NAME

nucalcsaa -- Calculate SAA passages for NuSTAR

USAGE

nucalcsaa hkfile orbitfile evtfile outfile [parameter = < value >]

DESCRIPTION

'nucalcsaa' calculates South Atlantic Anomaly (SAA) passages of NuSTAR. The SAA passages can be calculated with three alternative algorithms (named '1', '2' and '3') that can be set by the user through the input parameter 'saacalc'. For all types of calculations two different SAA calculation modes are implemented ('STRICT' and 'OPTIMIZED') and the user can choose the mode through the input parameter 'saamode'.

In the 'STRICT' mode the SAA passages are identified monitoring the level of the high-gain (low-gain) shield single rates stored in the 'SHLDHI' ('SHLDLO') column of the input housekeeping file for the '1' ('2' and '3') SAA calculation algorithm.

In the 'OPTIMIZED' mode the SAA passages found in the 'STRICT' mode are refined by requiring the presence of an increase of the CZT detector event count rates simultaneous to the observed shield single rates increase. The results for both SAA modes are written in a new column named 'SW_SAA' of the output housekeeping file.

In addition, by setting the input parameter 'tentacle' to 'yes', the task allows to identify and flag time intervals in which the CZT detector event count rates show an increase. This search is done only when the spacecraft is entering in the SAA region and a simultaneous shield single rates increase is not required. The results are written in a new column named 'SW_TENTACLE' of the output housekeeping file. As for the 'STRICT' and 'OPTIMIZED' mode, also the 'tentacle' algorithm is different in the three 'nucalcsaa' calculations ('1', '2' or '3').

The various numerical values used by the algorithms are stored in a specific CALDB file provided in input through the parameter 'saaparfile'.

By default ('saacalc=3' and 'eliminatesource=yes'), the CZT detector count rates are evaluated after the exclusion of the contribution of the brightest sources in the field of view. Note that for the case 'saacalc=1' the algorithm has been tested only for steady sources with fluxes not dominating over the detector background and no elimination of the target source is done.

The 'tentacle' option should be used only when the background count rate is not stable and shows time intervals of increased intensity. The time intervals identified by the task should be carefully checked by the user.

PARAMETERS

hkfile [file name]
Name of the input Housekeeping FITS File.

orbitfile [file name]
Name of the input Orbit FITS File.

evtfile [file name]
Name of the input Event FITS File.

outfile [file name]
Name of output Housekeeping FITS event file.

(saaparfile=CALDB) [file name]
Name of the input SAAPAR file or CALDB.

(saacalc=3) [integer]
SAA calculation algorithm [1, 2 or 3]

(saamode=OPTIMIZED) [string]
SAA calculation mode [NONE|STRICT|OPTIMIZED].

(tentacle=yes) [boolean]
If set to yes, calculate SAA tentacle flag.

(evtexpr="STATUS==b000000000x0xx000&&SHIELD==0&&GRADE.LE.26") [string]
Expression to select good events or NONE to do not make the selection.

(optimizedrms=4.5) [real]
Optimized SAA filtering RMS threshold (only if saacalc=2,3)

(tentaclerms=4.5) [real]
Tentacle SAA filtering RMS threshold (only if saacalc=2,3)

(eliminatesource=yes) [boolean]
Eliminate the source for events rate estimation? (yes/no) (only if saacalc=2,3)

(sourcethr=4.0) [real]
Sigma upper limit cut-off for source elimination (only if saacalc=2,3)

(tentacleregcut=yes) [boolean]
Apply Longitude restriction for tentacle calculation? (yes/no) (only if saacalc=2,3)

(optimizedsanitychecks=yes) [boolean]
Perform Sanity Checks for optimized SAA calculation? (yes/no) [only if saacalc=2,3; use 'no' for debugging]

(tentaclesanitychecks=yes) [boolean]
Perform Sanity Checks for tentacle SAA calculation? (yes/no) [only if saacalc=2,3; use 'no' for debugging]

(clobber=no) [boolean]
If set to yes, overwrite the output file.

(history=yes) [boolean]
If set to yes, write parameter values and other information in HISTORY blocks.

(chatter = 2) [integer]
Chatter Level (min=0, max=5).

EXAMPLES

  1. Calculate the 'SW_SAA' column using the optimized SAA calculation for 'saacalc=3'. The new column is stored in the ouput file 'nu40060001001A_fpm_out.hk'.

     > nucalcsaa hkfile=nu40060001001A_fpm.hk orbitfile=nu40060001001_orb.fits evtfile=nu40060001001A_uf.evt 
       outfile=nu40060001001A_fpm_out.hk saamode=OPTIMIZED tentacle=no
    

BUGS

SEE ALSO

LAST MODIFIED

July 2017