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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…
Investigating ionized disc models of the variable narrow-line Seyfert 1 PG 1404+226
Brandt, W. N.; Fabian, A. C.; Boller, Th. +1 more
We investigate the use of relativistically blurred photoionized disc models on an XMM-Newton observation of the narrow-line Seyfert 1 galaxy PG 1404+226. The model is designed to reproduce the radiation from the inner accretion disc around a Kerr black hole, and is more successful at fitting the spectrum than models based on a thermal soft excess.…
CLASS B0631+519: last of the Cosmic Lens All-Sky Survey lenses
Pearson, T. J.; McKean, J. P.; Blandford, R. D. +13 more
We report on the discovery of the new gravitational lens system CLASS B0631+519. Imaging with the Very Large Array, the Multi-Element Radio-Linked Interferometer Network (MERLIN) and the Very Long Baseline Array (VLBA) reveals a doubly imaged flat-spectrum radio core, a doubly imaged steep-spectrum radio lobe and possible quadruply imaged emission…
Plasma diagnostics of active-region evolution and implications for coronal heating
Mathioudakis, M.; Bloomfield, D. S.; Keenan, F. P. +2 more
A detailed study is presented of the decaying solar-active region NOAA 10103 observed with the Coronal Diagnostic Spectrometer (CDS), the Michelson Doppler Imager (MDI) and the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO). Electron-density maps formed using SiX (356.03 Å/347.41 Å) show that the …
HST and UKIRT imaging observations of z~ 1 6C radio galaxies - II. Galaxy morphologies and the alignment effect
Röttgering, H. J. A.; Inskip, K. J.; Best, P. N. +1 more
Powerful radio galaxies often display enhanced optical/ultraviolet emission regions, elongated and aligned with the radio jet axis. The aim of this series of papers is to investigate separately the effects of radio power and redshift on the alignment effect, together with other radio galaxy properties. In this second paper, we present a deeper ana…