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

TL;DR

This paper introduces a new pre-processing method and software tool, AMDC, to correct bias in interferometric visibilities caused by time-variable fringing noise in low SNR VLTI-AMBER data, improving data accuracy.

Contribution

The paper presents a novel bias correction method and software for VLTI-AMBER data, addressing fringing noise effects in low SNR observations, which was not previously available.

Findings

Effective bias correction demonstrated on simulated data.

Improved visibility accuracy in real observations.

Software available for community use.

Abstract

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 due to 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, called AMDC and available to the community, to be run before the standard reduction package. Results obtained on simulated and real observations are presented and discussed.