# Presentation: 553522

## GLAST SSC Development Plans

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

## Outline

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

## GLAST Introduction

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

## 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.**

## 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 year’s HUG**

## 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**

## 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 User’s 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.**

## 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.**

## 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**

## 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 don’t 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 User’s Committee.**
**LHEA personnel   **

## 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).  **

## 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).  **

## 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. **

## 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.**

## Supplemental Slides

## What Is GLAST?

**G****amma-ray ****L****arge ****A****rea ****S****pace ****T****elescope (****GLAST****)— successor to *****CGRO***
**Large Area Telescope (LAT)—GLAST’s main instrument, a follow-on to *****CGRO*****’s EGRET**
**GLAST Burst Monitor (GBM)—a smaller version of *****CGRO*****’s 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**

## Slide 17

## The LAT—Structure

**	****The LAT’s 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 tracker’s front or back may be analyzed separately.**

- Anticoincidence Detector

- Tracker

- Calorimeter

## The LAT—Characteristics

**The energy range will be <20 MeV to >300 GeV, with an energy resolution of <10% on axis for 0.1-10 GeV.**
**Peak effective area>8000 cm****2****.**
**1******** angular resolution <3.5° @100 MeV, <0.15° @10 GeV**
**Only a few Hz out of the 30 Hz events telemetered to Earth will be photons.**
**Deadtime: required <100 ********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 >30******** more sensitive than EGRET!**

## Large FOV 

**FOV>2 sr**
**A****eff****~1/2 of normal at 55°**
**Photons at large angles to normal will be scientifically usable.**
**Plot is from the proposal**