Markarian 817

Rings of brilliant blue stars encircle the bright, active core of this spiral galaxy named Markarian 817. Viewed nearly face-on, the galaxy shows intense star-forming regions and dark bands of interstellar dust along its spiral arms. Observations by Hubble’s Cosmic Origins Spectrograph have shown that the galaxy contains a huge disk of matter encircling a supermassive black hole 40 million times more massive than our Sun. The disk is driving material out of the galaxy through powerful winds produced by streams of charged particles moving as high as 9 million miles an hour. Some of the outflow is raining back onto the galaxy. The rest is driven into intergalactic space.