultraviolet (UV) resonance lines. For the OB supergiants in two systems, Vela X-1 and 4U1700-37, high-resolution UV spectra are available; for Cyg X-1, SMC X-1, and LMC X-4 low-resolution spectra are used. In order to account for the non-monot…
On the metal abundance in the core of M 87
Molendi, S.; Gastaldello, F.
We revisit the XMM-Newton observation of M 87 to make a new and more detailed measurement of the metal abundance profile. After having verified that spectral fits with single temperature models show a dramatic abundance drop within 1 arcmin of the cluster core, we show that more appropriate models, which include a multi-temperature component to ac…
Comparison of source detection procedures for XMM-Newton images
Valtchanov, I.; Pierre, M.; Gastaud, R.
Procedures based on current methods to detect sources in X-ray images are applied to simulated XMM-Newton images. All significant instrumental effects are taken into account, and two kinds of sources are considered - unresolved sources represented by the telescope PSF and extended ones represented by a beta -profile model. Different sets of test c…
Internal kinematics of the TW Hya association of young stars
Makarov, V. V.; Fabricius, C.
Thirty one probable kinematic members of the nearby TW Hya association of young stars are selected from the RASSBSC/Tycho-2 sample of stars luminous in X-rays, detected by ROSAT. Eight of them have been listed already as members of the association, and 23 are new candidates. The association occupies a volume of some 106 pc3, …
The nature of network oscillations
Doyle, J. G.; Banerjee, D.; O'Shea, E. +1 more
We examine time-series of spectral data obtained from the Coronal Diagnostic Spectrometer (CDS) and the Solar Ultraviolet Measurements of Emitted Radiation instrument (SUMER) onboard the Solar Heliospheric Observatory (SOHO) spacecraft, in the period 30-31 July 1996. The observations were obtained in lines, ranging in temperature from 12 000 K to …
First XMM-Newton observations of an isolated neutron star: RX J0720.4-3125
Haberl, F.; Motch, C.; Cropper, M. +6 more
We present the high resolution spectrum of the isolated neutron star RX J0720.4-3125, obtained with the Reflection Grating Spectrometer on XMM-Newton, complemented with the broad band spectrum observed with the EPIC PN camera. The spectrum appears smooth, with no evidence for strong photospheric absorption or emission features. We briefly discuss …
Cassiopeia A dust composition and heating
Pantin, E.; Lagage, P. O.; Douvion, T.
Material ejected by a supernova is directly observed in the form of Fast Moving Knots (FMK's) in the Cassiopeia A supernova remnant. Part of this material has condensed into dust. In this paper, by fitting the ISO mid-infrared emission of the dust, we derive the dust composition and discuss the dust heating. The dust is found to be made mainly of …
Wind circulation in selected rotating magnetic early-B stars
Smith, M. A.; Groote, D.
The rotating magnetic B stars are a class of variables consisting of He-strong and some beta Cep stars which have oblique dipolar magnetic fields. Such stars develop co-rotating, torus-shaped clouds by channeling wind particles from their magnetic poles to circumstellar regions centered around the plane of their magnetic equators. The rotation of …