Mission Overview
The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey ("CANDELS")
Primary Investigator: Sandra Faber
Co-Primary Investigator: Harry Ferguson
HLSP Authors: Anton Koekemoer and Norman Grogin (CANDELS HST image mosaics for all fields), Audrey Galametz and Paola Santini (CANDELS-UDS catalogs), Yicheng Guo and Thomas Dahlen (CANDELS-GOODS-S catalogs). Hooshang Nayyeri (CANDELS-COSMOS catalogs), Mauro Stefanon (CANDELS-EGS catalogs), Guillermo Barro (CANDELS multi-band catalogs for all fields), Dritan Kodra and Brett Andrews (CANDELS v2 photo-z catalogs for all fields)
Released: 2011-01-12
Updated: 2022-10-05
Primary Reference(s): Grogin et al. 2011, Koekemoer et al. 2011
DOI: 10.17909/T94S3X
Citations: See ADS Statistics
Slideshow
CANDELS footprints on the sky for the GOODS-N field.
CANDELS footprints on the sky for the GOODS-S field.
CANDELS footprints on the sky for the UDS field.
CANDELS footprints on the sky for the EGS field.
CANDELS footprints on the sky for the COSMOS field.
Overview
The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution from z = 8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IR and ACS. It will also discover and characterize Type Ia SNe beyond z > 1.5 and establish their accuracy as standard candles for cosmology. The program incorporates a "Wide" imaging survey to two-orbit J+H depth over 720 sq. arcmin in the COSMOS, EGS, and UDS fields. It also includes a "Deep" imaging survey to ~12-orbit Y+J+H depth in the two GOODS fields, tiling ~60 sq. arcmin in each field. In combination with ultra-deep imaging from the Hubble Ultradeep Field program (GO 11563), the result is a three-tiered strategy that effciently samples both bright/rare and faint/common extragalactic objects. Additional information about the survey design is available on the CANDELS public web site.
Note:
All the mosaics provided here have already had all distortion removed by drizzling, and correct astrometry is provided in their header WCS (represented by CRVAL1, CRVAL2, CRPIX1, CRPIX2, CD1_1, CD1_2, CD2_1, CD2_2). Their CTYPE keywords also correctly reflect this (being set to "RA---TAN" and "DEC--TAN'). However, the Astropy tools "all_pix2world" or "all_world2pix" (contained in "wcs") currently attempt to apply SIP coefficients that are found in the headers, and therefore may not give correct astrometry. A solution is instead to use the Astropy tools "wcs_pix2world" or "wcs_world2pix" (also contained in "wcs"), which do not make this error and which give correct astrometry for these mosaics. Another alternative is to not use Astropy but instead use WCSTools, available from CfA, which also correctly calculates astrometry for these mosaics.
Acknowledgements
When using data from the CANDELS survey, please include the following acknowledgement:
"This work is based on observations taken by the CANDELS Multi-Cycle Treasury Program with the NASA/ESA HST, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555."
Please also cite both of the following papers when discussing the CANDELS survey:
Grogin et al. 2011, ApJS, 197, 35G
Koekemoer et al. 2011, ApJS, 197, 36K
Latest Updates
Oct. 5 2022: CANDELS Team Releases Photo-z Catalog For All Fields
The CANDELS team released the full v2 photo-z catalog for all five fields (Kodra et al. 2023). This catalog includes photo-z PDFs produced by six groups within the collaboration, recalibrated versions of those PDFs, and combinations of the recalibrated PDFs that further improve the photo-z PDF quality. It also includes photo-z point estimates and uncertainty intervals.
Previous Updates
Use the 'Expand All' link to see a history of previous updates for CANDELS at MAST.
Aug 02, 2019: CANDELS team releases full GOODS-N v1 catalog
The CANDELS team has released the full v1 multi-band catalog of the GOODS-N field (Barro et al. 2019), based on the CANDELS v1.0 HST WFC3/IR F160W mosaic as the primary detection image. This catalog includes the CANDELS HST data as well as ground-based imaging data from KPNO 4m, LBT, GTC, Subaru, and CFHT, as well as space-based data from Spitzer and Herschel. In addition, the team releases value-added catalogs of IR-based star formation rates and quality flags for all 5 CANDELS fields.
Mar 17, 2017: CANDELS team releases full EGS v1 catalog
The CANDELS team has released the full v1 multi-band catalog of the EGS field (Stefanon et al. 2017), based on the CANDELS v1.0 HST WFC3/IR F160W mosaic as the primary detection image. This catalog contains measurements for 41457 sources across 23 different wavebands, including the CANDELS HST data as well as ground-based optical and near-infrared imaging from CFHT, NEWFIRM, and Spitzer/IRAC.
Dec 21, 2016: CANDELS team releases full COSMOS v1 catalog
The CANDELS team has released the full v1 multi-band catalog of the COSMOS field (Nayyeri et al. 2017), based on the CANDELS v1.0 HST WFC3/IR F160W mosaic as the primary detection image. This catalog contains measurements for 38761 sources across 43 different wavebands, including the CANDELS HST data as well as ground-based optical and near-infrared imaging from CFHT, Subaru, VISTA, NEWFIRM, and Spitzer/IRAC.
CANDELS team releases full-depth V1.0 mosaics for EGS and GOODS-N
The CANDELS team has released the V1.0 full-depth combined mosaics for EGS and GOODS-N, for all ACS and WFC3/IR data obtained by the team on these fields during Cycles 18-20, consisting of a total of 333 orbits, as well as including archival data obtained in these fields from other programs in the same filters used by CANDELS. For more details, and for direct links to the data, please see the MAST/GOODS-N and MAST/EGS pages. Note that there is an interactive display for both the GOODS-S and EGS full mosaics.
Dec 4, 2013: CANDELS team releases GOODS-N mosaics for final epoch 14
The CANDELS team has released the mosaics for epoch 14 of the GOODS-N field. This is the final epoch that was observed in the CANDELS program, and consists of WFC3/IR F125W and F160W observations of the GOODS-N-Deep region, together with parallel observations in ACS F814W. The mosaics that are being released for both WFC3 and ACS include drizzled science images, inverse variance weight images, and exposure time maps. Please see the MAST/GOODS-N page for specific details about this epoch, which also contains links to the Interactive Display Page.
Sep 20, 2013: CANDELS team releases V0.5 GOODS-N mosaics, up to Epoch 13
The CANDELS team has released new mosaics for GOODS-N, consisting of the v0.5 release for Epochs 11, 12 and 13, out of the total 14-epoch GOODS-N dataset. In this release, epoch 11 constitutes the last of the remaining WFC3/IR F105W (Y-band) data, for the south-west portion of the Wide region, while epochs 12 and 13 consist of the Deep region observed in WFC3/IR F125W (J-band) and F160W (H-band). All three epochs also contain mosaics constructed from the parallel ACS data, all obtained with F814W, and in all cases the mosaics for both WFC3 and ACS include drizzled science images, inverse variance weight images, and exposure time maps. Please see the MAST/GOODS-N page for specific details about this epoch, which also contains links to the Interactive Display Page .
Sep 17, 2013: CANDELS team releases V0.5 mosaics for the EGS-b field
The CANDELS team has released new v0.5 mosaics for the EGS-b field, for both epoch 01 and epoch 02. Please see the MAST/CANDELS page for overall details and the MAST/CANDELS EGS page for specific details about this epoch, which also contains links to the Interactive Display Page.
Aug 23, 2013: CANDELS team releases GOODS-S v1 photometric redshift training catalog (20,000 sources)
The CANDELS team has released the GOODS-S v1 photometric redshift training catalog (Dahlen et al. 2013), which was used as a foundation to calibrate and "train" a total of 11 different photometric redshift codes that were compared to one another in this project, as a precursor to the full photometric redshift catalogs which are currently in preparation. This training catalog contains 20,000 sources selected from the WFC3/IR F160W full-depth mosaics of the GOODS-S field, observed in a total of 14 different passbands including HST/ACS, HST/WFC3, ground-based U-band and Ks, and all 4 bands of Spitzer/IRAC.
Aug 09, 2013: CANDELS team releases full multi-band GOODS-S v1 catalog
The CANDELS team has released the full v1 multi-band catalog of the GOODS-S field (Guo et al. 2013), based on the v1.0 CANDELS HST WFC3/IR F160W mosaic as the primary detection image. This catalog contains measurements for 34930 sources across wavebands including the GOODS+CANDELS+ERS+HUDF HST data (ACS F435W, F606W, F775W, F814W, F850LP and WFC3/IR F098M, F105W, F125W, F160W) as well as ground-based U-band and near-infrared imaging data from CTIO and VLT, and also Spitzer/IRAC.
Jun 06, 2013: CANDELS team releases V0.5 GOODS-N mosaics, up to Epoch 10
The CANDELS team has released new mosaics for GOODS-N, consisting of the v0.5 release for Epochs 8, 9 and 10. This release also provides exposure-time mosaics (*exp.fits), corresponding to the total integrated exposure time at each pixel (after having accounted for geometric distortion and the difference between mosaic pixel size and the detector pixels). Please see the MAST/GOODS-N page for specific details about this epoch, which also contains links to the Interactive Display Page .
May 06, 2013: CANDELS team releases full UDS v1 catalog
The CANDELS team has released the full v1 multi-band catalog of the UDS field (Galametz et al. 2013), based on the v1.0 HST WFC3/IR F160W mosaic as the primary detection image. This catalog contains measurements for 35932 sources across 19 different wavebands, including the CANDELS HST data (ACS F606W, F814W and WFC3/IR F125W, F160W) as well as ground-based optical and near-infrared imaging from CFHT, Subaru, VLT and UKIRT, and Spitzer/IRAC.
Feb 22, 2013: CANDELS team releases v0.5 mosaics for GOODS-N epoch 07
The CANDELS team has released the v0.5 mosaics for GOODS-N epoch 07. For more details, and for direct links to the data, please see the MAST/CANDELS GOODS-N page and the Interactive Display Page.
Feb 07, 2013: CANDELS team releases V1.0 full-depth mosaics for COSMOS and GOODS-S
The CANDELS team has released the V1.0 full-depth combined mosaics for COSMOS and GOODS-S, for all ACS and WFC3/IR data obtained by the team on these fields during Cycles 18-20, consisting of a total of 318 orbits.For more details, and for direct links to the data, please see the MAST/GOOD-S and MAST/COSMOS pages. Note that there is an interactive display for both the GOODS-S and COSMOS full mosaics.
Data Products
Directory Structure
All CANDELS data products are organized into a subdirectory structure that follows this format:
<field>/<prod>/<ver>/
where:
- <field> = the name of the survey field, one of "cosmos", "egs", "goods-n", "goods-s", or "uds"
- <prod> = the type of product, one of "catalogs", "<epoch_name>", or "<combined_name>"
- <epoch_name> = the name of the epoch, which has the format of "cos<nn>", "egs[ab]<nn>", "gn<nn>", "gs[dw]<nn>", or "uds<nn>", depending on the survey field. <nn> is always a zero-padded, two-digit number.
- <combined_name> = the name used for the total combined mosaics, one of "cos-tot", "egs-tot", "gn-tot", "gs-tot", or "uds-tot"
- <ver> = "v0.5" for the <epoch_name> subdirectories, "v1.0" for the <combined_name> subdirectories, or "v1" for the "catalogs/" subdirectories
- NOTE: For GOODS-N, the images are further divided into subdirectories based on the spatial resolution, one of "30mas-acs" or "60mas-all"
An example subdirectory path for one of the GOODS-S epochs is:
goods-s/gsd04/v0.5/
Catalog Files
For detailed information on the catalog file naming conventions, click the Expand All link.
Version 2 Photometric Redshift Catalogs (COSMOS, EGS, GOODS-N, GOODS-S, UDS)
The version 2 photometric catalogs have the following naming convention:
hlsp_candels_hst_wfc3_<field>_multi_v2_<type>.<ext>
where:
- <field> = One of "cosmos", "egs", "goodsn", "goodss", or "uds"
- <type> = The type of catalog file
- <ext> = The file extension, one of "pdf", "txt", or "tar.gz"
Catalog file types:
| _photoz-pdfs-readme.pdf | README file for the photometric probability distributions. |
| _photoz-pdfs.tar.gz | Photometric probability distributions. |
| _redshift-cat-readme.pdf | README file for the photometric redshift catalog. |
| _redshift-cat.txt | Photometric redshift catalog. |
Physical Parameter Catalogs (COSMOS, EGS)
The physical parameter catalogs have the following naming convention:
hlsp_candels_hst_wfc3_<field>_multi_v1_<type>.<ext>
where:
- <field> = One of "cos" or "egs"
- <type> = One of "mass-cat", "photoz-cat", "physpar-cat", "physpar-readme", "mass-readme", or "photoz-readme"
- <ext> = The file extension, either "fits" or "txt" for the catalogs themselves, "pdf" for the catalog readme file
Catalog file types:
| _mass-cat.{fits, txt} | Catalog of stellar masses. |
| _photoz-cat.{fits, txt} | Photometric redshift catalog. |
| _physpar-cat.{fits, txt} | Catalog of galaxy physical properties. |
| *readme* | README file containing information on catalog columns. Note for COMOS all three catalogs are described in a single _physpar-readme.pdf file, whereas for EGS each catalog has it's own readme file: _mass-readme.pdf, _photoz-readme.pdf, and _physpar-readme.txt |
Multiband Source Catalogs (COSMOS, EGS, GOODS-S, UDS)
The multiband source catalogs have the following naming convetion:
hlsp_candels_hst_wfc3_<field>-tot-multiband_f160w_<ver>_<type>.<ext>
where:
- <field> = One of "cos", "egs", "goodss", or "uds"
- <ver> = Either "v1" or "v1-<type>" where <type> is one of "1photom", "2limcov", "3sext1", or "4sext2"
- <type> = Either "cat" for catalog files or "readme" for README files
- <ext> = Either "txt" for all and "fits" for some catalog files, or "pdf" for README files
Catalog file types:
| _v1-1photom_cat.{fits,txt} | Photometry catalog. |
| _v1-2limcov_cat.{fits, txt} | Limiting magnitude and covariance indexes. |
| _v1-3sext1_cat.{fits,txt} | SExtractor parameters derived from CANDELS HST data. |
| _v1-4sext2_cat.{fits,txt} | SExtractor parameters derived from CANDELS HST data. |
| _v1-cat.{fits,txt} | A singular catalog file combining the information from all four catalogs above. |
| _readme.pdf | README file containing information on the catalogs. |
Barro et al. 2019 Catalogs (COSMOS, EGS, GOODS-S, UDS)
The Barro et al. 2019 catalogs for these clusters have the following naming convention:
hlsp_candels_hst_wfc3_<field>-barro19_multi_v1_sfr-<type>.<ext>
where:
- <field> = The name of the field, one of "cosmos", "egs", "goodss", or "uds".
- <type> = The type of catalog file.
- <ext> = One of "fits" or "txt"
Catalog file types:
| _sfr-<field>-cat.{fits, txt} | Mid-to-far IR photometry and UV+IR star formation rate catalog. <field> is one of "cos", "egs", "goodss", or "uds". |
| _sfr-flag-mips-<field>-cat.{fits txt} | Mid-to-far IR photometric and proximity flags for Spitzer MIPS within the SFR catalog. |
| _sfr-flag-pacs-<field>-cat.{fits, txt} |
Mid-to-far IR photometric and proximity flags for Herschel PACS within the SFR catalog. |
| _sfr-flag-spire-<field>-cat.{fits, txt} |
Mid-to-far IR photometric and proximity flags for Herschel SPIRE within the SFR catalog. |
Barro et al. 2019 GOODS-N Catalogs (GOODS-N)
The Barro et al. 2019 catalogs for the GOODS-N field have the following naming convention:
hlsp_candels_hst_wfc3_goodsn-barro19_multi_v1_<type>.<ext>
where:
- <type> = The type of catalog file
- <ext> = One of "fits" or "txt"
Note: the README file is named differently:
hlsp_candels_hst_wfc3_goodsn-multiband_f160w_v1_readme.pdf
Catalog file types:
| _v1-1_photometry-cat.{fits, txt} | Photometry catalog. |
| _v1-2_photometry-cat.{fits, txt} |
Photometry catalog. |
| _v1-3_photometry-cat.{fits, txt} |
Photometry catalog. |
| _v1_emission-line-grism-g102-cat.{fits, txt} | Emission line catalog from G102 grism spectra. |
| _v1_emission-line-grism-g141-cat.{fits, txt} | Emission line catalog from G141 grism spectra. |
| _v1_mass-fast-cat.{fits, txt} | Stellar population properties from FAST. |
| _v1_mass-synthesizer-cat.{fits, txt} | Stellar population properties from Synthesizer. |
| _v1_photometry-shards-cat.{fits, txt} | SHARDS optical imaging photometric catalog. |
| _v1_redshift-cat.{fits, txt} | Redshift catalog (broad-band SED fitting, broad-band + SHARDS medium-band SED fitting, or broad- and medium-band SED fitting + grism spectra, depending on the source.) |
| _v1_sfr-flag-mips-gdn-cat.{fits, txt} |
Mid-to-far IR photometric and proximity flags for Spitzer MIPS within the SFR catalog. |
| _v1_sfr-flag-pacs-gdn-cat.{fits, txt} |
Mid-to-far IR photometric and proximity flags for Herschel PACS within the SFR catalog. |
| _v1_sfr-flag-spire-gdn-cat.{fits, txt} |
Mid-to-far IR photometric and proximity flags for Herschel SPIRE within the SFR catalog. |
| _v1_sfr-gdn-cat.{fits, txt} | Mid-to-far IR photometry and UV+IR SFR catalog. |
| _v1_supplementary-photoz-cat.{fits, txt} | Supplementary photometric redshift catalog using broad-band SEDs only by five different investigators. |
| _readme.pdf | README file. |
Santini et al. 2015 Physical Parameter Catalogs (GOODS-S, UDS)
The Santini et al. stellar mass catalogs have the following naming convention:
hlsp_candels_hst_wfc3_<field>_santini_v1_<type>.<ext>
where:
- <field> = The name of the field, either "goodss" or "uds"
- <type> = The type of catalog file
- <ext> = One of "fits" or "txt"
Catalog file types:
| _mass-cat.{fits, txt} |
Positions, flags, redshifts, and stellar masses. |
| _physpar-cat.{fits, txt} | Physical parameters and rest-frame magnitudes. |
| _readme.txt | README file. |
Dahlen et al. 2013 Photo-z Training Catalogs (GOODS-S)
The Dahlen et al. training and control catalogs have the following naming convention:
hlsp_candels_hst-spitzer-vlt_multi_goodss_multi_v1_photoz-<type>.<ext>
where:
- <type> = Type of catalog file
- <ext> = One of "txt", "tar", or "pdf"
Catalog file types:
| _photoz-control-cat.txt | Control catalog (589 objects). |
| _photoz-filters.tar | Transmission functions for the 14 filters used in the catalogs. |
| _photoz-training-cat.txt | Training catalog (580 objects). |
| _photoz-readme.pdf | README file. |
For detailed information on the image file naming conventions, click the Expand All link.
Image (Mosaic) Files
Epoch-level image products follow this naming convention:
hlsp_candels_hst_<ins>_<field><nnn>-<sect>_<filter>_v0.5_<type>.fits
where:
- <ins> = Instrument name, one of "acs" or "wfc3".
- <field> = Name of field, one of "cos", "egs", "gn", "gs", "uds".
- <nnn> = A sub-field designator when smaller tiles/sections are available, for COSMOS, GOODS-N, and UDS this is a two-digit, zero-padded number. For EGS this is one of "a01", "a02", "b01', or "b02". For GOODS-S this takes the form of <d##>, e.g., "d06", although the numbering is not consecutive (there is no "d05" for example).
- <sect> = A smaller-sized section of a given mosaic, of the form <sect##>, e.g., "sect34".
- <filter> = The name of the filter used, e.g., "f160w" or "f850lp".
- <type> = Type of image file, one of "drz", or "wht".
Total-combined image products, except GOODS-N, follow this naming convention:
hlsp_candels_hst_<ins>_<field>-tot-<sect>_<filter>_v1.0_<type>.fits
where:
- <ins> = Instrument name, one of "acs" or "wfc3".
- <field> = Name of field, one of "cos", "egs", "gs", "uds".
- <sect> = A smaller-sized section of a given mosaic, of the form <sect##>, e.g., "sect34".
- <filter> = The name of the filter used, e.g., "f160w" or "f850lp".
- <type> = Type of image file, one of "drz", or "wht".
Total-combined image products for the GOODS-N field follow this naming convention:
hlsp_candels_hst_<ins>_gn-tot-<res>-<sect>_<filter>_v1.0_<type>.fits
where:
- <ins> = Instrument name, one of "acs" or "wfc3".
- <res> = The spatial resolution, one of "30mas" or "60mas".
- <sect> = A smaller-sized section of a given mosaic, of the form <section##>, e.g., "sect34".
- <filter> = The name of the filter used, e.g., "f160w" or "f850lp".
- <type> = Type of image file, one of "drz", or "wht".
Data file types:
| _drz.fits | Drizzled mosaic image. |
| _wht.fits | Weight map files. |
Data Access
Citations
References
Reminder: please always cite both Grogin et al. 2011 and Koekemoer et al. 2011 when referencing CANDELS. The other papers are for the catalogs and should be cited, in addition, when appropriate.