NGC 1073, a barred spiral galaxy in Cetus

NGC 1073, a barred spiral galaxy in Cetus

NGC 1073 is a barred spiral galaxy of about 80,000 light-years across that lies some 55 million light-years away in the constellation of Cetus (The Sea Monster). It is moving away from us at 1208 kilometers per second. Our own Milky Way galaxy is a similar barred spiral, and the study of galaxies such as NGC 1073 helps astronomers learn more about our celestial home.

NGC 1073 has a prominent long bright bar of stars across the center, and a bright active nucleus that likely houses a supermassive black hole. Also visible in this image are dark filamentary dust lanes, young clusters of bright blue stars, and red emission nebulas of glowing hydrogen gas.

There are spiral galaxies with and without a central bar. Central bars, made of dense lines of stars at the galaxies’ centers, are thought to form as gravity causes density waves that push gas inward, supplying material for new stars. This inflow of gas can also feed the hungry giant black holes in the centers of most such galaxies.

The bars might form as galaxies age, in part because very distant galaxies dating from the Universe’s early days tend not to have them. In fact, about one-fifth of the spiral galaxies from early Universe contain bars, while more than two-thirds of spirals seen today have them. Adding to this idea is the fact that bars are more often found in galaxies full of older, redder stars, and less often in galaxies with bluer, younger stars.

This image also reveals an odd, rough ring-like structure around the galaxy that is the result of recent star formation. A bright X-ray source known as IXO 5 is located inside the ring and is most likely a binary system containing a star and black hole locked in orbit around each other.

NGC 1073 is also well-known due to its line-of-sight towards three brilliant quasars (two of which are visible at the bottom right), which are incredibly bright sources of light coming from billions of light-years away. This brightness is caused by matter heating up and falling into supermassive black holes at the heart of galaxies. The chance alignment through NGC 1073 make them look like they are part of the galaxy, while they are in fact some of the most distant objects observable in the Universe.

At the top of the image are several objects with a reddish hue, each of which is a distant galaxy lurking far beyond NGC 1073.

This image was taken by the Hubble Space Telescope.
Image Credit: NASA/ESA

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