{"dataset":{"slug":"galaxy-morphology-and-agn","title":"Galaxy Morphology & AGN","description":"The forms of galaxies, the types of active galactic nucleus, and the AGN unification model — spiral, elliptical, Seyfert, radio galaxy, blazar, and more.","version":"1.0.0","lastGenerated":"2026-06-29","license":"CC BY-SA 4.0","entityCount":13,"sources":["nasa","esa"]},"entities":[{"id":"galaxy_morphology:barred-spiral","name":"Barred Spiral Galaxy","type":"galaxy_morphology","domain":"science","description":"A spiral galaxy whose arms wind out from the ends of a straight bar of stars crossing the centre. The bar channels gas inward, feeding star formation and the central black hole. The Milky Way is one.","entryPath":"/galaxies/barred-spiral"},{"id":"agn_type:bl-lac-object","name":"BL Lac Object","type":"agn_type","domain":"science","description":"A blazar seen looking almost straight down its jet, so its light is dominated by the rapidly-variable, featureless glow of the jet itself rather than by emission lines — one of the most extreme, fast-varying kinds of active nucleus.","entryPath":"/galaxies/bl-lac-object"},{"id":"galaxy_morphology:dwarf","name":"Dwarf Galaxy","type":"galaxy_morphology","domain":"science","description":"A small galaxy with far fewer stars than a giant like the Milky Way. Dwarfs are by far the most numerous galaxies, and many orbit larger ones as satellites; they are dominated by dark matter.","entryPath":"/galaxies/dwarf"},{"id":"galaxy_morphology:elliptical","name":"Elliptical Galaxy","type":"galaxy_morphology","domain":"science","description":"A smooth, featureless ellipsoid of mostly old stars, with little gas and little ongoing star formation. The largest ellipticals sit at the centres of galaxy clusters and are thought to be built by mergers.","entryPath":"/galaxies/elliptical"},{"id":"galaxy_morphology:irregular","name":"Irregular Galaxy","type":"galaxy_morphology","domain":"science","description":"A galaxy with no regular spiral or elliptical structure, often small and gas-rich with vigorous star formation. Many are shaped by the gravitational pull of larger neighbours, like the Magellanic Clouds beside the Milky Way.","entryPath":"/galaxies/irregular"},{"id":"galaxy_morphology:lenticular","name":"Lenticular Galaxy","type":"galaxy_morphology","domain":"science","description":"A disk galaxy with a prominent bulge but no spiral arms — a transitional form between spirals and ellipticals, with an old stellar population and little cold gas left to form stars.","entryPath":"/galaxies/lenticular"},{"id":"agn_type:liner","name":"LINER","type":"agn_type","domain":"science","description":"A galactic nucleus whose spectrum is dominated by emission from weakly-ionized gas. LINERs are the most common type of active nucleus, though whether they are all powered by a black hole or partly by hot old stars is still debated.","entryPath":"/galaxies/liner"},{"id":"galaxy_morphology:peculiar","name":"Peculiar & Interacting Galaxy","type":"galaxy_morphology","domain":"science","description":"A galaxy distorted from any regular form — by a close encounter, an ongoing merger, or an active nucleus. The tidal tails and bridges of interacting pairs, like the Antennae, are the clearest signs of galaxies in collision.","entryPath":"/galaxies/peculiar"},{"id":"agn_type:radio-galaxy","name":"Radio Galaxy","type":"agn_type","domain":"science","description":"A galaxy — usually a giant elliptical — that pours enormous energy into twin jets and lobes of radio-emitting plasma, launched by its central black hole and reaching far beyond the visible galaxy. Centaurus A is the nearest.","entryPath":"/galaxies/radio-galaxy"},{"id":"galaxy_morphology:ring","name":"Ring Galaxy","type":"galaxy_morphology","domain":"science","description":"A galaxy with a bright ring of stars and gas around a comparatively empty centre, usually formed when a smaller galaxy plunges through the disk of a larger one, sending a wave of star formation outward.","entryPath":"/galaxies/ring"},{"id":"agn_type:seyfert-galaxy","name":"Seyfert Galaxy","type":"agn_type","domain":"science","description":"A spiral galaxy with a bright, compact active nucleus whose spectrum shows broad or narrow emission lines from gas swirling near the central black hole — a relatively low-luminosity active galactic nucleus in an otherwise normal-looking galaxy.","entryPath":"/galaxies/seyfert-galaxy"},{"id":"galaxy_morphology:spiral","name":"Spiral Galaxy","type":"galaxy_morphology","domain":"science","description":"A flattened, rotating disk of stars, gas, and dust wound into spiral arms, with a central bulge. The arms are where new stars form, tracing waves of star formation sweeping through the disk.","entryPath":"/galaxies/spiral"},{"id":"agn_model:unified-agn-model","name":"The Unified AGN Model","type":"agn_model","domain":"science","description":"The framework that the many types of active galactic nucleus — Seyferts, quasars, radio galaxies, blazars — are largely the same underlying object, a supermassive black hole accreting through a disk and torus, seen from different angles and at different luminosities. A model that explains the types, rather than a type itself.","entryPath":"/galaxies/unified-agn-model"}]}