Physics
Today: The Low-Frequency Array (LOFAR) is a network of
eight radio observatories—five in the Netherlands, three
in Germany—that operate in one of the most challenging
spectral regions for astronomy: wavelengths of 1–10
meters. Yesterday the LOFAR collaboration announced it had
achieved a significant milestone: its first high-resolution
image of a quasar. Observing in the 1-m to 10-m waveband is
difficult because of high background and weak signals. It's
worthwhile because at the high redshifts of galaxy formation an
important tracer of neutral hydrogen, the 21-cm emission line,
is redshifted into the waveband.
