SearcharxivSearch

arXiv · 1206.6885

4MOST - 4-metre Multi-Object Spectroscopic Telescope

Abstract

The 4MOST consortium is currently halfway through a Conceptual Design study for ESO with the aim to develop a wide-field (>3 square degree, goal >5 square degree), high-multiplex (>1500 fibres, goal 3000 fibres) spectroscopic survey facility for an ESO 4m-class telescope (VISTA). 4MOST will run permanently on the telescope to perform a 5 year public survey yielding more than 20 million spectra at resolution R~5000 ({\lambda}=390-1000 nm) and more than 2 million spectra at R~20,000 (395-456.5 nm & 587-673 nm). The 4MOST design is especially intended to complement three key all-sky, space-based observatories of prime European interest: Gaia, eROSITA and Euclid. Initial design and performance estimates for the wide-field corrector concepts are presented. We consider two fibre positioner concepts, a well-known Phi-Theta system and a new R-Theta concept with a large patrol area. The spectrographs are fixed configuration two-arm spectrographs, with dedicated spectrographs for the high- and low-resolution. A full facility simulator is being developed to guide trade-off decisions regarding the optimal field-of-view, number of fibres needed, and the relative fraction of high-to-low resolution fibres. Mock catalogues with template spectra from seven Design Reference Surveys are simulated to verify the science requirements of 4MOST. The 4MOST consortium aims to deliver the full 4MOST facility by the end of 2018 and start delivering high-level data products for both consortium and ESO community targets a year later with yearly increments.

Explore related subjects

Keep this discovery

BibTeXRIS

Roelof S. de Jong, Olga Bellido-Tirado, Cristina Chiappini, Éric Depagne, Roger Haynes, Diane Johl, Olivier Schnurr, Axel Schwope, Jakob Walcher, Frank Dionies, Dionne Haynes, Andreas Kelz, Francisco S. Kitaura, Georg Lamer, Ivan Minchev, Volker Müller, Sebastián E. Nuza, Jean-Christophe Olaya, Tilmann Piffl, Emil Popow, Matthias Steinmetz, Uğur Ural, Mary Williams, Roland Winkler, Lutz Wisotzki, Wolfgang R. Ansorgb, Manda Banerji, Eduardo Gonzalez Solares, Mike Irwin, Robert C. Kennicutt Jr, David King, Richard McMahon, Sergey Koposov, Ian R. Parry, Nicholas A. Walton, Gert Finger, Olaf Iwert, Mirko Krumpe, Jean-Louis Lizon, Mainieri Vincenzo, Jean-Philippe Amans, Piercarlo Bonifacio, Mathieu Cohen, Patrick Francois, Pascal Jagourel, Shan B. Mignot, Frédéric Royer, Paola Sartoretti, Ralf Bender, Frank Grupp, Hans-Joachim Hess, Florian Lang-Bardl, Bernard Muschielok, Hans Böhringer, Thomas Boller, Angela Bongiorno, Marcella Brusa, Tom Dwelly, Andrea Merloni, Kirpal Nandra, Mara Salvato, Johannes H. Pragt, Ramón Navarro, Gerrit Gerlofsma, Ronald Roelfsema, Gavin B. Dalton, Kevin F. Middleton, Ian A. Tosh, Corrado Boeche, Elisabetta Caffau, Norbert Christlieb, Eva K. Grebel, Camilla Hansen, Andreas Koch, Hans-G. Ludwig, Andreas Quirrenbach, Luca Sbordone, Walter Seifert, Guido Thimm, Trifon Trifonov, Amina Helmi, Scott C. Trager, Sofia Feltzing, Andreas Korn, Wilfried Boland. 2012-06-28. 4MOST - 4-metre Multi-Object Spectroscopic Telescope. https://doi.org/10.1117/12.926239

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

The EDD Radio Astronomy Backend Framework

Modern digital radio astronomy receivers produce increasingly wide-bandwidth, high bit-rate data streams that necessitate the development of flexible, scalable, and maintainable backend processing and recording systems. Historically, such backend instrumentation has been tightly coupled to telescope observing modes, limiting reuse between observatories and science cases. We present the Effelsberg Direct Digitisation (EDD) backend framework, a software-defined architecture for constructing real-time radio astronomy backends on commodity off-the-shelf computing infrastructure. We describe its design, implementation, supported observing modes, and operational deployments. EDD separates a common core framework from plugin-provided observing capabilities. The core provides orchestration, telescope interfaces, pipeline lifecycle management, monitoring, and deployment tooling, while plugins implement processing pipelines for specific observing modes. The framework is designed to support both single-dish and interferometric instruments through site-specific configuration and plugin selection. EDD currently supports spectroscopy and spectropolarimetry, pulsar timing and searching, baseband recording, very long baseline interferometry, correlation, and beamforming. Operational deployments include the Effelsberg 100-m telescope, the SKA-MPI prototype dish, the Thai National Radio Telescope, and the ARGOS interferometric prototype array. By separating common services, observing-mode plugins, and site-specific configuration, it allows backend capabilities to be deployed across heterogeneous telescope environments and provides a community resource for broadband radio astronomy instrumentation.

astro-ph.IM

Bayesian Superiority in On/Off analysis

We present a detailed comparison of Bayesian criteria with three non-informative priors - flat, Jeffreys, and scale-invariant - for testing a signal against an unknown background and compare them with the classical frequentist Li-Ma approach in the On/Off problem. We perform Monte Carlo simulations for various background levels and evaluate the Li-Ma and Bayesian criteria by their Type I error rates. We then simulate a nonzero signal and compare the criteria in terms of Type II error rates. We find that the Bayesian criterion with the Jeffreys prior yields lower Type I and Type II error rates than the Li-Ma criterion. In addition, we show that the Bayesian criteria are more robust than the Li-Ma criterion when the background distribution is overdispersed relative to the Poisson distribution.

astro-ph.IM

An RFSoC-based Backend and Timing System for the Balloon-borne Very Long Baseline Interferometry Experiment

We present the design and performance characterization of the digital backend and precision-timing system for the Balloon-borne Very Long Baseline Interferometry Experiment (BVEX), a pathfinder for high-frequency stratospheric VLBI at 22 GHz. The backend uses one of the four 14-bit analog-to-digital converter inputs on an AMD-Xilinx RFSoC 4x2. Although the converters support sampling rates up to 5 GSPS, the flight configuration digitizes the 2-4 GHz intermediate frequency at 4.096 GSPS. CASPER firmware provides both a high-resolution spectrometer for pointing and receiver verification, and a VLBI acquisition chain with two-bit requantization that records at a rate of about 8.2 Gbps. The timestamped data packets are sent over 100 Gigabit Ethernet (GbE) to a 16 TB NVMe array in a storage computer that draws approximately 70-80 W. The timing chain uses a Rakon oven-controlled crystal oscillator as a timing reference while a time-interval counter measures its drift relative to a GPS reference with approximately 60 ps resolution. This is the first deployment of an RFSoC-based VLBI backend and precision-timing system on a stratospheric balloon. Ground tests validated the backend, spectrometer, and timing chain. The August 2025 CSA STRATOS flight ended before reaching the target float altitude because of a balloon failure, and as a result no science observations were obtained. For the planned 2027 reflight, we are developing a conduction-cooled data storage computer with 24 TB of NVMe capacity and a direct data path from the 100 GbE interface to the NVMe array.

astro-ph.IM