GLAST Data & Software Release plans + Science Support Center Services

1Getting Involved with GLAST Workshop, CFA, 06/21/2007 - C. Shrader, NASA/GSFC

GLAST Data & Software Release plans + Science Support Center Services

C. Shrader, GLAST SSC GSFC, Code 661


Overview: GSSC Services• Develop and maintain public data archive as

part of HEASARC • Distribute & support GLAST analysis

software • Various aspects of proposal support• Web services including software

documentation, mission new & information• Help desk, phone support• ToO and timeline support • Guidance from project, NASA HQ and

GLAST Users Group


Data Analysis Support• GSSC has scientists at GSFC and both

instrument team sites• General “help desk” facility supported

via GSSC web site• GSSC plans to conduct data analysis

workshops and demonstrations Schedules, specific venues tbd (e.g.

future AAS, HEAD)• Visit the GSSC web site:

<http://glast.gsfc.nasa.gov/ssc/>


Proposal Support • Separate presentation

D. Band

• Cycle-1 materials are online

• Help desk, FAQs DB now active

• Proposals due September 7, 2007 Peer review Dec. 2007


GLAST Data: A Few Key Points• GLAST is primarily operated in scanning

mode Not traditional telescope “Observations”

All sources are observed at least once every two orbits; typical ~1/6 duty cycle

All data are time ordered• Survey data• Pointed observations (including AR’s, ToO’s)

Cannot isolate LAT events for single source analysis

PSF ~3.5º @ E=100 MeV, ~0.15º at E>10 GeV Analysis of spatial region required


GLAST Data (cont.) Exposure time tabulation is trickier than for

typical astronomical telescopeSW handles this, but cognizance is urged

All data stored in sky regions; new data is added to the region as it is received (~hrs)

GSSC data server will “carve out” data from the full-sky DB based user-defined cuts:. Will accept a spatial regionAllows for selection based on timeEnergy cuts are also supportedAdditional cuts downstream w/science tools


GLAST SAE• GLAST “Standard Analysis Environment” (SAE);

collaborative effort, GSSC and instrument teams• Will be distributed as an “FTOOLS” package

Adherence to broader HEASARC standards “Atomic” executables, FITS I/o, IRAF style param files Scriptable, easy GUI implementation

• GBM related tools released prior to Cycle 1 Full set of LAT tools prior to Cycle 2

• LAT analysis has unique complexities associated w/PSF, backgrounds, scanning Usability and viability demonstrated to 1st order

Data challenges (GLAST collaboration)Beta testing (GLAST Users Committee)


GLAST SAE• Overview of capabilities

Maximum likelihood tool—spatial-spectral analysis of region (source detection, flux)Includes background models

Pulsars—period analysis, blind searchesIncludes ephemerides DB

GRBs—temporal cuts, binned-spectral analysis using XSPEC

• Tools and documentation will be released through GSSC website release schedule driven by launch & data availability


GLAST SAE (cont.)

• Existing tools used when possible and appropriate ds9, fv, Root for visualization HEADAS (Ftools) libraries and basic utilities XSPEC for spectral model fitting (w/caveats)

• Stable support for standard tools & backward compatibility as warranted File formats conform to HEASARC standards Major analysis elements have been verified with existing tools

& simulated data

• Supported platforms Development is simultaneous on Linux and Windows All HEADAS supported platforms will be supported


GLAST SAE (cont.)

• A limited set of science tools are available for the first proposal period

• GBM analysis is supported by “gtbin” + Ftools & XSPEC

• A full release is scheduled for support of Cycle 2 2nd proposal period and analysis of the 1st year data

• Plans for pre-release beta testing are under discussion with GUG & in-house


SAE Release Schedule • Distributed via GSSC website or w/HEADAS

distribution• GBM tools: Launch + 0 months• LAT tools: Launch + 8 months• Documentation

Full set accompanies SW releaseGLAST Technical Handbook: online now

Multiple levels:Detailed descriptionIndividual tool descriptions (like Ftool help pages)Analysis threads


Basic Data Policy• Mission cycle 1: limited LAT data release

Selected high-level products Information on transient discoveries Full GBM data release

• Mission cycle 2 and beyond: All Science Data Are Public As Soon As Processed Automated pipeline, SLAC GSSC <2-day latency requirement, but expect ~hrs


GLAST Data Release Policy

• LAT instrument team is responsible for: Calibrations and analysis methods need to be verified Preparation of source list, point source catalog

• LAT high-level data product release Fluxes, spectra and lightcurves for ~25 sources Transients exceeding Fth~2x10-6 cm-2s-1

<http://glast.gsfc.nasa.gov/ssc/data/policy/LAT_Monitored_Sources.html>

• Full GBM release• Summary GBM and LAT burst information: locations,

spectra, durations, peak fluxes• Preliminary LAT source list @ 6 months• Auxiliary data (details under discussion)

Cycle 1


GLAST Data Release Policy

• Prompt release of all level-1 data products!• LAT events—energy, time, and direction of

events classified as photons FITS event list, following HEASARC conventions Also, accompanying FITS DB of spacecraft info

• GBM events—energy and time of events from burst

• All auxiliary data e.g. “Exposure Cubes” can in some cases be pre-

generated saving end-user CPU time

Cycle-2 and Beyond

GLAST Data & Software Release plans + Science Support Center Services

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