A galaxy that gives great feedback

This NASA/ESA Hubble Space Telescope Picture of the Week features the picturesque spiral galaxy NGC 4941, which lies about 67 million light-years from Earth in the constellation Virgo (The Maiden). Because this galaxy is nearby, cosmically speaking, Hubble’s keen instruments are able to pick out exquisite details such as individual star clusters and filamentary clouds of gas and dust.

The data used to construct this image were collected as part of an observing programme that investigates the star formation and stellar feedback cycle in nearby galaxies. As stars form in dense, cold clumps of gas, they begin to influence their surroundings. Stars heat and stir up the gas clouds in which they are born through winds, starlight, and — eventually, for massive stars — by exploding as supernovae. These processes are collectively called stellar feedback, and they impact the rate at which a galaxy can form new stars.

As it turns out, stars aren’t the only entities providing feedback in NGC 4941. At the heart of this galaxy lies an active galactic nucleus: a supermassive black hole feasting on gas. As the black hole amasses gas from its surroundings, the gas swirls into a superheated disc that glows brightly at wavelengths across the electromagnetic spectrum. Similar to stars — but on a much, much larger scale — active galactic nuclei shape their surroundings through winds, radiation, and powerful jets, altering not only star formation but also the evolution of the galaxy as a whole.

[Image Description: A spiral galaxy seen at a diagonal angle. Its very centre is a bright white glowing orb, surrounded by an inner disc of golden light. This is wrapped in a broad outer disc that glows more dimly, with patchy, broken spiral arms swirling around it, filled with small blue and pink star clusters. Dark reddish threads of dust also spiral through the disc, with some strands reaching into the core.]

Links

• Pan of NGC 4941