PMN J0948+0022
narrow-line Seyfert galaxy located in the constellation Sextans
PMN J0948+0022 is a narrow-line Seyfert 1 galaxy and quasar located 5.7 billion light years away in the constellation of Sextans. It has a redshift of (z) 0.5846, and is classified as radio-loud with a flat and inverted radio spectrum. First discovered in 2002 in the SDSS survey, this object is known to emit gamma-rays, and as such belongs to a new classification of gamma-ray emitting active galactic nuclei along with 1H 0323+342, PKS 2004-447 and PKS 1502+036.
Description
PMN J0948+0022 is constantly in an active state, in terms of emitting gamma-rays. A high energy outburst in July 2010 was detected by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. Two flares were detected during observations in 2011. A new gramma-ray flare was emitted by the object on January 1, 2013 when a peak flux was detected in the 0.1-100 GeV energy range, reaching (155 ± 31) × 10−8 ph cm−2 s−1 making it the most powerful then observed. A quasi-simultaneous flare was observed on December 30, 2012, detected in ultraviolet, optical and X-rays. In 2025 it displayed a radio flare.
The radio structure of PMN J0948+0022 is extended on kiloparsec-scales.
“PMN J0948+0022” enters the record as narrow-line Seyfert galaxy located in the constellation Sextans. Crown Archives preserves that source wording while asking what J0948, narrow-line and Seyfert can confirm, complicate or overturn.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Sep 3, 2026. The linked authority identifier is Q134966674. None of the 0 selected statements returned an explicit reference. The first chronological checks are 2002, 2004, 1502 and 2010.
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This entry incorporates text from “PMN J0948+0022” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.