ESA Science & Technology - Publication Archive
In response to ESA's call for space science themes in the frame of Cosmic Vision 2015-2025, the scientific community identified a Wide-Field Optical and Near Infrared Imager as a potential future science mission for Europe. Such a mission would search for Type Ia supernovae at low redshift in the optical and near infrared part of the spectrum with the aim to measure the changing rate of expansion of the universe and to determine the contributions of decelerating and accelerating energies such as the mass density, the vacuum energy density and other yet to be studied dark energies. To investigate the feasibility of this potential future mission the Science Payload & Advanced Concepts Office (SCI-A) at ESA initiated the Wide Field Imager (WFI) Technology Reference Study (TRS). The WFI would have a 2 m class telescope, a 1 square degree field of view imaging camera and a low-resolution integral field spectrometer. This paper summarizes the results of this ESA internal feasibility study of the WFI. The paper focuses on the spacecraft design and the critical subsystems and provides an overview of required technology development activities for such a mission.
This article is based on a lecture by Professor André Balogh to the Pro ISSI Association
Synoptic measurements from the DOUBLE STAR and CLUSTER spacecraft offer a unique opportunity to evaluate global models in simulating the complex topology and dynamics of the dayside merging region. We compare observations from the DOUBLE STAR TC-1 and CLUSTER spacecraft on May 8, 2004 with the predictions from a three-dimensional magnetohydrodynamic (MHD) simulation that uses plasma and magnetic field parameters measured upstream of the bow shock by the WIND spacecraft. Results from the global simulation are consistent with the large-scale features observed by CLUSTER and TC-1. We discuss topological changes and plasma flows at the dayside magnetospheric boundary inferred from the simulation results. The simulation shows that the DOUBLE STAR spacecraft passed through the dawn side merging region as the IMF rotated. In particular, the simulation indicates that at times TC-1 was very close to the merging region. In addition, we found that the bifurcation of the merging region in the simulation results is consistent with predictions by the antiparallel merging model. However, because of the draping of the magnetosheath field lines over the magnetopause, the positions and shape of the merging region differ significantly from those predicted by the model.
This is the final report of the ESA-ESO working group on Herschel/ALMA synergies, produced by the second joint ESA/ESO working group (Chairman: Tom Wilson, co-chair: David Elbaz).
The Herschel Satellite and the Atacama Large Millimeter Array (ALMA) are two very large sub-mm and far infrared (FIR) astronomy projects that are expected to come into operation in this decade. This report contains descriptions of these instruments, emphasising the overlaps in wavelength range and additional complementarities.
A short rationale for studying sub-mm and far infrared astronomy is given. Following this, brief presentations of Herschel and ALMA are presented, with references to more detailed documents and use cases. Emphasis is placed on the synergies between these facilities, and the challenges of comparing data produced using both. Specific examples of projects are given for a number of areas of astronomical research where these facilities will lead to dramatic improvements.
- INTEGRAL AO-4 Results
- INTEGRAL AO-5 Key Programme
- INTEGRAL Publication Status
- Science Highlights
- Science Operations - Highlights
- The ISOC Science Data Archive
- The 6th INTEGRAL Workshop
- Changes at ISOC
Context. In coded mask techniques, reconstructed sky images are pseudo-images: they are maps of the correlation between the image recorded on a detector and an array derived from the coded mask pattern.
Aims. The INTEGRAL/IBIS telescope provides images where the flux of each detected source is given by the height of the local peak in the correlation map. As such, it cannot provide an estimate of the flux of an extended source. What is needed is intensity sky images giving the flux per solide angle as typically done at other wavelengths.
Methods. In this paper, we present the response of the INTEGRAL IBIS/ISGRI coded mask instrument to extended sources. We develop a general method based on analytical calculations in order to measure the intensity and the associated error of any celestial source and validated with Monte-Carlo simulations.
Results. We find that the sensitivity degrades almost linearly with the source extent. Analytical formulae are given as well as an easy-to-use recipe for the INTEGRAL user. We check this method on IBIS/ISGRI data but these results are general and applicable to any coded mask telescope.