Team Only Data Release 2 - Complete Epoch 1
Feb 26, 2015
This is the second distribution of HDUV imaging data. It contains
background-subtracted, drizzled F275W and F336W images of the first complete epoch of the HDUV survey.
We are now about half-way through the survey, meaning that we got one epoch of F275W and F336W imaging data over all
5 pointings in GOODS-S, and we got 4 out of 8 pointings in GOODS-N completed.
The raw files were CTE-corrected, and WCS-aligned, before drizzling onto a common output grid. Compared to the first image release
we now perform a better destriping and background subtraction of the data. Specifically, after a first pass reduction, we mask all
objects and create a super sky dark image. This is shown in the figure below. The sky dark is subtracted from all images before the final
drizzle iteration.
Again, the WCS registration was performed relative
to the 3DHST HST images (Skelton et al. 2014; available here),
and the GOODS-N F275W data also contains all the CANDELS imaging taken over this
field. Those images were aligned using shifts determined by the F350LP
exposures taken just prior to the F275W frames.
We now also correctly stack the data using an inverse variance map weighting (including the postflash electrons), and we
provide the corresponding RMS maps of the final drizzled images in the release. These were renormalized to account for
correlated noise using the standard correction factors from
Casertano et al. (2000).
We provide images at 60mas and 30mas pixel scales. The 60mas images are drizzled to the same frames as the 3D-HST data, while the 30mas
images were trimmed to avoid excessively large file sizes.
The images in this release are thus:
GOODS-S 60mas
- hduv_goodss_epoch1_60mas_3dhst_f275w_v0.5_drz.fits.gz F275W science image on 3DHST pixel frame
- hduv_goodss_epoch1_60mas_3dhst_f275w_v0.5_rms.fits.gz F275W rms map
- hduv_goodss_epoch1_60mas_3dhst_f336w_v0.5_drz.fits.gz F336W science image on 3DHST pixel frame
- hduv_goodss_epoch1_60mas_3dhst_f336w_v0.5_rms.fits.gz F336W rms map
GOODS-N 60mas
- hduv_goodsn_epoch1_60mas_3dhst_f275w_v0.5_drz.fits.gz F275W science image on 3DHST pixel frame
- hduv_goodsn_epoch1_60mas_3dhst_f275w_v0.5_rms.fits.gz F275W rms map
- hduv_goodsn_epoch1_60mas_3dhst_f336w_v0.5_drz.fits.gz F336W science image on 3DHST pixel frame
- hduv_goodsn_epoch1_60mas_3dhst_f336w_v0.5_rms.fits.gz F336W rms map
GOODS-S 30mas
- hduv_goodss_epoch1_30mas_f275w_v0.5_drz.fits.gz F275W science image trimmed
- hduv_goodss_epoch1_30mas_f275w_v0.5_rms.fits.gz F275W rms map
- hduv_goodss_epoch1_30mas_f336w_v0.5_drz.fits.gz F336W science image trimmed
- hduv_goodss_epoch1_30mas_f336w_v0.5_rms.fits.gz F336W rms map
GOODS-N 30mas
- hduv_goodsn_epoch1_30mas_f275w_v0.5_drz.fits.gz F275W science image trimmed
- hduv_goodsn_epoch1_30mas_f275w_v0.5_rms.fits.gz F275W rms map
- hduv_goodsn_epoch1_30mas_f336w_v0.5_drz.fits.gz F336W science image trimmed
- hduv_goodsn_epoch1_30mas_f336w_v0.5_rms.fits.gz F336W rms map
You can download all the files using this script or access them individually here.
Note that the GOODS-S images do NOT include the UVUDF images. The lack of large scale dithers makes those data very difficult
to reduce and we found that our dark correction is likely still not as good as the one developed by the UVUDF team (see
also: future improvements). In particular, the small dither steps do not allow us to create a sky dark from the UVUDF data themselves. The reduced frames over the Hubble-Ultra Deep field by the UVUDF team can be accessed here.
Zeropoints:
The dust-free WFC3/UVIS AB zeropoints are:
- F275W: 24.1305
- F336W: 24.6682
The Schlafly & Finkbeiner (2011) E(B-V) for GOODS-S and -N are 0.0069 mag and 0.0105 mag (see
here). These result in a dust correction of 0.0434 mag and 0.0349 mag in GOODS-S and 0.066 mag and 0.053 mag in GOODS-N,
for F275W and F336W, respectively.
The Galactic dust-corrected WFC3/UVIS AB zeropoints to be used are thus:
GOODS-S |
F275W |
24.087 |
GOODS-S |
F336W |
24.633 |
GOODS-N |
F275W |
24.065 |
GOODS-N |
F336W |
24.615 |
Future Plans:
Over the last month we incorporated most of the TBDs from the first release, however, some further improvements can of course be made.
In particular, for a v1 dataset we are planning to work on:
- 1) CTE corrected darks, and generally improved handling of dark subtraction
- 2) refining alignment of individual exposures in a second pass