NGC 5728

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NGC 5728 is an active barred spiral galaxy in the Libra constellation, about 146 million light-years away. It was discovered by William Herschel in 1787. The galaxy is classified as SAB(r)a? and hosts a Seyfert 2 active nucleus powered by a supermassive black hole. Bright, ionized gas cones extend more than 2.5 kiloparsecs from the center, and X-ray and radio jets have been detected.

Inside, there may be a second, counter-rotating nuclear bar within about the inner 10 arcseconds, angled roughly 60 degrees from the main bar. The outer region features a ring-like structure and asymmetric gas, evidence of a past minor merger. The AGN is fed by filaments and dust lanes, but central gas has largely been used up, so star formation near the nucleus is now low, while the outflow from the core boosts star formation in the surrounding ring.

The galaxy’s mass is about 7.2×10^10 solar masses, and it spans roughly 100,000 light-years across. Its apparent brightness is magnitude 13.4 in visible light (B magnitude about 14.3). A Type Ia supernova, SN 2009Y, appeared near the center in 2009.