Mission Overview

CANDELS Lyman Alpha Emission at Reionization Survey (CLEAR)

 

Primary Investigator: Casey Papovich

HLSP AuthorsRaymond Simons, Casey Papovich, and Ivelina Momcheva

Released: 2023-03-15

Updated: 2023-03-15

Primary Reference(s): Simons, Papovich, Momcheva et al., 2023

DOI: 10.17909/9cjs-wy94

Citations: See ADS Metrics

Read Me 

Source Data:

Slideshow

Now showing slide 1 of 2

CLEAR Footprints

Footprints of the CLEAR fields in GOODS-North (left) and GOODS-South (right). Main panels: CLEAR G102 observations (blue, solid line) overlaid on the footprint of the CANDELS WFC3 imaging (gray). Also shown are the overlapping pointings of G102 (blue, dashed line) and G141 (red, solid line) grism observations from ancillary programs that are included in the data reduction and analysis. Top and bottom side panels: zoomed-in view of each of the 12 CLEAR fields.

GS5 CLEAR Example Spectra

The G102 and G141 spectra of a single galaxy (ID: 38616; z = 1.31) in the GS5 CLEAR field. The top row shows the 2D (spatial x spatial + spectral) spectra from the WFC3/G102 (left) and WFC3/G141 (right) grisms. The second row shows the respective continuum models. The third row shows the residual of the two (spectrum - continuum). Emission line flux (which is not included in the continuum model) appears as a bright feature in the 2D residual spectrum. Prominent emission line/line complexes are indicated. The bottom panel shows the 1D extracted spectrum (G102 in blue and G141 in red-orange) along with the full continuum + emission line fit (red line). The overlapping photometry is shown with the black squares. The faint grey points show the spectral flux density measured for each individual exposure.

Overview

The CANDELS Lyman-⍺ Emission at Reionization (CLEAR) survey is a HST Cycle 23 program that obtained 12-orbit depth observations with the HST/WFC3 using the G102 grism in the IR camera in 12 fields split between the GOODS-N and GOODS-S fields from the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). Combined with existing spectroscopic data (G102 and G141) from other programs, the dataset released here includes 1D and 2D spectra over (partially- or fully-covered) 0.8-1.7 um for 6048 galaxies in GOODS-South and GOODS-North to m_H = 25. In addition, this release includes updated photometric catalogs from the 3D-HST survey, and spectroscopic catalogs that include emission line fluxes and redshifts derived from the combination of the photometry and grism spectroscopy. 

The primary goal of CLEAR was to characterize the evolution of the Lyman-⍺ equivalent width distribution at 6 < z < 8 and to interpret this in the context of reionization. The CLEAR dataset also allows for studies of the stellar populations, star-formation, ionization, and chemical enrichment of galaxies in the distant universe (from redshifts z~0.5 to 3).

Data Products

Data Files

Data files are organized according to the following file structure:

data/<filetype>/

where:

  • <filetype> is the file type, one of "full", "beams", "stack" or "1d". See table below for descriptions.

Data files are named according to the following convention:

hlsp_clear_hst_wfc3_<target>-<source>_g102-g141_v4_<filetype>.fits

where:

  • <target> is the name of the target, one of "ersprime", "gn1", "gn2", "gn3", "gn4", "gn5", "gn7", "gs1", "gs2", "gs3", "gs4", or "gs5".
  • <source> is a five-digit extension corresponding to the source ID number.
  • <type> is the file type, one of "full", "beams", "stack" or "1d". See table below for descriptions.

Data file types:

_full.fits

The results of the continuum + emission line fits.

_beams.fits

 

The 2D G102 and G141 spectra and the F105W and F140W direct images.

_stack.fits

 

The stacked 2D G102 and G141 spectra of the source.

_1d.fits

 

The optimally-extracted 1D spectrum of the source.

 

Photometric Catalogs

The photometric catalog files, updated from the 3D-HST team to include F105W from CLEAR, are organized according to the following file structure: 

catalogs/<field>/photometric_catalog/

and the files are named according to the following convention:

hlsp_clear_hst_wfc3-acs_<field>-3dhst_multi_v4.6_<cat_type>.txt

where:

  • <field> is the target field, one of "gds" or "gdn".
  • <cat_type> is the type of catalog, one of "cat" (zeropoint-corrected) or "nzpcat" (not zeropoint-corrected).

 

Spectroscopic Catalogs

The spectroscopic catalog files are organized according to the following file structure:

catalogs/<field>/spectroscopic_catalog/

and the files are named according to the following convention:

hlsp_clear_hst_wfc3_<field>_multi_v4.1_clear.fits

where:

  • <field> is the target field, one of "gds" (GOODS-S) or "gdn" (GOODS-N).

 

EAZY Analysis Files

The files associated with EAZY analysis are organized according to the following file structure:

catalogs/<field>/eazy/

and the files are named according to the following convention:

hlsp_clear_hst_wfc3-acs_<field>-3dhst_multi_v4.6_<ext>

where:

  • <field> is the target field, one of "gds" (GOODS-S) or "gdn" (GOODS-N),
  • <ext> is the file type and extention, see table below for possible values.

Data file types:

_zphot.translate

 

Eazy-py filter translate file.

_zphot.param

Eazy-py parameter file.

_zout.fits

Eazy-py derived galaxy properties (stellar masses, rest-frame colors, photometric redshifts)

Data Access

Data Files

cURL scripts for downloading CLEAR data products for all targets can be accessed from the table below (see previous section for data product descriptions):

cURL Script Estimated Download Size
Full

118 GB

Beams

172 GB

Stack

6.1 GB

1D

0.3 GB

 

Catalog Files

Field Photometric Catalogs Spectroscopic Catalogs EAZY Files
GOODS-N With zeropoint correction | Without zeropoint correction Catalog

zphot.translate | zphot.param | zout.fits

GOODS-S With zeropoint correctionWithout zeropoint correction Catalog

zphot.translate | zphot.param | zout.fits

Citations

Please remember to cite the appropriate paper(s) below and the DOI if you use these data in a published work. 

Note: These HLSP data products are licensed for use under CC BY 4.0.

References