MF-PCA Continuum Fitting of SDSS-DR7 at High Redshifts in the Lyα Forest

Abstract

This paper is mainly concerned with mean flux regulated - principal component analysis (MF-PCA) continuum estimation technique. In this technique PCA fitting is carried out red ward of quasar Lyα line in order to provide a prediction for the shape of the Lyα forest continuum. The purpose of this paper is also to predict the continuum of bright QSO in the region by wavelengths longer than Lyα emission line using the statistical method of MF-PCA. The method applied to a sample of 892 high redshift with brightly luminous QSO; (MB≤ -28, S/N > 10 and 2.7≤ z ≤ 4.7) published in SDSS-DR7. The slope and amplitude of the continua were predicted by applying the estimated technique. We found that MF-PCA method reduces the errors to 3% RMS in S/N > 10 spectra with continuum of manual method.