SMART Data Structures

SMART utilises a number of data structures to store and manipulate data. The main ones are :

1. The 1D-data, (ie. spectra), are stored in the "IRS" spectral structure.
   This is the structure that is used whenever the user is directly operating on the structure. (ie. Command line and batch/script calls.)
2. Inside the SMART IDEA window processing the "IAAR" and "YAAAR" structures are used.

---

SMART IRS Data Structure

Datasets are passed within SMART in pointer arrays.
Each element of the pointer arrays contains a structure of the format :

        *ptr_aar(n) = {irs:     irs,   $
                       target:  str,   $  
                       filename:string}

irs	IDL data structure "irs", see below.
target	IDL string variable containing target name.
filename	IDL string variable containing file name.

"irs" is an IDL data structure of the form :

        irs = {type   : 'IRS',      $
               header : str,        $
               history: strarr(1) , $
               data   : data}

type	IDL string hard coded with the letters "IRS".

|header |IDL string variable containing a formated ASCII FITS header. This will contain all the important key words from the SSC pipeline. |

history	IDL one element string array. This can contain history information.
data	IDL data structure containg observational data.

"data" is an IDL data structure of the form :

        data = {wave:0.0, flux:0.0, stdev:0.0, order:0l, slitpos:0l, module:0l, bcd:0l, status:0l, sky:0.0, skye:0.0, flag:0l}

Note :

This is NOT the same as the "data" data structure in the "YAAAR" data structure described below.

where :

wave	Wavelength in microns.
flux	Flux density in Jy (TBC).
stdev	Uncertainty in flux density in Jy (TBC).
order	IRS orders SL, LL = 1 ,2 ,3 (bonus order) SH, LH = 11-20.
slit position	IRS Slit Position range 1:30 for SL1, SL2, LL1, LL2 and 1:5 for SH and LH.

|module |IRS module.
The low resolution modules (SL, LL) each have two entrance apertures so when a point source
is observed in order 1 it is not observed simultaneously in order 2.
Order 3 is the bonus order (very short) and it sees the same sky as order 2.

• 0 = SL1 (order 1 = target; order 2, 3 = sky)
• 1 = SL2 (order 2,3 = target; order 1 = sky)
• 2 = LL1
• 3 = LL2
• 4 = SH (order 11-20)
• 5 = LH (order 11-20)

|

bcd	IRS BCD numbers 1....n.
status	Will contain IRS status flag if we have one !
sky	Sky background in Jy (TBC).
skye	Sky background uncertainty in Jy (TBC).
flag	So we can mask the data. (BAD='40000000'XL, GOOD='BFFFFFFF'XL)

Notes :

1. Do not hard code in the maximum slit position, in case we decide for some reason to take a strip outside the nominal wavesamp.
2. This assumes the BCDs will start at 1 but they may start at 0 !
3. There may be additional data tags added to the structure, for now assume you will have at least the ones outlined above.
4. Use a tag value of -1 in command line routines if for example you wish to operate on all orders etc
5. if it doesn't make sense please ask before you start coding !

SMART IDEA Window Processing

The SMART-IDEA Window (based on the original ISAP GUI) passes the data inside the window environment
via a structure known as an AAR, (Auto Analysis Result) which is currently available in two versions for IRS data :

1. IAAR : "IRS AAR", spectral data.
2. YAAAR : "Yet Another AAR", a more generic, flexible AAR-like IDL data structure,
   for handling spectral data from any instrument providing it has wave, flux, stdev and flag data tags.

The SMART IDEA window will also handle the original ISO data formats allowing direct comparisons between Spitzer/SIRTF data and ISO data :

1. LAAR : LWS Auto Analysis Result.
2. SAAR : SWS Auto Analysis Result.
3. Browse Quality Products from the ISO Archive (LWS, SWS, CAM-CVF and PHOT_S) => stored in YAAAR format.

YAAAR

Currently the YAAAR format is used to pass IRS data into the SMART IDEA Window :

        yaaar = {type: 'YAAAR',       $
                 header: str,         $
                 history: strarr(1),  $
                 data: data}

type	IDL string hard coded with the letters "YAAAR".
header	IDL string variable containing a formated ASCII FITS header.
history	IDL one element string array. This can contain history information.
data	IDL data structure containg observational data.

"data" is an IDL data structure of the form :

        data = {wave:0.0, flux:0.0, stdev:0.0, det:0l, line:0l, sdir:0l, scnt:0l, status:0l, sky:0.0, skye:0.0, flag:0l}

Note :

This is NOT the same as the "data" data structure in the "IRS" data structure described above.

where :

IRS name	YAAAR Name	Description
order	det	IRS orders SL/LL = 1 ,2 ,3 (bonus order) SH/LH = 11-20
slitpos	line	IRS Slit Position -1 = whole slit, 1-30 = positions along SL/LL
module	sdir	SL1 = 0, SL2 = 1, LL1 = 2, LL2 = 3, SH = 4, LH = 5
bcd	scnt	IRS BCD nubers 1....n

Outside of SMART-IDEA

Command line routines use the IRS spectral structure described above.

SMART IDEA AAR

(This section is adapted from the ISAP WWW page "ISAP AAR" with all relevant acknowledgements.)

Input AAR:

The AAR FITS files for SWS and LWS are the final products of pipeline processing.
ISAP defines a new named structure with simpler data names and read these files into it.
This new AAR contains the following tags :

Type	Description
"LAAR'	for LWS FITS
'SAAR'	for SWS FITS
'YAAAR'	for processed AAR (stands for "Yet Another AAR")

header - Array of strings of 80 chars

history - Array of strings of 32700 chars each

data - array of structures of data containing the possible data tags as follows :

{WAVE, WAVEU, FLUX, STDEV, TINT, DET, ITK, UTK, RPID, SPARE, LINE, SDIR, SCNT, STATUS, FLAG}

The FITS primary and secondary headers are written into the header tag of AAR.
In addition, all HISTORY keywords found in FITS headers are saved in history tag.

The traslation of input FITS file parameters into ISAP AAR data tags is as follows :

SAAR/LAAR	SWS	LWS
WAVE	SWAAWAVE	LSANWAV
WAVEU		LSANWAVU
FLUX	SWAAFLUX	LSANFLX
STDEV	SWAASTDV	LSANFLXU
TINT	SWAATINT	LSANTINT
DET	SWAADETN	LSANDET
ITK	SWAAITK	LSANITK
UTK	SWAAUTK	LSANUTK
RPID	SWAARPID	LSANRPID
SPARE	SWAASPAR	LSANFILL
LINE	SWAALINE	LSANLINE
SDIR	SWAASDIR	LSANSDIR
SCNT	SWAASCNT	LSANSCNT
STATUS	SWAASTAT	LSANSTAT
FLAG	SWAAFLAG	LSANFLAG

YAAAR:

Input to ISAP are the files as described above. However, sometime during processing information is lost on certain data tags.
For example when you rebin/merge/average spectra from individual detectors into one final spectrum, you are loosing the information on individual detectors.
Thus, ISAP processed AAR , known as YAAAR, can have 4 to 15 data tags.
The minimum data tags expected are WAVE, FLUX, STDEV, and FLAG.