The ABYSS HUDF WFC3/IR project
The ABYSS HUDF project (Borlaff et al. 2019) is a new reduction of the Hubble Ultra Deep Field WFC3/IR data optimised for the study of the Low Surface Brightness Universe. Based on the HST near-IR observations of HUDF09 (α = 3h 32m 39.0s, δ = 27º 47' 29:1", J2000, Bouwens et al. 2011), HUDF12 (Koekemoer et al. 2013) and XDF (Illingworth et al. 2013) follow-up projects, we created a new version of the F105W, F125W, F140W, and F160W mosaics, paying special attention to preserve the properties of the low surface brightness regions around the extended objects.
Update (12/11/2018): The main paper has been accepted for publication on Astronomy & Astrophysics. The accepted version is freely available on ArXiV.
First release of the ABYSS HUDF mosaics: Download the V1.0 version of the ABYSS HUDF mosaics (data section).
In order to improve the quality of the previous reductions, we focused in four major points:
- Creation of dedicated sky-flat fields for each filter, using WFC3/IR science exposures taken at the same epoch than those of the HUDF (Pirzkal et al. 2011, Trujillo & Fliri 2016)
- Improved modelling and removal of nIR persistence contamination (Long et al. 2015).
- Correction of residual gradients through non-parametric noise-based methods (GNUAstro's NoiseChisel, Akhlaghi et al. 2015)
- Careful sky background correction based on robust statistics and source masking.
In this project we have reviewed many of these systematic effects and applied the methods on the deepest image of the Universe ever taken, the HUDF, creating our own version called ABYSS: a low surface brightness reduction for the HUDF WFC3/IR mosaics. We will make the results and the calibration files publicly available to the community - as well as the ABYSS pipeline (stand by for release and updates), hoping to promote further analysis and improvements to the proposed reduction methods.