The evolution of rest-frame B-band luminosities, stellar masses, and number densities of field galaxies in the Hubble Deep Field North and South are studied as a function of rest-frame B-band morphological type out to redshifts z ∼ 3 using a sample of 1231 I < 27 galaxies with spectroscopic and photometric redshifts. We find that the co-moving number, and relative number, densities of ellipticals and spirals declines rapidly at z > 1, although examples of both types exist at z > 2. The number and number fraction of peculiar galaxies consistent with undergoing major mergers rises dramatically and consistently at redshifts z > 2. Through simulations we argue that this change is robust at the 4 σ level against morphological k-corrections and redshift effects. We also trace the evolution of rest-frame B-band luminosity density as a function of morphology out to z ∼ 3, finding that the luminosity density is steadily dominated by peculiars at z > 1.5 with a peak fraction of 60-90% at z ∼ 3. By z ∼ 0.5 B-band luminosity fractions are similar to their local values. At z ∼ 1 the B-band luminosity densities of ellipticals and spirals are similar, with a combined contribution of ∼ 90% of the total luminosity at z < 1. The stellar mass density follows a similar trend as the luminosity density, with some important exceptions. At high redshifts, z > 2, 60-80% of stellar mass appears attached to peculiars, while at z < 1, 80% -95% of stellar mass is attached to ellipticals and spirals. The total integrated stellar mass density of peculiars slightly declines at lower redshift, suggesting that these systems evolve into normal galaxies. In contrast to the luminosity density, the stellar mass density of ellipticals is greater than spirals at z < 1, and the stellar masses of both types grow together at z < 1, while number densities remain constant. From a structural analysis of these galaxies we conclude that galaxy formation at z > 2 is dominated by major merging, while at z < 1 the dominate modes are either minor mergers or quiescent star formation produced by gas infall. Finally, at z ∼ 1.5 the co-moving luminosity, mass, and number densities of spirals, ellipticals and peculiars are nearly equal, suggesting that this is the 'equilibrium' point in galaxy evolution and an important phase transition in the universe's history.

Microlensing perturbations to the flux ratios of gravitationally lensed quasar images can vary with wavelength because of the chromatic dependence of the accretion disk's apparent size. Multiwavelength observations of microlensed quasars can thus constrain the temperature profiles of their accretion disks, a fundamental test of an important astrophysical process which is not currently possible using any other method. We present single-epoch broadband flux ratios for 12 quadruply lensed quasars in 8 bands ranging from 0.36 to 2.2 μm, as well as Chandra 0.5-8 keV flux ratios for five of them. We combine the optical/IR and X-ray ratios, together with X-ray ratios from the literature, using a Bayesian approach to constrain the half-light radii of the quasars in each filter. Comparing the overall disk sizes and wavelength slopes to those predicted by the standard thin accretion disk model, we find that on average the disks are larger than predicted by nearly an order of magnitude, with sizes that grow with wavelength with an average slope of ∼0.2 rather than the slope of 4/3 predicted by the standard thin disk theory. Though the error bars on the slope are large for individual quasars, the large sample size lends weight to the overall result. Our results present severe difficulties for a standard thin accretion disk as the main source of UV/optical radiation from quasars.

X-ray and optical observations of quadruply lensed quasars can provide a microarcsecond probe of the lensed quasar, corresponding to scale sizes of $10 2 Y10 4 gravitational radii of the central black hole. This high angular resolution is achieved by taking advantage of microlensing by stars in the lensing galaxy. In this paper we use X-ray observations of 10 lensed quasars recorded with the Chandra X-Ray Observatory as well as corresponding optical data obtained with either the Hubble Space Telescope or ground-based optical telescopes. These are analyzed in a systematic and uniform way with emphasis on the flux ratio anomalies that are found relative to the predictions of smooth lens models. A comparison of the flux ratio anomalies between the X-ray and optical bands allows us to conclude that the optical emission regions of the lensed quasars are typically larger than expected from basic thindisk models by factors of $3Y30.