3C 273
3C 273 er en kvasar i stjernebilledet Jomfruen som klassificeres som en blazar.
3C 273 er den optisk lysstærkeste kvasar på himlen, med en tilsyneladende størrelsesklasse på 12,9. Den er også et af de lysstærkeste objekter vi kender til i universet, med en absolut størrelsesklasse på -26,7. Det betyder at hvis kvasarens samlede lys var samlet i et punkt og placeret i 10 parsec afstand (ca.= 3,085 × 10^8 millioner km), dvs. standarden for måling af absolutte størrelsesklasser, skulle 3C 273 på denne afstand lyse ligeså kraftigt som Solen 149,6 millioner km væk.
Opdagelse
Maarten Schmidt opdagede i 1963, ved en nærmere granskning af tidligere katalogiserede kosmiske radiokilder, at 3C 273 fra Martin Ryles Third Cambridge Catalogue ("3C") har en ret stor rødforskydning, som ikke passede med datidens teorier om punktformede kilder. Radiogalaksen 3C 273 var derfor kun quasi stellar, hvilket førte til betegnelsen "quasar" (kvasar). 3C 273 har en rødforskydning z=0,158, svarende til en afstand på 746,9 Mpc, omregnet til cirka 2,4 milliarder lysår.
Referencer
- 3C 273's Database - INTEGRAL Science Data Centre (ESA) Arkiveret 3. marts 2016 hos Wayback Machine
- Parkes and 3C 273 – The Identification of the First Quasar Arkiveret 14. februar 2016 hos Wayback Machine
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(c) ESA/Hubble, CC BY 4.0
This image from Hubble’s Wide Field and Planetary Camera 2 (WFPC2) is likely the best of ancient and brilliant quasar 3C 273, which resides in a giant elliptical galaxy in the constellation of Virgo (The Virgin). Its light has taken some 2.5 billion years to reach us. Despite this great distance, it is still one of the closest quasars to our home. It was the first quasar ever to be identified, and was discovered in the early 1960s by astronomer Allan Sandage.
The term quasar is an abbreviation of the phrase “quasi-stellar radio source”, as they appear to be star-like on the sky. In fact, quasars are the intensely powerful centres of distant, active galaxies, powered by a huge disc of particles surrounding a supermassive black hole. As material from this disc falls inwards, some quasars — including 3C 273 — have been observed to fire off super-fast jets into the surrounding space. In this picture, one of these jets appears as a cloudy streak, measuring some 200 000 light-years in length.
Quasars are capable of emitting hundreds or even thousands of times the entire energy output of our galaxy, making them some of the most luminous and energetic objects in the entire Universe. Of these very bright objects, 3C 273 is the brightest in our skies. If it was located 30 light-years from our own planet — roughly seven times the distance between Earth and Proxima Centauri, the nearest star to us after the Sun — it would still appear as bright as the Sun in the sky.
WFPC2 was installed on Hubble during shuttle mission STS-125. It is the size of a small piano and was capable of seeing images in the visible, near-ultraviolet, and near-infrared parts of the spectrum.