NASA’s Hubble Space Telescope has captured an image of galaxy NGC 7090. The galaxy is viewed edge-on from the Earth, meaning astronomers are unable to easily see the spiral arms, which are full of young, hot stars.
However, a side-on view depicts the galaxy’s disc and the bulging central core, where a large group of cool old stars are packed in a compact, spheroidal region.
In addition, one is able to distinguish an intricate pattern of pinkish red regions over the whole galaxy – indicating the presence of clouds of hydrogen gas. These structures trace the location of ongoing star formation, visual confirmation of recent studies that classify NGC 7090 as an actively star-forming galaxy.
The image above also allows astronomers to observe dust lanes, depicted as dark regions inside the disc of the galaxy. In NGC 7090, these regions are primary located in lower half of the galaxy, showing an intricate filamentary structure.
Looking from the outside in through the whole disc, the light emitted from the bright center of the galaxy is absorbed by the dust, silhouetting the dusty regions against the bright light in the background. Dust in our galaxy, the Milky Way, has been one of the biggest opponents of observational astronomers for decades.
But this does not mean that these regions are only blind spots in the sky. At near-infrared wavelengths – slightly longer wavelengths than visible light – this dust is largely transparent and astronomers are able to study what is really behind it. At still longer wavelengths, the realm of radio astronomy, the dust itself can actually be observed, allowing astronomers study the structure and properties of dust clouds and their relationship with star formation.
Lying in the southern constellation of Indus (The Indian), NGC 7090 is located about thirty million light-years from the Sun. Astronomer John Herschel first observed this galaxy on October 4, 1834.