ESA Science & Technology - Publication Archive
- Hubble's Bequest to Astronomy
- PHLAG: Pipeline for Hubble Legacy Archive Grism Data
- ESA-ESO Topical Science Working Groups
- Solar System Bodies in Hubble Observations
- Staff Update
- Communication of the "Pluto Affair"
- NASA Award for ST-ECF Staff
- The International Year of Astronomy 2009
- Servicing Mission 4
We present the first identification of large-scale structures (LSS) at z < 1.1 in the Cosmic Evolution Survey (COSMOS). The structures are identified from adaptive smoothing of galaxy counts in the pseudo-3d space (R.A., Dec., z) using the COSMOS photometric redshift catalog. The technique is tested on a simulation including galaxies distributed in model clusters and a field galaxy population - recovering structures on all scales from 1 to 202 without a priori assumptions for the structure size or density profile. Our procedure makes no a priori selection on galaxy spectral energy distribution (SED, for example the Red Sequence), enabling an unbiased investigation of environmental effects on galaxy evolution. The COSMOS photometric redshift catalog yields a sample of 1.5 × 105 galaxies with redshift accuracy, delta zFWHM/(1 + z) d 0.1 at z < 1.1 down to IAB d 25 mag. Using this sample of galaxies, we identify 42 large-scale structures and clusters. Projected surface-density maps for the structures indicate multiple peaks and internal structure in many of the most massive LSS. The stellar masses (determined from the galactic SEDs) for the LSS range from M* ~ 1011 up to ~ 3 × 1013 Msun. Five LSS have total stellar masses exceeding 1013 Msun. (Total masses including non-stellar baryons and dark matter are expected to be ~ 50 - 100 times greater.) The derived mass function for the LSS is consistent (within the expected Poisson and cosmic variances) with those derived from optical and X-ray studies at lower redshift.
Venus Express was launched in late October, 2005, and arrived at the planet in April 2006, where it is now in orbit and the return to Earth of new information about Venus' atmosphere, surface, and space environment has begun. The purpose of this special issue of Planetary and Space Science is to lay out the background to the mission, in terms of the planet and its mysteries as well as the spacecraft, its instruments, and the planned observations, in order to review the context in which the new results will be analysed and interpreted.
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A summary of the study evolution has been provided in the previous XRO status report [RSStRep] issued at the end of March 2006. The work of ESA and JAXA on the revised mission scenario has progressed further over the past 6 months, including internal as well as industrial activities and dedicated technology developments.
In response to ESA's call for space science themes in the frame of Cosmic Vision 2015-2025, the scientific community identified a Far Infrared mission with very high spatial resolution as a potential future science mission for Europe. A future far infrared mission would typically work at wavelengths between 25-300 microns and combine high sensitivity with an angular resolution better than 1 arcsecond at the shortest wavelengths. Such requirements would call for very large telescope diameters or for an interferometer based design.
To investigate the feasibility of this potential future mission the Science Payload & Advanced Concepts Office (SCI-A) at ESA initiated a Far Infrared Interferometer (FIRI) Technology Reference Study (TRS). The selected baseline concept for this study is a single spacecraft Michelson interferometer (i.e. pupil plane recombination) with two light collecting telescopes and a central hub beam combiner, all cryogenically cooled. To enable such a mission concept many innovative design solutions and technology developments would be required in the area of cryogenics, mechanisms and optics.
In this paper an overview of the result of the internal feasibility study of the FIRI concept will be provided. Specific emphasis is on critical subsystems and on required future technology development activities.