Combining JEMX-1 and JEMX-2 mosaic images

j_ima_mosaic can combine JEM-X mosaics, provided that they have been obtained in the same energy bands, for the same sky area and in the same projection. As for the simple mosaic image the user may specify the coordinates of the center of the image (RAcenter and DECcenter parameters), as well as its size and resolution ( diameter and cdelt parameters), when creating the mosaics. Any mix, however, of JEMX-1 and JEMX-2 mosaics is allowed.

As an example, let us create a mosaic image of the Galactic Center region, which combines the JEMX-2 mosaic (see previous sub-section) with the JEMX-1.

To combine mosaics, these must be attached in a group, so the first step is to create an empty group:

dal_create obj_name=jemx_mosaics.fits template=""

This uses the default template, which is a standard group. Next, we need to attach the mosaics:

dal_attach jemx_mosaics.fits obs1/jmx1_mosa_ima.fits\
   obs2/jmx1_mosa_ima.fits obs3/jmx2_mosa_ima.fits ""

The final "" is necessary to signal to dal_attach that there are no more data structures to attach. Up to five data structures can be attached with a single dal_attach commands. Additional extensions can be added by issuing another dal_attach command.

The combination of the mosaic is then very easily performed using the command:

j_ima_mosaic inObsGrp=jemx_mosaics.fits outfile=combined_mosaic.fits moscomb=y radiusSelect=-1

Combined JEMX-1 and JEMX-2 mosaics have the same structure as JEMX-1 ones, with EXTNAME=''JMX1-MOSA-IMA''.