The Grism Lens-Amplified Survey from Space (GLASS). IV. Mass
  reconstruction of the lensing cluster Abell 2744 from frontier field imaging
  and GLASS spectroscopy
  We present a strong and weak lensing reconstruction of the massive cluster
Abell 2744, the first cluster for which deep Hubble Frontier Field (HFF) images
and spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) are
available. By performing a targeted search for emission lines in multiply
imaged sources using the GLASS spectra, we obtain 5 high-confidence
spectroscopic redshifts and 2 tentative ones. We confirm 1 strongly lensed
system by detecting the same emission lines in all 3 multiple images. We also
search for additional line emitters blindly and use the full GLASS
spectroscopic catalog to test reliability of photometric redshifts for faint
line emitters. We see a reasonable agreement between our photometric and
spectroscopic redshift measurements, when including nebular emission in
photometric redshift estimations. We introduce a stringent procedure to
identify only secure multiple image sets based on colors, morphology, and
spectroscopy. By combining 7 multiple image systems with secure spectroscopic
redshifts (at 5 distinct redshift planes) with 18 multiple image systems with
secure photometric redshifts, we reconstruct the gravitational potential of the
cluster pixellated on an adaptive grid, using a total of 72 images. The
resulting mass map is compared with a stellar mass map obtained from the deep
Spitzer Frontier Fields data to study the relative distribution of stars and
dark matter in the cluster. We find that the stellar to total mass ratio varies
substantially across the cluster field, suggesting that stars do not trace
exactly the total mass in this interacting system. The maps of convergence,
shear, and magnification are made available in the standard HFF format.
