Friday, January 18, 2013

1301.4041 (Ingo P. Waldmann et al.)

Blind extraction of an exoplanetary spectrum through Independent Component Analysis    [PDF]

Ingo P. Waldmann, Giovanna Tinetti, Pieter Deroo, Morgan D. J. Hollis, Sergey N. Yurchenko, Jonathan Tennyson
Blind-source separation techniques are used to extract the transmission spectrum of the hot-Jupiter HD189733b recorded by the Hubble/NICMOS instrument. Such a 'blind' analysis of the data is based on the concept of independent component analysis. The de-trending of Hubble/NICMOS data using the sole assumption that nongaussian systematic noise is statistically independent from the desired light-curve signals is presented. By not assuming any prior, nor auxiliary information but the data themselves, it is shown that spectroscopic errors only about 10 - 30% larger than parametric methods can be obtained for 11 spectral bins with bin sizes of ~0.09 microns. This represents a reasonable trade-off between a higher degree of objectivity for the non-parametric methods and smaller standard errors for the parametric de-trending. Results are discussed in the light of previous analyses published in the literature. The fact that three very different analysis techniques yield comparable spectra is a strong indication of the stability of these results.
View original: http://arxiv.org/abs/1301.4041

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