Image Credit: Pat Knezek (WIYN), NASA, ESA, and The Hubble Heritage Team (STScI/AURA)
NGC 1300 is a barred spiral galaxy of about 110,000 light-years across, located some 61.3 million light-years away from Earth in the constellation of Eridanus (the Ancient Greek name for the Po River, Italy) while it is receding from us at approximately 1577 kilometers per second. It is a member of the Eridanus Cluster, a cluster of some 200 galaxies.
Having a prominent bar, NGC 1300 is considered to be prototypical of barred spiral galaxies. Barred spirals differ from normal spiral galaxies in that the arms of the galaxy do not spiral all the way into the center, but are connected to the two ends of a straight bar of stars containing the nucleus at its center.
The current hypothesis is that the bar structure acts as a stellar nursery which actively creates new stars near the center. The dust lanes where actually stars are created are visible throughout the galaxy. Their presence within the bar helps corroborate this opinion. The bar is generally thought to be caused by a wave of higher density that extends from the galaxy’s center. At first, the wave changes the orbits of inner stars then, after billions of years, affects stars farther out and, over millions of millennia, elongates as it grows- thus creating this unusual structure.
We can see lots of details throughout NGC 1300’s arms, disk, bulge, and nucleus. Blue and red supergiants, clusters, and star-forming (H II) regions are well resolved across the spiral arms, and dust lanes trace out fine structures in the disk and bar, highlighting the asymmetry between the two sides of the galaxy.
In the core of the larger spiral structure of NGC 1300, the nucleus shows its own extraordinary and distinct “grand-design” spiral structure that is about 3,300 light-years long. Only galaxies with large-scale bars appear to have these grand-design inner disks — a spiral within a spiral. Models suggest that the gas in a bar can be funneled inwards, and then spiral into the center through the grand-design disk, where it can potentially fuel a central supermassive black hole. However, unlike other spiral galaxies (including our own Milky Way Galaxy) NGC 1300 is not known to have an active nucleus, indicating either that there is no black hole, or that it is not accreting matter.
The image was constructed from exposures taken in September 2004 by the Advanced Camera for Surveys onboard the Hubble Space Telescope in four filters. Numerous distant galaxies are visible in the background, and are seen even through the densest regions of NGC 1300.