Event and Analysis Classes

Analysis Classes

We have six analysis classes:

• classA (also known as GoodEvent3)
• all (also known as GoodEvent1)
• FrontA
• BackA
• FrontB
• BackB

Note: The two classes most suitable for science analysis are:

• Class A is the highest quality, with:
  • Best PSF
  • Lowest background contamination.

• all
  • More effective area, but
  • more background

These can be selected in any of the Science Tools which prompt for an IRF as DC2_A
(for class A) and DC2 (for all).

Notes:

• Instrument Response Functions. IRFs have been constructed so that each event belongs to one - and only one - event class. Event classes are combined to make the analysis classes that you select for analysis.

• ClassB Events. ClassB events are events which belong to All, but are not classA events.

• Front or Back. Each event class is further subdivided into front and back (depending on whether the event converted in the front or back section of the LAT).

• Individual Event Classes. Each event class can also be studied individually by selecting:

• DC2_FA (where FA = Front Event Class A)
• DC2_BA (where BA = Back Event Class A)
• DC2_FB (where FB = Front Event Class B)
• DC2_BB (where BB = Back Event Class B)

These are stored in the FTI in the EVENT_CLASS column as an integer ranging from 0-4.

• [0-1] – A Front, Back
• [2-3] – B Front, Back

The EVENT_CLASS column in FT1 is defined using a set of TCuts on the merit summary ntuple.

Note: Three EVENT_CLASS variables not defined in current FT1 documentation, but whose definitions are obvious, should also be mentioned here; these are:

EVENT_Class
RUN_ID
EVENT_ID

Choices that make sense for use with the Instrument Response Functions (IRF’s) are:

• All
• Any individual value
• 0 AND 1 (i.e., A only)
  

Also See

• Data Products and Servers

• Trigger and Filter Settings and Event Classes