3C 273

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3C 273

Quasar 3C 273, with its jet
Observation data (Epoch J2000)
Constellation Virgo
Right ascension 12h 29m 06.7s[1]
Declination +02° 03′ 09″[1]
Redshift 0.158339 ± 0.000067 [1]
Distance 2.44 Gly (749 Mpc)
Type Blazar; Sy1[1]
Apparent magnitude (V) 12.9[1]
Notable features First quasar discovered
Other designations
PGC 41121[1]
See also: Quasar, List of quasars
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3C 273 is a quasar located in the constellation Virgo.

It is the optically-brightest quasar in our sky (m ~ 12.9), and one of the closest with a redshift, z, of 0.158.[2] A luminosity distance of DL = 2.44 Giga light years (749 Mpc) may be calculated from z.[3] It is also one of the most luminous quasars known, with an absolute magnitude of -26.7. Its mass has been measured to be 886 ± 187 million solar masses through broad emission-line reverberation mapping.[4]

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[edit] Large-Scale Jet

The quasar has a large-scale visible jet, which measures ~200 kly (~62 kpc) long having an apparent size of 23″.[3] In 1995 Optical imaging using the HST of the jet revealed a structured morphology evidenced by repeated bright knots interlaced by areas of weak emission.[3]

[edit] History

The name signifies that it was the 273rd object (ordered by right ascension) of the Third Cambridge Catalog of Radio Sources (3C), published in 1959. After accurate positions were obtained using lunar occultation by Cyril Hazard at the Parkes Radio Telescope,[5] the radio source was quickly associated with an optical counterpart, an unresolved stellar object. In 1963, Maarten Schmidt and Bev Oke published a pair of papers in Nature reporting that 3C 273 has a substantial redshift, placing it several billion light-years away.

Prior to the discovery of 3C 273, several other radio sources had been associated with optical counterparts, the first being 3C 48. Also, many active galaxies had been misidentified as variable stars, including the famous BL Lac, W Com, and AU CVn. However, it wasn't understood what these objects were, since their spectra were unlike those of any known stars. 3C 273 was the first object to be identified as what we now know quasars to be — extremely luminous objects at cosmological distances.

3C 273 as imaged by the Hubble Space Telescope's Advanced Camera for Surveys. Credit: NASA/ESA.
3C 273 as imaged by the Hubble Space Telescope's Advanced Camera for Surveys. Credit: NASA/ESA.

3C 273 is a radio-loud quasar, and was also one of the first extragalactic X-ray sources discovered in 1970. However, even to this day, the process which gives rise to the X-ray emissions is controversial.[3] The luminosity is variable at nearly every wavelength from radio waves to Gamma rays on timescales of a few days to decades. Polarization with coincident orientation has been observed in radio, infrared, and optical light being emitted from the large-scale jet; these emissions are therefore almost certainly synchrotron in nature,[3] radiation that is created by a jet of charged particles moving at relativistic speeds. Such jets are believed to be created by the interaction of the central black hole and the accretion disk. VLBI radio observations of 3C 273 have revealed proper motion of some of the radio emitting regions, further suggesting the presence of relativistic jets of material.

3C 273 is visible in May in both the northern hemisphere and southern hemispheres. It is bright enough to be observed with larger amateur telescopes.


[edit] Trivia

[edit] External links

[edit] References

  1. ^ a b c d e f NASA/IPAC Extragalactic Database. Results for 3C 273. Retrieved on 2006-10-26.
  2. ^ Schmidt, M. (1963). "3C 273: a star-like object with large red-shift.". Nature 197: 1040-1040. doi:10.1038/1971040a0. 
  3. ^ a b c d e Uchiyama, Yasunobu; Urry, C. Megan; Cheung, C. C.; Jester, Sebastian; Van Duyne, Jeffrey; Coppi, Paolo; Sambruna, Rita M.; Takahashi, Tadayuki; Tavecchio, Fabrizio; Maraschi, Laura (2006). "Shedding New Light on the 3C 273 Jet with the Spitzer Space Telescope". The Astrophysical Journal 648 (2): 910-921. doi:10.1086/505964. 
  4. ^ Peterson, B. M.; Ferrarese, L.; Gilbert, K. M.; Kaspi, S.; Malkan, M. A.; Maoz,D. ; Merritt, D.; Netzer, H.; Onken, C. A.; Pogge, R. W.; Vestergaard, M.; Wandel, A. (2004). "Central Masses of AGNs. II.". The Astrophysical Journal 613: 682-699. 
  5. ^ Hazard, C.; Mackey, M. B.; Shimmins, A. J. (1963). "Investigation of the Radio Source 3C273 by the method of Lunar Occultations". Nature 197: 1037.