Key Takeaways:
- Quasars are the bright centers of young galaxies powered by supermassive black holes.
- Most quasars are very distant and faint, making them difficult to observe.
- One quasar, 0957+561, is gravitationally lensed, appearing as a double image.
- Observing this lensed quasar requires a large telescope and dark skies.
Quasars were a mystery when first discovered in the early 1960s. They are extremely distant, starlike objects that emit enormous amounts of energy. Years later, astronomers understood that quasars are the extremely energetic centers of young galaxies, powered by supermassive black holes. The fact that they are mostly young (the black holes generally quiet down later in time) means that most quasars are very distant, and therefore faint and really hard to observe.
They’re also hard to find, as most appear like faint stars. But some objects occur as pairs in the sky, and make each other somewhat easier to find. This is the case with a galaxy-quasar pair in Ursa Major, which consists of the edge-on galaxy NGC 3079, a barred spiral lying 50 million light-years away, and a nearby quasar. NGC 3079 is unusual in that it contains a supermassive black hole of about 2.4 million solar masses, and a “central superbubble” extending some 3,500 light-years above the galaxy’s disk, believed to be caused by a starburst event. The galaxy shines at magnitude 11.5 and spans 7.9’ by 1.4’.
Near this galaxy is a real treat: the double quasar 0957+561, discovered in 1979, the first gravitationally-lensed quasar to be found. It lies some 8.7 billion light-years away and is being lensed by an intervening galaxy, YGKOW G1. The twin images of the quasar glow faintly at magnitude 16.7 and have been imaged by dedicated and skilled backyard astronomers.
Astroimagers may want to put this strange object on their target list. The quasar lies at 10h01m21s, +55°53’57” (equinox 2000.0).
If you’re an imager and want a real challenge, try going after this distant lensed quasar. If you’re an observer with a very large and optically capable telescope and a dark sky, you might also go after it. Good luck!
