Journal article
HST imaging of four gravitationally lensed quasars
NF Bate, G Vernardos, MJ O'Dowd, DM Neri-Larios, RL Webster, DJE Floyd, RL Barone-Nugent, K Labrie, AL King, SY Yong
Monthly Notices of the Royal Astronomical Society | OXFORD UNIV PRESS | Published : 2018
Abstract
We present newHubble Space Telescope WFC3 imaging of four gravitationally lensed quasars: MG 0414+0534; RXJ 0911+0551; B 1422+231; WFI J2026-4536. In three of these systems we detect wavelength-dependent microlensing, which we use to place constraints on the sizes and temperature profiles of the accretion discs in each quasar. Accretion disc radius is assumed to vary with wavelength according to the power-law relationship r α λp, equivalent to a radial temperature profile of T α r-1/p. The goal of this work is to search for deviations from standard thin disc theory, which predicts that radius goes as wavelength to the power p = 4/3. We find a wide range of power-law indices, from p = 1.4+0.5..
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Grants
Awarded by Swinburne University of Technology
Funding Acknowledgements
We wish to thank the anonymous referee for a thorough and thoughful review, which significantly improved this paper. Nicholas Bate thanks the STFC for support under Ernest Rutherford Grant ST/M003914/1. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with HST Cycle 20 Program ID 12874, PI Floyd. Georgios Vernardos is supported through an NWO-VICI grant (project number 639.043.308). Rachel Webster acknowledges the support of ARC Grant DP150101727. This work was performed on the gSTAR national facility at Swinburne University of Technology. gSTAR is funded by Swinburne and the Australian Government's Education Investment Fund.