Entity

Time filter

Source Type

Bosisio Parini, Italy

Battistelli E.S.,University of Rome La Sapienza | Amico G.,University of Rome La Sapienza | Bau A.,University of Milan Bicocca | Berge L.,University Paris - Sud | And 38 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2012

Atmospheric emission is a dominant source of disturbance in ground-based astronomy at millimetric wavelengths. The Antarctic plateau is recognized as an ideal site for millimetric and submillimetric observations, and the French/Italian base of Dome Concordia (Dome C) is among the best sites on Earth for these observations. In this paper, we present measurements at Dome C of the atmospheric emission in intensity and polarization at a 2-mm wavelength. This is one of the best observational frequencies for cosmic microwave background (CMB) observations when considering cosmic signal intensity, atmospheric transmission, detector sensitivity and foreground removal. Using the B-mode radiation interferometer (BRAIN)-pathfinder experiment, we have performed measurements of the atmospheric emission at 150 GHz. Careful characterization of the airmass synchronous emission has been performed, acquiring more than 380 elevation scans (i.e. 'skydip') during the third BRAIN-pathfinder summer campaign in 2009 December/2010 January. The extremely high transparency of the Antarctic atmosphere over Dome C is proven by the very low measured optical depth, 〈τ I〉= 0.050 ± 0.003 ± 0.011, where the first error is statistical and the second is the systematic error. Mid-term stability, over the summer campaign, of the atmosphere emission has also been studied. Adapting the radiative transfer atmosphere emission model am to the particular conditions found at Dome C, we also infer the level of the precipitable water vapor (PWV) content of the atmosphere, which is notoriously the main source of disturbance in millimetric astronomy (mm). Upper limits on the airmass correlated polarized signal are also placed for the first time. The degree of circular polarization of atmospheric emission is found to be lower than 0.2per cent [95per cent confidence level (CL)], while the degree of linear polarization is found to be lower than 0.1per cent (95per cent CL). These limits include signal-correlated instrumental spurious polarization. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.


Tiedemann L.,Max Planck Institute for Extraterrestrial Physics | Breunig E.,Max Planck Institute for Extraterrestrial Physics | Burwitz V.,Max Planck Institute for Extraterrestrial Physics | Furmetz M.,Max Planck Institute for Extraterrestrial Physics | And 7 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

The μROSI (Micro Roentgen Satellite Instrument) miniature X-ray telescope is the first X-ray telescope specifically designed for an amateur micro satellite. Its mission is to perform an all-sky survey in the soft X-ray band on board the Italian satellite Max-Valier. Due to the limitations imposed by the small size of the spacecraft, the instrument features a silicon drift detector (SDD) with very low power consumption and a focusing optics that consists of 12 nested mirror shells. With a field of view of 1°, μROSI will perform an all-sky survey flying in sun-synchronous orbit (SSO). As a secondary mission objective, the telescope will observe the Earth's upper atmosphere during the all-sky survey, potentially detecting the O2 absorption line. This paper describes the overall telescope design and gives an overview of the key components of the telescope: the mirror subsystem and the detector subsystem. All subsystems have been tested with flight-like engineering models. The results of these tests are presented in this paper. The silicon drift detector (SDD) of the μROSI telescope has been tested with a breadboard electronics and the engineering model of the electronics is currently being manufactured. The breadboard test proved that the SDD together with the specifically developed electronics is capable of measuring high resolution spectra in the soft X-ray bandwidth. One demonstrator mirror shell has been produced and tested in the PANTER X-ray test facility to verify the X-ray properties. The measurements suggest that the final μROSI mirror system fulfills all requirements for conducting its mission successfully. © 2013 SPIE.


Wille E.,European Space Agency | Bavdaz M.,European Space Agency | Oosterbroek T.,European Space Agency | Collon M.,Cosine Research BV | And 18 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Athena (Advanced Telescope for High Energy Astrophysics) is an x-ray observatory using a Silicon Pore Optics telescope and was selected as ESA's second L-class science mission for a launch in 2028. The x-ray telescope consists of several hundreds of mirror modules distributed over about 15-20 radial rings. The radius of curvature and the module sizes vary among the different radial positions of the rings resulting in different technical challenges for mirror modules for inner and outer radii. We present first results of demonstrating Silicon Pore Optics for the extreme radial positions of the Athena telescope. For the inner most radii (0.25 m) a new mirror plate design is shown which overcomes the challenges of larger curvatures, higher stress values and bigger plates. Preliminary designs for the mounting system and its mechanical properties are discussed for mirror modules covering all other radial positions up to the most outer radius of the Athena telescope. © 2015 SPIE.


Burwitz V.,MPI Fur Extraterrestrische Physik | Predehl P.,MPI Fur Extraterrestrische Physik | Brauninger H.,MPI Fur Extraterrestrische Physik | Burkert W.,MPI Fur Extraterrestrische Physik | And 10 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

The eROSITA X-ray observatory that will be launched on board the Russian Spectrum-RG mission comprises seven X-ray telescopes, each with its own mirror assembly (mirror module + X-ray baffle), electron deflector, filter wheel, and CCD camera with its control electronics. The completed flight mirror modules are undergoing many thorough X-ray tests at the PANTHER X-ray test facility after delivery, after being mated with the X-ray baffle, and again after both the vibration and thermal-vacuum tests. A description of the work done with mirror modules/assemblies and the test results obtained will be reported here. We report also on the environmental tests that have been performed on the eROSITA telescope qualification model. © 2013 SPIE.

Discover hidden collaborations