ADASS XII Conference

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Data analysis software and systems

P3.1 Synchronous Observations of Ground Based Optical and X-ray Space Born Telescopes

Alexei Pozanenko (IKI) Sergei Bondar (State Technical Research Center-Kosmoten) Grigorii Beskin (SAO) Marat Gilfano (IKI/MPA) Vasilij Rumyantsev (CrAO)

Simultaneous multiwavelength observations are critically important for understanding physical and astronomical properties of many celestial phenomena. We consider simultaneous X- ray/optical observations of two types of objects that are of particular importance for high energy astrophysics: cosmic gamma-ray bursts (GRB) and low mass x-ray binaries (LMXB).

An important task of optical transients observation requires continuous wide field telescope surveys. Based on available observations we discuss criteria of development optical wide- field camera and present the current status of the automatic telescope that is being developed at IKI for the purpose of simultaneous optical observations of GRBs counterparts. The instrument will have the FOV = 15 deg, and limiting magnitude 10.5 at 0.1 s exposure. The flow of successive frames will be stored and compared with catalog for on-line identification of optical transients. The post analysis of accumulated frames increase limiting magnitude of the system up to 14 magnitude. Subsequent cross-analysis with x-ray telescopes improves probability of transient identification. Simultaneous observation with X-ray camera at HETE-2 spacecraft would result in few cases per year of simultaneous observation of GRB error box.

We also discuss details of synchronous optical/X-ray observations of LMXBs with high time resolution using the 6m telescope at SAO and Rossi X-ray Timing Explorer. We report preliminary results on the optical observations with sub- millisecond time resolution of Sco X-1 and Cyg X-2 during the 2002. The observations were performed on the 6-meter telescope of Special Astrophysical Observatory (SAO) of with Multichannel Panoramic Photometer-Polarimeter in the primary focus and MANIA registration system with time resolution of 2 microsec.

P3.2 An Interactive Java Plotting Package for Astronomy

Anzhen Zhang, John Good, Bruce Berriman (IPAC/Caltech)

This paper describes the architecture and functionality of QtPlot, a general purpose 2-dimensional plotting package for astronomy. It is a modification of an Open Source Java Plotting package, PtPlot, version 5.1p1, made available by the Ptolemy project at the University of California. QtPlot is on operation at the Infrared Science Archive (IRSA), where it supports interactive plotting of spectra from the Submillimeter Wave Astronomical Satellite (SWAS), and light curves from the American Association of Variable Star Observers (AAVSO). It has also been integrated into OASIS, IRSA's data fusion toolkit. QtPlot displays local files and remote files through HTTP protocols. It supports ASCII table files and XML files, which have been structured for astronomical plot directives. QtPlot has a rich suite of user-controlled functions, for modifying plot appearance (symbol, color etc.), plot boundaries, and annotation. Finally, QtPlot has a panning and zooming feature.

P3.3 SAS, the Scientific Analysis System of the XMM-Newton Observatory

Carlos Gabriel, Matteo Guainazzi (ESA / VILSPA) Fred Jansen, Uwe Lammers, Giuseppe Vacanti (ESA / ESTEC)

XMM-Newton, the most sensitive X-ray satellite ever built, is successfully operating since January 2000. It is providing the scientific astronomical community with the deepest X-ray images ever along more than two decades in energy (0.1-15 keV), as well as with high-resolution spectra (resolving power in the range 200-800) in the soft X-rays (0.5-2 keV). Simultaneous optical and UV coverage is ensured by the Optical Monitor on board.

The Scientific Analysis System (SAS) is a state-of-the-art interactive analysis package for the calibration and analysis of all the XMM-Newton data. It represents a combined effort of more than 30 scientific institutes in the world, coordinated by the Science Operation Center (Villafranca del Castillo, Spain) and the Science Survey Center (Leicester, UK).

Reduced and calibrated scientific products, directly usable for scientific analysis, are produced running SAS in a semi-automatic fashion by the SSC and distributed to the community.

A large and sophisticated part of the SAS is dedicated to make multidimensional data analysis easy, efficient and user friendly. This maximizes the exploitation of the basic four dimensional information (RA, DEC, energy and time) the XMM-Newton instruments are obtaining from each collected X-ray photon.

Special emphasis will be put on the high level quality control performed both on the software components as on the distributed data products. The large capabilities of the SAS will be demonstrated going over examples of scientific results achieved.

P3.4 XAssist: A System for the Automation of X-ray Astrophysics Analysis

Andrew Ptak (JHU) Richard Griffiths (CMU)

XAssist is a NASA AISR funded project for the automation of X-ray astrophysics, with emphasis on galaxies. It is nearing completion of its initially funded effort, and is working well for Chandra and ROSAT data. By the fall of 2002 ASCA processing should be well supported as well as initial support for XMM-Newton data. It is capable of data reprocessing, source detection, and preliminary spatial, temporal and spectral analysis for each source with sufficient counts. We intend XAssist to eventually become part of the NVO, and non-interactive access to tables at HEASARC is already implemented.

P3.5 Solving for Polarization Leakage in Radio Interferometers using Unpolarized Sources

Sanjay Bhatnagar (NRAO-Socorro,USA/NCRA-Pune,India) R.V. Urvashi (BITS-Pilani,India/NCRA-Pune,India) R. Nityanada (NCRA-Pune,India)

Polarization leakage in the antennas of a radio interferometer can occur due to mechanical imperfections or dipole mis-alignment or due to imperfect electronics. These leakages manifest themselves as closure errors in co-polar visibility measurements of unpolarized sources. For many working radio telescopes, these leakage amplitudes range from a few percent to as much as ten percent. Further, many telescopes offer lower integration times and/or larger number of frequency channels across the RF band for co-polar observations. Consequently, significant fraction of observations are done in co-polar mode. Computation of antenna based leakage gains using co-polar visibilities is therefore scientifically useful as well as valuable for debugging and calibrating the instrument.

This paper presents an algorithm for solving antenna based leakage gains in a radio interferometer using co-polar observations of unpolarized sources. Complex antenna gains and leakage gains, modeled as additive terms, are solved for simultaneously. An additional transformation of the solutions which maximizes the power in the antenna gains, then separates the leakage gains from the usual antenna gains. The algorithm is robust in the presence of RFI or otherwise corrupted data and was extensively tested with simulations and with controlled experiments with the Giant Meterwave Radio Telescope (GMRT). Degeneracy in the solutions due to the use of unpolarized sources is also discussed. Interpretation of the leakage gains on the Poincare sphere and the connection between the leakage induced closure phase and the Pancharatnam phase of optics is also discussed.

P3.6 Generalized Self-Calibration for Space VLBI Image Reconstruction

Sergey F. Likhachev

Generalized self-calibration (GSC) algorithm as a solution of a non-linear optimization problem is considered. The algorithm allows one to work easily with the first and the second derivatives of visibility function phases and amplitudes. This approach is important for high orbiting Space VLBI data processing. The implementation of the GSC algorithm for radio astronomy image restoration is shown. The comparison with other self-calibration algorithms is demonstrated. The GSC algorithm was implemented in the radio astronomy imaging software project Astro Space Locator (ASL) for Windows developed at the Astro Space Center.

P3.7 FUSE Flat-Field Calibration using Wavelets

Paul Barrett (STScI) Alex Fullerton (JHU)

This paper describes an investigation into using Wavelets to characterize and then to create FUSE flat-field calibration files. The basic approach is to transform the FUSE ground flat data, which has a relatively high number of counts per pixel (~20) and uniform illumination, into the Flight Aligned Reference Frame (FARF). We apply wavelet techniques to enhance detector features in the ground and in-flight data by filtering and de-noising in the frequency and spatial domains. Small subarrays of the enhanced ground and in-flight flats are then cross-correlated over the entire image to determine the transformation matrix or the local offset in pixels between the two sets of data.

P3.8 Projecting 3-D Simulations Into Pseudo Observations

Alex Antunes, John Wallin (GMU)

We present methods for converting particle method three-dimensional simulations into observationally verifiable projected column densities, channel maps, fluxes, and velocity contours. Such projections are suitable for direct comparison with radio data (such as produced by AIPS), X-ray observations (e.g. ximage), optical, and IR. Whereas modeling usually involves NBody, mesh, SPH, or LPR calculations upon an idealized 3-D space, our observational data is always limited to a single line of sight projection, observing only one `plane' of the object, emission from which may or may not include extinction. For models to have any validity, we must be able to generate pseudo-observational data from the model, to compare with actual observations. This connects our modeling with the real universe we see; herein we discuss the methods for creating such projections.

P3.9 PacketLib: a C++ Library for Satellite Telemetry Oriented Applications

Andrea Bulgarelli, Fulvio Gianotti, Massimo Trifoglio (CNR/IASF Bologna)

PacketLib is a C++ open-source software library for writing applications which deal with satellite telemetry source packets, provided that the packets are compliant with the ESA Telemetry and Telecommand Standards. The library is being used in the context of the space mission AGILE of Italian Space Agency (ASI) for simulation, graphical display, processing and decoding of the telemetry generated by the Test Equipment of two AGILE detectors and by the AGILE Payload EGSE. From an input stream of bytes, the library is able to recognize automatically the source packets (described by a simple configuration file), and provides a simple access to each packet field by means of an object-oriented interface. In the same way the library writes source packets to the output stream. Various types of input and output streams are abstracted by a software layer. This paper presents the architecture of the library and some examples of applications developed with it.

P3.10 Chandra Ray Tracer (ChaRT): A Web Interface to Chandra PSF Simulations

Clayton Carter, Margarita Karoska, Diab Jerius, Ken Glotfelty, Steve Beikman (Harvard-Smithsonian Center for Astrophysics)

Calculation of point spread functions (PSF) for the Chandra High Resolution Mirror Assembly (HRMA) and detectors is an important part of the analysis of Chandra data. Since the HRMA PSFs are highly variable, no analytical model exists and each PSF must be simulated individually. Existing methods for doing so have a limiting accuracy; while the most direct and accurate method is subject to a steep learning curve, prodigious computing requirements and implementations that are proprietary in nature. With the introduction of Chandra Ray Tracer (ChaRT), we hope to address all of these complications.

ChaRT is a web application by which users can easily generate SAOsac simulations of the HRMA PSF. Users are allowed to specify multiple source locations, each characterized by either a monochromatic energy or an input spectrum. ChaRT then verifies and submits these sources for SAOsac to simulate, notifying the user when their data are available for download. This is accomplished using scripts, developed at the Chandra X-ray Center (CXC), that work in conjunction with some commonly available software components on a distributed computer network at the CXC. Additionally, the system was designed to be extensible and ChaRT's infrastructure may be used as a model for future projects experiencing the same complications as Chandra's PSF calculations.

In this paper we will review the software components and hardware architecture used to implement this system, and we will address possible future work. This project is supported by the Chandra X-ray Center under NASA contract NAS8-39073.

P3.11 Calibration of BIMA Data in AIPS++

Daniel Goscha, David Mehringer, Raymond Plante (NCSA) Anuj Sarma (University of Illinois)

We summarize the general approach to calibration of millimeter interferometer data from the BIMA telescope using AIPS++ and illustrate the use of the relevant software tools. In particular, we will discuss flagging, phase calibration, flux calibration, and polarization calibration, and we will show how we take advantage of the unique capabilities of AIPS++ to meet the special needs of BIMA data. We will show how BIMA calibration tools can be used to hide some of the complexity of the processes while still allowing access to specialized variations if desired. We will illustrate how these tools are pipelined together for end-to-end processing both within the BIMA Image Pipeline and on the user's desktop. Finally, we will present some a comparison of data calibrated in MIRIAD and AIPS++.

P3.12 Status of the BIMA Imaging Pipeline

David M. Mehringer, Raymond L. Plante

We report on the current status of the metadata-driven BIMA Imaging Pipeline. At the time of abstract submission, we are nearing production mode in which we will produce first-order images of target sources as well as plots of images and calibration solutions. All these products will be ingested into the BIMA Data Archive where they will be available to users.

P3.13 AIPS++ Reduction and Analysis of GBT Single-Dish Spectral Data

James Braatz, Joseph McMullin, Robert Garwood, Athol Kemball (NRAO)

The Green Bank Telescope (GBT) is a new 100-m diameter antenna with an unblocked aperture and an active surface. It is designed to observe at frequencies from 300 MHz to 100 GHz, and includes state of the art continuum and spectral backends. AIPS++ is the integral software package for analysis of GBT data both for scientific analysis as well as for control and engineering analysis of the component systems. We will give an overview of how the AIPS++ system is used in processing spectral line data. AIPS++ allows a layered approach to software development whose usefulness is highlighted by the spectral analysis capabilities. At the heart of AIPS++ is a suite of tools which are capable of astronomy-specific calculations as well as general purpose mathematical analysis, data visualization, GUI development, and scripting. A tool for analyzing single-dish data, DISH, is developed on this platform. DISH includes a number of modern features such as bulk processing of datasets and versatile GUI interaction. A simplified CLI interface designed to work with scan-based data is a recent addition to DISH, and was originally built as a thin layer on the DISH core structure. The Interim Automated Reduction and Display System (IARDS) is built as another layer on DISH and provides the run-time display of GBT spectra.

P3.14 Spectral Extraction using aXe

Norbert Pirzkal, Anna Pasquali, Richard Hook, Jeremy Walsh, Rudi Albrecht (ST-ECF)

New large-format spectroscopic instruments have become available to the astronomical community. These produce images containing large numbers of spectra and can be very time consuming to analyze. One of these is the Advanced Camera for Surveys (ACS), which has recently been installed on HST. The ACS provides for both grism and prism slitless spectroscopy and these modes can result in data sets containing hundreds of spectra on the large format detectors. A method of easily extracting the information from these data and quickly producing spectra of individual objects is highly desirable. To this end we have developed a new extraction software package called aXe which was specifically designed to handle the ACS spectrophotometric data. Using a pair of direct/grism or direct/prism images, aXe can extract tilted spectra, estimate and subtract the local background, wavelength calibrate, flat-field, and flux calibrate them.

Due to the increasing number of instruments on modern telescopes capable of performing spectrophotometric observations similar to those of ACS, aXe was designed to also be used with non-ACS data. In this poster, we describe aXe and its use with ACS grism data, as well as with grism and short slit spectroscopic data from the ESO VLT FORS instrument.

P3.15 CIR: A New Package for Interactive Data Reduction of ISOCAM Data

Rene D. Gastaud (DAPNIA/SIDE, CEA/SACLAY) Pierre Chanial (DAPNIA/SAP, CEA/SACLAY)

There is already a good tool for interactive data reduction of ISOCAM data: CIA1, based upon IDL. We describe here a new package of IDL routines, which kept all the main functionalities of the previous one, but has been completely re-drawn, using our 8 years of experience with ISOCAM data reduction, and some new features of IDL. Architecture is simplified, routines are re-written. The package is slimmed down from 1000 to less than 200 routines and is quicker (up to twice). The code is easier to understand, to maintain and to evolve. It has been used for 2 years at SAP Saclay. Sources with HTML documentation and examples are freely available. This tool has also been used to simulate some Herschel/PACS data. This tool can help to quickly test new algorithms and data structure for new IR cameras (SIRTIF).

1ADASS X 2000 CIA v 5.0 The legacy Package for ISOCAM Interactive Analysis

P3.16 New Features of SAOImage DS9

William Joye (SAO)

SAOImage DS9 is an astronomical imaging and data visualization application. DS9 supports FITS images and binary tables, multiple frame buffers, region manipulation, and many scale algorithms and colormaps. It provides for easy communication with external analysis tasks and is highly configurable and extensible.

A number of new important features have been developed for DS9. They include:


Acknowledgments: This work was performed in large part under a grant from NASA's Applied Information System Research Program (NAG5-3996), with support from the (Chandra) High Resolution Camera (NAS8-38248) and the Chandra X-ray Science Center (NAS8-39073).

P3.17 Migrating Astronomical Software Systems from Tcl/Tk to Java

Alberto Maurizio Chavan, Tim Canavan, Dario Dorigo, Nick Kornweibel, Fabio Sogni (ESO)

ESO began developing its Phase I proposal management system in 1994, while development of the Phase II tools began two years later. This first generation of the tools was developed using Tcl/Tk. In 1998 it was decided to migrate all tools to Java, and that activity is now nearing completion. This paper describes the rationale behind the decision to migrate, the migration process itself, and the lessons we learned during these years. We will not attempt to compare two very different programming languages: we'll try instead to describe the challenges and risks we faced in migrating medium-sized, mission-critical systems from one language to the other.

P3.18 New IRAF Messaging Applications

Francisco Valdes, Michael Fitzpatrick, Robert Seaman (NOAO)

New examples of IRAF applications interacting using a low-volume, socket-based text messaging scheme are described and demonstrated. The tasks may be distributed across multiple CPUs or locations, using a many-to-one or one-to-many client-server architecture. Server applications respond to messages without blocking so other activities such as data processing, user interaction through a GUI, or responding to another client application, may take place.

Messaging is based on a simple text-based scheme consisting of either commands beginning with a colon or data in keyword/value pairs. This also allows any non-IRAF application which understands the protocol to participate as either a new client or server application. The commands have the same form as IRAF GUI commands so that applications may easily interact with GUI tasks. One such server application demonstrated is a GUI IRAF processing monitor. IRAF (or non-IRAF) data reduction tasks send status and processing information to GUI server tasks which provide graphical displays and interaction with the received information.

One motivation for this is the powerful and easily customizable nature of IRAF GUIs by means of the GUI description files (which are currently TCL interpreted modules), and the need for such a component in the NOAO Mosaic Data Product Pipeline. This pipeline uses multiple IRAF data reduction tasks and data parallel processing distributed across a network, requiring a central monitoring facility to ensure proper operation of the pipeline. Other applications of this messaging scheme are also discussed.

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