In this communication an extraction procedure that takes into account the spectral dispersion function (the spectral analog of the PSF) is presented. The method is named least-squares deconvolution. It allows the recovery of the relative line-to-continuum visibility amplitude ratio and the relative line to continuum visibility phase difference. The method only uses as input the AMBER data making the sole hypotheses that the spectral broadening of the spectra in the photometric channel is the same as that of the interferometric data. A subset of this hypothesis is the case of unresolved lines. It is extremely robust being able to recover line to continuum visibility and phase at very low signal-to-noise ratio. It is shown that it is superior to other differential visibility and phase methods presented in the literature, which in certain conditions are biased. The method can be trivially generalized to similar instruments as those available at CHARA and Keck-I. Least squares deconvolution opens the possibility of delivering legacy quality measurements from the AMBER archive without relying on visibility calibration or environmental effects such as vibrations. It is a key tool for the astrophysical exploitation of this instrument.

Date Published: 12 September 2012
PDF: 10 pages
Proc. SPIE 8445, Optical and Infrared Interferometry III, 844517 (12 September 2012); doi: 10.1117/12.925280

Published in SPIE Proceedings Vol. 8445:
Optical and Infrared Interferometry III
Françoise Delplancke; Jayadev K. Rajagopal; Fabien Malbet, Editor(s)