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... > galactic and extragalactic astronomy > galaxy > galactic nucleus > active galactic nucleus > blazar > BL Lacertae object
high-energy astrophysics > active galactic nucleus > blazar > BL Lacertae object
... > galactic and extragalactic astronomy > galaxy > active galaxy > active galactic nucleus > blazar > BL Lacertae object

Preferred term

BL Lacertae object  

Definition

  • A BL Lacertae object (BL Lac object) is a type of active galactic nucleus (AGN) characterized by a nearly featureless spectrum (i.e., virtually devoid of spectral lines), rapid, marked variability at radio, infrared, and optical wavelengths (often by several magnitudes over a few days or weeks), and strong, variable polarization at radio and optical wavelengths. The prototype, in the constellation Lacerta, was originally classified as a variable star. BL Lac objects belong to the category of AGN now known as blazars and are believed to be essentially quasars viewed directly down the axis of their powerful jets. (Encyclopedia of Science, by David Darling, https://www.daviddarling.info/encyclopedia/B/BL_Lacertae_object.html)

Broader concept

Related concepts

Entry terms

  • BL Lac object
  • BL Lac type object

In other languages

URI

http://data.loterre.fr/ark:/67375/MDL-VLZ89NWN-5

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