Strong lenses have become an important astronomical tool: they allow us to make accurate measurements of galaxy masses, they provide a magnified view of the distant universe, and they allow us to constrain cosmological parameters. I will show some recent results in these areas, including a brief update on the Hubble's constant from the galaxy-scale lens B1608. Strong lensing science is currently limited by relatively small sample sizes; this will change in the coming years, as we enter the era of wide-field optical imaging surveys. I will give an overview of what we can expect from the next generation of ground-based imaging surveys, assessing the prospects of, among others, PS1 and LSST. In particular, the technical challenges of these projects need addressing now, in preparation for their start. Discovering thousands of lenses in these datasets will require efficient automation: I will give an update on the progress of our lens-finding "robot" and its application in the HST/ACS archive as part of the HAGGLeS project. I will then describe an orthogonal effort to find new multiply-imaged quasars in the PS1 survey - with no u-band, we are using the variability of quasars to identify them, and then investigating their spatial extent. Experiments in the SDSS stripe 82 area suggest we are on the right track: the actual lens search is just beginning.

In the widely-accepted scenario of LCDM galaxy formation, galaxies observed around us today were formed from the merging of a series of smaller systems over cosmic time. Although a highly successful theory in high-resolution cosmological simulations, direct observation of this process has been challenging. This is especially true at high redshift where galaxies are fainter and less resolved and where, to date, identification has been restricted to less-understood rest-frame ultraviolet morphology. I will discuss recent work that has shown that Lyman-alpha transition and associated spectral features provide a unique indicator of galaxy interactions in ground-based optical data during a critical epoch of formation (2 < z < 6). In addition, I will present a new and simple technique to select very large numbers of high-redshift galaxies having desired Lyman-alpha behavior, including the population of Lyman-alpha emitters, from "cheap and deep" broadband imaging. This technique enables fundamental properties such as spatial distribution, mass, and typical star formation rates to be traced consistently, and to high precision, from 2 < z < 6. A detailed analysis of broadband-selected galaxies using space- and ground-based morphology and spectroscopy indicates the presence of a bimodal distribution that has strikingly similar spectral and inferred mass trends as that seen in a population of quasar absorption-line systems. These data suggest two different formation mechanisms for the bulk of Lyman-alpha emitting and absorbing galaxies that may provide the framework for the two distinct classifications of galaxies seen today.

I will discuss recent works on the wave dynamics of accretion disk around a black hole, focusing on global disk instabilities and (inertial-acoustic) wave modes trapped in the inner disk region. I will explain the role of wave super-reflection and wave absorption at the corotation resonance, as well as how general relativistic effects help to drive these modes overstable. Applications to the quasi-periodic oscillations obsereved in accreting black hole systems (X-ray binaries and AGNs) will also be discussed.

As gas is accreted onto halos its gravitational energy is converted into thermal energy. This process usually involves strong shocks ("virial shocks"). I will discuss the stability of virial shocks in the presence of significant cooling, and show that when halos are smaller than ~10^12 solar masses the halo gas cannot be in hydrostatic equilibrium around galaxies. Rather, accreted gas will free-fall until it hits the galaxies. In some conditions, cold filaments will survive within a hot, diffuse halo. I will relate that phenomena to high-z star forming galaxies, and discuss interactions of these cold streams with the galaxy. Then, I will present an analysis of the stability of the virial shocks in galaxy cluster, and possible observational implications of oscillations in the virial shocks there.