15 Mpc Structure at 2.1 < z < 3.3 from the Ly alpha Forest

Session 13 - Large Scale Structure & Cosmology.
Display session, Monday, January 13
Metropolitan Ballroom,

[13.06] 15 Mpc Structure at 2.1 < z < 3.3 from the Ly alpha Forest

G. Williger (NOAO at NASA/GSFC), A. Smette (Kapteyn Inst., Groningen, Netherlands), C. Hazard (U. Pittsburgh and IOA, Cambridge, UK), J. Baldwin (IOA, Cambridge, UK and CTIO, La Serena, Chile), R. McMahon (IOA, Cambridge, UK)

We have conducted a survey of the Ly\alpha forest in the redshift domain 2.15 < z < 3.37 in front of nine QSOs within a 1^\circ field to probe spatial structure along planes perpendicular to the line-of-sight. The sample consists of 377 Ly\alpha lines with rest equivalent width W_0\geq 0.1 Å\ significant at the 5\sigma level, and separated from the background QSO by \Delta v \geq 5000 km s^-1. We find statistical evidence for correlations of the Ly\alpha absorption line wavelengths through the whole redshift range at angular separations of up to 60 arcmin, and, at z>2.8, of their equivalent widths. The correlations span velocity separations of 50<\Delta v < 400 km s^-1. We find similar behavior in a smaller dataset taken from the literature. Such correlations are consistent with the emerging picture that Ly\alpha lines arise in filaments or large, flattened structures.

Program listing for Monday