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RXTE GOF	ASM Data Products	RXTE FAQ

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For the latest ASM weather map results results,
visit the RXTE ASM X-ray Weather Map

For the latest results for a particular source
visit the ASM Source Catalog

For the latest calibration news on the FITS products
visit the ASM Events page

For a comprehensive 'how-to' on data analysis techniques
visit to the ASM Recipe

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• Introduction
• Useage Notes
• Access to the ASM data products
• More information about the ASM

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When you use ASM data products in a paper or talk, please include the phrase: "results provided by the ASM/RXTE teams at MIT and at the RXTE SOF and GOF at NASA's GSFC."

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Introduction

The ASM Products Database makes available results from the RXTE All Sky Monitor. These results include light curves for around 350 sources, intensities in three sub-energy bands (or "colors") for each of these sources, a history of the ASM pointings, and information on the fits used to generate the intensities. The database provides these data files in FITS format. (MIT's ASM Light Curves Overview page provides GIF images and ASCII files for the light curves.)

The database consists of both Quicklook and Definitive versions of the Products. The Quicklook Products are derived from analysis of the real-time data performed in the RXTE SOF. They are normally updated every three hours and include data from up to the previous two weeks. The Quicklook Products are superceded by updates to the Definitive Products, which are produced at MIT from the final production data. The Definitive Products are usually updated weekly.

Quicklook ASM results are also available via the ASM Weather Map. The map provides an "at a glance" look at the X-ray sky, and an accompanying table provides the latest x-ray intensity values for active sources in the ASM catalogue. Selecting a source name from the table produces a plot and ASCII table of the light curve over the previous two weeks.

A more complete description of the ASM products may be found in The XTE All Sky Monitor Data Products. (This document is also available via anonymous FTP as the PostScript file asm_products_v150.ps.) The recipe Working with the ASM Products offers tips for analyzing the ASM data products.

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Useage Notes

• Note that in these products the error bars consist of counting statistics convolved with a 3 percent systematic uncertainty as derived from Crab data. In many cases this results in an underestimate of uncertainties in the intensity values. See "About the Uncertainties" on MIT's ASM Light Curves Overview page for further details.
• Users should note that there is a 1 mCrab positive bias in the light curve intensities. This bias is only evident when enough data are averaged so that the statistical uncertainties are driven to be very small. This generally requires binning or analyzing the light curves on time scales of many days or longer.
• Users should also note that all systematic effects may be amplified for positions near the Galactic Center.

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Access to the ASM Data Products

1. Via FTP: The ASM Data Products are accessible via anonymous FTP from this page in the following subdirectories of /xte/data/archive/ASMProducts.
   • The Definitive Products may be found in:
     • Light curves: definitive_1dwell/lightcurves
     • Colors: definitive_1dwell/colors
     • Pointings: definitive_1dwell/supplemental/pointings

   • The Quicklook Products may be found in:
     • Light curves: realtime_current/lightcurves
     • Colors: realtime_current/colors
     • Pointings: realtime_current/supplemental/pointings

   Direct anonymous FTP access via legacy.gsfc.nasa.gov is also available.

2. Via Browse:
   • For the Definitive Products, choose the XTE All-Sky Monitor Long-term Observed Sources (XTEASMLONG) catalog. After giving the name or coordinates of a particular source, the user may then either choose to retrieve the products individually or in data product sets. The STANDARD set consists of both the light curve and the color file for the object. The POINTINGS set consists of all of the weekly ASM pointing files.

   • For the Quicklook Products choose the XTE All-Sky Monitor Quicklook Observed Targets (XTEASMQUICK) catalog. After giving the name or coordinates of a particular source, Browse will list the intensity values at times spanning the previous two weeks. After choosing any of these rows, the user may then choose to retrieve the quicklook products either individually or in the data product sets. As with the definitive products, the STANDARD set consists of both the light curve and the color file for the object. The POINTINGS set consists of all the daily ASM pointing files presently in the real-time archive.

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More Information about the ASM

• ASM Weather Map - a sky map of the latest ASM source intensities.
• Working with the ASM Products - tips for analyzing the ASM data products.
• ASM Source Activity Reports from MIT.
• ASM Light Curves Overview page from MIT.
• Current ASM catalogue
• New Sources in the ASM Products Archive
• Latest ASM status report
• ASM and EDS Teams

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If you have a question about RXTE, please send email to one of our help desks.

This page is maintained by the RXTE GOF and was last modified on Monday, 20-Aug-2001 08:33:01 EDT.