ACIS Science Instrument Background (Level 2 Data)

Enteir Period

Last Three Months

This page shows scientific instrument background (SIB) data based on ACIS observations, using Level 2 data. The SIB is computed using the following steps.

• First, locate the main source and remove about 200 pixel radius around the source.
• Locsate all point sources using celldetect function
• To lower the probability of leakage from bright sources, increase the size of covered area around the sources to three times of that of celldetect estiamate
• Add up all the removed area. The ratio / will be used later to correct SIB value.
• Compute SIB of the data
• SIB value is corrected by deviding the ratio esitmated above

If you are interested in checking the scientific instrument background computed with Level 1 data set, please to go to level 1 SIB page.

On each page, you find:

• All CCD combined SIB plots
• CCD5, 6, and 7 SIB plots
• Each CCD plot with no energy range separated
• Each CCD plot with 6 energy ranges. The energy ranges are: