GLAST SSC Development Plans

1
GLAST SSC Development Plans

• Robert Schaefer
• (GLAST SSC - GSFC/L-3 Communications)

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Outline

• Introduction
• GLAST Development Activities HUG Input
• GLAST HEASARC/FITS coordination
• GLAST Science Analysis Tools
• GLAST Databases
• Other activities (Ingest / Proposal Preparation)
• Conclusions

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GLAST Introduction

• HUG presentation last year David Band - general
  characteristics of GLAST, and the science that
  can be done

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Concerns raised at last HUG

• From the minutes of last HUG meeting
• The HUG was quite concerned that Glast appeared
  to be developing custom software for the LAT
  without input/consultation with HEASARC or the
  general user community.
• The HUG would recommend pressuring the Glast team
  to conform to the extent possible with standard
  formats, interfaces and procedures, and pay
  attention to portability of the analysis system
  to multiple platforms.
• The HUG hopes that Glast data and analysis tools
  will be easier to access and apply than for
  example those that were available for Egret or
  Comptel.

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Progress since last HUG

• One year later, our development Plans are now
  much more specific.
• This presentation will be a quick overview of
  development plans of interest to the HEASARC
• Specifically how we have addressed concerns
  raised at last years HUG

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Plans

• Subsystems of the GSSC
• Science Analysis Tools
• Databases
• Ingest
• Proposal Preparation Tools
• Science Tools
• for local products (mostly pictures for the web)
• observation simulation
• Planning and Scheduling
• The first four of these are most relevant to
  HEASARC

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Development Coordination with HEASARC

• Multiple meetings with our liaison (Mike
  Corcoran) and other people from HEASARC
• Indirect input from review panels with
  representation from LHEA and HEASARC personnel.
• GLAST Users committee
• Peer Reviews
• Work on HEASARC-GSSC Memorandum Of
  Understanding was begun over a year ago. Hope
  to have it baselined by our upcoming second Peer
  review.

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FITS File Definitions

• We are following HEASARC FITS standards.
• GLAST FITS Format Definition Working Group headed
  by Masa Hirayama working on FITS definitions
• Web page with current GLAST definitions and open
  issues http//glast.gsfc.nasa.gov/ssc/dev/fits_def
  /
• This committee is working with HEASARC FITS
  working group to ensure
• Compliance with OGIP standards
• Compatibility with FITS definitions for other
  missions.

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Science Analysis Tools

• Instrument teams responsible for delivering
  Analysis tools, but GSSC is heavily involved in
  development. Much effort expended to ensure the
  tools can function as FTOOLs.
• Analysis tool properties
• GLAST analysis environment
• Use PIL for parameter passing/storage.
• FITS files defined for all types of data read or
  produced.
• Use cfitsio (and other parts of HEAdas)
• ANSI C (HEAdas now includes HOOPS - C OO
  interface to PIL)
• Ability to run ballistically
• XSPEC for burst analyses
• System architects looking to identify existing
  FTOOLS for GLAST analysis tasks.
• Uses CALDB (currently used response functions
  have been FITS-ified).
• Extension beyond FTOOLS to serve the High Energy
  Physics community.
• Support for MS Windows - requirement of the HEP
  community.
• Provide C libraries with an API to allow access
  to
• Response functions (derived from CALDB
  information)
• Data objects

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Analysis Tools (continued)

• Multiplatform support
• Development stage (Windows and Linux support)
• After maturity, extend support to all other
  FTOOLs supported platforms
• Periodic builds on other platforms during
  development to ensure we dont go down a platform
  specific development path.
• Direct participation in tool design from FTOOL
  developer James Peachey (appointed co-code
  architect of the main science tools development)
• Ease of use/relevance/operation of analysis tools
  will be reviewed by
• GLAST collaboration scientists around the world
  in 3 Data challenges
• First one ends today
• One a year for next 2 years
• GLAST Users Committee.
• LHEA personnel

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Data and Databases

• Databases with data stored and delivered in FITS
  files
• Lists of particle photon events.
• Spacecraft positions, orientation, and modes.
• Burst and transient data
• Pre-packaged popular source datasets (e.g.,
  3C279, etc.)
• Results of virtual observations (custom data
  selections created on-the-fly)
• Calibration (CALDB)
• Other data
• GLAST source catalogs
• Spacecraft Timelines
• Information about proposals, ToOs, and bursts
• Access to data eventually will be available
  through W3Browse or W3Bbrowse-like web page
  (virtual observation page).

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Ingest

• Attempting use LAB/NASA software.
• Working to get Data Transfer System (DTS)
  approved for data transfer to/from MOC and IOCs.
• Doing trade study to determine if OPUS pipeline
  is sufficient for handling ingest pipeline.
• Will use cfitsio for validation, extraction of
  metadata, etc., from incoming data. (ICD
  specifies that GSSC will receive data in FITS
  files).

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Proposal Preparation tools

• Use RPS for proposal submission
• Multiple levels of tools with increasing
  sophistication to estimate necessary exposure and
  possible time windows for proposing observations
• At lowest level source estimates will be done
  using PIMMs
• Planning to use XSPEC to simulate sources with a
  specific spectrum
• Other more sophisticated tools will also be
  provided for more detailed simulations.

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Conclusions

• GLAST SSC is working hard to make GLAST a member
  in good standing with the HEASARC and the general
  astronomy community.
• Coordination with HEASARC will continue on
• FITS file design
• FTOOLS/HEAdas tool development
• Database/data access design (including CALDB)
• Hope to have GSSC - HEASARC Memorandum of
  Understanding baselined soon.

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Supplemental Slides
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What Is GLAST?

• Gamma-ray Large Area Space Telescope (GLAST)
  successor to CGRO
• Large Area Telescope (LAT)GLASTs main
  instrument, a follow-on to CGROs EGRET
• GLAST Burst Monitor (GBM)a smaller version of
  CGROs BATSE
• The LAT is a NASA-DOE collaboration with foreign
  contributions. PI Peter Michelson (Stanford
  SLAC)
• The GBM is a MSFC-German collaboration. PI Chip
  Meegan (NSSTC)
• Scheduled launch is September, 2006, into low
  earth orbit
• The minimum mission is 5 years, with a goal of
  10 years!
• The spacecraft will be built by Spectrum Astro,
  the company that built the Swift spacecraft

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The LATStructure

• The LATs Tracker subsystem will consist of 16
  tungsten planes (for pair production) and 18
  silicon strips planes (to track the pairs).
  Below these W-Si planes are 8 planes of CsI
  logs to measure energies. Surrounding the LAT
  are plastic anti-coincidence scintillator tiles.
  Photons that pair-produce in the trackers front
  or back may be analyzed separately.

Anticoincidence Detector
Tracker
Calorimeter
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The LATCharacteristics

• The energy range will be lt20 MeV to gt300 GeV,
  with an energy resolution of lt10 on axis for
  0.1-10 GeV.
• Peak effective areagt8000 cm2.
• 1? angular resolution lt3.5 _at_100 MeV, lt0.15 _at_10
  GeV
• Only a few Hz out of the 30 Hz events telemetered
  to Earth will be photons.
• Deadtime required lt100 ?s, actual 20 ?s!
• In normal operation GLAST will survey the sky,
  thus most data will be taken at different angles
  to the LAT.
• The LAT will be gt30? more sensitive than EGRET!

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Large FOV

• FOVgt2 sr
• Aeff1/2 of normal at 55
• Photons at large angles to normal will be
  scientifically usable.
• Plot is from the proposal