Dear colleagues,

We are pleased to announce a new v0.5 release for the cluster Abell 370, which completes the full 70 HST orbits for epoch 2 of this cluster from program ID 14038 (PI: J. Lotz), as well as completion of all the observations for the entire Frontier Fields program. The full dataset for this cluster also includes public archival ACS and WFC3/IR imaging data from programs 11108 (PI: E. Hu), 11507 (PI: K. Noll), 11591 (PI: J.-P. Kneib), 13459 (PI: T. Treu), and 14216 (PI: R. Kirshner). These have all been combined to provide the most complete full-depth mosaics in the ACS/WFC and WFC3/IR filters that are used for the Frontier Fields program, where all data have been fully reprocessed using the most current calibration files. These mosaics have all been processed beyond the default pipeline calibration, in order to produce the best possible quality, science-ready full-depth mosaics. For ACS, these mosaics incorporate CTE correction and bias destriping, as well as a set of mosaics that have been processed with the new selfcal approach to better correct for low-level dark current structure. The WFC3/IR mosaics have been masked for persistence and bad pixels, and in addition include a set of mosaics that have been corrected for time-variable sky emission that can occur during the orbit and can otherwise impact the up-the-ramp count-rate fitting if not properly corrected. All these mosaics are aligned to a common pixel grid as well as to an absolute astrometric frame based on pre-existing catalogs of this field. Further details are provided in the readme file, which can be obtained along with all the mosaics at the following link:

* Latest mosaics:
* All mosaics:

More general information about the data for this project can be obtained from our Frontier Fields MAST archive website:
as well as our main Frontier Fields HST project website:
and our Frontier Fields astronomer's blog and other social media:

We hope that these high-level science products are useful for your research, and we welcome any suggestions or questions that you may have about them.

Best regards,
Anton Koekemoer
and the STScI Frontier Fields Team
David Cottle

UBB Owner & Administrator