  Ground-based, high-resolution bolometric (sub)millimeter continuum mapping
observations on spatially extended target sources are often subject to
significant missing fluxes. This hampers accurate quantitative analyses.
Missing flux can be recovered by fusing high-resolution images with
observations that preserve extended structures. However, the commonly adopted
image fusion approaches do not maintain the simplicity of the beam response
function and do not try to elaborate the details of the yielded beam response
functions. These make the comparison of the observations at multiple
wavelengths not straightforward. We present a new algorithm, J-comb, which
combines the high and low-resolution images linearly. By applying a taper
function to the low-pass filtered image and combining it with a high-pass
filtered image using proper weights, the beam response functions of our
combined images are guaranteed to have near-Gaussian shapes. This makes it easy
to convolve the observations at multiple wavelengths to share the same beam
response functions. Moreover, we introduce a strategy to tackle the specific
problem that the imaging at 850 um from the present-date ground-based
bolometric instrument and that taken with the Planck satellite do not overlap
in the Fourier domain. We benchmarked our method against two other widely-used
image combination algorithms, CASA-feather and MIRIAD-immerge, with mock
observations of star-forming molecular clouds. We demonstrate that the
performance of the J-comb algorithm is superior to those of the other two
algorithms. We applied the J-comb algorithm to real observational data of the
Orion A star-forming region. We successfully produced dust temperature and
column density maps with ~10" angular resolution, unveiling much greater
details than the previous results.
