European astronomers have developed a new, dramatically successful technique for finding and analyzing distant galaxies that have previously been invisible against the glare of brighter background objects.
The astronomers were looking for a way to find relatively dim galaxies located between Earth and a bright quasar, which drowned out their light. Facing a problem a bit like seeing the light of a firefly buzzing in front of searchlight, they approached the issue in much the same way, looking first for evidence of an interstellar shadow.
Using the European Organization for Astronomical Research in the
Southern Hemisphere's (ESO) Very Large Telescope, the observers first looked at known quasars, analyzing the light spectrum emitted to determine whether any "dips" could be found, representing the absorption of light at certain frequencies.
From that point, the VLT's Sinfoni tool, which delivers very sharp images along with high-resolution color or spectra information, let them distinguish the light emitted by galaxies from that of the quasars in
14 of 20 patches of sky selected.
Moreover, the galaxies found seem in most cases to be very young, in the process of forming new stars at a rapid rate – up to the equivalent of 20 suns per year – and so are of deep interest to astronomers, the team said:
The approach is likely to be widely adopted in the process of galaxy discovery, the team said.
Galaxy 'Hunting' Made Easy [ESO]
(Photo: Images of the regions around quasars, where galaxies have been found. Curved lines represent the quasars, while the colors depict relative hydrogen flux. Credit: ESO)
