3C 273

3C 273
source
Name	3C 273
Type	Quasar
Constellation	Virgo
Epoch	J2000
Ra	12, 29, 06.7
Dec	+02, 03, 09
Z	0.158
Appmag v	12.9
Absmag v	-26.7
Notes	First identified quasar

3C 273 is a quasar located in the constellation of Virgo. It holds the historic distinction of being the first such object to be identified, a breakthrough that resolved the mystery of powerful radio sources with stellar appearances. Its enormous redshift and corresponding distance revealed it to be an extraordinarily luminous active galactic nucleus, fundamentally altering the understanding of cosmology and galactic evolution.

Discovery and identification

The object was cataloged as a strong radio source in the Third Cambridge Catalogue of Radio Sources compiled by the Mullard Radio Astronomy Observatory. Its optical counterpart was pinpointed in 1962 by Cyril Hazard using the Parkes Observatory during an occultation by the Moon. Maarten Schmidt of the California Institute of Technology subsequently obtained its optical spectrum with the Palomar Observatory's Hale Telescope, making the critical realization that its unusual emission lines were those of familiar hydrogen but shifted dramatically toward the red. This measurement of its redshift proved it was not a nearby star but an immensely distant and powerful object, solving the puzzle of quasi-stellar radio sources.

Physical characteristics

With a redshift of 0.158, 3C 273 resides approximately two billion light-years from Earth. It is the optically brightest quasar in the sky, powered by accretion onto a supermassive black hole estimated to have a mass exceeding one billion solar masses. The system exhibits a prominent and highly variable relativistic jet extending over 60,000 light-years, observable in radio wave and X-ray wavelengths. Its extreme luminosity, outshining entire galaxies, arises from the conversion of gravitational energy in the accretion disk surrounding the black hole.

Observation and research history

Following its identification, observations with instruments like the Very Large Array and the Hubble Space Telescope have detailed its structure, separating the brilliant nucleus from its host galaxy. Long-term monitoring campaigns, including those by the Compton Gamma Ray Observatory, revealed it to be a strong and variable emitter across the electromagnetic spectrum, from radio to gamma-rays. It served as a crucial calibration source for the Hipparcos satellite and continues to be a primary target for studies of jet physics and black hole accretion with facilities like the Chandra X-ray Observatory and the Event Horizon Telescope collaboration.

Role in astronomy

The identification of 3C 273 was a watershed moment for 20th-century astronomy, proving that quasars were distant cosmological beacons and not local objects. This discovery bolstered the acceptance of the Big Bang theory and the expansion of the universe, while also providing the first clear evidence for the existence of supermassive black holes. It established a fundamental class of active galactic nucleus, critical for understanding galaxy formation and cosmic evolution. The object remains a foundational yardstick in extragalactic astronomy for testing theories of relativistic astrophysics and high-energy astrophysics.

In popular culture

While not a common household name, 3C 273 has permeated scientific popularization as the archetypal quasar. It is frequently featured in documentary series such as those produced by the BBC and the Discovery Channel, often highlighted in episodes concerning the history of astronomy or the mysteries of black holes. The object is also cited in notable works of popular science literature by authors like Carl Sagan and Stephen Hawking, symbolizing humanity's discovery of the violent, energetic universe. Its designation appears in the technical lore of several science fiction works, including episodes of the BBC series Doctor Who, as a distant cosmic landmark.

Category:Quasars Category:Virgo (constellation) Category:Radio sources Category:3C objects Category:Astronomical discoveries