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INTEGRAL/SPI data segmentation to retrieve sources intensity variations

Bouchet, Laurent and Amestoy, Patrick and Buttari, Alfredo and Rouet, François-Henry and Chauvin, Maxime INTEGRAL/SPI data segmentation to retrieve sources intensity variations. (2013) Astronomy & Astrophysics, vol. 555 (n° A55). pp. 1-22. ISSN 0004-6361

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Official URL: http://dx.doi.org/10.1051/0004-6361/201219605

Abstract

Context. The INTEGRAL/SPI, X/γ-ray spectrometer (20 keV–8 MeV) is an instrument for which recovering source intensity variations is not straightforward and can constitute a difficulty for data analysis. In most cases, determining the source intensity changes between exposures is largely based on a priori information. Aims. We propose techniques that help to overcome the difficulty related to source intensity variations, which make this step more rational. In addition, the constructed “synthetic” light curves should permit us to obtain a sky model that describes the data better and optimizes the source signal-to-noise ratios. Methods. For this purpose, the time intensity variation of each source was modeled as a combination of piecewise segments of time during which a given source exhibits a constant intensity. To optimize the signal-to-noise ratios, the number of segments was minimized. We present a first method that takes advantage of previous time series that can be obtained from another instrument on-board the INTEGRAL observatory. A data segmentation algorithm was then used to synthesize the time series into segments. The second method no longer needs external light curves, but solely SPI raw data. For this, we developed a specific algorithm that involves the SPI transfer function. Results. The time segmentation algorithms that were developed solve a difficulty inherent to the SPI instrument, which is the intensity variations of sources between exposures, and it allows us to obtain more information about the sources’ behavior.

Item Type:Article
Additional Information:Thanks to EDP Sciences editor. The definitive version is available at http://www.aanda.org/articles/aa/abs/2013/07/aa19605-12/aa19605-12.html
HAL Id:hal-01124774
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National des Etudes Spatiales - CNES (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
French research institutions > Institut de Recherche pour le Développement - IRD (FRANCE)
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS (FRANCE)
Université de Toulouse > Université Toulouse - Jean Jaurès - UT2J (FRANCE)
Université de Toulouse > Université de Toulouse I-Sciences Sociales - UT1 (FRANCE)
Other partners > Météo France (FRANCE)
Other partners > University of California - UC Berkeley (USA)
Laboratory name:
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Deposited By: IRIT IRIT
Deposited On:06 Mar 2015 10:18

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