CTA-102

In astronomy, CTA 102, also known by its B1950 coordinates as 2230+114 (QSR B2230+114) and its J2000 coordinates as J2232+1143 (QSO J2232+1143), is a blazar-type quasar discovered in the early 1960s by a radio survey carried out by the California Institute of Technology.[3] It has been observed by a large range of instruments since its discovery, including WMAP, EGRET, GALEX, VSOP and Parkes,[1] and has been regularly imaged by the Very Long Baseline Array since 1995.[4] It has also been detected in gamma rays, and a gamma-ray flare has been detected from it.[5]

CTA 102
Observation data (Epoch J2000)
Constellation	Pegasus
Right ascension	22^h 32^m 36.4^s[1]
Declination	+11° 43′ 51s″[1]
Redshift	1.037[1]
Distance	8 billion light years[2]
Other designations
CTA-102 , Q2230+11 , QSR B2230+114 , QSO J2232+1143 , 4C +11.69 ,
See also: Quasar, List of quasars

In 1963 Nikolai Kardashev proposed that the then-unidentified radio source could be evidence of a Type II or III extraterrestrial civilization on the Kardashev scale.[3] Follow-up observations were announced in 1965 by Gennady Sholomitskii, who found that the object's radio emission was varying;[6] a public announcement of these results on April 12, 1965, caused a worldwide sensation.[7] The idea that the emission was caused by a civilization was rejected when the radio source was later identified as one of the many varieties of a quasar.[3]

CTA 102 is one of the two great false alarms in the history of the search for extra-terrestrial life, the other being the discovery of pulsars, specifically PSR B1919+21, which are rotating neutron stars.

The American folk rock band The Byrds whimsically reflected the original view that CTA-102 was a sign of extraterrestrial intelligence in their song "C.T.A.-102" from their 1967 album Younger Than Yesterday.[8]

In late 2016 CTA 102, usually glowing around magnitude +17, had a bright outburst in visible light to magnitude +11 (~250 times brighter than usual).[9][10] This likely was the most luminous blazar state ever observed,[11] with an absolute magnitude in excess of -32.

A new outburst began in December 2017, with increased gamma-ray[12] and optical activity.[13] As of 22 December 2017, it has reached magnitude +14.[14]

References

1. "CTA 102 in the NASA Extragalactic Database". Retrieved 2008-12-24.
2. "Galaxy 8 billion light years away offers insight into supermassive black holes". 19 December 2017. Retrieved 5 August 2019.
3. "CTA-102". Internet Encyclopedia of Space; David Darling. Retrieved 2008-12-14.
4. "MOJAVE Sample: 2230+114". Retrieved 2008-12-25.
5. "Fermi LAT detection of a GeV flare from blazar CTA 102". Astronomers Telegram. 3 May 2011. Retrieved 3 May 2011.
6. Sholomitsky, G. B. (1965). "Variability of the Radio Source CTA-102". Information Bulletin on Variable Stars. 83: 1. Bibcode:1965IBVS...83....1S.
7. "Is Man Not Alone in the Universe? Space Signals Stir Experts", Milwaukee Sentinel, April 13, 1965, p1-3
8. Rogan, Johnny (2011). Byrds: Requiem for the Timeless. Rogan House. pp. 317–320. ISBN 978-0-95295-408-8.
9. http://www.skyandtelescope.com/observing/quasar-cta-102-historically-bright-violently-variable/
10. "Swift XRT and UVOT flares accompany brightest ever gamma-ray flare of CTA 102". Astronomers Telegram. 1 Jan 2017. Retrieved 23 July 2020.
11. "CTA 102 brightens up to the most luminous optical blazar state ever detected". Astronomers Telegram. 16 Dec 2016. Retrieved 23 July 2020.
12. "AGILE detection of increasing gamma-ray activity from CTA 102". Astronomers Telegram. 9 Dec 2017. Retrieved 23 July 2020.
13. "CRTS-II Detection of Increased Optical Activity from CTA 102". Astronomers Telegram. 9 Dec 2017. Retrieved 23 July 2020.
14. https://www.aavso.org/apps/webobs/results/?start=2017-12-01&end=2017-12-23&num_results=25&obs_types=all&star=CTA+102

See also

• LGM-1, the first pulsar discovered, mistaken for an alien radio signal
• Radio signal from HD 164595