G16A003

Measuring dark matter substructure in the gravitational lens JVAS B1555+375

Abstract

We request 14 hrs Global VLBI observations at 1.65 GHz of the gravitational lens system
JVAS B1555+375. This system shows one of the most extreme flux ratio anomalies known,
which can be caused by a local perturbation to the mass model and it would be a signature of
dark matter substructure. However, from infrared imaging we have found evidence for an
edge-on disc passing through the pair of images that exhibit the flux ratio anomaly.
Therefore, the aim of these observations is to image the extended gravitational arc at mas
resolution in order to detect small perturbations produced by the possible low mass
substructures on the arc and understand the role of the edge-on disc in the observed flux
ratio anomaly of B1555+372. Global VLBI observations will clarify the origin of the flux ratio
anomaly and will give more stringent constraints to the low end of the substructure mass
function.

Investigators

Name Institution
David Lagattuta California at Davis, University of
Matthew Auger California at Davis, University of; Cambridge, University of
Leon Koopmans Kapteyn Astronomical Institute
Simona Vegetti Massachusetts Institute of Technology
Chris Fassnacht California at Davis, University of
John McKean Netherlands Institute for Radio Astronomy; Kapteyn Astronomical Institute
Cristiana Spingola * Kapteyn Astronomical Institute; Istituto Nazionale di Astrofisica; Bologna, Università degli Studi di

* indicates the PI