This describes the V2.0 version data release of the Hubble Legacy Fields (HLF) project for the GOODS-South (ECDF-S) region from the HST archival program AR-13252. The V2.0 version of the HLF dataset provides WFC3/UV, ACS/WFC and WFC3/IR source catalogs and images covering a 25 x 25 arcminute area plus (smaller) cutouts of four deep areas in the GOODS-South field. All the data covering the original HUDF field within the GOODS-South area were previously released as a high level science product as the eXtreme Deep Field (XDF — sometimes referred to as the XDF/HUDF field).
HLF Release: The release combines exposures from Hubble's two main workhorse cameras, the Advanced Camera for Surveys Wide Field Channel (ACS/WFC) and the Wide Field Camera 3 (WFC3), including data from both the infraRed channel (WFC3/IR) and the UV/visible channel (WFC3/UVIS). These data were taken over more than a decade between mid-2002 to the end of 2016. The HLF includes essentially all the near-uv (WFC3/UV F225W, F275W, F336W), optical (ACS/WFC F435W, F606W, F775W, F814W and F850LP filters) and infrared (WFC3/IR F098M, F105W, F125W, F140W and F160W filters) filters. The HLF includes data taken by Hubble over the original CDF-South region including the GOODS-South, CANDELS, ERS, the Extended CDF-S (ECDF-S), numerous SNe followup programs, and many other programs. Given that this dataset combines all images in the archive on the ECDF-S to date from numerous different programs, the HST AR-13252 proposal identified the product under a single global name "Hubble Legacy Field".
Astrometric Frame: A particularly challenging aspect, given the large area, was to establish a robust astrometric framework. A global astrometric solution was bootstrapped from the smaller datasets. All the HLF image mosaics have been produced using a coordinate grid tied to an absolute Gaia DR2 reference frame. We also provide an alternate coordinate system using the same tangent point as the original GOODS-S dataset.
Exposure Time: The total HST on-target exposure time of all the data incorporated in the HLF-GOODS-S is 6.4 MSec. The final HLF GOODS-S dataset derives from 7491 exposures taken by 20 different HST programs. This on-target exposure time is equivalent to that of about 2665 orbits (assuming that the exposure in a typical orbit is 2400 s). This total exposure corresponds to nearly ~75% of a full HSTresource cycle! The HLF dataset also includes four very deep pointings from observations made in parallel when HUDF was primary (the HLF-HUDFP1-4 parallel fields). Unlike the XDF/HUDF, these parallel fields have a smaller set of filters and have varying depths, but still constitute a resource of unusually deep fields.
Catalog: A catalog of all the sources in the dataset, with photometry for sources in each of the 13 filters, is also made available with this release. The photometric catalog includes 103,098 objects, selected in either of two near-IR filters (F850LP and F160W). The photometric results are measured in 0.7′′ diameter apertures and corrected to total fluxes based on the F160W curve of growth.
HLF Team: The HLF Team is The HLF Team is Garth Illingworth, Daniel Magee, Rychard Bouwens, Pascal Oesch, Kate Whitaker, Ivo Labbe, Pieter van Dokkum, Mauro Stefanon, Bradford Holden, Marijn Franx, and Valentino Gonzalez. The catalog was led by Katherine Whitaker. Please credit Illingworth et al (2019) when using the HLF HSLP data and products, and and Whitaker et al (2019) for the catalog. The UVUDF dataset was graciously provided by Harry Teplitz, Anton Koekemoer, Marc Rafelski, Norman Grogin and the UVUDF Team. If you use any of the UV data, please cite Teplitz et al. (2013) and Rafelski et al. (2015).
A major change from the HLF-GOODS-S V1.5 data release to the V2.0 release is the inclusion of three UV datasets. These sets constitute a substantial body of UV data, totaling 280 orbits of HST WFC3/UVIS imaging, or about 0.5 Msec of data. The three UV datasets are the Early Release Science (ERS) observations (Windhorst et al 2011), the UltraViolet Ultra-Deep Field (UVUDF) dataset (Teplitz et al. (2013), Rafelski et al. (2015)) and the Hubble Deep UltraViolet (HDUV) legacy dataset Oesch et al 2018, see also Vanzella et al 2016). These datasets were updated and astrometrically-matched to the V1.5/V2.0 release of the HLF-GOODS-S. The ERS dataset required a full processing since that has not be available in processed form on MAST. Thus the HLF provides for the first time the release of the WFC3/UV 2009 ERS dataset as a HLSP.
The steps that were taken to assemble the HST UV data along with the HST optical and near-IR data are described in the paper that discusses the assembly of the HLF- GOODS-S dataset (Illingworth et al 2019).
As noted above the V2.0 release now includes a catalog of over 100,000 sources with photometry in all 13 filters (or those sources for which the S/N was adequate for inclusion). See Whitaker et al 2019.
Additionally, we have organized the ACS/WFC and WFC3/IR data into twelve one year epochs from the fourteen years of observations on the ECDF-S, starting with the first epoch from May 2002 to April 2003 (there were two years where no significant additional data was obtained due to ACS/WFC failure in January 2007). See HLF_v2.0_goodss_epoch_by_filter.pdf.
Field | RA | Dec | Epoch |
---|---|---|---|
HLF-GOODS-S | 3h32m29s | -27d48m18s | J2000.0 |
Shown (left) is the outline (red) of the regions covered by each filter in the HLF-GOODS-S HLSP dataset. The XDF/HUDF region is shown by the yellow square. The filters include a total of 13 WFC3/UV, ACS/WFC and WFC3/IR filters (F225W, F275W, F336W, F435W, F606W, F775W, F814W, F850LP, F098M, F105W, F125W, F140W & F160W). Shown (right) are the exposure time maps in the same 13 filters. The maps here total ~7500 exposures that comprise the HLF-GOODS-S dataset.
Field | RA | Dec | Epoch |
---|---|---|---|
HLF-HUDFP1 | 3h33m04s | -27d41m02s | J2000.0 |
HLF-HUDFP2 | 3h33m01s | -27d50m50s | J2000.0 |
HLF-HUDFP3 | 3h32m42s | -27d55m17s | J2000.0 |
HLF-HUDFP4 | 3h32m01s | -27d48m17s | J2000.0 |
The five deep regions within HLF-GOODS-S (HUDF parallels in red and the XDF/HUDF in yellow). Each of these deep regions constitutes an usually deep set of observations, though with varying depth and reduced numbers of filters compared to the XDF/HUDF.
Observations included in this version of the HLF-GOODS-S Field were taken from July 2002 to October 2016 from 20 different HST programs.
Filter | Exposure Time (s) | # of Exposures |
---|---|---|
HLF-GOODS-S Field | ||
F225W | 89576 | 64 |
F275W | 207222 | 108 |
F336W | 216150 | 108 |
F435W | 526952 | 443 |
F606W | 537944 | 712 |
F775W | 770190 | 849 |
F814W | 840211 | 1288 |
F850LP | 1495092 | 1902 |
F098M | 53499 | 68 |
F105W | 484734 | 429 |
F125W | 440755 | 598 |
F140W | 115590 | 218 |
F160W | 596277 | 704 |
Totals | 6374192 | 7491 |
Program ID | Program Title | Program PI |
---|---|---|
9352 | The Deceleration Test from Treasury Type Ia Supernovae at Redshifts 1.2 to 1.6 | Adam Riess |
9425 | The Great Observatories Origins Deep Survey: Imaging with ACS | Mauro Giavalisco |
9480 | Cosmic Shear With ACS Pure Parallels | Jason D. Rhodes |
9488 | Cosmic Shear - with ACS Pure Parallel Observations | Kavan Ratnatunga |
9500 | The Evolution of Galaxy Structure from 10, 000 Galaxies with 0.1<z<1.2 | Hans-Walter Rix |
9575 | ACS Default {Archival} Pure Parallel Program | William B. Sparks |
9793 | The Grism-ACS Program for Extragalactic Science {GRAPES} | Sangeeta Malhotra |
9803 | Deep NICMOS Images of the UDF | Rodger I. Thompson |
9978 | The Ultra Deep Field with ACS | Steven Beckwith |
9984 | Cosmic Shear With ACS Pure Parallels | Jason D. Rhodes |
10086 | The Ultra Deep Field with ACS | Steven Beckwith |
10189 | PANS-Probing Acceleration Now with Supernovae | Adam Riess |
10258 | Tracing the Emergence of the Hubble Sequence Among the Most Luminous and Massive Galaxies | Claudia Kretchmer |
10340 | PANS | Adam Riess |
10530 | Probing Evolution And Reionization Spectroscopically {PEARS} | Sangeeta Malhotra |
10632 | Searching for galaxies at z>6.5 in the Hubble Ultra Deep Field | Massimo Stiavelli |
11144 | Building on the Significant NICMOS Investment in GOODS: A Bright, Wide-Area Search for z>=7 Galaxies | Rychard Bouwens |
11359 | Panchromatic WFC3 survey of galaxies at intermediate z: Early Release Science program for Wide Field Camera 3. | Robert W. O'Connell |
11563 | Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to <0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields | Garth D. Illingworth |
12007 | Supernova Followup | Garth D. Illingworth |
12060 | Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey — GOODS-South Field, Non-SNe-Searched Visits | Sandra M. Faber |
12061 | Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey — GOODS-South Field, Early Visits of SNe Search | Sandra M. Faber |
12062 | Galaxy Assembly and the Evolution of Structure over the First Third of Cosmic Time - III | Sandra M. Faber |
12099 | Supernova Follow-up for MCT | Adam Riess |
12177 | 3D-HST: A Spectroscopic Galaxy Evolution Treasury | Pieter Van Dokkum |
12461 | Supernova Follow-up for MCT | Adam Riess |
12498 | Did Galaxies Reionize the Universe? | Richard S. Ellis |
12534 | The Panchromatic Hubble Ultra Deep Field: Ultraviolet Coverage | Harry Teplitz |
12866 | A Morphological Study of ALMA Identified Sub-mm Galaxies with HST/WFC3 | Mark Swinbank |
12990 | Size Growth at the Top: WFC3 Imaging of Ultra-Massive Galaxies at 2.0 < z < 3 | Adam Muzzin |
13779 | The Faint Infrared Grism Survey (FIGS) | Sangeeta Malhotra |
13872 | The GOODS UV Legacy Fields: A Full Census of Faint Star-Forming Galaxies at z~0.5-2 | Pascal Oesch |
14088 | Unveiling the Lyman continuum morphology with HST | Eros Vanzella |
The process begins with individual flt files requested from the MAST HST archive. These images have already been subject to bias correction, dark subtraction, flat-field correction, and cosmic ray rejection. The flt files obtained from the MAST are reasonably well calibrated, given that the on-the-fly pipeline processing by STScI already takes advantage of darks and flat fields constructed from latest on-orbit calibration data. But further effort was needed to ensure that the images used in the construction of the HLF were of a uniform high quality.
All images used to produce the HLF were first visually inspected to identify any data quality issues (loss of guiding, excessive background, pointing accuracy) and any image which could not be corrected was rejected for processing. During this visual inspection we also identify images affected by satellite trails and optical ghosts from filter reflections in the ACS/WFC generated by bright stars and updated the data quality array to ensure these artifacts were masked during final processing.
Due to the slow but clear degradation in the performance of the ACS wide-field camera CCDs (ACS/WFC), we needed to correct later data for charge transfer efficiency (CTE) degradation. In particular, for ACS/WFC data taken after HST Servicing Mission 4 (SM4) we used images that have been corrected for CTE losses and bias striping
The HLF ACS/WFC dataset were reduced by the HLF data processing pipeline HLFRED (built on DrizzlePac) which can be found on Github. The steps undertaken by HLFRED are described in Illingworth, Magee et al 2019.
We would like to thank Harry Teplitz, Anton Koekemoer, Marc Rafelski, Norman Grogin and the UVUDF team for graciously providing the flt images that were used in generating the UV dataset on the HUDF. These data required additional processing that is unavailable in the standard WFC3 calibration pipeline provided by STScI (See the README file for the V2.0 UVUDF data). If you use these data, please cite Teplitz et al. (2013) and Rafelski et al. (2015).
The HLF WFC3/UV and WFC3/IR dataset were also reduced by the HLF data processing pipeline HLFRED The HLFRED processing of the WFC3/IR observations in the HLF follows the procedure as described in (Magee, Bouwens & Illingworth 2011) but with a few additional corrections in order to improve the reductions.
While most WFC3/IR flt files requested from MAST can be used readily, in some cases CALWF3 can falsely flag nearly all pixels as cosmic rays, due to a varying background during the exposure. For WFC3/IR MultiAccum mode observations, CALWF3 assumes that accumulating background counts over the entire observation is a linear function. This assumption may not be the true for all observations. Depending on circumstances of the observation the background count rate may vary over the duration of the observation. In order to determine if the background count rate is sufficiently non-linear, we compared the average exposure time in a flt file's TIME array extension with the exposure time listed in the header EXPTIME keyword. If the we find the exposure time varies by more than 2% we correct the background signal in the raw image using code developed by the Frontier Fields team. This additional step assures the background count rate is linear before reprocessing the image with CALWF3. For more info on time-varying background see Instrument Science Report WFC3 2014-03.
We also mask out pixels on WFC3/IR images that were affected by source persistence. This masking was performed by utilizing persistence models generated by the STScI WFC3 Persistence Project. A persistence model is created for each WFC3/IR exposure which incorporates an internal persistence model (persistence within a visit) and an external persistence model (persistence from earlier visits). Using this model of the total persistence we flagged all pixels above a threshold of 0.2 electrons/s thus ensuring that our final reductions are not significantly affected by source persistence.
This release includes fully reduced, science ready images (*_sci.fits) together with the associated weight maps (*_wht.fits) at 30mas/pixel (for WFC3/UV and ACS only) and 60mas/pixel (for ACS+WFC3/UV/IR images) and source catalogs.
The data are organized into sets of images by passband (WFC3/UV F225W, F275W & F336W, ACS/WFC F435W, F606W, F775W, F814W & F850LP, WFC3/IR F105W, F098M F125W, F140W & F160W) and image scale. Each 60 milli-arcsecond/pixel HLF-GOODS-S image is 25k x 25k pixels and each 30 milli-arcsecond/pixel image is 50k x 50k pixels. For each filter we provide the drizzled science image and a weight image. All images use a coordinate grid tied to the Gaia DR2 reference frame (with a tangent point of R.A. = 53.122782389, Dec. = -27.805161222). Previous data releases were made available in April 2016 February 2017. The V2.0 supersedes the V1.0 dataset and the V1.5 dataset due to additional UV data and catalogs.
All images used a drizzle pixfrac parameter value of 0.8 (final_pixfrac=0.8). The weight map image is equal to the inverse variance (i.e., 1/rms^2) per pixel. A detailed discussion of weight map conventions and noise correlation in drizzling, can be found in Casertano et al. 2000, AJ, 120, 2747, especially Section 3.5 and Appendix A.
These data may also be downloaded with anonymous FTP (ftp archive.stsci.edu then cd /hlsps/hlf/2.0). The data are viewable from a browser at https://archive.stsci.edu/hlsps/hlf. A script (hlsp_hlf_v2.0_download.txt) is provided which uses the command line tool curl to download the entire dataset or can be edited to download only the files needed. Individual images can be downloaded through a web browser here.
The data may be displayed and explored with an HLA-like display.
The pixel values of the science images report the flux count rate calibrated in electron/second. The zero points to convert the count rate into an AB magnitude for five ACS/WFC passbands and the five WFC3/IR passbands are the following:
Filter | Zero Point ABMAG |
---|---|
WFC3/UV | |
F225W | 24.04 |
F275W | 24.13 |
F336W | 24.67 |
ACS/WFC | |
F435W | 25.68 |
F606W | 26.51 |
F775W | 25.69 |
F814W | 25.94 |
F850LP | 24.87 |
WFC3/IR | |
F098M | 25.68 |
F105W | 26.27 |
F125W | 26.23 |
F140W | 26.45 |
F160W | 25.94 |
Catalogs are provided for the 13 HST bandpasses, including three WFC3/UV (F225W, F275W and F336W) filters, five ACS filters (F435W, F606W, F775W, F814W and F850LP) and five WFC3 filters (F098M, F105W, F125W, F140W and F160W). We use an ultra-deep detection image that combines the PSF-homogenized, noise-equalized F850LP, F125W, F140W and F160W mosaics. Photometry is extracted in 0.7′′ diameter apertures and corrected to total fluxes based on the F160W curve of growth. The photometric catalog includes 103,098 objects, with a suggested first selection based either (1) “use f160w”, which selects galaxies with S/N>3 in F160W and coverage in 5 HST bandpasses, or (2) “use f850lp”, which selects galaxies covering a wider on-sky area by requiring S/N>3 in F850LP but no minimum coverage of HST bandpasses.
Update [5/28/2020]: The HLF GOODS-S photometric catalog has been updated from v2.0 to v2.1. The only change is to reduce the relative weight threshold from 1% to 0.01%, as three filters with a combination of extremely deep and shallow pointings (e.g., F606W, F775W, and F850LP) had fluxes for about 50k-67k objects changed to -99 that may still be reliable. This increases the estimated area for F850LP coverage from 343 arcmin^2 to 525 arcmin^2 and could therefore be important for the shallow imaging coverage in these particular filters. Note that the only figure that slightly changes is the number counts comparison of F850LP (Figure 16), all other figures yield identical measurements to those presented in the publication.
Using the most up-to-date version v2.1 is recommended, though the catalog is largely unchanged.
Please cite Whitaker et al. 2019, ApJS, 244, 16
Convolved images and detection image used to create the V2.1 catalog can be found here: https://archive.stsci.edu/hlsps/hlf/v2.0/60mas_conv
Type | Catalog | |
---|---|---|
HLF-GOODS-S Field - WFC3/UV, ACS/WFC & WFC3/IR | ||
ASCII | hlsp_hlf_hst_60mas_goodss_v2.1_catalog.txt | |
FITS | hlsp_hlf_hst_60mas_goodss_v2.1_catalog.fits |
The HLF Team is The HLF Team is Garth Illingworth, Daniel Magee, Rychard Bouwens, Pascal Oesch, Kate Whitaker, Ivo Labbe, Pieter van Dokkum, Mauro Stefanon, Bradford Holden, Marijn Franx, and Valentino Gonzalez.
The description of the Hubble Legacy Fields high level science products delivered to MAST will be published. Please reference Illingworth, Magee, Bouwens, Oesch et al, 2019 and Whitaker, Ashas, Illingworth, Magee et al, 2019. If you use any UV data, please cite Teplitz et al. (2013) and Rafelski et al. (2015).
Last update: 2020-07-01