R. Laureijs, R. Vavrek, G. Racca, R. Kohley, P. Ferruit, V. Pettorino, T. Bönke, A. Calvi, L. Gaspar Venancio, L. Campos, E. Maiorano, O. Piersanti, S. Prezelus, U. Ragnit, P. Rosato, C. Rosso, H. Rozemeijer, A. Short, P. Strada, D. Stramaccioni, M. Szafraniec, B. Altieri, G. Buenadicha, X. Dupac, P. Gómez Cambronero, K. Henares Vilaboa, C. Hernandez de la Torre, J. Hoar, M. Lopez-Caniego Alcarria, P. Marcos Arenal, J. Martin Fleitas, M. Miluzio, A. Mora, S. Nieto, R. Perez Bonilla, P. Teodoro Idiago, F. Cordero, J. Mendes, F. Renk, A. Rudolph, M. Schmidt, J. Schwartz, Y. Mellier, H. Aussel, M. Berthé, P. Casenove, M. Cropper, J. Cuillandre, J. Dinis, A. Gregorio, K. Kuijken, T. Maciaszek, L. Miller, R. Scaramella, M. Schirmer, I. Tereno, A. Zacchei, S. Awan, G. Candini, P. Liebing, R. Nakajima, S. Dusini, P. Battaglia, E. Medinaceli, C. Sirignano, I. Baldry, C. Baugh, F. Bernardeau, F. Castander, A. Cimatti, W. Gillard, L. Guzzo, H. Hoekstra, K. Jahnke, T. Kitching, E. Martin, J. Mohr, W. Percival, J. Rhodes
During its 6-year nominal mission, Euclid shall survey one third of the sky, enabling us to examine the spatial distributions of dark and luminous matter during the past 10 Gyr of cosmic history. The Euclid satellite was successfully launched on a SpaceX Falcon 9 launcher from Cape Canaveral on 1 July 2023 and is fully operational in a halo orbit around the Second Sun-Earth Lagrange point. We present an overview of the expected and unexpected findings during the early phases of the mission, in the context of technological heritage and lessons learnt. The first months of the mission were dedicated to the commissioning of the spacecraft, telescope and instruments, followed by a phase to verify the scientific performance and to carry out the in-orbit calibrations. We report that the key enabling scientific elements, the 1.2-meter telescope and the two scientific instruments, a visual imager (VIS) and a near-infrared spectrometer and photometer (NISP), show an inorbit performance in line with the expectations from ground tests. The scientific analysis of the observations from the Early Release Observations (ERO) program done before the start of the nominal mission showed sensitivities better than the prelaunch requirements. The nominal mission started in December 2023, and we allocated a 6-month early survey operations phase to closely monitor the performance of the sky survey. We conclude with an outlook of the activities for the remaining mission in the light of the in-orbit performance.
Euclid, an ESA mission designed to characterise dark energy and dark matter, passed its Mission Critical Design Review in November 2018. It was demonstrated that the project is ready to start integration and test of the main systems, and that it has the ability to fulfil its top-level mission requirements. In addition, based on the performances at M-CDR, the scientific community has verified that the science requirements can be achieved for the Weak Lensing and Galaxy Clustering dark energy probes, namely a dark energy Figure of Merit of 400 and a 2% accuracy in the growth factor exponent gamma. We present the status of the main elements of the Euclid mission in the light of the demanding high optical performance which is the essential design driver is the to meet the scientific requirements. We include the space segment comprising of a service module and payload module hosting the telescope and its two scientific instruments, and the ground segment, which encompasses the operational and science ground segment. The elements for the scientific success of the mission for a timely release of the data are shortly presented: the processing and calibration of the data, and the design of the sky survey. Euclid is presently on schedule for a launch in September 2022.
KEYWORDS: Bolometers, Data modeling, Image processing, Distortion, Image analysis, Image quality, Data processing, Photometry, Neodymium, Picture Archiving and Communication System
We discuss Generalised Least Squares (GLS) map-making for the data of the Herschel satellite’s photometers, which is a difficult task, due to the many disturbances affecting the data, and requires appropriate pre- and post-processing. Taking an existing map-maker as a reference, we propose several advanced techniques, which can improve both the quality of the estimate and the efficiency of the software. As a main contribution we discuss two disturbances, which have not been studied yet and may be detrimental to the image quality. The first is a data shift, due to delays in the timing system or in the processing chain. The second is a random noise, termed pixel noise, due to the jitter and the approximation of the pointing information. For both these disturbances, we develop a mathematical model and propose a compensation method. As an additional contribution, we note that the performance can be improved by properly adapting the algorithm parameters to the data being processed and discuss an automatic setting method. We also provide a rich set of examples and experiments, illustrating the impact of the proposed techniques on the image quality and the execution speed.
J. Amiaux, R. Scaramella, Y. Mellier, B. Altieri, C. Burigana, Antonio Da Silva, P. Gomez, J. Hoar, R. Laureijs, E. Maiorano, D. Magalhães Oliveira, F. Renk, G. Saavedra Criado, I. Tereno, J. Auguères, J. Brinchmann, M. Cropper, L. Duvet, A. Ealet, P. Franzetti, B. Garilli, P. Gondoin, L. Guzzo, H. Hoekstra, R. Holmes, K. Jahnke, T. Kitching, M. Meneghetti, W. Percival, S. Warren
KEYWORDS: Signal to noise ratio, Near infrared, Point spread functions, Visible radiation, Stars, Calibration, Near infrared spectroscopy, Photometry, Space operations, Galactic astronomy
Euclid is an ESA Cosmic-Vision wide-field-space mission which is designed to explain the origin of the acceleration of
Universe expansion. The mission will investigate at the same time two primary cosmological probes: Weak gravitational
Lensing (WL) and Galaxy Clustering (in particular Baryon Acoustic Oscillations, BAO). The extreme precision
requested on primary science objectives can only be achieved by observing a large number of galaxies distributed over
the whole sky in order to probe the distribution of dark matter and galaxies at all scales. The extreme accuracy needed
requires observation from space to limit all observational biases in the measurements. The definition of the Euclid
survey, aiming at detecting billions of galaxies over 15 000 square degrees of the extragalactic sky, is a key parameter of
the mission. It drives its scientific potential, its duration and the mass of the spacecraft. The construction of a Reference
Survey derives from the high level science requirements for a Wide and a Deep survey. The definition of a main
sequence of observations and the associated calibrations were indeed a major achievement of the Definition Phase.
Implementation of this sequence demonstrated the feasibility of covering the requested area in less than 6 years while
taking into account the overheads of space segment observing and maneuvering sequence. This reference mission will be
used for sizing the spacecraft consumables needed for primary science. It will also set the framework for optimizing the
time on the sky to fulfill the primary science and maximize the Euclid legacy.
KEYWORDS: Bolometers, Astronomy, Electronics, Sensors, Calibration, Particles, Interference (communication), Photometry, Signal detection, Picture Archiving and Communication System
The CEA/LETI and CEA/SAp started the development of far-infrared filled bolometer arrays for space applications
over a decade ago. The unique design of these detectors makes possible the assembling of large focal planes
comprising thousands of bolometers running at 300 mK with very low power dissipation. Ten arrays of 16x16
pixels were thoroughly tested on the ground, and integrated in the Herschel/PACS instrument before launch in
May 2009. These detectors have been successfully commissioned and are now operating in their nominal environment
at the second Lagrangian point of the Earth-Sun system. In this paper we briefly explain the functioning
of CEA bolometer arrays, and we present the properties of the detectors focusing on their noise characteristics,
the effect of cosmic rays on the signal, the repeatability of the measurements, and the stability of the system.
On December 10th 2004 the XMM-Newton observatory celebrated its 5th year in orbit. Since the beginning of the mission steady health and contamination monitoring has been performed by the XMM-Newton SOC and the instrument teams. Main targets of the monitoring, using scientific data for all instruments on board, are the behaviour of the Charge Transfer Efficiency, the gain, the effective area and the bad, hot and noisy pixels. The monitoring is performed by combination of calibration observations using internal radioactive calibration sources with observations of astronomical targets. In addition a set of housekeeping parameters is continuously monitored reflecting the health situation of the instruments from an engineering point of view. We show trend behaviour over the 5 years especially in combination with events like solar flares and other events affecting the performance of the instruments.
The great collecting area of the mirrors coupled with the high quantum efficiency of the EPIC detectors have made XMM-Newton the most sensitive X-ray observatory flown to date. This is particularly evident during slew exposures which, while giving only 15 seconds of on-source time, actually constitute a 2-10 keV survey ten times deeper than current "all-sky" catalogues. Here we report on progress towards making a catalogue of slew detections constructed from the full, 0.2-12 keV energy band and discuss the challenges associated with processing the slew data. The fast (90 degrees per hour) slew speed results in images which are smeared, by different amounts depending on the readout mode, effectively changing the form of the point spread function. The extremely low background in slew images changes the optimum source searching criteria such that searching a single image using the full energy band is seen to be more sensitive than splitting the data into discrete energy bands. False detections due to optical loading by bright stars, the wings of the PSF in very bright sources and single-frame detector flashes are considered and techniques for identifying and removing these spurious sources from the final catalogue are outlined. Finally, the attitude reconstruction of the satellite during the slewing maneuver is complex. We discuss the implications of this on the positional accuracy of the catalogue.
XMM-Newton was launched into space on a highly eccentric 48 hour orbit on December 10th 1999. XMM-Newton is now in its fifth year of operation and has been an outstanding success, observing the Cosmos with imaging, spectroscopy and timing capabilities in the X-ray and optical wavebands. The EPIC-MOS CCD X-ray detectors comprise two out of three of the focal plane instruments on XMM-Newton. In this paper we discuss key aspects of the current status and performance history of the charge transfer ineffiency (CTI), energy resolution and spectral redistribution function (rmf) of EPIC-MOS in its fifth year of operation.
KEYWORDS: Signal to noise ratio, Point spread functions, Stars, Roentgenium, Data modeling, Cameras, Sensors, Calibration, Ultraviolet radiation, Molybdenum
ESA's large X-ray space observatory XMM-Newton is in its fifth year of operations. We give a general overview of the status of calibration of the five X-ray instruments and the Optical Monitor. A main point of interest in the last year became the cross-calibration between the instruments. A cross-calibration campaign started at the XMM-Newton Science Operation Centre at the European Space Astronomy Centre in collaboration with the Instrument Principle Investigators provides a first systematic comparison of the X-ray instruments EPIC and RGS for various kind of sources making also an initial assessment in cross calibration with other X-ray observatories.
The XMM-Newton observatory has the largest collecting area flown so
far for an X-ray imaging system, resulting in a very high sensitivity
over a broad spectral range. In order to exploit fully these
performances, an accurate calibration of the XMM-Newton
instruments is required. This calibration is being continuously
updated, in order to refine the stable calibration parameters as well
as to account for the detector response changes induced by radiation damage. We report here on the current overall status of the EPIC/MOS cameras calibrations, and in particular on the recent work involving Charge Transfer Inefficiency evolution and recovery.
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