Imaging extended sources with coded mask telescopes: application to the INTEGRAL IBIS/ISGRI instrument

Renaud, Matthieu and Gros, Aleksandra and Lebrun, Francois and Terrier, R. and Goldwurm, A. and Reynolds, Stephen and Kalemci, Emrah (2006) Imaging extended sources with coded mask telescopes: application to the INTEGRAL IBIS/ISGRI instrument. Astronomy and Astrophysics, 456 (1). pp. 389-394. ISSN 0004-6361

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Official URL: http://dx.doi.org/10.1051/0004-6361:20065156


Context: In coded mask techniques, reconstructed sky images are pseudo-images: they are maps of the correlation between the image recorded on a detector and an array derived from the coded mask pattern. Aims: The INTEGRAL /IBIS telescope provides images where the flux of each detected source is given by the height of the local peak in the correlation map. As such, it cannot provide an estimate of the flux of an extended source. What is needed is intensity sky images giving the flux per solide angle as typically done at other wavelengths. Methods: In this paper, we present the response of the INTEGRAL IBIS /ISGRI coded mask instrument to extended sources. We develop a general method based on analytical calculations in order to measure the intensity and the associated error of any celestial source and validated with Monte-Carlo simulations. Results: We find that the sensitivity degrades almost linearly with the source extent. Analytical formulae are given as well as an easy-to-use recipe for the INTEGRAL user. We check this method on IBIS /ISGRI data but these results are general and applicable to any coded mask telescope.

Item Type:Article
Uncontrolled Keywords:methods: data analysis; methods: observational; telescopes; gamma rays: observations
Subjects:Q Science > QB Astronomy
Q Science > QC Physics
ID Code:6426
Deposited By:Emrah Kalemci
Deposited On:25 Oct 2007 16:04
Last Modified:25 May 2011 14:03

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