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Our understanding of the engines and progenitors of gamma-ray bursts has expanded through the ages as a broader set of diagnostics has allowed us to test our understanding of these objects. Here we review the history of the growth in our understanding, focusing on 3 leading engines and 9 potential progenitors. The first gravitational wave detection of a short burst is the latest in a series of breakthrough observations shaping this understanding and we study the importance of multi-diagnostic, multi-messenger observations on these engines and their progenitors. Our understanding based on a detailed study of nearby bursts can be applied to make predictions for the trends expected as we begin to observe high redshift bursts and we discuss these trends., Comment: 19 pages, 10 figures

We present the software tool FITDisk, a precompiled-binary Windows GUI version of our smoothed particle hydrodynamics cataclysmic variable accretion disk research code. Cataclysmic variables are binary star systems in which a compact stellar remnant, typically a white dwarf star, is stripping mass from a lower-main-sequence companion star by way of an accretion disk. Typically the disk is the brightest component of the system, because the plasma is heated dramatically as it spirals down in the gravitational well of the primary white dwarf star. The shortest-period systems can display disk "superhump" oscillations driven by the rotating tidal field of the secondary star. FITDisk models these accretion disk phenomena using a fully three-dimensional hydrodynamics calculation, and data can be visualized as they are computed or stored to hard drive for later playback at a fast frame rate. Simulations are visualized using OpenGL graphics and the viewing angle can be changed interactively. Pseudo light curves of simulated systems can be plotted along with the associated Fourier amplitude spectrum. FITDisk is available for free download at www.astro.fit.edu/cv/fitdisk.html., Comment: 16 pages, 4 color figures, one line figure. Accepted for March 2006 issue of Publ. Ast. Soc. Pacific. v2: fixed a typo in the references