3C 454.3 is a blazar (a type of quasar with a jet oriented toward Earth) located away from the galactic plane. It is one of the brightest gamma ray sources in the sky,[2] and is one of the most luminous astronomical object ever observed, with a maximum absolute magnitude of -31.4.[3] It has the brightest blazar gamma ray flare recorded, twice as bright as the Vela Pulsar in the Milky Way galaxy. It also flares at radio and visible wavelengths – in red light, the blazar brightened by more than 2.5 times to magnitude 13.7 – and it is very bright at high radio frequencies.[4]
It is possible that a binary supermassive black hole might lie in the center of 3C 454.3 based on observations.[7] Additionally, it has a bright radio core and radio jet described as one-sided, with its jet components moving in superluminal motion.[8][9] An arc-structure has also been detected on parsec-scales around the region of its core.[10]
History
In July and August 2007, 3C 454.3 flared to near-historic levels, only two years after its record-breaking 2005 optical flare. Luckily, Spitzer Space Telescope and Chandra X-ray Observatory were already scheduled for simultaneous observations. Swift, RXTE and the new gamma-ray AGILE spacecraft responded to this target of opportunity, and were joined by observatories around the world.
The Fermi Large Area Telescope AGN science group started a multiwavelength campaign for blazar 3C454.3 (2251+158), in July and continuing through August 2007. This Ad Hoc Intensive Campaign (AIC) was prompted by brightening in the radio, optical and X-ray.
