[Previous] | [Session 74] | [Next]
C. Y. Peng, C. D. Impey (Steward Observatory), E. E. Falco (Harvard Center for Astrophysics), C. R. Keeton (Steward Observatory), C. S. Kochanek, J. Lehar, B. A. McLeod, J. A. Munoz (Harvard Center for Astrophysics), H. W. Rix (MPIA, Heidelberg)
We present 15 Einstein Rings and arcs in the CfA--Arizona--Space Telescope Gravitational Lensing survey (CASTLES), the majority of which are candidate quasar host galaxies. All of the objects are at z\ge1.3, thus lensing provides one of the largest quasar hosts samples beyond z>1. Gravitational lensing stretches out quasar hosts into Einstein rings and arcs, enhancing host detections and enabling measurements of host starlight, scale length, color, shape, and morphology. Lens models suggest that most quasar hosts in our sample are compact, fainter than L \lesssim 1 L*, and are consistent with 1 L* Sc-type star formation histories (SFH), or sub-L* elliptical SFH. Non-detections place even tighter constraints on the luminosities because of lens magnification. We see a mix of galaxies that have de Vaucouleurs and exponential disk profiles. Taken together with results of low redshift quasar host studies, these current findings suggest a hierarchical galaxy formation picture, but a range of other star formation histories at z\approx 2 need to be explored in detail.