GLAST  Sensitivity Estimates

Toby Burnett
Analysis group presentation, 11-Oct-04. (updated 10-Oct-2004 19:17 -0700)

All of these plots and numbers are preliminary, for GLAST internal use only!!! (With exception below)

Previous Analysis Group presentations on this subject

• 24-May-04
• 19-July-04
• 13-Sept-04

Detailed documents, recently updated

• AM-04355 "A simple functional representation for the GLAST PSF"
  Introducing the following very successful function, with detailed analysis of its properties for point source detection and localization

• AM-04356 "LAT Effective Area and Point Spread Function"
  An evaluation of post-DC1 performance, with fits to the PSF parameters s, g in 8 energy x 8 angle bins for both front and back sections.
• AM-04369 "Sensitivity for point-source detection"
  Combining the PSF analysis with a simplified model to the PSF and Aeff functional dependence to predict point source sensitivity

What is new?

• PSF function:
  • Analysis of point source localization - see the 13-Sept-04 presentation
  • Plots of 68% and 95% percentile points (g_p is the gamma parameter defined above)

  

• Effective area and PSF analysis
  • Create a fit to measured average Aeff (0-66⁰) that does not "droop".
    Note: average is defined by an integral over the sphere:
        
    
• Point-source sensitivity
  • Now uses the logistic functional form of aeff, constant above 10 GeV: see above
  • Adjust assumed background to SRD figure. (from 1.57 to 1.50).
  • Emphasize that times are all live time, not elapsed time
  • New plot to show sensitivity for specific energies
    This plot, or the data it displays, has been approved for general release if labeled "preliminary".
  • 
    New plot, to calculate the "Morselli" integral sensitivity used to compare with other missions and ground-based detectors.