ESA Science & Technology - Publication Archive
The European space Agency (ESA) undertook a bold experiment with the Mars Express mission: to develop rapidly a low cost platform for planetary exploration. The myriad scientific achievements of this mission prove the success of the experiment. ESA took a second bold step by adapting the Mars platform for the Venus Express mission, and doing so rapidly and most cost-effectively. While the differences in Venus and Mars necessitated several changes in instrumentation, there are many objectives that remain the same at the two planets. When we issued a call to the MEX and VEX communities for a volume of brief articles covering the latest results from these two missions, the response from those examining the interaction of the solar wind and energetic particles with the planets was most swift. The authors were asked to keep their presentations to four published pages. The guest editor in turn attempted to shepherd these papers through the reviewing process quickly. In those instances where the editor had a conflict of interest, R. J. Strangeway assumed the duties of the editor.
The articles that passed review before the press deadline are included therein. They include discussions of the various plasma boundaries at Venus and Mars, the nature of their plasma environments, the discovery of energetic neutral particles, the configuration of the magnetic field near the planets, space weather and the loss of atmosphere. Papers included contain both modeling and observational work and are written by some of the newest members of the community as well as many of the veteran research scientists. We especially thank the referees of these papers who responded promptly to help speed these early results to the readers of Planetary and Space Science.
Aims: We aim to probe the low gas densities expected in the large-scale structure filaments by observing a filament connecting the massive clusters of galaxies A 222 and A 223 (z = 0.21), which has a favorable orientation approximately along our line-of-sight. This filament has been previously detected using weak lensing data and as an over-density of colour-selected galaxies.
Methods: We analyse X-ray images and spectra obtained from a deep observation (144 ks) of A 222/223 with XMM-Newton.
Results: We present observational evidence of X-ray emission from the filament connecting the two clusters. We detect the filament in the wavelet-decomposed soft-band (0.5-2.0 keV) X-ray image with a 5-sigma significance. Following the emission down to the 3-sigma significance level, the observed filament is ~1.2 Mpc wide. The temperature of the gas associated with the filament, determined from the spectra, is kT = 0.91±0.25 keV, and its emission measure corresponds to a baryon density of (3.4±1.3)×10-5(l/15 Mpc)-1/2
Methods. A bright source, XMMSL1 J070542.7-381442, was detected on 9 Oct. 2007 at a position where no previous X-ray source had been seen. The XMM slew data and optical data acquired with the Magellan Clay 6.5 m telescope were used to classify the new object.
Results. No XMM slew X-ray counts are detected above 1 keV and the source is seen to be 750 times brighter than the ROSAT All-Sky Survey upper limit at that position. The normally mV ~ 16 star, USNO-A2.0 0450-03360039, which lies 3.5" from the X-ray position, was seen in our Magellan data to be very much enhanced in brightness. Our optical spectrum showed emission lines that identified the source as a nova in the auroral phase; hence, this optical source is undoubtedly the progenitor of the X-ray source - a new nova (now also known as V598 Pup). The X-ray spectrum indicates that the nova was in a super-soft state (with kTeff ~ 35 eV). We estimate the distance to the nova to be ~ 3 kpc. Analysis of archival robotic optical survey data shows a rapid-decline light curve consistent with what is expected for a very fast nova.
Conclusions. The XMM-Newton slew data present a powerful opportunity to find new X-ray transient objects while they are still bright. Here we present the first such source discovered by the analysis of near real-time slew data.