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Photometry in UV astronomical images of extended sources in crowded field using deblended images in optical visible bands as Bayesian priors

Vibert, D. and Zamojski, M. and Conseil, S. and Llebaria, A. and Arnouts, S. and Milliard, B. and Guillaume, M. (2009) Photometry in UV astronomical images of extended sources in crowded field using deblended images in optical visible bands as Bayesian priors. In: Computational Imaging VII. Proceedings of SPIE. No.7246. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 72460U. ISBN 9780819474964. https://resolver.caltech.edu/CaltechAUTHORS:20181113-090555025

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Abstract

Photometry of astrophysical sources, galaxies and stars, in crowded field images, if an old problem, is still a challenging goal, as new space survey missions are launched, releasing new data with increased sensibility, resolution and field of view. The GALEX mission, observes in two UV bands and produces deep sky images of millions of galaxies or stars mixed together. These UV observations are of lower resolution than same field observed in visible bands, and with a very faint signal, at the level of the photon noise for a substantial fraction of objects. Our purpose is to use the better known optical counterparts as prior information in a Bayesian approach to deduce the UV flux. Photometry of extended sources has been addressed several times using various techniques: background determination via sigma clipping, adaptative-aperture, point-spread-function photometry, isophotal photometry, to lists some. The Bayesian approach of using optical priors for solving the UV photometry has already been applied by our team in a previous work. Here we describe the improvement of using the extended shape inferred by deblending the high resolution optical images and not only the position of the optical sources. The resulting photometric accuracy has been tested with simulation of crowded UV fields added on top of real UV images. Finally, this helps to converge to smaller and flat residual and increase the faint source detection threshold. It thus gives the opportunity to work on 2nd order effects, like improving the knowledge of the background or point-spread function by iterating on them.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.1117/12.810228DOIArticle
Additional Information:© 2009 Society of Photo-optical Instrumentation Engineers (SPIE).
Subject Keywords:UV astronomical imagery, photometry, Data fusion, Bayesian estimation, Point spread function modeling, minimization
Series Name:Proceedings of SPIE
Issue or Number:7246
Record Number:CaltechAUTHORS:20181113-090555025
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20181113-090555025
Official Citation:D. Vibert, M. Zamojski, S. Conseil, A. Llebaria, S. Arnouts, B. Milliard, M. Guillaume, "Photometry in UV astronomical images of extended sources in crowded field using deblended images in optical visible bands as Bayesian priors," Proc. SPIE 7246, Computational Imaging VII, 72460U (2 February 2009)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90856
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:13 Nov 2018 17:46
Last Modified:03 Oct 2019 20:29

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