Sky subtraction for deep surface photometry of the intergalactic light from clusters of galaxies

Citation
J. Melnick et al., Sky subtraction for deep surface photometry of the intergalactic light from clusters of galaxies, PUB AST S P, 111(765), 1999, pp. 1444-1450
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
ISSN journal
0004-6280 → ACNP
Volume
111
Issue
765
Year of publication
1999
Pages
1444 - 1450
Database
ISI
SICI code
0004-6280(199911)111:765<1444:SSFDSP>2.0.ZU;2-3
Abstract
A new observing procedure and method of analysis of CCD observations are pr esented. The observing procedure maximizes the on-source time without the n eed for observing separate blank sky fields. It is shown that a substantial improvement in the correction of sky and detector systematics can be achie ved by explicitly separating the sky subtraction from the calibration of th e spatial gain variations of the CCD, or flat-fielding. When we perform the sky subtraction before flat-fielding, the requirements on the latter are n ot as stringent. We test this method with deep IT-band images obtained unde r extremely challenging observing conditions. Because of the presence of il lumination gradients due to moonlight, a flat field with an accuracy of bet ter than 10% could not be obtained. Nevertheless, a sky subtraction with an accuracy of approximately 0.1% of the sky brightness was achieved over the whole mosaic.