The world’s highest observatory has produced spectacularly detailed images of a distant galaxy being gravitationally lensed. Astronomers at the European Southern Observatory (ESO) in Chile used the observatory’s Atacama Large Millimeter/submillimeter Array [ALMA] to produce images of the monstrous galaxy located 11.7 billion light-years away from Earth. It means the light from that galaxy took 11.7 billion years to reach Earth, more than twice the age of our planet.
ALMA sees the galaxy just 2.4 billion years after the Big Bang
ALMA consists of 66 high-precision antennas spread over a distance of ten miles. The images show a magnified view of the distant galaxy’s star-forming regions at a level of detail never seen before in a galaxy so remote. The galaxy, named SDP.81 is seen by ALMA just 2.4 billion years after the Big Bang. It means the Universe was only 15% of its current age.
The new images are far more detailed than those obtained using the Hubble Space Telescope, and show star-forming clumps in the galaxy. Astronomers used a technique called gravitational lensing to study the distant galaxy with the help of ALMA. They used a galaxy between Earth and SDP.81 as a lens to study SDP.81.
This smaller galaxy significantly magnified the light of SDP.81 and warped it. It is a perfect example of “Einstein’s Ring,” a gravitational lens that bends the light from an object behind it. “The ALMA image of the reconstructed galaxy is spectacular,” said Rob Ivison, the ESO’s Director for Science. The galaxy that was used for gravitational lensing is four billion light years away from our planet.
ALMA could not detect the center of SDP.81
The images show giant dusty clouds in SDP.81, made up of cold molecular gases from which planets and stars are formed. However, ALMA could not detect the center of SDP.81 because of the presence of “a supermassive black hole more than 200–300 million times the mass of the Sun” in the galaxy that researchers had used for gravitational lensing.
Using spectral data gathered by ALMA, astronomers were also able to measure how the distant galaxy rotates. They also estimated its mass. Findings of the study were published in the Astrophysical Journal Letters.