Probing primordial non-Gaussianity: the 3D Bispectrum of Ly-α forest and the redshifted 21-cm signal from the post reionization epoch

• Published in: Journal of cosmology and astroparticle physics 2013-04, Vol.2013 (4), p.1-13
• Main Authors: Sarkar, Tapomoy Guha, Hazra, Dhiraj Kumar
• Format: Article
• Language: English
• Subjects: ASTROPHYSICS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Automotive components; Constraining; COSMOLOGY; DENSITY; Forests; Formalism; GALAXIES; HYDROGEN; LYMAN LINES; NONLUMINOUS MATTER; Perturbation methods; PERTURBATION THEORY; QUASARS; RED SHIFT; Three dimensional; Three dimensional models; THREE-DIMENSIONAL CALCULATIONS; Tracers
• ISSN: 1475-7516; 1475-7516
• DOI: 10.1088/1475-7516/2013/04/002

We explore possibility of using the three dimensional bispectra of the Ly- alpha forest and the redshifted 21-cm signal from the post-reionization epoch to constrain primordial non-Gaussianity. We first present the general formalism for the auto and cross bispectrum of two arbitrary three dimensional biased tracers and then apply it to the specific case. We have modeled the 3D Ly- alpha transmitted flux field as a continuous tracer sampled along 1D skewers which corresponds to quasars sight lines. For the post reionization 21-cm signal we have used a linear bias model. We find that bounds on f sub(NL) obtained in our analysis (6 [< or =, slant] Delta f sub(NL) [< or =, slant] 65) is competitive with CMBR and galaxy surveys and may prove to be an important alternative approach towards constraining primordial physics using future data sets. This shall be important in the quest towards understanding the mechanism behind the generation of primordial perturbations.