Dec 172013

Now that the first epoch of Abell 2744 observations has completed, we are releasing the v1.0 data products.  These are products include all 70 orbits on the main cluster with WFC3/IR (in F105W, F125W, F140W and F160W) and on the parallel field with ACS (in F435W, F606W, F814W).

The v1.0 data products are made from a complete reprocessing, including these steps:

  • recalibration of exposures using the latest, up-to-date reference files and improving the bad pixel and cosmic ray rejection
  • exposures in all filters are combined with other observations, as available, to make the deepest possible mosaics
  • for ACS data, an additional “self-calibration” step is included, which improves both the calibration and alignment
  • for WFC3 data, refined flagging and removal of pixels affected by observational anomalies, including persistence, detector defects, and time-variable sky background.

These complete products are expected to reach final depths of ~28.7 – 29th ABmag. Complete details on these specially crafted calibrations can be found in the Frontier Fields Science Data Pipeline and Products Readme file.  We have made every effort to document all the special handling the Frontier Fields data is receiving, so that everyone can make use of what we have learned works best.

Mosaics are distortion-corrected, combined and registered to a common pixel scale, ready for you to use immediately!  You can find all of these products at our MAST web page:

Our data is ready to be mined for science!

 Posted by at 2:52 pm
Dec 052013

The lensing maps for all six Frontier Fields clusters were released November 27, 2013.  The MAST lensing model web site provides

  • interactive interfaces for exploring the mass (kappa), shear (gamma), and magnification maps pre-computed at z = 1, 2, 4, and 9
  • a tool to deliver magnification estimates with uncertainties from all models at a given RA, DEC, and redshift
  • direct access to the lensing models.

These models were produced by five independent groups:

  • M. Bradac (PI)  A. Hoag, and collaborators
  • Clusters as TelescopeS Team (CATS):  H. Ebeling (PI), J. Richard, M. Limousin, and collaborators
  • J. Merten (co-PI) ,  A. Zitrin (co-PI), and collaborators
  • K. Sharon (PI), T. Johnson, and collaborators
  • L. Williams (PI) and collaborators

We hope the community sees these models as valuable resources.  If you find them useful, please acknowledge these map makers according to the instructions at the bottom of the web site.  Thank you!

Here’s just one example of what you can see with the interactive viewer for MACSJ0416.1-2403, of which data will be coming soon!  Clicking on the image below will take you directly to the interactive viewer.

Sharon, et al. lensing models of MACSJ0416.1-2403, showing z = 1, 4, 9.

K. Sharon, T Johnson, et al. magnification maps of MACSJ0416.1-2403, showing z = 1 (blue), 2 (green), 9 (red).

You can now go explore all of the Frontier Fields cluster lensing maps!

 Posted by at 9:00 am
Dec 042013

We now have all the data from epoch 1 of Abell 2744 in hand!

HST obtained the last exposures of this epoch on 28 November 2013. This completes a total of 70 orbits of WFC3/IR imaging on the main cluster and ACS imaging on the parallel field.  Other, contributing programs (by B. Siana, S. Rodney, and R. Dupke) added a combined 38 orbits of ACS and WFC3/IR data.  Please see the Frontier Fields MAST web site for full details.

Our fast-turnaround v0.5 mosaics of all the above data (v0.5-20131129, released on November 29, 2013) are now available.  These mosaics are full-depth, but the calibrations are still preliminary.

During the next couple of weeks, we will be creating the recalibrated, version 1.0 of this dataset.  Recalibrations for WFC3/IR data will include:

  • improved persistence correction
  • bad pixel masking
  • time-variable sky treatment,

while for ACS we expect to also include:

  • improved bad-pixel masking
  • updated darks and biases
  • possibly self-calibration of all the ACS exposures.

The details of these recalibration steps are still being refined, so stay tuned!

 Posted by at 10:18 am