Along with hosting a supermassive black hole at its heart, the
center of the radio-loud galaxy Centaurus A is home to a stellar
nursery that tells a tale of the galaxy’s past. The presence of
a dark band of dust, as well as the galaxy’s powerful emissions
in the radio end of the spectrum, suggest it formed in a
collision between a giant elliptical galaxy and a smaller spiral
galaxy. But that dark dust band blocks out the galaxy’s bright
center, and to see past it, astronomers have to look in longer
wavelengths of light. Today’s pretty space pic reveals the
position and motion of the gas clouds at Centaurus A’s center,
the sharpest and most sensitive images ever made. The colors are
the result of the Doppler effect as the gas clouds swirl around.
ALMA can detect signatures with a wavelength around 1.3
millimeters, which corresponds to carbon monoxide. As the gas
moves around, it causes changes to this wavelength as seen from
here. Greener features correspond to gas coming toward us, while
orange areas represen