Transcript ppt

GLAST LAT Project
Source
identification
for the LAT
catalogue
Gamma-ray Large
Area Space
Telescope
I. A. Grenier
CEA Saclay
S. W. Digel
Stanford Linear Accelerator Center
LAT Collaboration meeting, 30 August 2005
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GLAST LAT Project
source properties
• Catalogue description for the sources detected with the
automatic pipeline
– name
– positions (l, b, , , in decimal units)
– 67% and 99% error ellipses
– variability index (?) and error bars
– flux and source significance per month/week (regular/bright
source) for some large energy band
– average flux in several energy bands
– single power-law spectral index (used for the instrument
response) and 1 error
– identification if firm (based on variability or periodicity, or
very small error box with unambiguous single counterpart)
– list of potential counterparts based on spatial coincidence
and figure of merit
LAT Collaboration meeting, 30 August 2005
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GLAST LAT Project
identification
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cross-correlation with other catalogues using A2 tool
– A2 under control
– cross-identification of X-ray sources not available
develop and implement normalized figures of merit
– not a prioritization figure
– for known source types: blazars and pulsars (unpulsed,
plerion…), SNRs
– prepare for likely source types: radiogalaxies, microquasars,
galaxy clusters
normalization problems
– all-sky surveys with known sensitivity available for radiosources,
for a fraction of radio pulsars, from WMAP/Planck, 2Mass, SDSS
sources, from ROSAT (but not sensitive enough for high-z
blazars), …
– many catalogues have no sensitivity information
calibration of figure of merit against samples of identified sources
LAT Collaboration meeting, 30 August 2005
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GLAST LAT Project
urgent need
• work out figures of merit!
LAT Collaboration meeting, 30 August 2005
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