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arXiv · 1306.5923

Noise reduction methods in analysis of near infrared lunar occultation light curves for high angular resolution measurements

Tapas Baug·Thyagarajan Chandrasekhar
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Abstract

Lunar occultation (LO) technique in the near-infrared provides angular resolution down to milliarcseconds on the occulted source even with ground-based 1m class telescopes. LO observations are limited to brighter objects because they require high signal to noise ratio (S/N ~ 40) for proper extraction of angular diameter values. Hence, methods to improve the S/N ratio by reducing noise using Fourier and Wavelet transforms have been explored in this study. A sample of 54 near-infrared LO light curves observed with IR Camera at Mt Abu observatory has been used. It is seen that both Fourier and Wavelet methods have shown improvement in S/N, compared to the original data. However, the application of wavelet transforms results in slight smoothening of the fringes resulting in a higher angular diameter value. Fourier transforms which reduce discrete noise frequencies do not distort the fringe. Fourier transform method seems to be effective in S/N improvement, as well as improved model fit particularly in the fainter regime of our sample. They also provide a better model fit for brighter sources in some cases though there may not be significant S/N improvement.

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Tapas Baug, Thyagarajan Chandrasekhar. 2013-06-25. Noise reduction methods in analysis of near infrared lunar occultation light curves for high angular resolution measurements. https://doi.org/10.1088/1674-4527/13/11/007

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