Probing IGM large-scale flows: warps in galaxies at shells of voids

¹ Instituto de Astrofísica de Canarias, C/.Vía Láctea, s/n, 38200 La Laguna (S/C de Tenerife), Spain e-mail: martinlc@iac.es
² Departamento de Física Teórica y del Cosmos, Universidad de Granada, Spain
³ Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
⁴ School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
⁵ Estin & Co Strategy Consulting, 43 Av. de Friedland, 75008 Paris, France
⁶ Centro Astronómico Hispano Alemán, Almería, Spain
⁷ Case Western Reserve University, Cleveland (Ohio), USA

Received: 11 June 2007
Accepted: 6 June 2008

Abstract

Context. Hydrodynamical cosmological simulations predict flows of the intergalactic medium along the radial vector of the voids, approximately in the direction of the infall of matter at the early stages of the galaxy formation.

Aims. These flows might be detected by analysing the dependence of the warp amplitude on the inclination of the galaxies at the shells of the voids with respect to the radial vector of the voids. This analysis will be the topic of this paper.

Methods. We develop a statistical method of analysing the correlation of the amplitude of the warp and the inclination of the galaxy at the void surface. This is applied to a sample of 97 edge-on galaxies from the Sloan Digital Sky Survey. Our results are compared with the theoretical expectations, which are also derived in this paper.

Results. Our results allow us to reject the null hypothesis (i.e., the non-correlation of the warp amplitude and the inclination of the galaxy with respect to the void surface) at 94.4% C. L., which is not conclusive. The absence of the radial flows cannot be excluded at present, although we can put a constraint on the maximum average density of baryonic matter of the radial flows of .