NGC 3079: A Barred Spiral Galaxy with a Superbubble

NGC 3079 is a barred spiral galaxy located approximately 50 million light-years away in the constellation Ursa Major. This galaxy is notable for its unusual structure and high-energy phenomena, particularly a vast “superbubble” of hot gas emanating from its core.

Physical Characteristics

NGC 3079 has a prominent central bar, a feature that channels gas towards the galactic nucleus, fueling star formation and possibly feeding its active galactic nucleus (AGN). Its spiral arms are tightly wound, rich in interstellar dust and gas, and dotted with bright star-forming regions. The galaxy spans about 70,000 light-years, making it slightly smaller than the Milky Way.

One of its most striking features is the large bubble of hot ionized gas extending from the central region, reaching over 3,000 light-years in height. This structure is likely caused by the collective outflows from supernova explosions and stellar winds produced by massive stars in an intense starburst region near the core. The energy from these explosions heats surrounding gas, pushing it outward in the form of a galactic wind.

The picture above (acquired by the Hubble Space Telescope) shows the bubble in the center of the galaxy's disk.

Image credits: NASA, Gerald Cecil (University of North Carolina), Sylvain Veilleux (University of Maryland), Joss Bland-Hawthorn (Anglo- Australian Observatory), and Alex Filippenko (University of California at Berkeley).

Active Galactic Nucleus (AGN) and Supermassive Black Hole

At the heart of NGC 3079 lies a suspected supermassive black hole, similar to the one in the Milky Way’s center but possibly more active. Observations in radio waves and X-rays suggest that the nucleus produces energetic outflows, which contribute to the large superbubble seen in the galaxy. The AGN is classified as a Seyfert galaxy or a low-ionization nuclear emission-line region (LINER), indicating moderate activity compared to more powerful quasars.

Scientific Importance

NGC 3079 has been studied extensively because it provides insight into how galaxies regulate star formation through feedback mechanisms like galactic winds. The presence of the superbubble makes it an ideal candidate for understanding the interactions between AGN activity and starburst-driven outflows. Additionally, observations of NGC 3079 in radio wavelengths have detected water masers, which are crucial for measuring black hole masses and refining distance calculations in astronomy.

Conclusion

As a dynamically active galaxy with both a central bar and an energetic superbubble, NGC 3079 serves as an excellent case study in galactic evolution. Its combination of intense star formation, AGN activity, and outflowing gas provides astronomers with valuable data on how galaxies form, evolve, and regulate their internal processes.