j_ima_mosaic

This executable combines input sky maps produced by j_ima_iros to make JEM-X mosaic images in a single FITS file (named by default jmxi_mosa_ima.fits) comprising each energy band found in the input observation group or selected by the user.

The input intensity IMATYPE (RECONSTRUCTED or RECTIFIED or RAWINTENSITY) is selected by use of the parameter "mapSelect". Note that if the user wants to extract fluxes from the image, only "RECONSTRUCTED" (recommended) or "RECTIFIED" make sense. There are four parameters defining the mosaic skymaps produced in the output file so it can have, for each energy band, up to four image extensions (depending on the chosen options) showing in the following respective order:

1. RECONSTRUCTED (default) or RECTIFIED or RAWINTENSITY (depending on the input intensity IMATYPE; see above): it is the weighted intensity map (counts/dm2/s) produced by use of the parameter "viewIntens",
2. VARIANCE: the weighted variance map (use "viewVar"),
3. SIGNIFICANCE: the significance map (use "viewSig") defined as the intensity divided by the square root of the variance at each pixel.
4. EXPOSURE: the effective exposure times (use "viewTime") expressed in seconds taking account of the dead time, grey filter effects and vignetting of the JEM-X instruments (Notice: the vignetting used is normalised to 1 at the center of JEM-X FoV so as this corresponds to an effective detector aera of about 70 cm2 in average, depending on the actual energy range). With the latter option an additional map is also produced in the last extension OBS_TIME of the output file that shows the accumulated raw observation times (in seconds).

If sky coordinates (RAcenter, DECcenter) are given as parameters to define the center of the mosaic map, an ordered list of the input images as a function of their respective weights at the given coordinates is displayed for each energy band in the log file.

Since OSA10 it is possible (switching the new parameter view_nb to ``yes'') to output in a separate extension the number of SCWs contributing to each pixel of the mosaic. This new image will be of type NB_SING, and will be the last extension of the mosaic fits file.

j_ima_mosaic can combine any set of JEM-X mosaics, even if they have been obtained with different units. It is however mandatory that the user must attach all the requested mosaics to a group. For instance, if the user wants combine mosaics from the three OSA analyses: mysrc_1_jmx1, mysrc_2_jmx1, mysrc_3_jmx2, the user shall type:

dal_create mos_group.fits ""
dal_attach  mos_group.fits obs/mysrc_1_jmx1/jmx1_mosa_ima.fits
   obs/mysrc_2_jmx1/jmx1_mosa_ima.fits
   obs/mysrc_3_jmx2/jmx2_mosa_ima.fits "" ""

("" in the first line indicates that we use the default template, which is a group; the final "" "" represents two empty child parameters of dal_attach; indeed dal_attach can attach up to five children in a single invocation).

Now the group is ready, and one can call j_ima_mosaic:

j_ima_mosaic inObsGrp=mos_group.fits outfile=combined_mosaic.fits moscomb=y

The moscomb parameter is very important, as it tells j_ima_mosaic that we are trying to combine mosaics. The user can use either JMX1 or JMX2.

j_ima_mosaic can now produce mosaics either in the default tangential projection or using AIToff-Hammer projection (useful in particular when mosaicking large parts of the sky, such as for the Galactic Plane Scans). AIToff-Hammer projection can be selected with the parameter IMA2_AITproj="yes".

Table 23: j_ima_mosaic parameters

Name	Type	Description
inObsGrp	string	DOL of observation group default `` ''
mapSelect	string	Default for Reconstructed (Residual+Sources) Intensity maps, else RECTI for Rectified Intensity maps or RAWIN for Raw Intensity maps default ``RECON''
dolBPL	string	DOL of the vignetting maps, e.g., ../../ic/jmx1/rsp/jmx1_bpl_grp_0002.fits[JMX1-DMAP-BPL] default `` ''
radiusSelect	real	Input images selection radius in deg default ``5''
eminSelect	real	Minimum energy (keV) to select energy interval default ``0''
emaxSelect	real	Maximum energy (keV) to select energy interval default ``80''
diameter	real	Diameter in degrees of the mosaic image; 0 allows to fit the size from the angle between input images, : may be used to force larger mosaics default ``0''
cdelt	real	Pixel size in degrees at mosaic center default ``0.026''
RAcenter	real	Center of the mosaic image Right Ascension in degrees (if use the computed middle position of the mosaic) default ``-1''
DECcenter	real	Center of the mosaic image Declination in degrees (not used if RAcenter ) default ``0''
outfile	string	Mosaic FITS file prefix name (optional) default `` ''
viewTime	boolean	Create total exposure Time map? (if Y: produce both raw exposure time map and energy dependent effective exposure maps) default ``Y''
viewIntens	boolean	Create raw Intensity map? default ``Y''
viewVar	boolean	Create Variance map? default ``Y''
viewSig	boolean	Create Significance map? default ``Y''
view_nb	boolean	Create a map that shows the number of input images contributing to each pixel? default ``N''
AITproj	boolean	Produce map in galactic coordinates using AIToff-Hammer projection? default ``N''
print_ScWs	boolean	List input Science Windows in mosaic headers? default ``N''
chatter	integer	Level of test output default ``2''