ALMA’s Long Baseline Campaign has produced a spectacularly detailed image of a distant galaxy being gravitationally lensed.
The image shows a magnified view of the galaxy’s star-forming regions, the likes of which have never been seen before at this level of detail in a galaxy so remote.
The new observations are far more detailed than those made using the NASA/ESA Hubble Space Telescope, and reveal star-forming clumps in the galaxy equivalent to giant versions of the Orion Nebula.
The reconstructed ALMA image of the galaxy is spectacular, says co-author Rob Ivison, adding that ALMA’s huge collecting area, the large separation of its antennas and the stable atmosphere above the Atacama desert all lead to exquisite detail in both images and spectra.
He added that that means that they get very sensitive observations, as well as information about how the different parts of the galaxy are moving. They can study galaxies at the other end of the Universe as they merge and create huge numbers of stars.
Using the spectral information gathered by ALMA, astronomers also measured how the distant galaxy rotates, and estimated its mass. The data showed that the gas in this galaxy is unstable; clumps of it are collapsing inwards, and will likely turn into new giant star-forming regions in the future.
The study appears in Astrophysical Journal Letters.