Modern astrophysics relies on intricate instrument setups to meet the demands of sensitivity, sky coverage, and multi-channel observations. An example is the CONCERTO project, employing advanced technology like kinetic inductance detectors and a Martin-Puplett interferometer. This instrument, installed at the APEX telescope atop the Chajnantor plateau, began commissioning observations in April 2021. Following a successful commissioning phase that concluded in June 2021, CONCERTO was offered to the scientific community for observations, with a final observing run in December 2022. CONCERTO boasts an 18.5 arcmin field of view and a spectral resolution down to 1.45 GHz in the 130–310 GHz electromagnetic band. We developed a comprehensive instrument model of CONCERTO inspired by Fourier transform spectrometry principles to optimize performance and address systematic errors. This model integrates instrument noises, subsystem characteristics, and celestial signals, leveraging both physical data and simulations. Our methodology involves delineating simulation components, executing on-sky simulations, and comparing results with real observations. The resulting instrument model is pivotal, enabling a precise error correction and enhancing the reliability of astrophysical insights obtained from observational data. In this work, we focus on the description of three white-noise noise components included in the instrument model that characterize the white-noise level: the photon, the generation-recombination, and the amplifier noises.
CarbON CII line in post-rEionization and ReionizaTiOn (CONCERTO) is a low-resolution spectrometer with an instantaneous field-of-view of 18.6 arcmin, operating in the 130–310 GHz transparent atmospheric window. It is installed on the 12-meter Atacama Pathfinder Experiment (APEX) telescope at 5 100 m above sea level. The Fourier transform spectrometer (FTS) contains two focal planes hosting a total of 4 304 kinetic inductance detectors. The FTS interferometric pattern is recorded on the fly while continuously scanning the sky. One of the goals of CONCERTO is to characterize the large-scale structure of the Universe by observing the integrated emission from unresolved galaxies. This methodology is an innovative technique and is called line intensity mapping. In this paper, we describe the CONCERTO instrument, the effect of the vibration of the FTS beamsplitter, and the status of the CONCERTO main survey.
Daniel Espada, Masao Saito, Lars-Åke Nyman, Juan Cortes, Andy Biggs, Felix Stoehr, Itziar de Gregorio, Stephane Leon, Ruediger Kneissl, Liz Humphreys, Emilio Barrios, Gautier Mathys, Thomas Wiklind, Crystal Brogan, Carol Lonsdale, Anthony Remijan, Baltasar Vila-Vilaro, Eric Villard, Andreas Lundgren, Paola Andreani, Ken'ichi Tatematsu, John Hibbard
The transition from construction to full operations of the Atacama Large Millimeter/submillimeter Array (ALMA) brings the challenge to have not only software subsystems that are functional and stable but also to develop a system that works flawlessly as a single entity from proposal preparation to the delivery of the final data products to ALMA users. This is especially challenging as the different subsystems have to be constantly updated and improved to accommodate new observing modes and increasing capabilities. We present recent progress and future initiatives in the different offline subsystems that are currently being developed and used in ALMA operations: proposal preparation, submission and observation preparation (Observing Tool and submission server), proposal review process (Ph1M), project tracking (Project Tracker, Life Cycle), observation bookkeeping (Shift Log Tool), calibrator database (Source Catalogue), monitor and control of observations (Operations Monitoring and Control tool), dynamic scheduler, data reduction pipeline, quality assurance and trend analysis (AQUA), archive, as well as additional user support systems such as the Science Portal.
Lars-Åke Nyman, Pierre Cox, Stuartt Corder, Masao Saito, Andreas Lundgren, Baltasar Vila-Vilaro, Daniel Espada, Eric Villard, Emilio Barrios, Paola Andreani, John Hibbard, Ken'ichi Tatematsu
The Atacama Large Millimeter/submillimeter Array (ALMA) is a new interferometer operated on Llano de Chajnantor at 5050 m altitude in the Chilean Andes. It consists of 66 antennas operating in the mm/submm windows between 3 and 0.3 mm wavelength. Early science observations using 16 antennas (known as Cycle 0) started in parallel with construction in September 2011, in order to provide useful results to the astronomy community and to facilitate the ongoing characterization of its system. ALMA is currently in Cycle 2 of early science observations. This presentation describes the development and progress of ALMA observations and data processing from Cycle 0 towards full operations.
Andreas Lundgren, Lars-Ake Nyman, Masao Saito, Baltasar Vila Vilaro, Gautier Mathys, Paola Andreani, John Hibbard, Sachiko Okumura, Ken'ichi Tatematsu, Bill Dent, Mark Rawlings, Eric Villard, Lewis Ball
The Atacama Large Millimeter/submillimeter Array (ALMA) is a major new interferometer operated on Llano
de Chajnantor at 5050 m altitude in the Chilean high Andes. This location is considered one of the world's
outstanding sites for submillimeter astronomy.
ALMA is still under construction, but science observations has started already in what is commonly known
as ALMA Early Science Cycle 0. The purpose of ALMA Early Science Cycle 0 is to deliver scientically
useful results to the astronomy community and to facilitate the ongoing characterization of ALMA systems and
instrumentation as the capability of the array continues to grow. Early Science will continue through Cycle 1
and until construction and commissioning of ALMA is complete.
This publication aims to give an insight into the challenges we face operating telescope of this scale at
Chajnantor, a plateau 4800{5100 meter above sea level in one of the driest places of earth. It also will also
present statistics from the proposal submission, describe the path from an accepted proposal to a calibrated data
product, and nally an outlook for the future.
The database of the relocatable VLTI Auxiliary Telescopes was used to study their stability and long-term trends
in their pointing models. The model parameters are functions of mechanical properties of the telescopes and
station pads. The index error in elevation and non-perpendicularity in elevation depend mainly on telescope
characteristics, while the tilt parameters on the pads. After some trends present in 2007-2010 the mechanical
characteristics of all four VLTI 1.8m telescopes are stabilized. Some tilt trends are still present in recently opened
stations, but unlike in APEX, the tilts are not significantly affected by seasonal temperature variations.
APEX, the Atacama Pathfinder EXperiment, is being operated successfully, now for five years, on Llano de Chajnantor
at 5107m altitude in the Chilean High Andes. This location is considered one of the worlds outstanding
sites for submillimeter astronomy, which the results described in this contribution are underlining. The primary
reflector with 12 m diameter is cautiously being maintained at about 15 μm by means of holography. This
allows to access all atmospheric submillimeter windows accessible from the ground, up to 200 μm. Telescope and
instrument performance, operational experiences and a selection of scientific results are given in this publication.
We report on developments of submillimeter heterodyne arrays for high resolution spectroscopy with APEX. Shortly, we will operate
state-of-the-art instruments in all major atmospheric windows accessible from Llano de Chajnantor. CHAMP+, a dual-color 2×7 element heterodyne array for operation in the 450 μm and 350 μm atmospheric windows is in operation since late 2007. With its
state-of-the-art SIS detectors and wide tunable local oscillators, its cold optics with single sideband filters and with 3 GHz of processed IF bandwidth per pixel, CHAMP+ does provide outstanding observing capabilities. The Large APEX sub-Millimeter Array (LAsMA) is in the final design phase, with an installation goal in 2009. The receiver will operate 7 and 19 pixels in the lower submillimeter windows, 285-375 GHz and 385-520 GHz, respectively. The front-ends are served by an array of digital wideband Fast Fourier Transform spectrometers currently processing up to 32×1.5 (optionally 1.8) GHz of bandwidth. For CHAMP+, we process 2.8 GHz of instantaneous bandwidth (in 16.4 k channels) for each of the 14 pixels.
R. Güsten, R. Booth, C. Cesarsky, K. Menten, C. Agurto, M. Anciaux, F. Azagra, V. Belitsky, A. Belloche, P. Bergman, C. De Breuck, C. Comito, M. Dumke, C. Duran, W. Esch, J. Fluxa, A. Greve, H. Hafok, W. Häupl, L. Helldner, A. Henseler, S. Heyminck, L. Johansson, C. Kasemann, B. Klein, A. Korn, E. Kreysa, R. Kurz, I. Lapkin, S. Leurini, D. Lis, A. Lundgren, F. Mac-Auliffe, M. Martinez, J. Melnick, D. Morris, D. Muders, L. Nyman, M. Olberg, R. Olivares, M. Pantaleev, N. Patel, K. Pausch, S. Philipp, S. Philipps, T. Sridharan, E. Polehampton, V. Reveret, C. Risacher, M. Roa, P. Sauer, P. Schilke, J. Santana, G. Schneider, J. Sepulveda, G. Siringo, J. Spyromilio, K.-H. Stenvers, F. van der Tak, D. Torres, L. Vanzi, V. Vassilev, A. Weiss, K. Willmeroth, A. Wunsch, F. Wyrowski
APEX, the Atacama Pathfinder Experiment, has been successfully commissioned and is in operation now. This novel submillimeter telescope is located at 5107 m altitude on Llano de Chajnantor in the Chilean High Andes, on what is considered one of the world's outstanding sites for submillimeter astronomy. The primary reflector with 12 m diameter has been carefully adjusted by means of holography. Its surface smoothness of 17-18 μm makes APEX suitable for observations up to 200 μm, through all atmospheric submm windows accessible from the ground.
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