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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Active galactic nucleus | 4/4 | https://en.wikipedia.org/wiki/Active_galactic_nucleus | reference | science, encyclopedia | 2026-05-05T13:31:44.530837+00:00 | kb-cron |
=== Quasar === 3C 273: The first identified Quasar, notable for its relativistic jets (z=0.158). 3C 48: One of the earliest known Quasar with a measured redshift (z=0.367). TON 618: An ultra-luminous quasar hosting one of the most massive known black holes (~66 billion solar masses), located at a redshift of z=2.219. Twin Quasar: The first gravitationally lensed quasar, split into two images by an intervening galaxy (z=1.41). Einstein Cross: A quasar lensed into four images forming a cross, demonstrating gravitational lensing predicted by general relativity (z=1.695). Pōniuāʻena: One of the most distant quasars known (z=7.52), formed ~700 million years after the Big Bang, offering insights into early black hole formation. CTA-102: A radio-loud quasar known for its variability (z=1.037). Cloverleaf Quasar: A quasar lensed into four images resembling a cloverleaf, brightest known high-redshift source of CO emission (z=2.558).
=== Radio Galaxy === Messier 87: A giant elliptical galaxy with a supermassive black hole (6.5 billion solar masses), imaged by the Event Horizon Telescope in 2019. Its jets extend thousands of light-years (z=0.00428). Centaurus A: One of the closest radio galaxies, known for its dust lanes and relativistic jets (0.00183). Cygnus A: A powerful radio source identified with a tidally distorted galaxy, a benchmark for studying AGN feedback (z=0.0561). Hercules A: Features massive radio jets spanning ~1 million light-years, observed with radio telescopes like VLA (z=0.154). Alcyoneus: The largest known radio galaxy, with jets extending 16.3 million light-years, discovered using LOFAR (z=0.2467). TGSS J1530+1049: The most distant radio galaxy known (z=5.72), providing insights into early universe structures.
=== Seyfert Galaxy === Messier 77: A prototypical Type 2 Seyfert with star-forming rings, extensively studied using ALMA for black hole interactions (z=0.00379). NGC 4151: A classic Type 1 Seyfert, noted for variable X-ray emission and a well-studied accretion disk (z=0.00332). Circinus Galaxy: A nearby Type 2 Seyfert with ejected gas rings, bright in infrared due to dust (z=0.00145). NGC 7469: A luminous infrared Seyfert 1 with starburst activity, included in early Seyfert studies (z=0.0163). NGC 7319: Part of Stephan's Quintet, harbors a hidden AGN revealed by Webb Telescope observations (z=0.0225). Markarian 231: A ultraluminous infrared galaxy with a quasar-like AGN, showing evidence of a major merger (z=0.0415).
=== Blazar === BL Lacertae: The prototype BL Lac object, characterized by minimal emission lines and variability (z=0.069). Markarian 501: A TeV blazar known for gamma-ray flares and jet studies; a key target for high-energy astronomy (z=0.034). PKS 0537-286: A distant gamma-ray blazar, one of NASA's top gamma-ray sources, probing early universe black holes (z=3.104).
== See also == M–sigma relation – Concept in astronomy Quasar – Active galactic nucleus (AGN) containing a supermassive black hole Radio galaxy – Type of active galaxy that is very luminous at radio wavelengths Relativistic jet – Stream of ionized matter flowing away from a rotating astronomical object Supermassive black hole – Largest type of black hole Reverberation mapping – Astrophysical technique
== References ==
== External links == Media related to Active galactic nuclei at Wikimedia Commons