Output Files

 

A list of all output files for spatial analysis is given in Table 5.33. The tables with the default names lslst1.tbl, mslst1.tbl, mplst.tbl, solst.tbl and mllst.tbl are source parameter tables. They are created with the commands DETECT/LOCAL, DETECT/MAP, MERGE/SOURCE_TABLES, DETECT/MAXLIK, DETECT/SOURCES, and COMPUTE/UPPER_LIMITS (Table 5.28). Column ID is a command identifier.

  
Table 5.28: Commands by which source tables are created

All parameters of the source tables are listed in Table 5.29 in alphabetical order.

  
Table 5.29: All source table parameters, cf. Table 5.20

• BACKG are the background counts per image pixel determined at the source position by different methods, the local detection (command DETECT/LOCAL), the map detection (command DETECT/MAP) or the merging of the local and map detection table (command MERGE/SOURCE_TABLES). The size of an image pixel can be determined from the descriptors STEP(1) and SKY_PIX_SIZE of the image. The area of an image pixel is STEP(1)*STEP(1)*SKY_PIX_SIZE*SKY_PIX_SIZE arcsec.  
• BG_ML are the background counts per image pixel at the source position determined by the maximum likelihood method (commands DETECT/MAXLIK, DETECT/SOURCES or COMPUTE/UPPER). The size of an image pixel can be determined from the descriptors STEP(1) and SKY_PIX_SIZE of the image. The area of an image pixel is
  STEP(1)*STEP(1)*SKY_PIX_SIZE*SKY_PIX_SIZE arcsec.  
• CERR is the 1 error in counts determined by the maximum likelihood method.  
• CLUFL is a cluster flag, this flag is not filled or used in any application.
• COFL is the number of continuation lines in the merged source table created by the command MERGE/SOURCE_TABLES. It gives the number of sources merged to one merged source position. In the merged source table all members contributing to one merged position appear with COFL=0.
• COUNT are the source counts determined by the local detection (command DETECT/LOCAL), by the map detection (command DETECT/MAP) or by the merging of the local and map detection tables (command MERGE/SOURCE_TABLES). The counts are background subtracted, they are not corrected for the mirror efficiency (vignetting).  
• CTS are the source counts determined by the maximum likelihood method (command DETECT/MAXLIK). They are background subtracted, they are not corrected for the mirror efficiency (vignetting). This can be done by multiplication with the vignetting correction factor VIG_COR.  
• CTS_MP are the source counts determined after the merging of the source tables (command MERGE/SOURCE_TABLES). They are background subtracted, they are not corrected for the mirror efficiency (vignetting).  
• DUMMY is a dummy parameter neither filled nor evaluated in any task.
• ERATE is the error in the source count rate (s ). It will be the error in the source count rate corrected for vignetting and dead time in case the descriptors TIM_INT and LIF_TIM are existing with the background image. As no point-spread-function correction is applied to the counts (and error in the counts), the error in the count rate will be underestimated in case a too small cut radius has been chosen in the maximum likelihood or upper limit program.  
• EXT is the source extention (the Gaussian of the extension) in units of image pixels determined by the maximum likelihood method. To convert to arcsec, EXT has to be multiplied by the value of the descriptors STEP(1) and SKY_PIX_SIZE. To convert from Gaussian to FWHM EXT has to be multiplied by a value of 2.3548.  
• EXTERR is the 1 error in the source extention (the Gaussian of the source extension) in units of image pixels, see description for parameter EXT.  
• EXI_ML is the likelihood of existence. The likelihood is defined as EXI_ML = ln(1-P), where P is the probability of existence of the source. A probability of 0.683, 0.954, 0.997, 0.99994, 0.9999994 corresponds to a likelihood of existence of 1.15, 3.09, 5.91, 9.66, 14.3 and to 1, 2, 3, 4, 5 Gaussian . The absolute value of the likelihood of existence depends strongly on the background value. A too low background leads to a too high likelihood. A a too high background (in case the source is still accepted) leads to a too low likelihood. In case there are large regions of extended structure in the data (supernova remnants etc.), the spline-fitted background image may not properly reproduce the structures. Then plenty of spurious sources may show up with a relatively high likelihood of existence.  
• EXTFL is an extent flag, this flag is not filled or used in any application.
• EXT_ML is the likelihood for extention.  
• FA is a factor specifying the fraction of a ring (with a inner radius of 0.4 CUT_RADIUS, the cut-out radius of the source photons in units of the FWHM and with outer radius 1.0 CUT_RADIUS) outside the source, that was found with enhanced background due to a close by neighbour source and that was therefore excluded from the maximum likelihood analysis.
• INDEX is a source index. It is the sequence number of the source.
• IND_MP is the index of the source in the merged source table. This information is given in the maximum likelihood source tables.
• ML_MP is the likelihood of existence of the source as determined after the merging process. This information is given in the maximum likelihood source tables.
• PRIO is the source priority. The priority is calculated from the parameter IMAGE_PRIORITY. To each image (energy band) a priority is assigned. The priority determines in which band and by which detection process the source was found.
• RATE is the source count rate (s ). It will be the count rate corrected for vignetting and dead time in case the descriptors TIM_INT and LIF_TIM are existing with the background image. As no point-spread-function correction is applied to the counts, the count rate will be underestimated in case a too small cut radius has been chosen in the maximum likelihood or upper limit program.  
• RIBD is the distance of the source to the rib or edge of the image (in units of compressed image pixels).  
• SIGNA is the existence likelihood of the source detected by the local or map detection process. This likelihood is determined by a chi-square, binomial, or poissonian probability, respectively.  
• SOURD is the distance to the next detected source (in units of image pixels).  
• TOTNUM is the total number of photons analysed by the maximum likelihood technique. These photons are read from the (small map sorted) photon event table.
• UL_CTS are the upper limit counts determined by the command COMPUTE/UPPER. They are only calculated in case the likelihood of existence of the source falls below a threshold value UL_THR. In case the likelihood of existence of the source falls above UL_THR best fit counts are calculated and are written to the column CTS.  
• VIG_COR is the vignetting correction factor (mirror efficiency). This value is . CTS VIG_COR and UL_CTS VIG_COR are the counts corrected for the vignetting. To correct counts for exposure the exposure image can be used (if existing). The exposure image coming from the ROD exposure.bdf contains already the vignetting correction. This means CTS and UL_CTS have to be divided by the value of exposure read from the exposure image at the position of the source WITHOUT correcting for vignetting.  
• XERR is the 1 error in x-position of the source (in units of image pixels) determined by the maximum likelihood technique.  
• X_IMA is the source x-position (in units of image pixels) determined by the maximum likelihood technique.  
• X_POS is the source x-position (in units of image pixels)
• YERR is the 1 error in y-position of the source (in units of image pixels) determined by the maximum likelihood technique.  
• Y_IMA is the source y-position (in units of image pixels) determined by the maximum likelihood technique.  
• Y_POS is the source y-position (in units of image pixels)
• WINDO is the size of the detection cell (1 means a cell of 3 3 image pixels, 2 means a cell of 6 6 image pixels, 3 means a cell of 12 12 image pixels).  

The command TRANSFORM/COORDINATES transforms the source positions X_IMA and Y_IMA (or X_POS and Y_POS) in the source tables LDETECT_LIST_N, MDETECT_LIST_N, MERGED_LIST, ML_LIST_ACCEP ML_LIST_ALL, UL_LIST_ACCEP and UL_LIST_ALL to sky pixel, equatorial, ecliptic and galactic coordinates. It also determines the off-axis angle, the FWHM and the distance to the next source minus 3  of that source.

  
Table 5.30: Coordinate information from TRANSFORM/COORDINATES

 
• Cleanup