Euclid

Description Data Releases Quick Data Release 1 (Euclid Q1)Early Release Observations (Euclid ERO)Data Access

Figure: Sky location of the Euclid's wide survey (blue) and deep survey (yellow) fields in the Galactic coordinates (the bright horizontal band corresponds to the plane of the Milky Way galaxy). Credit: ESA/Euclid/Euclid Consortium/NASA/Planck Collaboration/A. Mellinger – Acknowledgment: Jean-Charles Cuillandre, João Dinis and Euclid Consortium Survey Group

Description

Euclid is a space mission of the European Space Agency (ESA) with the primary goal of studying dark matter and dark energy using two main probes, weak gravitational lensing and galaxy clustering (Euclid Collaboration: Mellier et al. 2024). Euclid uses a 1.2-m diameter Korsch telescope with a field of view of 0.54 square degrees, imaged by two instruments, VIS (Euclid Collaboration: Cropper et al. 2024) and the Near-Infrared Spectrometer and Photometer (NISP; Euclid Collaboration: Jahnke et al. 2024), with the mission of conducting the Euclid Wide Survey (EWS), covering 14,000 square degrees of the extragalactic sky (Euclid Collaboration: Scaramella et al. 2022). VIS is a broad-band optical imager with a spatial resolution of 0.''18, designed to measure the distortion of galaxy shapes with Iₑ ≲ 24.5. NISP combines the capabilities of an imager in the near-infrared (NIR) bands Yₑ, Jₑ, and Hₑ (Euclid Collaboration: Schirmer et al. 2022) to derive the photometric redshifts of the galaxies whose shapes are measured with VIS, together with a near-infrared slitless spectrograph to measure accurate redshifts of galaxies with bright emission lines.

The VIS single Iₑ band is too wide to allow for the determination of the photometric redshifts of the objects whose shapes are being measured. To this end, the Euclid space data are combined with ground-based photometry in the u, g, r, i, and z bands from large-area surveys. In the southern sky, the Dark Energy Survey (DES; Abbott et al. 2021) is currently used until deeper data from the Vera C. Rubin Observatory (Ivezic et al. 2019) become available. In the northern sky, a new collaboration has been set up, the Ultraviolet Near-Infrared Optical Northern Survey (UNIONS; Gwyn et al., in prep.), with the aim to survey the sky in the ugriz bands. This is a joint effort between the Canada-France Imaging Survey (CFIS; Ibata et al. 2017) for the u and r bands, the Panchromatic Survey Telescope and Rapid Response System (Pan-STARRS; Chambers et al. 2016) for the i band, and the Subaru Hyper Suprime Camera (HSC; Miyazaki et al. 2018) for both the g band, through the Waterloo-Hawaii-IfA g-band Survey (WHIGS, PIs K. C. Chambers and M. J. Hudson), and the z band, through the Wide Imaging with Subaru-Hyper SuprimeCam Euclid Sky survey (WISHES, PI M. Oguri). In the Euclid project, we refer to these external data as 'EXT'. They are ingested and recalibrated to a flux scale in common with the VIS and NISP data. Together, the space- and ground-based data form the Euclid mission data set.

For more information about Euclid, see the Euclid website.

The euclid_q1.object table has been crossmatched against our default reference datasets within a 1.5 arcsec radius, nearest neighbor only. These tables will appear with x1p5 in their name in our table browser. Example: euclid_q1.x1p5__object__gaia_dr3__gaia_source

Data Releases

Quick Data Release 1 (Euclid Q1)

The first Euclid Quick Data Release, Q1, comprises 63.1 square degrees of the Euclid Deep Fields (EDFs) to nominal wide-survey depth. It encompasses visible and near-infrared space-based imaging and spectroscopic data, ground-based photometry in the u, g, r, i, and z bands, as well as corresponding masks. Overall, Q1 contains about 30 million objects in three areas near the ecliptic poles around the EDF-North and EDF-South, as well as the EDF-Fornax field in the constellation of the same name. The purpose of this data release – and its associated technical papers – is twofold. First, it is meant to inform the community of the enormous potential of the Euclid survey data, to describe what is contained in these data, and to help prepare expectations for the forthcoming first major data release DR1. Second, it enables a wide range of initial scientific projects with wide-survey Euclid data, ranging from the early Universe to the Solar System. The Q1 data were processed with early versions of the processing pipelines, which already demonstrate good performance, with numerous improvements in implementation compared to pre-launch development.

Euclid Q1 Tables
Table Name	Description
object	Source catalog
phz_photo_z	Contains photometric redshift and its PDF for each object
spe_classification	Classification information for processed spectra
spe_galaxy_candidates	Contains up to 5 redshift candidates for each object_id classified as a galaxy
spe_qso_candidates	Contains up to 5 redshift candidates for each object_id classified as a QSO
spe_quality	Quality flags for each spectrum. Flag bits described here
spe_star_candidates	Contains 1 relative velocity candidate for for each object_id classified as a star

Note that for the euclid_q1.object table, we have excluded the aperture fluxes beyond 1 FWHM. Additionally, we have removed the following columns since they were entirely empty:

right_ascension_psf_fitting
declination_psf_fitting
flag_u_ext_decam
flag_u_ext_lsst
flag_g_ext_lsst
flag_r_ext_lsst
flag_i_ext_lsst
flag_z_ext_lsst
flag_g_ext_jpcam
flag_z_ext_panstarrs
flux_u_ext_decam_1fwhm_aper
flux_u_ext_lsst_1fwhm_aper
flux_g_ext_lsst_1fwhm_aper
flux_r_ext_lsst_1fwhm_aper
flux_i_ext_lsst_1fwhm_aper
flux_z_ext_lsst_1fwhm_aper
flux_g_ext_jpcam_1fwhm_aper
flux_z_ext_panstarrs_1fwhm_aper
fluxerr_u_ext_decam_1fwhm_aper
fluxerr_u_ext_lsst_1fwhm_aper
fluxerr_g_ext_lsst_1fwhm_aper
fluxerr_r_ext_lsst_1fwhm_aper
fluxerr_i_ext_lsst_1fwhm_aper
fluxerr_z_ext_lsst_1fwhm_aper
fluxerr_g_ext_jpcam_1fwhm_aper
fluxerr_z_ext_panstarrs_1fwhm_aper
flux_u_ext_decam_templfit
flux_u_ext_lsst_templfit
flux_g_ext_lsst_templfit
flux_r_ext_lsst_templfit
flux_i_ext_lsst_templfit
flux_z_ext_lsst_templfit
flux_g_ext_jpcam_templfit
flux_z_ext_panstarrs_templfit
fluxerr_u_ext_decam_templfit
fluxerr_u_ext_lsst_templfit
fluxerr_g_ext_lsst_templfit
fluxerr_r_ext_lsst_templfit
fluxerr_i_ext_lsst_templfit
fluxerr_z_ext_lsst_templfit
fluxerr_g_ext_jpcam_templfit
fluxerr_z_ext_panstarrs_templfit
flux_vis_to_u_ext_decam_templfit
flux_vis_to_u_ext_lsst_templfit
flux_vis_to_g_ext_lsst_templfit
flux_vis_to_r_ext_lsst_templfit
flux_vis_to_i_ext_lsst_templfit
flux_vis_to_z_ext_lsst_templfit
flux_vis_to_g_ext_jpcam_templfit
flux_vis_to_z_ext_panstarrs_templfit
fluxerr_vis_to_u_ext_decam_templfit
fluxerr_vis_to_u_ext_lsst_templfit
fluxerr_vis_to_g_ext_lsst_templfit
fluxerr_vis_to_r_ext_lsst_templfit
fluxerr_vis_to_i_ext_lsst_templfit
fluxerr_vis_to_z_ext_lsst_templfit
fluxerr_vis_to_g_ext_jpcam_templfit
fluxerr_vis_to_z_ext_panstarrs_templfit
flux_u_ext_decam_sersic
flux_u_ext_lsst_sersic
flux_g_ext_lsst_sersic
flux_r_ext_lsst_sersic
flux_i_ext_lsst_sersic
flux_z_ext_lsst_sersic
flux_g_ext_jpcam_sersic
flux_z_ext_panstarrs_sersic
fluxerr_u_ext_decam_sersic
fluxerr_u_ext_lsst_sersic
fluxerr_g_ext_lsst_sersic
fluxerr_r_ext_lsst_sersic
fluxerr_i_ext_lsst_sersic
fluxerr_z_ext_lsst_sersic
fluxerr_g_ext_jpcam_sersic
fluxerr_z_ext_panstarrs_sersic
flux_vis_disk_sersic
flux_y_disk_sersic
flux_j_disk_sersic
flux_h_disk_sersic
flux_u_ext_decam_disk_sersic
flux_g_ext_decam_disk_sersic
flux_r_ext_decam_disk_sersic
flux_i_ext_decam_disk_sersic
flux_z_ext_decam_disk_sersic
flux_u_ext_lsst_disk_sersic
flux_g_ext_lsst_disk_sersic
flux_r_ext_lsst_disk_sersic
flux_i_ext_lsst_disk_sersic
flux_z_ext_lsst_disk_sersic
flux_u_ext_megacam_disk_sersic
flux_r_ext_megacam_disk_sersic
flux_g_ext_jpcam_disk_sersic
flux_i_ext_panstarrs_disk_sersic
flux_z_ext_panstarrs_disk_sersic
flux_g_ext_hsc_disk_sersic
flux_z_ext_hsc_disk_sersic
fluxerr_vis_disk_sersic
fluxerr_y_disk_sersic
fluxerr_j_disk_sersic
fluxerr_h_disk_sersic
fluxerr_u_ext_decam_disk_sersic
fluxerr_g_ext_decam_disk_sersic
fluxerr_r_ext_decam_disk_sersic
fluxerr_i_ext_decam_disk_sersic
fluxerr_z_ext_decam_disk_sersic
fluxerr_u_ext_lsst_disk_sersic
fluxerr_g_ext_lsst_disk_sersic
fluxerr_r_ext_lsst_disk_sersic
fluxerr_i_ext_lsst_disk_sersic
fluxerr_z_ext_lsst_disk_sersic
fluxerr_u_ext_megacam_disk_sersic
fluxerr_r_ext_megacam_disk_sersic
fluxerr_g_ext_jpcam_disk_sersic
fluxerr_i_ext_panstarrs_disk_sersic
fluxerr_z_ext_panstarrs_disk_sersic
fluxerr_g_ext_hsc_disk_sersic
fluxerr_z_ext_hsc_disk_sersic
sersic_fract_vis_disk_sersic
sersic_fract_y_disk_sersic
sersic_fract_j_disk_sersic
sersic_fract_h_disk_sersic
sersic_fract_u_ext_decam_disk_sersic
sersic_fract_g_ext_decam_disk_sersic
sersic_fract_r_ext_decam_disk_sersic
sersic_fract_i_ext_decam_disk_sersic
sersic_fract_z_ext_decam_disk_sersic
sersic_fract_u_ext_lsst_disk_sersic
sersic_fract_g_ext_lsst_disk_sersic
sersic_fract_r_ext_lsst_disk_sersic
sersic_fract_i_ext_lsst_disk_sersic
sersic_fract_z_ext_lsst_disk_sersic
sersic_fract_u_ext_megacam_disk_sersic
sersic_fract_r_ext_megacam_disk_sersic
sersic_fract_g_ext_jpcam_disk_sersic
sersic_fract_i_ext_panstarrs_disk_sersic
sersic_fract_z_ext_panstarrs_disk_sersic
sersic_fract_g_ext_hsc_disk_sersic
sersic_fract_z_ext_hsc_disk_sersic
sersic_fract_vis_disk_sersic_err
sersic_fract_y_disk_sersic_err
sersic_fract_j_disk_sersic_err
sersic_fract_h_disk_sersic_err
sersic_fract_u_ext_decam_disk_sersic_err
sersic_fract_g_ext_decam_disk_sersic_err
sersic_fract_r_ext_decam_disk_sersic_err
sersic_fract_i_ext_decam_disk_sersic_err
sersic_fract_z_ext_decam_disk_sersic_err
sersic_fract_u_ext_lsst_disk_sersic_err
sersic_fract_g_ext_lsst_disk_sersic_err
sersic_fract_r_ext_lsst_disk_sersic_err
sersic_fract_i_ext_lsst_disk_sersic_err
sersic_fract_z_ext_lsst_disk_sersic_err
sersic_fract_u_ext_megacam_disk_sersic_err
sersic_fract_r_ext_megacam_disk_sersic_err
sersic_fract_g_ext_jpcam_disk_sersic_err
sersic_fract_i_ext_panstarrs_disk_sersic_err
sersic_fract_z_ext_panstarrs_disk_sersic_err
sersic_fract_g_ext_hsc_disk_sersic_err
sersic_fract_z_ext_hsc_disk_sersic_err
avg_trans_wave_vis
avg_trans_wave_y
avg_trans_wave_j
avg_trans_wave_h
avg_trans_wave_u_ext_decam
avg_trans_wave_u_ext_lsst
avg_trans_wave_g_ext_lsst
avg_trans_wave_r_ext_lsst
avg_trans_wave_i_ext_lsst
avg_trans_wave_z_ext_lsst
avg_trans_wave_g_ext_jpcam
avg_trans_wave_z_ext_panstarrs
blended_prob
extended_prob
semimajor_axis_err
position_angle_err
ellipticity_err
kron_radius_err

Early Release Observations (Euclid ERO)

The Euclid Early Release Observations (ERO) showcase Euclid's capabilities in advance of its main mission, targeting 17 astronomical objects, from galaxy clusters, nearby galaxies, globular clusters, to star-forming regions observed with both the Visible Camera (VIS) and the Near-Infrared Spectrometer and Photometer (NISP) instruments. A total of 24 hours observing time was allocated in the early months of operation, engaging the scientific community through an early public data release. They report a point spread function (PSF) with a full width at half maximum of 0.''16 in the optical Iₑ-band, and 0.''19 in the near-infrared (NIR) bands Yₑ, Jₑ, and Hₑ. The VIS mean absolute flux calibration is accurate to about 1%, and 10% for NISP due to a limited calibration set; both instruments have considerable color terms for individual sources. The median depth is 25.3 and 23.2 AB mag with a signal-to-noise ratio (S/N) of 10 for galaxies, and 27.1 and 24.5 AB mag at an S/N of 5 for point sources for VIS and NISP, respectively. Euclid's ability to observe diffuse emission is exceptional due to its extended PSF nearly matching a pure diffraction halo, the best ever achieved by a wide-field, high-resolution imaging telescope. Euclid offers unparalleled capabilities for exploring the low-surface brightness (LSB) Universe across all scales, providing high precision within a wide field of view (FoV), and opening a new observational window in the NIR. Median surface-brightness levels of 29.9 and 28.3, AB mag arcsec⁻² are achieved for VIS and NISP, respectively, for detecting a 10'' × 10'' extended feature at the 1σ level.

Astro Data Lab hosts the Euclid ERO source catalogs, organized by the observed field and the instrument used. There are a total of 34 tables in the euclid_ero schema, each described below. Note that unlike other datasets, we did not produce pre-crossmatched tables for this dataset.

Euclid ERO Tables
Table Name	Description
abell2390_nisp	Abell2390 field; NISP instrument; Y, J, H-bands; ERO-11: A Glimpse Into Euclids Universe Through a Giant Magnifying Lens; H. Atek (Institut d Astrophysique de Paris)
abell2390_vis	Abell2390 field; VIS instrument; I-band; ERO-11: A Glimpse Into Euclids Universe Through a Giant Magnifying Lens. H. Atek (Institut d Astrophysique de Paris)
abell2764_nisp	Abell2764 field; NISP instrument; Y, J, H-bands; ERO-11: A Glimpse Into Euclids Universe Through a Giant Magnifying Lens. H. Atek (Institut d Astrophysique de Paris)
abell2764_vis	Abell2764 field; VIS instrument; I-band; ERO-11: A Glimpse Into Euclids Universe Through a Giant Magnifying Lens. H. Atek (Institut d Astrophysique de Paris)
barnard30_nisp	Barnard30 field; NISP instrument; Y, J, H-bands; ERO-02: A first glance at free-floating baby Jupiters with Euclid. E. Martin (Instituto de Astrofisica de Canarias)
barnard30_vis	Barnard30 field; VIS instrument; I-band; ERO-02: A first glance at free-floating baby Jupiters with Euclid. E. Martin (Instituto de Astrofisica de Canarias)
dorado_nisp	Dorardo field; NISP instrument; Y, J, H-bands; ERO-09: The Fornax galaxy cluster seen with Euclid. A. Lancon (Observatoire de Strasbourg)
dorado_vis	Dorardo field; VIS instrument; I-band; ERO-09: The Fornax galaxy cluster seen with Euclid. A. Lancon (Observatoire de Strasbourg)
fornax_nisp	Fornax field; NISP instrument; Y, J, H-bands; ERO-09: The Fornax galaxy cluster seen with Euclid. A. Lancon (Observatoire de Strasbourg)
fornax_vis	Fornax field; VIS instrument; I-band; ERO-09: The Fornax galaxy cluster seen with Euclid. A. Lancon (Observatoire de Strasbourg)
holmbergii_nisp	HolmbergII field; NISP instrument; Y, J, H-bands; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
holmbergii_vis	HolmbergII field; VIS instrument; I-band; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
horsehead_nisp	Horsehead field; NISP instrument; Y, J, H-bands; ERO-02: A first glance at free-floating baby Jupiters with Euclid. E. Martin (Instituto de Astrofisica de Canarias)
horsehead_vis	Horsehead field; VIS instrument; I-band; ERO-02: A first glance at free-floating baby Jupiters with Euclid. E. Martin (Instituto de Astrofisica de Canarias)
ic10_nisp	IC10 field; NISP instrument; Y, J, H-bands; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
ic10_vis	IC10 field; VIS instrument; I-band; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
ic342_nisp	IC342 field; NISP instrument; Y, J, H-bands; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
ic342_vis	IC342 field; VIS instrument; I-band; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
messier78_nisp	Messier78 field; NISP instrument; Y, J, H-bands; ERO-02: A first glance at free-floating baby Jupiters with Euclid. E. Martin (Instituto de Astrofisica de Canarias)
messier78_vis	Messier78 field; VIS instrument; I-band; ERO-02: A first glance at free-floating baby Jupiters with Euclid. E. Martin (Instituto de Astrofisica de Canarias)
ngc2403_nisp	NGC2403 field; NISP instrument; Y, J, H-bands; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
ngc2403_vis	NGC2403 field; VIS instrument; I-band; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
ngc6254_nisp	NGC6254 field; NISP instrument; Y, J, H-bands; ERO-03: Euclid view of Milky Way globular clusters. D. Massari (INAF OAS, Bologna)
ngc6254_vis	NGC6254 field; VIS instrument; I-band; ERO-03: Euclid view of Milky Way globular clusters. D. Massari (INAF OAS, Bologna)
ngc6397_nisp	NGC6397 field; NISP instrument; Y, J, H-bands; ERO-03: Euclid view of Milky Way globular clusters. D. Massari (INAF OAS, Bologna)
ngc6397_vis	NGC6397 field; VIS instrument; I-band; ERO-03: Euclid view of Milky Way globular clusters. D. Massari (INAF OAS, Bologna)
ngc6744_nisp	NGC6744 field; NISP instrument; Y, J, H-bands; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
ngc6744_vis	NGC6744 field; VIS instrument; I-band; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
ngc6822_nisp	NGC6822 field; NISP instrument; Y, J, H-bands; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
ngc6822_vis	NGC6822 field; VIS instrument; I-band; ERO-08: A Euclid showcase of nearby galaxies. L. Hunt (INAF-AO Arcetri, Firenze)
perseus_nisp	Perseus field; NISP instrument; Y, J, H-bands; ERO-10: Cluster of Galaxies. J.-C. Cuillandre (CEA, AIM, Universite Paris-Saclay)
perseus_vis	Perseus field; VIS instrument; I-band; ERO-10: Cluster of Galaxies. J.-C. Cuillandre (CEA, AIM, Universite Paris-Saclay)
taurus_nisp	Taurus field; NISP instrument; Y, J, H-bands; ERO-02: A first glance at free-floating baby Jupiters with Euclid. E. Martin (Instituto de Astrofisica de Canarias)
taurus_vis	Taurus field; VIS instrument; I-band; ERO-02: A first glance at free-floating baby Jupiters with Euclid.

Data Access

The Euclid data are accessible by a variety of means:

Data Lab Table Access Protocol (TAP) service

TAP provides a convenient access layer to the DECaPS catalog database. TAP-aware clients (such as TOPCAT) can point to https://datalab.noirlab.edu/tap, select the euclid_q1 database, and see the database tables and descriptions. You can also view the Euclid tables and descriptions in the Data Lab table browser.

Data Lab Query Client

The Query Client is available as part of the Data Lab software distribution. The Query Client provides a Python API to Data Lab database services. These services include anonymous and authenticated access through synchronous or asynchronous queries of the catalog made directly to the database. Additional Data Lab services for registered users include personal database storage and storage through the Data Lab VOSpace.

The Query Client can be called from a Jupyter Notebook on the Data Lab Notebook server. Example notebooks are provided to users upon creation of their user account (register here), and are also available to browse on GitHub at https://github.com/astro-datalab/notebooks-latest.