{
  "schema_version": "1.0.0",
  "release": "3.1.0",
  "curated_on": "2026-10-30",
  "scope": "Publisher-rendered telescope images and explicitly identified inferred overlays. No image pixels are fitted or used to initialize the test-particle simulation. Sky references are publisher image centres except Bullet Cluster, for which the publisher object reference is retained; none are measured 3D positions.",
  "targets": [
    {
      "id": "norma",
      "title": "Inside the Great Attractor region",
      "object": "Norma Cluster · Abell 3627",
      "category": "LOCAL STRUCTURE",
      "default_layer": "hubble",
      "question": "Which galaxies trace the local pull?",
      "context": "The Norma Cluster lies in the Great Attractor region, behind a crowded foreground of Milky Way stars. It is one part of a larger gravitational environment, not a destination toward which every galaxy in the universe is falling.",
      "observed": "Galaxies and foreground stars emit the light in these images. Dust in our own galaxy obscures some of the background. The narrow Hubble field includes the edge-on galaxy ESO 137-002.",
      "inferred": "A cluster's gravitational influence depends on its total mass and surroundings. A photograph alone does not give its mass, a galaxy's independent distance or its peculiar velocity.",
      "next": "Match galaxy identities to spectroscopy and independent distance indicators. Fit line-of-sight velocities with distance errors, survey selection and calibration covariance before testing local versus distant attraction.",
      "comparison": "These are different pointings, orientations and fields of view. Switching images is a context comparison, not a registered overlay or a time sequence.",
      "research_link": "https://github.com/Biswajit1999/cosmic-expansion-lab/blob/main/docs/GREAT_ATTRACTOR_RESEARCH_PLAN.md",
      "research_label": "Read the local-flow experiment",
      "layers": [
        {
          "id": "hubble",
          "label": "Hubble · galaxy detail",
          "kind": "observed_light",
          "file": "assets/observations/norma-hubble.jpg",
          "source_id": "potw1302a",
          "source": "https://esahubble.org/images/potw1302a/",
          "download": "https://cdn.esahubble.org/archives/images/screen/potw1302a.jpg",
          "instrument": "Hubble / ACS",
          "bands": "475 nm + 814 nm; assigned display colours",
          "released": "2013-01-14",
          "centre": "RA 16h 13m 34.23s · Dec −60° 52′ 34.12″",
          "field": "3.23 × 3.33 arcmin",
          "credit": "ESA/Hubble & NASA",
          "usage": "https://esahubble.org/copyright/",
          "license": "CC BY 4.0",
          "alt": "Hubble view of the Norma Cluster field, with an edge-on galaxy and many bright foreground stars.",
          "interpretation": "Light from galaxies and stars. Their apparent size and brightness do not directly specify their distance or motion.",
          "width": 1280,
          "height": 1320,
          "sha256": "321fa066ecc0b6ac09edc33cdceac90357d04fd38b2ab9e4e23da88f0b2ac15c",
          "bytes": 367943,
          "verified_on": "2026-10-30",
          "pixel_modifications": "None; unmodified publisher JPEG"
        },
        {
          "id": "eso",
          "label": "ESO · wider environment",
          "kind": "observed_light",
          "file": "assets/observations/norma-eso.jpg",
          "source_id": "eso9954c",
          "source": "https://www.eso.org/public/images/eso9954c/",
          "download": "https://cdn.eso.org/images/screen/eso9954c.jpg",
          "instrument": "MPG/ESO 2.2-m / WFI",
          "bands": "B, R and 816 nm; assigned colours and logarithmic intensity",
          "released": "1999-12-21",
          "centre": "RA 16h 14m 22.57s · Dec −60° 52′ 06.63″",
          "field": "33.69 × 32.63 arcmin",
          "credit": "ESO",
          "usage": "https://www.eso.org/public/outreach/copyright/",
          "license": "CC BY 4.0",
          "alt": "Wide-field ESO image toward the Norma Cluster, with a dense foreground star field and background galaxies.",
          "interpretation": "A much larger patch of sky reveals the crowded observing conditions. The brightest points can be foreground stars rather than cluster members.",
          "width": 1280,
          "height": 1240,
          "sha256": "3c9485b8834e8bd5b9add10884b1fc46ea24aaa34148b4cefed314c1571e567f",
          "bytes": 1103649,
          "verified_on": "2026-10-30",
          "pixel_modifications": "None; unmodified publisher JPEG"
        }
      ]
    },
    {
      "id": "pandora",
      "title": "A cluster acting as a lens",
      "object": "Pandora's Cluster · Abell 2744",
      "category": "GRAVITATIONAL LENSING",
      "default_layer": "webb",
      "question": "What can distorted background galaxies tell us?",
      "context": "Abell 2744 is a distant merging cluster at redshift z = 0.308. It is a comparison system for studying mass through lensing, not a component of the nearby Great Attractor model.",
      "observed": "Hubble and Webb record light in different wavelength bands. Some stretched images are background galaxies whose light has been deflected by foreground mass.",
      "inferred": "A gravitational-lens model uses image positions, source redshifts and other constraints to estimate projected mass. A visible arc is evidence to model, not a direct image of dark matter.",
      "next": "Use calibrated exposures, astrometry, multiple-image identifications, spectroscopic redshifts and ensembles of lens models. Compare uncertainties rather than estimating mass from a colour JPEG.",
      "comparison": "Hubble and Webb views differ in pointing, orientation, coverage, filters and processing. They are not pixel-aligned; apparent colour differences are not evidence for motion or physical change.",
      "research_link": "https://esawebb.org/images/weic2305a/",
      "research_label": "Read the Webb observation release",
      "layers": [
        {
          "id": "webb",
          "label": "JWST · infrared",
          "kind": "observed_light",
          "file": "assets/observations/pandora-webb.jpg",
          "source_id": "weic2305a",
          "source": "https://esawebb.org/images/weic2305a/",
          "download": "https://cdn.esawebb.org/archives/images/screen/weic2305a.jpg",
          "instrument": "JWST / NIRCam",
          "bands": "1.15, 1.50, 2.00, 2.77, 3.56, 4.44 μm; assigned colours",
          "released": "2023-02-15",
          "centre": "RA 00h 14m 18.28s · Dec −30° 22′ 44.51″",
          "field": "5.88 × 4.47 arcmin",
          "credit": "NASA, ESA, CSA, I. Labbe (Swinburne University of Technology), R. Bezanson (University of Pittsburgh), A. Pagan (STScI)",
          "usage": "https://esawebb.org/copyright/",
          "license": "CC BY 4.0",
          "alt": "Webb infrared view of Abell 2744 with bright cluster galaxies, many faint background galaxies and gravitationally stretched arcs.",
          "interpretation": "Near-infrared light rendered in visible colours. This layer contains no added dark-matter mass contours.",
          "width": 1280,
          "height": 974,
          "sha256": "9b546b999da365af4426c7aef8eae0572f99ac98df4a0a6974c5c1b9f88de7c7",
          "bytes": 235395,
          "verified_on": "2026-10-30",
          "pixel_modifications": "None; unmodified publisher JPEG"
        },
        {
          "id": "hubble",
          "label": "Hubble · optical + infrared",
          "kind": "observed_light",
          "file": "assets/observations/pandora-hubble.jpg",
          "source_id": "heic1401a",
          "source": "https://esahubble.org/images/heic1401a/",
          "download": "https://cdn.esahubble.org/archives/images/screen/heic1401a.jpg",
          "instrument": "Hubble / ACS + WFC3",
          "bands": "435, 606, 814 nm and 1.05, 1.25, 1.40, 1.60 μm",
          "released": "2014-01-07",
          "centre": "RA 00h 14m 20.99s · Dec −30° 23′ 47.53″",
          "field": "1.96 × 2.18 arcmin",
          "credit": "NASA, ESA, and J. Lotz, M. Mountain, A. Koekemoer, and the HFF Team (STScI).",
          "usage": "https://esahubble.org/copyright/",
          "license": "CC BY 4.0",
          "alt": "Hubble Frontier Fields image of Abell 2744, showing cluster galaxies and elongated background images.",
          "interpretation": "Optical and near-infrared light. The narrower field is shown in full; its displayed size is not the same angular scale as the Webb view.",
          "width": 1280,
          "height": 1428,
          "sha256": "f4efd2d076591ad2689f4179133f20ab596ded7ba01f5763ca1c173207b936ac",
          "bytes": 277376,
          "verified_on": "2026-10-30",
          "pixel_modifications": "None; unmodified publisher JPEG"
        }
      ]
    },
    {
      "id": "bullet",
      "title": "Where the light and mass separate",
      "object": "Bullet Cluster · 1E 0657−56",
      "category": "GAS / GALAXIES / INFERRED MASS",
      "default_layer": "composite",
      "question": "Does the gravitating mass follow the hot gas?",
      "context": "Two distant galaxy clusters are colliding. Their gas and galaxies respond differently to the encounter. This system is a test of matter physics, not a photograph of the Great Attractor.",
      "observed": "Webb detects near-infrared starlight. Chandra detects X-rays from hot gas, displayed in pink. Switch between the publisher's layers to see which structures emit in each band.",
      "inferred": "The blue component of the composite is a lensing-derived mass distribution. Its separation from the gas supports a substantial dark-matter component under the gravitational model used; the blue colour is not detected dark-matter light.",
      "next": "A quantitative offset or dark-matter-interaction test needs calibrated images, a lensing mass posterior, gas-centroid errors and merger geometry. The rendered blue overlay cannot supply those uncertainties.",
      "comparison": "These layers come from the same 2025 publisher image set, but the standalone X-ray JPEG has a different crop and aspect ratio. No new registration is applied. Do not measure offsets between these displayed frames; they are not a collision movie.",
      "research_link": "https://www.chandra.harvard.edu/photo/2025/bullet/index.html",
      "research_label": "Read the multiwavelength release",
      "layers": [
        {
          "id": "composite",
          "label": "Light + inferred mass",
          "kind": "observations_plus_inference",
          "file": "assets/observations/bullet-composite.jpg",
          "source_id": "chandra-bullet-2025-composite",
          "source": "https://www.chandra.harvard.edu/photo/2025/bullet/index.html",
          "download": "https://www.chandra.harvard.edu/photo/2025/bullet/bullet.jpg",
          "instrument": "JWST + Chandra + lens model",
          "bands": "Near-infrared galaxies; pink X-ray gas; blue inferred mass",
          "released": "2025-06-30",
          "centre": "RA 06h 58m 37.9s · Dec −55° 57′ 00″ (J2000) · object reference",
          "field": "About 5.8 arcmin across",
          "credit": "X-ray: NASA/CXC/SAO; Near-infrared: NASA/ESA/CSA/STScI; Image processing: NASA/STScI/J. DePasquale",
          "usage": "https://www.chandra.harvard.edu/photo/image_use.html",
          "license": "Publisher image-use policy; see source and credit",
          "alt": "Bullet Cluster composite: galaxies in near-infrared light, pink X-ray-emitting gas and blue lensing-inferred mass, with gas and mass spatially separated.",
          "interpretation": "Pink = observed hot-gas emission. Blue = inferred mass. The overlay is the publisher's scientific interpretation, not an additional telescope wavelength.",
          "width": 864,
          "height": 363,
          "sha256": "1a5ae2aa8ac4d8900992faeade6824deb87b35d863a87bc956339f77c77cddd7",
          "bytes": 161044,
          "verified_on": "2026-10-30",
          "pixel_modifications": "None; unmodified publisher JPEG"
        },
        {
          "id": "webb",
          "label": "JWST · starlight",
          "kind": "observed_light",
          "file": "assets/observations/bullet-webb.jpg",
          "source_id": "chandra-bullet-2025-nircam",
          "source": "https://www.chandra.harvard.edu/photo/2025/bullet/more.html",
          "download": "https://www.chandra.harvard.edu/photo/2025/bullet/bullet_nircam.jpg",
          "instrument": "JWST / NIRCam",
          "bands": "Near-infrared; assigned display colours",
          "released": "2025-06-30",
          "centre": "RA 06h 58m 37.9s · Dec −55° 57′ 00″ (J2000) · object reference",
          "field": "About 5.8 arcmin across",
          "credit": "X-ray: NASA/CXC/SAO; Near-infrared: NASA/ESA/CSA/STScI; Image processing: NASA/STScI/J. DePasquale",
          "usage": "https://www.chandra.harvard.edu/photo/image_use.html",
          "license": "Publisher image-use policy; see source and credit",
          "alt": "Webb near-infrared layer of the Bullet Cluster, showing stars and galaxies without the pink gas or blue mass overlay.",
          "interpretation": "Light from stars and galaxies; the dark-matter overlay is absent. Full image-set credit is retained.",
          "width": 864,
          "height": 363,
          "sha256": "694a3ebf207d99067fe59cdc4c115c46c4aaf7b889984aa0e71bd657d726dc22",
          "bytes": 157075,
          "verified_on": "2026-10-30",
          "pixel_modifications": "None; unmodified publisher JPEG"
        },
        {
          "id": "chandra",
          "label": "Chandra · hot gas",
          "kind": "observed_light",
          "file": "assets/observations/bullet-xray.jpg",
          "source_id": "chandra-bullet-2025-xray",
          "source": "https://www.chandra.harvard.edu/photo/2025/bullet/more.html",
          "download": "https://www.chandra.harvard.edu/photo/2025/bullet/bullet_xray.jpg",
          "instrument": "Chandra / ACIS",
          "bands": "X-rays; pink display colour",
          "released": "2025-06-30",
          "centre": "RA 06h 58m 37.9s · Dec −55° 57′ 00″ (J2000) · object reference",
          "field": "Standalone crop differs; angular extent not verified for this JPEG",
          "credit": "X-ray: NASA/CXC/SAO; Near-infrared: NASA/ESA/CSA/STScI; Image processing: NASA/STScI/J. DePasquale",
          "usage": "https://www.chandra.harvard.edu/photo/image_use.html",
          "license": "Publisher image-use policy; see source and credit",
          "alt": "Chandra X-ray layer of the Bullet Cluster with diffuse pink gas emission and a concentrated bullet-shaped feature.",
          "interpretation": "Emission from hot ordinary matter. X-rays reveal gas that is not visible in the starlight layer; this is not dark matter.",
          "width": 864,
          "height": 692,
          "sha256": "96b9a4bcc32e612326b48c13557a6065a56c20907ee62ab0779f869b8df49fca",
          "bytes": 59301,
          "verified_on": "2026-10-30",
          "pixel_modifications": "None; unmodified publisher JPEG"
        }
      ]
    },
    {
      "id": "supernova",
      "title": "A distance indicator, not a dark-energy photo",
      "object": "SN 1994D · NGC 4526",
      "category": "DISTANCES / COSMIC EXPANSION",
      "default_layer": "hubble",
      "question": "How does light become evidence for expansion?",
      "context": "A Type Ia supernova can be standardized using its light curve and colour. Comparing many calibrated distances with redshifts tests the expansion history. One photograph cannot establish cosmic acceleration.",
      "observed": "Hubble resolves the host galaxy and the bright supernova. Photometric measurements over time, rather than this display image, are used to construct a light curve.",
      "inferred": "Standardized supernova luminosities provide distance estimates. Cosmological fits to a population constrain expansion; dark energy is an interpretation of accelerated expansion, not a luminous component in this image.",
      "next": "The expansion lab already fits the pinned Pantheon+ / SH0ES table and covariance. This photograph illustrates the method; no catalog identity join or pixel-level fit for SN 1994D is made here.",
      "comparison": "The release date below is the image's publication date, not a supernova explosion date. This is a single observational view, not a time series.",
      "research_link": "index.html#catalog",
      "research_label": "Explore the measured supernova sample",
      "layers": [
        {
          "id": "hubble",
          "label": "Hubble · SN 1994D",
          "kind": "observed_light",
          "file": "assets/supernova-1994d.jpg",
          "source_id": "opo9919i",
          "source": "https://esahubble.org/images/opo9919i/",
          "download": "https://cdn.esahubble.org/archives/images/screen/opo9919i.jpg",
          "instrument": "Hubble Space Telescope",
          "bands": "Publisher colour image; see original release",
          "released": "1999-05-25",
          "centre": "RA 12h 34m 03.00s · Dec +07° 41′ 56.71″",
          "field": "0.49 × 0.49 arcmin",
          "credit": "NASA/ESA, The Hubble Key Project Team and The High-Z Supernova Search Team",
          "usage": "https://esahubble.org/copyright/",
          "license": "CC BY 4.0",
          "alt": "Hubble image of NGC 4526 with its dark dust lane and the bright point of supernova SN 1994D beside the galaxy.",
          "interpretation": "Observed starlight, dust absorption and a supernova. There is no dark-energy overlay because dark energy has not been photographed.",
          "width": 1280,
          "height": 1280,
          "sha256": "58ce737025ae4ab85b2485b87e9cf13e513bba0753f9f6a2e2fb73046f752d28",
          "bytes": 137171,
          "verified_on": "2026-10-30",
          "pixel_modifications": "None; unmodified publisher JPEG"
        }
      ]
    }
  ]
}