Andromedas Parachute, Quasar J014709+463037
It wasn't that long ago when in the summer of 2017 a paper announced the discovery of a quadruple lensed quasar (QSO) in the constellation Andromeda.
Because of the arrangement of the four lensed images, it was nicknamed "Andromeda's Parachute." The official name, however, is "J014709+463037".
Its redshift is z= 2.38, which corresponds to a light travel time of 11.2 billion years. But due to the expansion of the universe, the distance has now grown to
almost 19 billion light years. The QSO continues to move away at a speed of 250,000 kilometers per second, which is 84% of the speed of light. The four
individual images of the quasar have a brightness of 15.4...17.7mag and a distance to each other of 1.3"...3.4" (arcseconds). Assuming a mean magnitude of
17mag, the absolute magnitude of the QSO can calculated to be M= -25.6mag, which corresponds to a luminosity of 1.5 trillion suns.
The lensing galaxy is much closer to us with a distance of 5.6 billion light years and cannot be seen on the published images. Therefore, a model simulation
was used to determine the distance.
----------------------------------------------------------------------------------------------------------------------------------------------
In my 20" f/3.2 the surrounding is unusually rich in stars and even at 120x a very faint star is visible at the position of the quasar, which flashes from time to
time. At 270x things become much easier and "Andromeda's Parachute" is easy to hold. If you magnify to 370x, you get the impression that the star is not
absolutely point-like, but slightly elongated. But this observation is very difficult and I succeeded only in a few moments with perfect seeing. To see the three
brightest components separately, you need more aperture and a much higher magnification. But I don't have both... Not yet... ;)
Even if it didn't work out with the single components, the observation was a great thing, especially considering that the light travel time was 11 billion years.
So it was pretty "old" photons I caught with my telescope. Amazing!
