Skip to Main content Skip to Navigation
Journal articles

A ~6 Mpc overdensity at z ≃ 2.7 detected along a pair of quasar sight lines: filament or protocluster?

Abstract : Simulations predict that gas in the intergalactic medium (IGM) is distributed in filamentary structures that connect dense galaxy clusters and form the cosmic web. These structures of predominantly ionized hydrogen are difficult to observe directly due to their lack of emitting regions. We serendipitously detected an overdensity of log N(H i) > 18.0 absorbers at z ≃ 2.69 along the lines of sight toward a pair of background quasars. Three main absorption regions spanning ~ 2000 km s-1 (corresponding to 6.4 h70-1 Mpc proper) are coincident in the two lines of sight, which are separated by ~ 90 h70-1 kpc transverse proper distance. Two regions have [Fe/H] <-1.9 and correspond to mild overdensities in the IGM gas. The third region is a sub-DLA with [Fe/H] = -1.1 that is probably associated with a galaxy. We discuss the possibility that the lines of sight probe along the length of a filament or intercept a galaxy protocluster.

Based on observations with X-shooter on the Very Large Telescope at the European Southern Observatory under program 089.A-0855.

Complete list of metadata
Contributor : Hal Sorbonne Université Gestionnaire Connect in order to contact the contributor
Submitted on : Monday, April 25, 2022 - 4:20:24 PM
Last modification on : Monday, April 25, 2022 - 4:20:26 PM


Publisher files allowed on an open archive



Hayley Finley, Patrick Petitjean, Pasquier Noterdaeme, Isabelle Pâris. A ~6 Mpc overdensity at z ≃ 2.7 detected along a pair of quasar sight lines: filament or protocluster?. Astronomy & Astrophysics, 2014, 572, ⟨10.1051/0004-6361/201423961⟩. ⟨insu-03645241⟩



Record views


Files downloads