However, for Gaia, the community has already proposed to continue observations for a total of 10 years if fuel consumption and the hardware on-board continue to operate as expected. The measurement concept for obtaining global astrometric measurements only possible from space is well-defined and well demonstrated. Indeed, the concept is identical to that of the currently flying Gaia mission where the nominal mission lifetime is 5–6 years. Ideally we would like to see our mission launching around 2045 which is slightly later than originally proposed - this just reflects the great success of Gaia and its 5 year mission extension. Efforts are now underway to understand and identify suitable detector technologies and to prepare for writing mission proposals. Our proposal was highlighted as both a potential future large-class mission or as a future medium-class mission with international cooperation. (2019) submitted A science case white paper to ESA's Voyage 2050 call for new mission proposals. Voyage 2050 finally set sail in June 2021 when ESA selected a number of future science mission themes. The required technology is also being pursued elsewhere, for example, the Australian National University is developing NIR astronomical detector technology with TDI capabilities.Īlso in 2019 Hobbs et al. (2019) submitted White Papers to the US decadal survey (ASTRO 2020) outlining the science cases and a possible US-European collaboration. Twenty six proposals were received and three were selected for further study - including NIR global astrometry. In late 2017 ESA conducted a Concurrent Design Facility (CDF) study of our proposal and the results were published in early 2018. Such a NIR space observatory is however not possible today: it requires new types of Time Delay Integration (TDI) NIR detectors to scan the entire sky and to measure global absolute parallaxes and developing such TDI-NIR detectors is a significant challenge. (2016) proposed to the European Space Agency (ESA) a new all-sky NIR astrometry mission, called GaiaNIR. All-sky space-based astrometry leads to a global solution and provides a rigid sphere for a celestial reference frame that cannot be accurately obtained with any other method. The science cases have been roughly divided into three Sections 1) NIR science cases 2) improved proper motion science cases and 3) reference frame science cases. A space-based mission avoids the limitations caused by the turbulent atmosphere and the use of Earth rotation parameters and models of nutation and precession. The accuracy of the new mission should be at least that of Gaia using tried and trusted instrumentation, techniques, and lessons learned from Gaia to unveil a wealth of new and more accurate information about our Galaxy. Gaia is already one of the most transformational missions ever as measured in terms of scientific output. Hence, it is very desirable to repeat the measurements of Gaia after about 20 years to maintain the positional accuracy of the stars and the visible reference frame. However, this accurate positional information and the accuracy of the link to the VLBI reference frame will slowly degrade due to the small uncertainties in the proper motions of the stars. After the publication of the final Gaia catalogue the positions of stars will be accurately known at the chosen reference epoch. Additionally, having two 5 or 10-year Gaia-like missions separated by 20 years would give 10–20 times better proper motions for a few billion common stars and also improved parallax determinations with new observations. An obvious technological improvement to the current Gaia mission is to also go into the non-thermal Near-InfraRed (NIR) with a wavelength cutoff in the K-band allowing the new mission to probe deeper through the Galactic dust to observe the structure and kinematics of the star-forming regions in the disc, the spiral arms and the bulge region, to give model independent distances and proper motions in these obscured parts of the sky.
0 Comments
Leave a Reply. |