Free Astronomy Magazine March-April 2019

16 MARCH-APRIL 2019 SPACE CHRONICLES color is diluted to resemble that of a normal galaxy. Fan proposes that many other re- mote quasars have been missed due to this light con- tamination. His team got lucky with finding J043947.08 +163415.7, because the quasar is so bright it drowns out the starlight from the especially faint foreground lensing gal- axy. “Without this high level of magnification, it would make it impossible for us to see the galaxy,” said team member Feige Wang of the University of California, Santa Barbara. “We can even look for gas around the black hole and what the black hole may be influencing in the galaxy.” The object was selected by its color by combining photometric data from the United Kingdom In- frared Telescope Hemisphere Survey, the Panoramic Survey Telescope and Rapid Response System (Pan- STARRS1) at optical wavelengths, and NASA’s Wide-field Infrared Sur- T his image shows the distant quasar J043947.08+163415.7 as it was observed with the NASA/ESA Hubble Space Telescope. The quasar is one of the brightest objects in the early Universe. How- ever, due to its dis- tance, it only became visible as its image was made brighter and larger by gravitational lensing. The system of the lensed images and the actual lens is so compact that Hubble is the only optical tele- scope able to resolve it. [NASA, ESA, X. Fan (University of Arizona)] T his animation depicts how the mass of a galaxy is bending the light of a much more distant quasar through gravitational lensing. This way the quasar appear three times larger and 50 times brighter on the night sky. [ESA/Hubble, L. Calçada] vey Explorer archive in the mid-in- frared. Follow-up spectroscopic ob- servations were conducted by the University of Arizona’s Multi-Mirror Telescope, the Gemini Observatory and the Keck Observatory. These ob- servations revealed the signature of a very faint foreground galaxy di- rectly between the quasar and Earth that is magnifying the quasar image. However, because the source looks fuzzy in the ground-based observa- tions (and so could be mistaken for only a galaxy), the researchers used Hubble’s exquisite imaging capabili- ties to confirm it is a lensed quasar. “It’s a hard system to photograph because it turns out to be so com- pact, which requires the sharpest view from Hubble,” Fan said. The quasar is ripe for future scrutiny. Fan’s team is analyzing a detailed 20-hour spectrum from the Euro- pean Southern Observatory’s Very Large Telescope, which would show gas absorption features to identify chemical composition and tempera- tures of intergalactic gas in the early universe. Astronomers also will use the Atacama Large Millimeter/sub- millimeter Array, and eventually NASA’s James Webb Space Tele- scope, to look within 150 light-years of the black hole to directly detect the influence of the black hole’s gravity on gas motion and star for- mation in its vicinity. !