Heart of largest spiral galaxy studied

Malin 1 is a distant galaxy with an extremely low surface brightness. It’s the largest spiral galaxy known, with a mass over two trillion times that of our sun.

The largest spiral galaxy known to astronomers is Malin 1. Its disk of stars measures 650,000 light-years across, several times the diameter of the disk of our Milky Way galaxy.

In 2007, a newly found image from the Hubble Space Telescope revealed that the central part of Malin 1 looks like an ordinary barred spiral galaxy, somewhat like our Milky Way. Aaron Barth of the University of California at Irvine found the image and identified the barred spiral structure of the galaxy’s core.

Malin 1 is so far away – 1.1 billion light-years from Earth – that it’s been hard for astronomers to glimpse small details about the galaxy. Its barred spiral core notwithstanding, Malin 1 remains a remarkable galaxy. No other galaxy has such an enormous disk, which extends far beyond the barred spiral core Barth discovered.

Unlike most galaxies, it’s isolated, with no other galaxy near it. It’s thought that’s why Malin 1 has been able to acquire gas and grow larger over time. Because the gas in this galaxy is so spread out, it gives birth to few new stars. And that’s why most of this galaxy has the appearance of a ghost.

Our thanks today to Research Corporation, a foundation for the advancement of science.

Our thanks to:
Aaron Barth
University of California at Irvine