Astr112 Photography Projects, Fall 2007

Sculptor Galaxy (NGC 253), Elise Gray

The Sculptor Galaxy was first discovered by Caroline Herschel on September 23, 1783. It is the brightest member of the Sculptor group of galaxies which is the closest group of galaxies to our local group. The Sculptor Galaxy is a spiral galaxy, which means it has a flat, rotating disk of stars, gas, and dust, and a central concentration of stars known as the bulge. It is 10 million LY away.

In the image, we see dim arms around the outside which consist of mainly young, hot, blue stars and their associated H II regions (ionized Hydrogen), indicating ongoing star formation. There are dust lanes around the center, which means that the dark parts we see are being obscured by dust, creating lanes. The inner, brighter part is the bulge, which consists of tightly packed stars. It is a yellowish color which means that the stars in the bulge are cooler and older. We are viewing this galaxy almost edge on but on a tilt, which is why it looks so long and skinny. It is speculated that many bulges have a super massive black hole in the center. The linear size is 58,000LY across.

References:
Frommert, Hartmut, and Christine Kronberg. "NGC 253." The RASC's Finest N.G.C. Objects List. 29 Mar. 1998. 6 Dec. 2007 <http://www.seds.org/messier/xtra/ngc/n0253.html>.

Freedman, Roger A., and William J. Kaufmann III. Stars and Galaxies: Universe. 3rd ed. New York: W.H. Freeman and Company, 2007.