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GALPROP  
GBM(Gamma-ray Burst Monitor)
The GBM is the other instrument on Fermi. It is made of 12 NaI (sodium iodide) and 2 BGO (bismuth germanate) detectors.
The GBM detects emission from gamma-ray bursts, solar flares, terrestrial gamma-ray flashes ...		 
GCN(Gamma-ray Coordinates Network)  
GEANT  
ghostsGhosts are events where two particles enter the LAT in a small enough time frame that the LAT considers the interactions a single event.
A typical example would be a gamma ray and proton entering the LAT near simultaneously.
This caused a fraction of gamma-ray events to be vetoed.
This problem was first addressed in Pass7 and substantial improvements have been made in Pass8 to recover gamma-ray data from these ghost events.		 
GI(Guest Investigator) 
GLAST(Gamma-ray Large Area Space Telescope)
GLAST is the name that Fermi was referred to before it was launched.
It is tradition to give NASA missions a different name after launch, as a good-luck superstition.		 
GlastRelease  
GLEAM  
GRB (group)(Gamma-Ray Burst)
GRB group pagegt_____The standard set of software used to analyze LAT data are called the Science Tools.
Each individual tool has a specific function.
The names all start with "gt", for "GLAST", which was the original pre-launch name of Fermi.has detected high-energy emission (>100 MeV) from ~80 GRBs since launch.
In some cases, it detects the prompt emission (the short "burst" of photons lasting anywhere from less than a second to hundreds of seconds),
and in the majority of cases it detects the afterglow (the long lasting, slowly fading emission).
The Gamma-ray Burst Monitor has detected keV-MeV emission from over 1000 GRBs. 		GRB group page
gt_____The standard set of software used to analyze LAT data is called the Science Tools.
Each individual tool has a specific function.
The names all start with "gt", for "GLAST", which was the original pre-launch name of Fermi.		Science Tools references
   
   

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HEASARC(High Energy Astrophysics Science Archive Research Center)HEASARC NASA page
   
   
   
   
   

I

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IRF(Instrument Response Function)Cicerone
ISOC(Instrument Science Operations Center) 
  Science Tools references 
   
  

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   HEASARC(High Energy Astrophysics Science Archive Research Center)HEASARC NASA page
   
   
   
   
   

IJ

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JIRA IRF(Instrument Response Function) 
  ISOC(Instrument Science Operations Center) 
   
   
   

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L

   
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L1Proc(Level 1 Processing)  
   
LAT(Large Area Telescope)
The LAT is the main instrument on Fermi.
The parts of the LAT are the Tracker, Calorimeter, and ACD. 		   
light curve

A light curve is generally a plot of the photon flux versus time.
For pulsars, a light curve is usually a plot of the photon flux versus the pulsar phase. 

  
likelihood   
livetime  

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LLE(LAT Low Energy) 
LLE is a loose event selection that starts at 30 MeV (while the standard LAT event classes start at 100 MeV).
The LLE is background-dominated, so it is only appropriate for short, transient events such as gamma-ray bursts or solar flares.
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JIRA  
    
LMC(Large Magellanic Cloud) 
LPA  
   

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L1ProcMC(Level 1 ProcessingMonte Carlo) 
LAT(Large Area Telescope) 
light curve  
likelihood  
livetime  
LLE(LAT Low Energy)  
LMC(Large Magellanic Cloud) 
LPA  

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MC(Monte Carlo) 
merit / merit file  
MET(Mission Elapsed Time)
Many missions record times in MET, which is the number of seconds since January 1, 2001.		A tool for converting
from MET to dates 
MIP(minimum ionizing particle) 
MOC  
MSP(millisecond pulsar) 
MW(multiwavelength) 

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merit / merit file  
MET(Mission Elapsed Time)
Many missions record times in MET, which is the number of seconds since January 1, 2001.		A tool for converting
from MET to dates 
MIP(minimum ionizing particle) 
MOC(Mission Operations Center) 
MSP(millisecond pulsar) 
multimessengerMultimessenger studies include data from instruments that detect things other than light.
For instance, one might combine LAT data (photons) with neutrinos, cosmic rays, gravitational waves, etc. 		 
MW(multiwavelength)
Multiwavelength studies are conducted across different wavelengths and energies.
For instance, one might combine LAT data (MeV-GeV) with optical, radio, IR, TeV, etc. data. 		 

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nadirThe nadir is the line going from Fermi pointing directly to the center of the Earth. 
nadir observationsWhen Fermi conducts nadir observations, it reorients itself so that it is essentially upside down.
During normal operations, Fermi is looking at the sky, but during nadir observations it observes photons from the Earth.
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nadir  
nadir observations  
NaI

(sodium iodide)
The Gamma-ray Burst Monitor (GBM), the second instrument on Fermi, is made of 12 NaI detectors (and 2 BGO ones).
The NaIs detect photons between ~8 keV and 1 MeV.
They are positioned around the spacecraft to view the entire sky at all times.
The GBM team uses the amount of signal in each NaI detector to calculate localizations.

 
   

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RA(right ascension) 
ROI(region of interest)
The ROI is the region of space that is being analyzed. A typical ROI for an individual source (such as a pulsar or a gamma-ray burst)
is 10 or 12 degrees, although the exact size can differ and depends on the many factors.		 
ROOT, .root fileROOT is an object oriented software package built on C++ by particle physicists at CERN to analyze large amounts of data.
The Merit files are root files and require ROOT to read the data from said file.		http://root.cern.ch/drupal/

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SAA

(South Atlantic Anomaly)
The SAA is a region of the sky over the southern part of the Atlantic ocean that contains a lot of charged particle activity.
Both the LAT and the GBM detect charged particles as part of the background, so when the spacecraft enters the SAA,
the detectors are turned off (data is not stored).
The LAT and GBM have slightly different definitions of the borders of the SAA. 

 
Science Tools  
SeeVogh SeeVogh is the video conferencing software that is used by the LAT collaboration.SeeVogh Research Network
selection  
senior review  
SMC(Small Magellanic Cloud) 
SNR(supernova remnant)SNR group page
source (event class)  
survey mode  
star trackers  

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