NGC 247 is a spiral galaxy in the Sculptor Group some 11 million light-years from Earth. This Hubble image shows a zoomed-in view of NGC 247’s central region. Click the picture for a larger-scale version that reveals more distant galaxies. Image credit: ESA/Hubble & NASA.This NASA/ESA Hubble Space Telescope image shows the central region of a spiral galaxy known as NGC 247. NGC 247 is a relatively small spiral galaxy in the southern constellation of Cetus (The Whale). Lying at a distance of around 11 million light-years from us, it forms part of the Sculptor Group, a loose collection of galaxies that also contains the more famous NGC 253 (otherwise known as the Sculptor Galaxy).
NGC 247’s nucleus is visible here as a bright, whitish patch, surrounded by a mixture of stars, gas and dust. The dust forms dark patches and filaments that are silhouetted against the background of stars, while the gas has formed into bright knots known as H II regions, mostly scattered throughout the galaxy’s arms and outer areas.
This galaxy displays one particularly unusual and mysterious feature — it is not visible in the image above, but can be seen clearly in wider views of the galaxy, such as the picture below from ESO’s MPG/ESO 2.2-metre telescope. The northern part of NGC 247’s disc (to the right in the following image) hosts an apparent void, a gap in the usual swarm of stars and H II regions that spans almost a third of the galaxy’s total length.This picture of the spiral galaxy NGC 247 was taken using the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. Image credit: ESO.There are stars within this void, but they are quite different from those around it. They are significantly older, and as a result much fainter and redder. This indicates that the star formation taking place across most of the galaxy’s disc has somehow been arrested in the void region, and has not taken place for around one billion years. Although astronomers are still unsure how the void formed, recent studies suggest it might have been caused by gravitational interactions with part of another galaxy.
A supernova remnant in the Large Magellanic cloud, imaged by the Hubble Space Telescope in 2006, shows the spectacular aftermath of a supernova blast, generating a cloud of debris expanding at 18 million kilometres per hour (11 million mph).
Showcased at the centre of this NASA/ESA Hubble Space Telescope image is an emission-line star known as IRAS 12196-6300 that lies some 2,300 light-years from Earth in the southern constellation of Crux. Under 10 million years old and not yet burning hydrogen at its core — unlike the Sun — this star is still in its infancy.
To understand the physics of the evolution and formation of galaxies it is crucial to know at what rate galaxies form stars, referred to as the star-formation rate. A group of researchers used Earth- and space-based telescopes to create a complete multi-wavelength picture of distant galaxies.
