{
  "family": "galaxies",
  "name": "Galaxies",
  "generatedAt": "2026-10-14",
  "count": 7,
  "objects": [
    {
      "id": "obj:messier-31",
      "slug": "andromeda-galaxy-m31",
      "canonicalName": "Andromeda Galaxy (Messier 31)",
      "aliases": [
        "M31",
        "NGC 224",
        "UGC 454"
      ],
      "constellation": "Andromeda",
      "path": "/objects/galaxies/andromeda-galaxy-m31/",
      "coordinates": {
        "raHours": 0.712306,
        "raSexagesimal": "00h 42m 44.33s",
        "decDegrees": 41.26875,
        "decSexagesimal": "+41° 16′ 07.5″",
        "epoch": "J2000.0",
        "sourceId": "src:simbad-cds"
      },
      "classification": {
        "primaryClass": "Barred spiral galaxy (Local Group largest spiral)",
        "morphologicalType": "SA(s)b"
      },
      "measurements": [
        {
          "id": "obj:messier-31:vmag",
          "entityId": "obj:messier-31",
          "property": "apparent_magnitude_v",
          "label": "Integrated visual magnitude (V)",
          "value": 3.44,
          "unit": "mag",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.05
          },
          "method": "Wide-field integrated galaxy surface photometry",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:messier-31:dist-pc",
          "entityId": "obj:messier-31",
          "property": "distance_pc",
          "label": "Extragalactic distance",
          "value": 765000,
          "unit": "pc",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 11000
          },
          "method": "HST/JWST Cepheids + Tip of the Red Giant Branch (TRGB) + detached eclipsing binaries (2.495 ± 0.036 Mly)",
          "sourceId": "src:shoes-2022",
          "datasetVersion": "2022 Baseline Cepheid + SN Ia",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:messier-31:ang-size",
          "entityId": "obj:messier-31",
          "property": "angular_size_arcmin",
          "label": "Apparent major axis (25 mag/arcsec² isophote)",
          "value": 178,
          "unit": "arcmin",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 5
          },
          "method": "Optical disk isophotal diameter (~3.0° × 1.0°)",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:messier-31:vrad",
          "entityId": "obj:messier-31",
          "property": "radial_velocity_km_s",
          "label": "Heliocentric radial velocity",
          "value": -300,
          "unit": "km/s",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 4
          },
          "method": "Optical & H I 21-cm systemic Doppler shift (~−110 km/s galactocentric approach)",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:messier-31:mass",
          "entityId": "obj:messier-31",
          "property": "mass_solar",
          "label": "Total virial halo mass",
          "value": 1500000000000,
          "unit": "M☉",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 400000000000
          },
          "method": "Satellite galaxy kinematics & H I rotation curve (~1.5 × 10^12 M☉)",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "model-dependent"
        }
      ],
      "sources": [
        "src:ngc-ic-steinicke",
        "src:shoes-2022",
        "src:gaia-dr3"
      ]
    },
    {
      "id": "obj:triangulum-galaxy-m33",
      "slug": "triangulum-galaxy-m33",
      "canonicalName": "Triangulum Galaxy (Messier 33)",
      "aliases": [
        "M33",
        "NGC 598",
        "Pinwheel Galaxy in Triangulum"
      ],
      "constellation": "Triangulum",
      "path": "/objects/galaxies/triangulum-galaxy-m33/",
      "coordinates": {
        "raHours": 1.564139,
        "raSexagesimal": "01h 33m 50.89s",
        "decDegrees": 30.659944,
        "decSexagesimal": "+30° 39′ 35.8″",
        "epoch": "J2000.0",
        "sourceId": "src:ngc-ic-steinicke"
      },
      "classification": {
        "primaryClass": "Late-type unbarred spiral galaxy (3rd largest Local Group member)",
        "morphologicalType": "SA(s)cd"
      },
      "measurements": [
        {
          "id": "obj:triangulum-galaxy-m33:vmag",
          "entityId": "obj:triangulum-galaxy-m33",
          "property": "apparent_magnitude_v",
          "label": "Integrated visual magnitude (V)",
          "value": 5.72,
          "unit": "mag",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.1
          },
          "method": "Wide-field integrated aperture photometry",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:triangulum-galaxy-m33:dist-pc",
          "entityId": "obj:triangulum-galaxy-m33",
          "property": "distance_pc",
          "label": "Extragalactic distance",
          "value": 859000,
          "unit": "pc",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 24000
          },
          "method": "Cepheids + TRGB + VLBA water-maser geometric proper motion (2.80 ± 0.08 Mly)",
          "sourceId": "src:shoes-2022",
          "datasetVersion": "2022 Baseline Cepheid + SN Ia",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:triangulum-galaxy-m33:ang-size",
          "entityId": "obj:triangulum-galaxy-m33",
          "property": "angular_size_arcmin",
          "label": "Apparent major axis",
          "value": 71,
          "unit": "arcmin",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 3
          },
          "method": "Optical disk isophotal dimensions (71′ × 42′)",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:triangulum-galaxy-m33:sb",
          "entityId": "obj:triangulum-galaxy-m33",
          "property": "surface_brightness_mag_arcsec2",
          "label": "Mean visual surface brightness",
          "value": 23,
          "unit": "mag/arcsec²",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.2
          },
          "method": "Derived from V=5.72 spread over 71′ × 42′ face-on disk",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        }
      ],
      "sources": [
        "src:ngc-ic-steinicke",
        "src:shoes-2022",
        "src:simbad-cds"
      ]
    },
    {
      "id": "obj:messier-87",
      "slug": "messier-87",
      "canonicalName": "Messier 87 (Virgo A / NGC 4486)",
      "aliases": [
        "M87",
        "Virgo A",
        "NGC 4486",
        "3C 274",
        "M87*"
      ],
      "constellation": "Virgo",
      "path": "/objects/galaxies/messier-87/",
      "coordinates": {
        "raHours": 12.513728,
        "raSexagesimal": "12h 30m 49.42s",
        "decDegrees": 12.391122,
        "decSexagesimal": "+12° 23′ 28.0″",
        "epoch": "J2000.0",
        "sourceId": "src:eht-m87-sgra"
      },
      "classification": {
        "primaryClass": "Supergiant cD elliptical galaxy & active galactic nucleus (Virgo Cluster center)",
        "morphologicalType": "E0-1 pec / cD"
      },
      "measurements": [
        {
          "id": "obj:messier-87:vmag",
          "entityId": "obj:messier-87",
          "property": "apparent_magnitude_v",
          "label": "Integrated visual magnitude (V)",
          "value": 8.6,
          "unit": "mag",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.1
          },
          "method": "Integrated CCD aperture photometry",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:messier-87:dist-pc",
          "entityId": "obj:messier-87",
          "property": "distance_pc",
          "label": "Extragalactic distance",
          "value": 16400000,
          "unit": "pc",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 500000
          },
          "method": "Surface-brightness fluctuations (SBF) & TRGB (16.4 ± 0.5 Mpc / 53.5 Mly)",
          "sourceId": "src:eht-m87-sgra",
          "datasetVersion": "2019 ApJL 875 L1 & 2022 ApJL 930 L12",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:messier-87:smbh-mass",
          "entityId": "obj:messier-87",
          "property": "mass_solar",
          "label": "Central black hole mass (M87*)",
          "value": 6500000000,
          "unit": "M☉",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 900000000
          },
          "method": "Event Horizon Telescope 1.3-mm VLBI photon-ring diameter (42 ± 3 μas)",
          "sourceId": "src:eht-m87-sgra",
          "datasetVersion": "2019 ApJL 875 L1 & 2022 ApJL 930 L12",
          "qualityStatus": "definitive",
          "disagreementNote": "EHT horizon-scale imaging (6.5 ± 0.9 × 10^9 M☉) agrees closely with stellar-dynamical orbit modeling (~6.1 × 10^9 M☉), whereas earlier ionized-gas-disk kinematics yielded ~3.5 × 10^9 M☉ due to non-gravitational gas turbulence."
        },
        {
          "id": "obj:messier-87:vrad",
          "entityId": "obj:messier-87",
          "property": "radial_velocity_km_s",
          "label": "Heliocentric recession velocity",
          "value": 1284,
          "unit": "km/s",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 5
          },
          "method": "Optical stellar absorption spectroscopy (z = 0.00428)",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "definitive"
        }
      ],
      "sources": [
        "src:eht-m87-sgra",
        "src:ngc-ic-steinicke",
        "src:simbad-cds"
      ]
    },
    {
      "id": "obj:whirlpool-galaxy-m51",
      "slug": "whirlpool-galaxy-m51",
      "canonicalName": "Whirlpool Galaxy (Messier 51 & NGC 5195)",
      "aliases": [
        "M51",
        "NGC 5194",
        "NGC 5195",
        "Rosse's Question Mark"
      ],
      "constellation": "Canes Venatici",
      "path": "/objects/galaxies/whirlpool-galaxy-m51/",
      "coordinates": {
        "raHours": 13.497972,
        "raSexagesimal": "13h 29m 52.70s",
        "decDegrees": 47.19525,
        "decSexagesimal": "+47° 11′ 42.9″",
        "epoch": "J2000.0",
        "sourceId": "src:ngc-ic-steinicke"
      },
      "classification": {
        "primaryClass": "Interacting grand-design spiral galaxy pair",
        "morphologicalType": "SA(s)bc pec + SB0 pec"
      },
      "measurements": [
        {
          "id": "obj:whirlpool-galaxy-m51:vmag",
          "entityId": "obj:whirlpool-galaxy-m51",
          "property": "apparent_magnitude_v",
          "label": "Integrated visual magnitude (V)",
          "value": 8.4,
          "unit": "mag",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.1
          },
          "method": "Integrated CCD aperture photometry (NGC 5195 companion = 9.6 mag)",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:whirlpool-galaxy-m51:dist-pc",
          "entityId": "obj:whirlpool-galaxy-m51",
          "property": "distance_pc",
          "label": "Extragalactic distance",
          "value": 8580000,
          "unit": "pc",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 280000
          },
          "method": "Tip of the Red Giant Branch (TRGB) + expanding photosphere of SN 2005cs & SN 2011dh (8.58 ± 0.28 Mpc)",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:whirlpool-galaxy-m51:ang-size",
          "entityId": "obj:whirlpool-galaxy-m51",
          "property": "angular_size_arcmin",
          "label": "Apparent major axis",
          "value": 11.2,
          "unit": "arcmin",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.5
          },
          "method": "Optical isophotal dimensions (11.2′ × 6.9′)",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:whirlpool-galaxy-m51:vrad",
          "entityId": "obj:whirlpool-galaxy-m51",
          "property": "radial_velocity_km_s",
          "label": "Heliocentric recession velocity",
          "value": 463,
          "unit": "km/s",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 3
          },
          "method": "H I 21-cm and optical systemic velocity",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "definitive"
        }
      ],
      "sources": [
        "src:ngc-ic-steinicke",
        "src:simbad-cds",
        "src:jwst-archive"
      ]
    },
    {
      "id": "obj:sombrero-galaxy-m104",
      "slug": "sombrero-galaxy-m104",
      "canonicalName": "Sombrero Galaxy (Messier 104 / NGC 4594)",
      "aliases": [
        "M104",
        "NGC 4594"
      ],
      "constellation": "Virgo",
      "path": "/objects/galaxies/sombrero-galaxy-m104/",
      "coordinates": {
        "raHours": 12.6665,
        "raSexagesimal": "12h 39m 59.43s",
        "decDegrees": -11.623056,
        "decSexagesimal": "-11° 37′ 23.0″",
        "epoch": "J2000.0",
        "sourceId": "src:ngc-ic-steinicke"
      },
      "classification": {
        "primaryClass": "Unbarred early-type spiral / lenticular-halo galaxy with edge-on dust ring",
        "morphologicalType": "SA(s)a"
      },
      "measurements": [
        {
          "id": "obj:sombrero-galaxy-m104:vmag",
          "entityId": "obj:sombrero-galaxy-m104",
          "property": "apparent_magnitude_v",
          "label": "Integrated visual magnitude (V)",
          "value": 8,
          "unit": "mag",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.1
          },
          "method": "Integrated CCD aperture photometry",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:sombrero-galaxy-m104:dist-pc",
          "entityId": "obj:sombrero-galaxy-m104",
          "property": "distance_pc",
          "label": "Extragalactic distance",
          "value": 9550000,
          "unit": "pc",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 310000
          },
          "method": "HST Tip of the Red Giant Branch (TRGB, McQuinn et al. 2016: 9.55 ± 0.31 Mpc / 31.1 Mly)",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:sombrero-galaxy-m104:ang-size",
          "entityId": "obj:sombrero-galaxy-m104",
          "property": "angular_size_arcmin",
          "label": "Apparent major axis",
          "value": 8.7,
          "unit": "arcmin",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.3
          },
          "method": "Optical isophotal dimensions (8.7′ × 3.5′)",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:sombrero-galaxy-m104:vrad",
          "entityId": "obj:sombrero-galaxy-m104",
          "property": "radial_velocity_km_s",
          "label": "Heliocentric recession velocity",
          "value": 1091,
          "unit": "km/s",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 5
          },
          "method": "Slipher 1912 / modern optical absorption spectroscopy",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "definitive"
        }
      ],
      "sources": [
        "src:ngc-ic-steinicke",
        "src:jwst-archive",
        "src:simbad-cds"
      ]
    },
    {
      "id": "obj:bodes-galaxy-m81",
      "slug": "bodes-galaxy-m81",
      "canonicalName": "Bode's Galaxy (Messier 81 / NGC 3031)",
      "aliases": [
        "M81",
        "NGC 3031"
      ],
      "constellation": "Ursa Major",
      "path": "/objects/galaxies/bodes-galaxy-m81/",
      "coordinates": {
        "raHours": 9.925889,
        "raSexagesimal": "09h 55m 33.17s",
        "decDegrees": 69.065278,
        "decSexagesimal": "+69° 03′ 55.0″",
        "epoch": "J2000.0",
        "sourceId": "src:ngc-ic-steinicke"
      },
      "classification": {
        "primaryClass": "Grand-design spiral galaxy (dominant member of the M81 Group)",
        "morphologicalType": "SA(s)ab"
      },
      "measurements": [
        {
          "id": "obj:bodes-galaxy-m81:vmag",
          "entityId": "obj:bodes-galaxy-m81",
          "property": "apparent_magnitude_v",
          "label": "Integrated visual magnitude (V)",
          "value": 6.94,
          "unit": "mag",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.05
          },
          "method": "Integrated wide-field CCD photometry",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:bodes-galaxy-m81:dist-pc",
          "entityId": "obj:bodes-galaxy-m81",
          "property": "distance_pc",
          "label": "Extragalactic distance",
          "value": 3630000,
          "unit": "pc",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 140000
          },
          "method": "HST Key Project Cepheids + TRGB (3.63 ± 0.14 Mpc / 11.84 Mly)",
          "sourceId": "src:shoes-2022",
          "datasetVersion": "2022 Baseline Cepheid + SN Ia",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:bodes-galaxy-m81:ang-size",
          "entityId": "obj:bodes-galaxy-m81",
          "property": "angular_size_arcmin",
          "label": "Apparent major axis",
          "value": 26.9,
          "unit": "arcmin",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 1
          },
          "method": "Optical isophotal dimensions (26.9′ × 14.1′)",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:bodes-galaxy-m81:vrad",
          "entityId": "obj:bodes-galaxy-m81",
          "property": "radial_velocity_km_s",
          "label": "Heliocentric radial velocity",
          "value": -34,
          "unit": "km/s",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 4
          },
          "method": "H I 21-cm systemic velocity (slight blueshift due to Solar Galactic rotation)",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "definitive"
        }
      ],
      "sources": [
        "src:ngc-ic-steinicke",
        "src:shoes-2022",
        "src:simbad-cds"
      ]
    },
    {
      "id": "obj:cigar-galaxy-m82",
      "slug": "cigar-galaxy-m82",
      "canonicalName": "Cigar Galaxy (Messier 82 / NGC 3034)",
      "aliases": [
        "M82",
        "NGC 3034",
        "3C 231"
      ],
      "constellation": "Ursa Major",
      "path": "/objects/galaxies/cigar-galaxy-m82/",
      "coordinates": {
        "raHours": 9.931222,
        "raSexagesimal": "09h 55m 52.43s",
        "decDegrees": 69.679722,
        "decSexagesimal": "+69° 40′ 46.9″",
        "epoch": "J2000.0",
        "sourceId": "src:ngc-ic-steinicke"
      },
      "classification": {
        "primaryClass": "Prototype edge-on starburst galaxy with bipolar superwind",
        "morphologicalType": "I0 / Sbc pec"
      },
      "measurements": [
        {
          "id": "obj:cigar-galaxy-m82:vmag",
          "entityId": "obj:cigar-galaxy-m82",
          "property": "apparent_magnitude_v",
          "label": "Integrated visual magnitude (V)",
          "value": 8.41,
          "unit": "mag",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.08
          },
          "method": "Integrated CCD aperture photometry",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:cigar-galaxy-m82:dist-pc",
          "entityId": "obj:cigar-galaxy-m82",
          "property": "distance_pc",
          "label": "Extragalactic distance",
          "value": 3530000,
          "unit": "pc",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 150000
          },
          "method": "HST Tip of the Red Giant Branch (TRGB: 3.53 ± 0.15 Mpc / 11.5 Mly)",
          "sourceId": "src:simbad-cds",
          "datasetVersion": "2026-10 release",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:cigar-galaxy-m82:ang-size",
          "entityId": "obj:cigar-galaxy-m82",
          "property": "angular_size_arcmin",
          "label": "Apparent major axis",
          "value": 11.2,
          "unit": "arcmin",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.4
          },
          "method": "Optical edge-on disk dimensions (11.2′ × 4.3′)",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "definitive"
        },
        {
          "id": "obj:cigar-galaxy-m82:sb",
          "entityId": "obj:cigar-galaxy-m82",
          "property": "surface_brightness_mag_arcsec2",
          "label": "Mean visual surface brightness",
          "value": 19.6,
          "unit": "mag/arcsec²",
          "uncertainty": {
            "kind": "symmetric",
            "plusMinus": 0.2
          },
          "method": "Derived from V=8.41 mag over 11.2′ × 4.3′ spindle",
          "sourceId": "src:ngc-ic-steinicke",
          "datasetVersion": "2024/2026 edition",
          "qualityStatus": "high-confidence"
        }
      ],
      "sources": [
        "src:ngc-ic-steinicke",
        "src:jwst-archive",
        "src:simbad-cds"
      ]
    }
  ]
}