EDP Sciences
Free access
Volume 479, Number 2, February IV 2008
Page(s) 589 - 595
Section Astronomical instrumentation
DOI http://dx.doi.org/10.1051/0004-6361:20077629

A&A 479, 589-595 (2008)
DOI: 10.1051/0004-6361:20077629

De-biasing interferometric visibilities in VLTI-AMBER data of low SNR observations

G. Li Causi1, S. Antoniucci1, 2, and E. Tatulli3, 4

1  INAF - Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monteporzio Catone, Italy
    e-mail: licausi@oa-roma.inaf.it
2  Università degli Studi di Roma "Tor Vergata", via della Ricerca Scientifica 1, 00133 Roma, Italy
3  INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
4  Laboratoire d'Astrophysique Observatoire de Grenoble, BP 53, 38041 Grenoble Cedex 9, France

(Received 11 April 2007 / Accepted 26 November 2007)

Aims. We have found that the interferometric visibilities of VLTI-AMBER observations, extracted via the standard reduction package, are significantly biased when faint targets are concerned. The visibility biases derive from a time variable fringing effect (correlated noise) appearing on the detector.
Methods. We have developed a method to correct this bias that consists in a subtraction of the extra power caused by such correlated noise, so that the real power spectrum at the spatial frequencies of the fringing artifact can be restored.
Results. This pre-processing procedure is implemented in a software program called AMDC, available to the community, which is to be run before the standard reduction package. Results obtained on simulated and real observations are presented and discussed.

Key words: instrumentation: interferometers -- instrumentation: detectors -- methods: data analysis -- techniques: interferometric

© ESO 2008