{
  "schema": "noah-desi-fusion-provenance/v1",
  "retrievedAtUTC": "2026-10-16T20:37:39.561Z",
  "source": {
    "provider": "NSF NOIRLab Astro Data Lab",
    "release": "DESI DR1",
    "spectroscopicProduction": "iron",
    "tables": [
      "desi_dr1.zpix",
      "desi_dr1.photometry"
    ],
    "endpoint": "https://datalab.noirlab.edu/query/query",
    "documentation": "https://datalab.noirlab.edu/data/desi",
    "databaseDocumentation": "https://data.desi.lbl.gov/doc/access/database/",
    "coordinateDocumentation": "https://www.legacysurvey.org/dr9/catalogs/",
    "sourceObservationCoverage": "DESI Main Survey Year 1 spectra, May 2021–June 2022; distinct from retrieval time and the current display clock",
    "snapshotBoundary": "Public DR1 database copy as retrieved; provider supplies no immutable database snapshot identifier. Raw response and captured rows are hash-bound below.",
    "query": "SELECT z.targetid,p.ra,p.dec,z.z,z.zerr,z.zwarn,z.deltachi2,z.zcat_primary,z.spectype,z.survey,z.program,z.healpix,CAST(z.random_id AS DOUBLE PRECISION) AS random_id,z.mean_mjd FROM desi_dr1.zpix AS z JOIN desi_dr1.photometry AS p ON z.targetid=p.targetid WHERE z.survey='main' AND z.spectype='GALAXY' AND z.zcat_primary='true' AND z.zwarn=0 AND z.z>0.001 AND z.z<2.0 AND z.random_id>=42.0 AND z.random_id<42.1 ORDER BY z.random_id,z.targetid LIMIT 20001",
    "requestUrl": "https://datalab.noirlab.edu/query/query?sql=SELECT+z.targetid%2Cp.ra%2Cp.dec%2Cz.z%2Cz.zerr%2Cz.zwarn%2Cz.deltachi2%2Cz.zcat_primary%2Cz.spectype%2Cz.survey%2Cz.program%2Cz.healpix%2CCAST%28z.random_id+AS+DOUBLE+PRECISION%29+AS+random_id%2Cz.mean_mjd+FROM+desi_dr1.zpix+AS+z+JOIN+desi_dr1.photometry+AS+p+ON+z.targetid%3Dp.targetid+WHERE+z.survey%3D%27main%27+AND+z.spectype%3D%27GALAXY%27+AND+z.zcat_primary%3D%27true%27+AND+z.zwarn%3D0+AND+z.z%3E0.001+AND+z.z%3C2.0+AND+z.random_id%3E%3D42.0+AND+z.random_id%3C42.1+ORDER+BY+z.random_id%2Cz.targetid+LIMIT+20001&ofmt=csv&out=None&async=False&profile=default",
    "responseBytes": 2215564,
    "responseSha256": "bb581ea59674ea2ffecd64f6f4c1a741929fbaad4ab28bace33a3d7ca294525d",
    "countQuery": "SELECT COUNT(*) AS n FROM desi_dr1.zpix AS z JOIN desi_dr1.photometry AS p ON z.targetid=p.targetid WHERE z.survey='main' AND z.spectype='GALAXY' AND z.zcat_primary='true' AND z.zwarn=0 AND z.z>0.001 AND z.z<2.0 AND z.random_id>=42.0 AND z.random_id<42.1",
    "countResponseSha256": "564b8f4488346a36a5f9aac3eebda66df08176579663bbf89c7d06feb9a9e8ff",
    "independentlyCountedRows": 12768,
    "metadataQuery": "SELECT table_name,column_name,datatype,unit,description FROM TAP_SCHEMA.columns WHERE table_name IN ('desi_dr1.zpix','desi_dr1.photometry') AND column_name IN ('targetid','ra','dec','z','zerr','zwarn','deltachi2','zcat_primary','spectype','survey','program','healpix','random_id','mean_mjd') ORDER BY table_name,column_name LIMIT 100",
    "metadataResponseSha256": "1f1833a75e8d6702cf36a0fe3220176d4a8a7c20c325dcb711ea3262dcf4e439",
    "columnMetadata": [
      {
        "table_name": "desi_dr1.photometry",
        "column_name": "dec",
        "datatype": "adql:DOUBLE",
        "unit": "deg",
        "description": "Declination"
      },
      {
        "table_name": "desi_dr1.photometry",
        "column_name": "ra",
        "datatype": "adql:DOUBLE",
        "unit": "deg",
        "description": "Right ascension"
      },
      {
        "table_name": "desi_dr1.photometry",
        "column_name": "random_id",
        "datatype": "adql:REAL",
        "unit": "",
        "description": "Random ID in the range 0.0 => 100.0 (not unique)"
      },
      {
        "table_name": "desi_dr1.photometry",
        "column_name": "targetid",
        "datatype": "adql:BIGINT",
        "unit": "",
        "description": "Unique DESI target ID"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "deltachi2",
        "datatype": "adql:DOUBLE",
        "unit": "",
        "description": "Delta-chi-squared for template fit from Redrock"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "healpix",
        "datatype": "adql:INTEGER",
        "unit": "",
        "description": "HEALPixel containing this location at NSIDE=64 in the NESTED scheme"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "mean_mjd",
        "datatype": "adql:DOUBLE",
        "unit": "day",
        "description": "Mean value of the Modified Julian Date (when the shutter was open for exposures used in the coadded spectrum)"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "program",
        "datatype": "adql:VARCHAR",
        "unit": "",
        "description": "DESI program type - BRIGHT, DARK, or BACKUP"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "random_id",
        "datatype": "adql:REAL",
        "unit": "",
        "description": "Random ID in the range 0.0 => 100.0 (not unique)"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "spectype",
        "datatype": "adql:VARCHAR",
        "unit": "",
        "description": "Spectype from Redrock file"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "survey",
        "datatype": "adql:VARCHAR",
        "unit": "",
        "description": "Survey name"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "targetid",
        "datatype": "adql:BIGINT",
        "unit": "",
        "description": "Unique DESI target ID"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "z",
        "datatype": "adql:DOUBLE",
        "unit": "",
        "description": "Redshift measured by Redrock"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "zcat_primary",
        "datatype": "adql:BOOLEAN",
        "unit": "",
        "description": "True/False flag for the primary coadded spectrum in this zcatalog"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "zerr",
        "datatype": "adql:DOUBLE",
        "unit": "",
        "description": "Redshift error from Redrock"
      },
      {
        "table_name": "desi_dr1.zpix",
        "column_name": "zwarn",
        "datatype": "adql:BIGINT",
        "unit": "",
        "description": "Redshift warning bitmask measured by Redrock"
      }
    ],
    "queryLanguage": "PostgreSQL SQL",
    "accessProtocol": "Official NOIRLab QueryManager synchronous CSV, default profile, SDK public anonymous mode; no personal credentials",
    "protocolReference": "https://github.com/astro-datalab/datalab/blob/master/dl/queryClient.py",
    "anonymousModeReference": "https://github.com/astro-datalab/datalab/blob/master/dl/Util.py"
  },
  "sampling": {
    "method": "Fixed random_id interval, not an ordered TOP-N spatial slice",
    "randomIdWindow": {
      "lowerInclusive": 42,
      "upperExclusive": 42.1,
      "fullRange": [
        0,
        100
      ]
    },
    "nominalSamplingFraction": 0.001,
    "nominalPercentage": 0.1,
    "randomIndexDocumentation": "https://datalab.noirlab.edu/help/index.php?qa=1120&qa_1=select-a-random-set-of-rows&show=1121",
    "where": "z.survey='main' AND z.spectype='GALAXY' AND z.zcat_primary='true' AND z.zwarn=0 AND z.z>0.001 AND z.z<2.0 AND z.random_id>=42.0 AND z.random_id<42.1",
    "stableOrder": [
      "random_id ascending",
      "TARGETID ascending for exact ties"
    ],
    "samplingIndexSerialization": "Promote underlying REAL to DOUBLE in the SELECT list to preserve its exact original value in CSV; original SQL predicate is unchanged. No rounding tolerance is applied to selection, coordinates or redshifts.",
    "hardMaximum": 20000,
    "hardMaximumReached": false,
    "completeWindowCaptured": true,
    "selectionMeaning": "A documented randomized 0.1% selection of eligible DR1 main-survey catalog rows; random_id is fixed for the observed database copy, not a new random draw on each page visit.",
    "representativeness": "Preserves the filtered catalog distribution in expectation, with sampling variation. It is not uniform in sky area or comoving volume, does not remove DESI target-selection biases or footprint gaps, and is not a completeness-corrected science sample."
  },
  "changes": [
    "Select classified main-survey galaxies with primary coadd, ZWARN = 0 and 0.001 < z < 2.",
    "Join photometric RA/Dec by the unique TARGETID, rather than using mean fiber pointing.",
    "Select documented fixed random_id window; preserve values as returned and TARGETID as an exact decimal string.",
    "Serialize only the listed catalog columns and add derived descriptive histograms; no galaxy positions synthesized, no measured fields filled.",
    "Retain sourced redshift and uncertainty; do not convert to distance without a separately named cosmology."
  ],
  "quality": {
    "rowCount": 12768,
    "uniqueTargetIds": 12768,
    "flags": {
      "zcatPrimaryTrue": 12768,
      "zwarnZero": 12768,
      "redrockSpectypeGalaxy": 12768
    },
    "raRangeDegrees": [
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      359.9794974055068
    ],
    "decRangeDegrees": [
      -19.37139765817436,
      81.13435164489435
    ],
    "redshiftQuantiles": [
      {
        "probability": 0,
        "value": 0.001113377852648892
      },
      {
        "probability": 0.05,
        "value": 0.08677442472182212
      },
      {
        "probability": 0.25,
        "value": 0.2239200469252882
      },
      {
        "probability": 0.5,
        "value": 0.4502326423535519
      },
      {
        "probability": 0.75,
        "value": 0.9276335900340907
      },
      {
        "probability": 0.95,
        "value": 1.40090518048798
      },
      {
        "probability": 1,
        "value": 1.696897264359536
      }
    ],
    "redshiftErrorQuantiles": [
      {
        "probability": 0,
        "value": 3.966898542663812e-7
      },
      {
        "probability": 0.05,
        "value": 0.000004827385714662835
      },
      {
        "probability": 0.25,
        "value": 0.00001747438572104904
      },
      {
        "probability": 0.5,
        "value": 0.00004716103395677795
      },
      {
        "probability": 0.75,
        "value": 0.00008494583765679678
      },
      {
        "probability": 0.95,
        "value": 0.0001537241406913601
      },
      {
        "probability": 1,
        "value": 0.0005801681022289041
      }
    ],
    "deltaChi2Quantiles": [
      {
        "probability": 0,
        "value": 9.019949868321419
      },
      {
        "probability": 0.05,
        "value": 28.33582227863371
      },
      {
        "probability": 0.25,
        "value": 116.2637899518013
      },
      {
        "probability": 0.5,
        "value": 297.3846781374887
      },
      {
        "probability": 0.75,
        "value": 806.0641715526581
      },
      {
        "probability": 0.95,
        "value": 3861.931033611298
      },
      {
        "probability": 1,
        "value": 377613.9323997498
      }
    ],
    "meanMjdRange": [
      59349.13779999,
      59743.44547615
    ],
    "programs": {
      "dark": 6977,
      "bright": 5780,
      "backup": 11
    },
    "quantileMethod": "Lower empirical order statistic at floor((n-1)*probability)",
    "angularHistogram": {
      "raEdgesDegrees": [
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        30,
        60,
        90,
        120,
        150,
        180,
        210,
        240,
        270,
        300,
        330,
        360
      ],
      "sinDeclinationEdges": [
        -1,
        -0.6666666666666667,
        -0.33333333333333337,
        0,
        0.33333333333333326,
        0.6666666666666667,
        1
      ],
      "declinationEdgesDegrees": [
        -90,
        -41.8103148957786,
        -19.471220634490695,
        0,
        19.471220634490688,
        41.8103148957786,
        90
      ],
      "countsByDecThenRa": [
        [
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          0,
          0,
          0,
          0,
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          0,
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        ],
        [
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        ],
        [
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        ],
        [
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        ]
      ],
      "occupiedEqualAreaCells": 40,
      "totalCells": 72,
      "meaning": "Sample counts in coarse equal-area cells; occupied-cell count is not measured survey solid angle or completeness."
    },
    "redshiftHistogram": {
      "edges": [
        0.001,
        0.1,
        0.3,
        0.5,
        0.7,
        1,
        1.3,
        1.6,
        2
      ],
      "counts": [
        830,
        3807,
        1992,
        992,
        2627,
        1524,
        903,
        93
      ]
    },
    "suggestedField": {
      "method": "Median-redshift actual sampled target in the most populated 30-degree-RA/equal-sine-Dec cell; an editorial camera suggestion, not a new measured structure",
      "targetid": "39628070759436366",
      "raDegrees": 234.4977575118031,
      "decDegrees": 11.65058534236437,
      "redshift": 0.5730523095485724,
      "cellCount": 767
    }
  },
  "artifact": {
    "url": "/celestial/fusion-v1/desi-dr1-galaxies.json",
    "bytes": 2397348,
    "sha256": "cc4d7d10c856a9074c28c88166caf75484bace9cbea8303d361c30b05c90433b",
    "rowsSha256": "02ee8aa61fb23a706fddff69ad986f516e4f90c43d5db715dc165fc6e6e2d288",
    "count": 12768,
    "targetIdsPreservedAsStrings": true
  },
  "license": {
    "name": "Creative Commons Attribution 4.0 International",
    "spdx": "CC-BY-4.0",
    "url": "https://creativecommons.org/licenses/by/4.0/",
    "officialRequirements": "https://data.desi.lbl.gov/doc/acknowledgments/",
    "attribution": "DESI Collaboration; Lawrence Berkeley National Laboratory; U.S. DOE; NSF NOIRLab Astro Data Lab.",
    "paper": {
      "author": "DESI Collaboration et al.",
      "year": 2026,
      "title": "Data Release 1 of the Dark Energy Spectroscopic Instrument",
      "bibcode": "2026AJ....171..285D",
      "url": "https://ui.adsabs.harvard.edu/abs/2026AJ....171..285D/abstract"
    },
    "acknowledgmentsSource": "https://data.desi.lbl.gov/doc/acknowledgments/#acknowledgments",
    "providerAcknowledgments": "https://datalab.noirlab.edu/data/desi#acknowledgments"
  },
  "limitations": [
    "This is a selected public DR1 sample, not the 47-million-object five-year survey milestone or full catalog.",
    "Catalog point markers and redshift depth are data visualizations, not resolved galaxy photographs or nearby Solar System bodies.",
    "Earth location/time rotates the viewing frame; no appreciable physical galaxy parallax is manufactured by a 500 km Earth orbit.",
    "Redrock classification, ZWARN and delta-chi-squared are retained quality metadata, not a guarantee that every catalog measurement is correct.",
    "A zero count in a sampled region can reflect the survey footprint, target selection and sampling; it is not evidence that the Universe is empty there."
  ]
}