Search Publications
The nature of a gravitationally lensed submillimetre arc in MS0451.6-0305: two interacting galaxies at z~ 2.9?
Donahue, Megan; Smith, Graham P.; Kneib, Jean-Paul +6 more
We present a new SCUBA image of the cluster MS 0451.6-0305, which exhibits strong, extended submillimetre flux at 850 µm. The most striking feature in the map is an elongated region of bright submillimetre emission, with a flux density of ~10 mJy over several beam sizes. This region is apparently coincident with a previously known optical ar…
Rosetta target comet 67P/Churyumov-Gerasimenko. Postperihelion gas and dust production rates
Schulz, R.; Boehnhardt, H.; Stüwe, J. A.
The evolution of the activity and composition of the coma of ROSETTA target comet 67P/Churyumov-Gerasimenko was studied along its postperihelion orbit from 2.29 AU to 3.22 AU. The comet had a major drop of activity between 2.5 AU and 2.9 AU, which manifested most obviously in its light curve (the brightness decreased by 3 mag), but is also confirm…
RHESSI e+-e- Annihilation Radiation Observations: Implications for Conditions in the Flaring Solar Chromosphere
Smith, David M.; Lin, Robert P.; Share, Gerald H. +2 more
RHESSI has measured the positron-electron annihilation line and continuum in three solar flares: 2002 July 23, 2003 October 28, and 2003 November 2. The 511 keV line was broad (~4-8 keV) in all three flares, consistent with annihilations in an ambient ionized medium at temperatures above 105 K. The measured continuum from positronium an…
XMM-Newton observations of Sagittarius A East
Decourchelle, A.; Warwick, R. S.; Predehl, P. +1 more
We present an analysis of a recent XMM-Newton observation of Sgr A East, a supernova remnant located close to the Galactic Centre. Very high-quality X-ray spectra reveal many emission lines from highly ionized atoms consistent with a multitemperature thin thermal plasma in ionization equilibrium. We use a two-temperature model to fit the spectra a…
Speckle interferometry of nearby multiple stars. II.
Weigelt, G.; Schertl, D.; Balega, Y. Y. +4 more
This paper is a continuation of diffraction-limited speckle interferometry of binary and multiple stars carried out at the 6-m telescope of the Special Astrophysical Observatory in Zelenchuk. The program has concentrated on nearby (π>10 mas) close binaries discovered or measured during the Hipparcos mission. Here, we present 132 measurements of…
Cluster observations of finite amplitude Alfvén waves and small-scale magnetic filaments downstream of a quasi-perpendicular shock
Fazakerley, A. N.; Maksimovic, M.; Alexandrova, O. +7 more
The Cluster satellites crossed the Earth's bow shock several times on 31 March 2001. For all these crossings the bow shock was supercritical and quasi-perpendicular. We present here the results of a detailed analysis of the magnetic field fluctuations observed downstream of the shock. We use data from the four Cluster spacecraft to determine the b…
XMM-Newton Observations of PSR B1706-44
Cropper, M.; McGowan, K. E.; Kennea, J. A. +5 more
We report on the XMM-Newton observations of the young 102 ms pulsar PSR B1706-44. We have found that both a blackbody plus power law and a magnetized atmospheric model plus power law provide an excellent fit to the European Photon Imaging Camera (EPIC) spectra. The two scenarios are therefore indistinguishable on a statistical basis, although we a…
An HST parallax of the distant cataclysmic variable V1223 Sgr, its system parameters, and accretion rate
Gänsicke, B. T.; Beuermann, K.; McArthur, B. E. +2 more
Using the Hubble space Telescope Fine Guidance Sensor, we have measured the trigonometric parallax of the bright cataclysmic variable 1223 Sgr. The absolute parallax is πabs= 1.96± 0.18 mas, making V1223 Sgr the most distant CV with a well-determined trigonometric parallax. This distance, a Lutz-Kelker correction, and the previously mea…
The soft X-ray absorption lines of the Seyfert 1 galaxy MCG-6-30-15
Vaughan, S.; Fabian, A. C.; Lee, J. C. +1 more
The absorption lines in the soft X-ray spectrum of MCG-6-30-15 are studied using the reflection grating spectrometer data from the 2001 XMM-Newton 320-ks observation. A line search of the full time-averaged spectrum reveals 51 absorption lines and one emission line. The equivalent widths of the lines are measured and the majority of the lines iden…
The Dynamical Distance to M15: Estimates of the Cluster's Age and Mass and of the Absolute Magnitude of Its RR Lyrae Stars
Baumgardt, H.; Harrison, T. E.; McNamara, B. J.
Newly determined high-precision relative proper motions determined from the Hubble Space Telescope Wide Field Planetary Camera 2 are used along with radial velocity measurements to determine the dynamical distance to the globular cluster M15. A comparison of the proper motion and radial velocity dispersions from a sample of 237 stars, located at a…