The student accidentally opened one of the rarest objects observed from Earth. Features of lensing a quasar will help astronomers study it from different angles and learn more about the nature of the lens itself.
Quasars – in fact, the nucleus of galaxies, similar to the Milky Way. Each large galaxy in the center has a supermassive black hole that absorbs the surrounding matter, which can accumulate outside the first, forming a disk. Friction inside it heats it to incredible temperatures, causing it to shine brightly. In some cases this disc may shine more strongly than all stars. In science, they are better known as active galaxies, differing in characteristics.
Usually quasars are located very far from us. The very first of the detected, 3C 273, is a billion light years away from the Earth. Most – even further.
Recently, a student George Nelson observed variable quasars at the US Naval Observatory and noticed something unusual. Using the Pan-STARRS telescope (a 1.8-meter telescope on the Haleakala volcano in Maui), he discovered a quasar distorted by a powerful gravitational lens.
Quasar J014709 + 463037 (named so because of its celestial coordinates) is located in the distant 11 billion light-years away from us – it is almost 80% of the visible universe. The lens is a galaxy located just 5.6 billion years from the Earth. The geometry of lensing produces several images of the quasar around it: three on top and one, more dim, from below.
Subsequent observations were made with the help of a huge Keck telescope (also in Hawaii): they confirmed that this is really a quasar, and also clarified the distance to it and the lens.
One of the reasons why such objects are of interest is that each of the visible images of the quasar has come down to us in various ways, and some of them are longer than others. So, if suddenly a black hole of a quasar absorbs a huge gas cloud and “lights up”, we’ll see this in four images at different times. The delay can be calculated in days, weeks or even months – depending on the geometry. This makes it possible to repeatedly observe the same event – akin to traveling in time. Since the distortion is due to the gravity of the galaxy between us and the quasar, which, in fact, depends on its mass, the lens can also help scientists to map the distribution of material in this galaxy.
In total, about 40 similar quasars with quadruple lensing are known. J014709 + 463037 was the first to be seen in the Pan-STARRS data.
Because of the shape of the lensed image and its location in the sky, the quasar was nicknamed the Andromeda Parachute.