TEST FOR SUBSTRUCTURE IN THELENSING GALAXY OF RADIO-QUIETQUASAR LENSES BY RADIOIMAGING

Abstract

This paper examines the viability of studying substructure in lens systems by radioimaging of the radio-quiet lens systems HE0435-1223 and RXJ0911+0551. Theobservations are carried out by the JVLA, the data reduction is done in AIPSand the modelling is performed by the Igloo modelling software. In HE0435-1223,one of the images is found to be much fainter in the optical than in the radio,which may be due to either microlensing or dust extinction. This means that theflux ratio anomaly in Fadely, Keeton [Fadely and Keeton, 2012b] is not causedby substructure and the radio fluxes can be well fitted by a smooth SIE model.Therefore, there is no evidence for a subhalo as claimed in [Fadely and Keeton,2012b]. In RXJ0911+0551, two of the images are affected by dust extinction. Thecusp relation violation is still present, for the JMFIT fluxes Rcusp = 0.092 ± 0.018(where JMFIT is a program in AIPS which fits Gaussian models to an image) andfor the Difmap fluxes Rcusp = 0.143. Both are significantly lower than the near-infrared [Keeton et al., 2003] Rcusp = 0.23 ± 0.06. This indicates that substructureis possibly in the system, but the revised cusp violation is not as strong as previouslythought.

Date of Award	31 Dec 2014
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Neal Jackson (Supervisor)