Meritorious Applications (continued)

2.2 Collaborative Computational Astrophysics

1. Astronomy has made numerous advances recently through the use of high-speed processors and multi-dimensional visualization. At the University of Wyoming, faculty in the department of Physics and Astronomy are currently involved in two large scale computational modeling problems. One is the calculation of evolutionary sequences of interacting binary stars from formation along the asymptotic giant branch (AGB) to demise as faint, weakly interacting degenerate star-brown dwarf pair. Development of the EVOLve model, in collaboration with other astronomers at MIT, Arizona State University, and University College London, has recently made major advances in the field via the addition of new equation of state calculations added to the code and advanced computational algorithms for the beginning evolutionary sequences. The development of the secular evolution code for this model includes the latest brown dwarf interior models and was funded by NSF and NASA.

2. Further involvement of this collaboration is moving towards the next logical step, that of real time interaction with the code. Model formation and evolution involves many complex steps with multiple possible branches for the outcome. Working with the various models in such a manner as to be able to effect their outcome along the proper lines is essential. Otherwise, numerous uninteresting, time consuming and computationally intensive paths get explored, making the progress for the specific project slow. One method of dealing with this issue would be to allow each collaborator to view each progressing model and each total ensemble, as they progress in time. This would involve not only fast processors but multi-dimensional graphics distributed across the net to our collaborators. The University of Wyoming, which leads this collaborative effort, cannot currently proceed in this direction because of our limited bandwidth and high latency situation.

3. The second computationally intensive project involves numerical investigations of the formation and evolution of accretion disks. These disks of material which form encircling numerous astronomical objects such as quasars, cataclysmic variables, and proto-planetary disks, are the result of gravitational in-fall of material from a source surrounding a gravitation potential such as a star or black hole. Disks are dynamic objects and can not be correctly modeled in 1-D or as time independent entities. They must involve temporal constraints and at least 2-dimensional structures. At times, accretion disks can undergo outbursts during which time local hydrodynamic variables change over orders of magnitude and within very short dynamic times. These changes are critical to understand in order to pass information from one model step in the calculations to another. As before, without real time interaction and complex visualization by remotely located investigators, the keys to allowing efficient solution of these problems are unavailable.

4. Tools such as those discussed above are also ideal for use as educational mechanisms. Allowing students, not only at the University of Wyoming, but throughout the state and country, to benefit from the ability to "see" models built in real time, to "see" the power of computational physics, and to "see" how they themselves can interact with models and explore the parameter space of the physical world, is one of the greatest learning tools potentially available. We currently have an in-house wire-frame interacting binary model which allows a few physical parameters to be varies, but the "realness" of the model is limited.

5. Current bandwidth limitations and latency are the biggest hurdles to the advancing research in both of the above situations. Numerous sites exist for fast computation, advanced graphics, three-dimensional model visualization, etc. but our usage of these in a real time, interactive manner is limited today. Wire-frame graphics, low-resolution imagery, and limited color tables are also the current norm. Usage of these already developed codes and/or already existing complex, expensive peripherals would save additional costs to these projects, but these devices often only exist at remote sites, thereby requiring efficient connectivity. In addition, already developed resources at Wyoming could be used in a likewise manner from other sites. For example, porting codes, like Java scripts, which tie all the above together, across the net from Wyoming to collaborators machines, would be an ideal solution to many of these issues.

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