TY - GEN
T1 - Flux reconstruction for the NIR camera CAGIRE at the focus of the Colibrí telescope
AU - de la Flèche, Alix Nouvel
AU - Atteia, Jean Luc
AU - Valentin, Hervé
AU - Larrieu, Marie
AU - Boy, Jérémie
AU - Gravrand, Olivier
AU - Boulade, Olivier
AU - Clemens, Jean Claude
AU - Secroun, Aurélia
AU - Kajfasz, Eric
AU - Llido, Olivier
AU - Basa, Stéphane
AU - Dolon, François
AU - Floriot, Johan
AU - Lombardo, Simona
AU - Lamoure, Adrien
AU - Rubaldo, Laurent
AU - Fieque, Bruno
AU - Roumegoux, Julien
AU - Geoffray, Hervé
AU - Watson, Alan M.
AU - Lee, William H.
AU - Butler, Nathaniel
N1 - Funding Information:
The calibration data used in the first parts of this paper were acquired at CEA by O. Boulade. The data has been provided to IRAP in agreement with ESA. CAGIRE is partly funded by the French Centre National d’Etudes Spatiales (CNES). The PhD contract of A. Nouvel de la Flèche is financed by CNES and LYNRED. This work has been partially supported by the LabEx FOCUS ANR-11-LABX-0013.
Funding Information:
The on sky data used in this paper were acquired with the RATIR instrument, funded by the University of California and NASA Goddard Space Flight Center, and the 1.5-meter Harold L. Johnson telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, operated and maintained by the Ob-servatorio Astronómico Nacional and the Instituto de Astronomía of the Universidad Nacional Autónoma de México. Operations are partially funded by the Universidad Nacional Autónoma de México (DGAPA/PAPIIT IG100414, IT102715, AG100317, IN109418, IG100820, and IN105921). We acknowledge the contribution of Leonid Georgiev and Neil Gehrels to the development of RATIR.
Publisher Copyright:
© 2022 SPIE.
PY - 2022
Y1 - 2022
N2 - CAGIRE is the near infrared camera of the Colibrí robotic telescope, designed for the follow-up of SVOM alerts, mainly Gamma Ray Bursts (GRBs), and the quick imaging of sky regions where transient sources are detected by the SVOM satellite. CAGIRE is based on the Astronomical Large Format Array (ALFA) 2k x 2k SWIR sensor from the French consortium CEA-LYNRED. In the context of CAGIRE the sensor is operated in “Up the Ramp” mode to observe the sky in a square field of view of 21.7 arcmin on a side, in the range of wavelengths from 1.1 to 1.8 µm. An observation with CAGIRE consists of a series of short (1-2 minutes) exposures during which the pixels are read out every 1.3 second, continuously accumulating charges proportionally to the received flux, building a ramp. The main challenge is to quickly process and analyse these ramps, in order to identify and study the near infrared counterparts of the bursts, within 5 minutes of the reception of an alert. Our preprocessing, which is under development, aims at providing reliable flux maps for the astronomy pipeline. It is based on a sequence of operations. First, calibration maps are used to identify saturated pixels, and for each pixel, the usable (non saturated) range of the ramp. Then, the ramps are corrected for the electronic common mode noise, and differential ramps are constructed. Finally, the flux is calculated from the differential ramps, using a previously calibrated map of pixel non-linearities. We present here the sequence of operations performed by the preprocessing, which are based on previous calibrations of the sensor response. These operations lead to the production of a flux map corrected from cosmic-rays hits, a map depicting the quality of the fit, a map of saturated pixels and a map of pixels hit by cosmic-rays, before the acquisition of the next ramp. These maps will be used by the astronomy pipeline to quickly extract the scientific results of the observations, like the identification of uncatalogued or quickly variable sources that could be GRB afterglows.
AB - CAGIRE is the near infrared camera of the Colibrí robotic telescope, designed for the follow-up of SVOM alerts, mainly Gamma Ray Bursts (GRBs), and the quick imaging of sky regions where transient sources are detected by the SVOM satellite. CAGIRE is based on the Astronomical Large Format Array (ALFA) 2k x 2k SWIR sensor from the French consortium CEA-LYNRED. In the context of CAGIRE the sensor is operated in “Up the Ramp” mode to observe the sky in a square field of view of 21.7 arcmin on a side, in the range of wavelengths from 1.1 to 1.8 µm. An observation with CAGIRE consists of a series of short (1-2 minutes) exposures during which the pixels are read out every 1.3 second, continuously accumulating charges proportionally to the received flux, building a ramp. The main challenge is to quickly process and analyse these ramps, in order to identify and study the near infrared counterparts of the bursts, within 5 minutes of the reception of an alert. Our preprocessing, which is under development, aims at providing reliable flux maps for the astronomy pipeline. It is based on a sequence of operations. First, calibration maps are used to identify saturated pixels, and for each pixel, the usable (non saturated) range of the ramp. Then, the ramps are corrected for the electronic common mode noise, and differential ramps are constructed. Finally, the flux is calculated from the differential ramps, using a previously calibrated map of pixel non-linearities. We present here the sequence of operations performed by the preprocessing, which are based on previous calibrations of the sensor response. These operations lead to the production of a flux map corrected from cosmic-rays hits, a map depicting the quality of the fit, a map of saturated pixels and a map of pixels hit by cosmic-rays, before the acquisition of the next ramp. These maps will be used by the astronomy pipeline to quickly extract the scientific results of the observations, like the identification of uncatalogued or quickly variable sources that could be GRB afterglows.
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U2 - 10.1117/12.2627826
DO - 10.1117/12.2627826
M3 - Conference contribution
AN - SCOPUS:85140070258
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - X-Ray, Optical, and Infrared Detectors for Astronomy X
A2 - Holland, Andrew D.
A2 - Beletic, James
PB - SPIE
T2 - X-Ray, Optical, and Infrared Detectors for Astronomy X 2022
Y2 - 17 July 2022 through 20 July 2022
ER -