Jul 282014
 

We are thrilled to announce the v1.0 release of Abell 2744, Epoch 2, which completes all the Frontier Fields observations of our first cluster!

The Abell 2744 cluster with all observations from both Frontier Fields epochs.

The Abell 2744 cluster with all observations from both Frontier Fields epochs.

This second epoch consisted of 70 orbits on the main cluster with ACS (in F435W, F606W, F814W) and on the parallel field with WFC3/IR (in F105W, F125W, F140W and F160W), thereby complementing the 70 orbits obtained in Epoch 1 with WFC3/IR on the main cluster and ACS on the parallel field, in the same filters.

Abell 2744 parallel field, with observations from both Frontier Fields epochs.

Abell 2744 parallel field, with all observations from both Frontier Fields epochs.

The v1.0 mosaics for this epoch are completely reprocessed and include the following:

  • recalibration of all exposures using the latest, up-to-date reference files for dark current, read-noise and bad pixel masks
  • high-quality astrometric alignment, generally achieving accuracies within 0.01 pixel for the mean offset measurements of exposures relative to one another.
  • for ACS data, an additional “self-calibration” step is included, which improves especially the low-level noise in the images by means of a more accurate treatment of the underlying dark current structure
  • for WFC3/IR data, improved flagging of pixels affected by persistence and detector defects, as well as correction and removal of issues related to time-variable sky background.

Together with the previous Epoch 1 release, the full dataset achieves final depths of ~28.7 – 29th ABmag across all filters. Further details on these science-ready mosaics can be found in the Readme file,
along with the full mosaics, which are all available at our MAST webpages:

http://archive.stsci.edu/prepds/frontier/

All of these mosaics are immediately ready for science!  What will you discover?

 Posted by at 3:31 pm