Search Publications
Geometrical constraints upon the unipolar model of V407 Vul and RXJ0806.3+1527
Wilms, J.; Marsh, T. R.; Groot, P. +5 more
V407 Vul and RX J0806.3+1527 are X-ray emitting stars with X-ray light curves that are 100 per cent modulated on periods of 569 and 321 s, respectively. These periods and no others are also seen at optical and infrared wavelengths. These properties have led to the suggestion that the periods are the orbital periods of ultracompact pairs of white d…
New insights into the dust properties of the Taurus molecular cloud TMC-2 and its surroundings
del Burgo, C.; Laureijs, R. J.
We present ISOPHOT observations at 120 and 200 µm of a 31 × 57 arcmin2 region, with optical extinction AV ranging between ~ 0.5 and 11 mag, that encloses the Taurus molecular cloud TMC-2. The far-infrared emission is separated into a warm and a cold component using the ISOPHOT data and IRAS measurements at 60 and 100 &m…
Constraints on the distribution of absorption in the X-ray-selected AGN population found in the 13HXMM-Newton/Chandra deep field
McHardy, I.; Page, M. J.; Sasseen, T. +4 more
We present an analysis of the X-ray properties of sources detected in the 13HXMM-Newton deep (200-ks) field. In order to constrain the absorbed active galactic nuclei (AGN) population, we use extensive Monte Carlo simulations to compare directly the X-ray colours of observed sources with those predicted by several model distributions. I…
Simultaneous XMM-Newton and ESO VLT observations of supernova 1995N: probing the wind-ejecta interaction
Turatto, M.; Cappellaro, E.; Benetti, S. +3 more
We present the results of the first XMM-Newton observation of the interacting Type IIn supernova 1995N, performed in 2003 July. We find that the 0.2-10.0 keV unabsorbed flux dropped to a value of ~=1.8 × 10-13ergcm-2s-1, almost one order of magnitude lower than that of a previous ASCA observation of 1998 January. F…
The symmetric dust shell and the central star of the bipolar planetary nebula NGC6537*†
Waters, L. B. F. M.; Zijlstra, A. A.; Gray, M. D. +2 more
We present high-resolution images of the strongly bipolar planetary nebula NGC6537, obtained with the Hubble Space Telescope (HST) and with the infrared adaptive optics system on the Very Large Telescope. The central star is detected for the first time. Using the multiband photometry and constraints from the dynamical age of the nebula, we derive …
A possible line-like emission feature at 8 keV in the Seyfert 1.2 UGC 3973
Pietsch, W.; Fabian, A. C.; Boller, Th. +1 more
Two short X-ray exposures (<3600 s each) of the radio-quiet Seyfert 1.2 galaxy UGC 3973 (Mrk 79) were conducted with XMM-Newton as part of an active galactic nucleus snapshot survey. In this paper we concentrate on the significance and possible origin of a narrow 8-keV (rest frame) line-like emission feature detected with the pn instrument duri…
The chemical composition of δ Scuti⋆
Kovtyukh, V.; Soubiran, C.; Kim, Chulhee +4 more
We present chemical abundances in the photosphere of δ Scuti (δ Sct) - a prototype of the class of pulsating variables - determined from the analysis of a spectrum obtained by using the 2-m telescope at the Peak Terskol Observatory and a high-resolution spectrometer with R= 52 000, a signal-to-noise ratio 250 and from International Ultraviolet Exp…
Internal colour gradients for E/S0 galaxies in Abell 2218
Driver, Simon P.; De Propris, Roberto; Colless, Matthew +2 more
We determine colour gradients of -0.15 +/- 0.08 mag per decade in radius in F450W-F606W and -0.07 +/- 0.06 mag per decade in radius in F606W-F814W for a sample of 22 E/S0 galaxies in Abell 2218. These gradients are consistent with the existence of a mild (~-0.3 dex per decade in radius) gradient in metal abundance (cf. previous work at lower and h…
XMM-Newton observations of UW CrB: detection of X-ray bursts and evidence for accretion disc evolution
Ramsay, Gavin; Mukai, Koji; Hakala, Pasi +4 more
UW CrB (MS 1603+2600) is a peculiar short-period X-ray binary that exhibits extraordinary optical behaviour. The shape of the optical light curve of the system changes drastically from night to night, without any changes in overall brightness. Here we report X-ray observations of UW CrB obtained with XMM-Newton. We find evidence for several X-ray …
Optical spectroscopy of X-Mega targets - V. The spectroscopic binary HD 93161 A and its visual companion HD 93161 B*
Gosset, E.; Nazé, Y.; Rauw, G. +2 more
We present the analysis of an extensive set of high-resolution spectroscopic observations of HD 93161, a visual binary with a separation of 2 arcsec. HD 93161 A is a spectroscopic binary, with both components clearly detected throughout the orbit. The primary star is most probably of spectral type O8V, while the secondary is likely an O9V. We obta…