ADASS XII Conference

Optimizing Science

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O8.1 New Science with LIGO: Past, Present and Future (Invited)

Kent Blackburn (California Institute of Technology)

Significant analysis of data from LIGO's laser interferometric gravitational wave detector project began with a 25-hour stretch of data collected from its 40-meter prototype instrument located on the Caltech campus in 1994. Since then, construction of LIGO's 4-kilometer laser interferometric gravitational wave observatories in the states of Louisiana and Washington has been completed. Beginning in the spring of 2000, a series of multi-day engineering runs using these new multi-kilometer interferometers have collected 40 terabytes of data. The seventh of these engineering runs, also known as the upper limits run, collected data from both observatories continuously for a 17-day span in late 2001 and early 2002. During this upper limits run, data was analyzed in near real time for instrumental effects, terrestrial effects and astrophysical bursts and binary inspirals. After the data were collected, analyses for stochastic and periodic gravitational wave signals began. To handle the large data analysis requirement of LIGO data, each of the observatories along with MIT and Caltech have been equipped with distributed computer systems known as LDAS. These systems use custom software to integrate concurrent job control, parallel compute clusters and databases, managing the continuous data analysis requirements in near real time or better. LIGO will begin its first scientific run in late summer of 2002. LDAS again will be utilized to carry out scientific searches for gravitational waves as LIGO endeavors to open this new window on the universe.

O8.2 AstroVirgil: Interactive X-ray Analysis for EPO and First Look

Steve McDonald (University of Massachusetts at Boston and Silicon Spaceships) Srikanth Buddha (University of Massachusetts at Boston)

This paper reviews AstroVirgil, a user friendly program for the analysis Chandra event files. AstroVirgil integrates photon filtering and visualization into a single GUI based tool. Photons can be filtered based spatial position (in multiple coordinate systems), photon energy level (using multiple measures) or time of arrival using various custom GUI panels. Filtered photons can be displayed as images, a spectrums or a lightcurves. Each display can be adjusted and improved using a variety of GUI controls. Many existing Chandra tools use a command line interface. This paper reviews some of the performance and memory consequences of performing non-disk file based processing.

It is hoped that a user friendly, GUI based, platform independent tool can reach broader community than traditional "high-end" Chandra tools. The initial evaluation from both amateur astronomers and the educational community will be discussed.

AstroVirgil is GPLed pure Java program. It is built on top of JSky, a collection of reusable Java components developed at the ESO and first described at ADASS'99. It is available at www.SiliconSpaceships.com.

O8.3 An End-to-End Architecture for Science Goal Driven Observing

Anuradha Koratkar (STScI) Sandy Grosvenor, Jeremy Jones (NASA/GSFC) Karl Wolf (Aquilent, Inc.)

Many of the upcoming missions will not only have better detectors, greater on-board storage capacity, and on-board processing capabilities, they will also generate vast volumes of data. Although significant research and development efforts are underway to increase the download capacities, it is prudent to use the available bandwidth efficiently. The transmission efficiency of large data volumes is critical because, even when we have the high bandwidth it will come at a cost. The cost of downlink time and limitations of bandwidth will end the era where all exposure data is downloaded and all data processing is performed on the ground.

In addition, observing campaigns involving inherently variable targets will need scheduling flexibility to focus observing time and data download on exposures that are scientifically interesting. The ability to quickly recognize and react to such events by re-prioritizing the observing schedule will be an essential characteristic for maximizing scientific returns. It will also be a step towards increasing spacecraft autonomy, a major goal of NASA's strategic plan.

The science goal monitoring (SGM) system is a proof-of-concept effort to address these challenges. The SGM will have an interface to help capture higher level science goals from the scientists and translate them into a flexible observing strategy that SGM can execute and monitor. We are developing an interactive distributed system that will use on-board processing and storage combined with event-driven interfaces with ground-based processing and operations, to enable fast re-prioritization of observing schedules, and to minimize time spent on non-optimized observations.

This talk will focus on our strategy for developing SGM and the technical challenges that we have encountered. The SGM architecture and interfaces are designed for easy adaptability to other observing platforms, including ground-based systems and to work with different scheduling and pipeline processing systems.

O8.4 Small Theory Data and the Virtual Observatory

Jonathan McDowell (SAO)

The integration of large theoretical simulation archives with the VO has been widely discussed. I suggest it is also important to include smaller theoretical datasets and functional relationships in a structured way, and outline some possible standards.

First, I discuss metadata for simulations by drawing an analogy with X-ray spectral analysis, a domain in which complex new theoretical models have been rapidly integrated with the standard data analysis tools via a simple parameterized-function description. This paradigm can easily be extended to image simulations.

Secondly, I address the issue of resource discovery for tabular and functional theoretical and phenomenological results such as extinction laws, luminosity functions, isochrones, and distance indicators. A structured extension of the CDS concept of UCDs could make tabular data of this kind easily available not only to astronomers but also to interoperable software.

This project is supported by the Chandra Xray Center under NASA contract NAS8-39073

O8.5 Federating Catalogs and Interfacing Them with Archives: A VO Prototype

Douglas J. Mink, Michael J. Kurtz (SAO)

A common scientific requirement is to perform a joint query on two or more remote catalogs, then use the resulting combined catalog as input to query an archive or catalog. We have developed techniques which enable the routine federation of several of the largest astrometric and photometric catalogs from either in-house or remote copies, and use this federated output to query the several archives of spectral and imaging data which we either manage or maintain local copies of.

Allowing the federation of arbitrary sections of large catalogs, with user defined match criteria; and then allowing this result to be used to query several large archives of spectral and imaging data (also subject to user constraints) is a key goal of all VO projects. The problems we have solved in developing our methods will also have to be addressed by any VO project which delivers similar capabilities.