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
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.