SMA High Angular Resolution Imaging of the Lensed Quasar APM08279+5255

TL;DR

This study uses high-resolution submillimeter imaging and lens modeling to resolve the dust emission in a distant lensed quasar, revealing its size, temperature, and heating source, and providing insights into its structure and energy sources.

Contribution

First high-resolution submillimeter imaging of APM08279+5255 with lens modeling to determine intrinsic dust emission size and heating mechanisms.

Findings

Intrinsic dust emission size ~80pc

Dust temperature estimated at 150-220K

Emission mainly heated by AGN, not starburst

Abstract

We present Submillimeter Array observations of the z=3.91 gravitationally lensed broad absorption line quasar APM08279+5255 which spatially resolve the 1.0mm (0.2mm rest-frame) dust continuum emission. At 0.4" resolution, the emission is separated into two components, a stronger, extended one to the northeast (46+/-5mJy) and a weaker, compact one to the southwest (15+/-2mJy). We have carried out simulations of the gravitational lensing effect responsible for the two submm components in order to constrain the intrinsic size of the submm continuum emission. Using an elliptical lens potential, the best fit lensing model yields an intrinsic (projected) diameter of ~80pc, which is not as compact as the optical/near-infrared (NIR) emission and agrees with previous size estimates of the gas and dust emission in APM08279+5255. Based on our estimate, we favor a scenario in which the 0.2mm (rest-frame) emission originates from a warm dust component (T_d=150-220K) that is mainly heated by the AGN rather than by a starburst (SB). The flux is boosted by a factor of ~90 in our model, consistent with recent estimates for APM08279+5255.