A Dwarf Galaxy

NGC 5949 is a dwarf galaxy around 44 million light-years from us. NGC 5949 is a relatively bulky example of a dwarf galaxy with a mass of about one percent of the Milk Way’s. It’s classified as a dwarf because of its relatively small number of constituent stars, but with loosely-bound spiral arms it is also classified as a barred spiral galaxy.

Image Credit: ESA / NASA

NGC 1483

ngc-1483-smallNGC 1483 us a barred spiral galaxy a bit over 60 million light-years away.  Barred spiral galaxies are so named because of the prominent bar-shaped structures found in their center. Roughly two-thirds of all spiral galaxies, including the Milky Way, are barred. It’s been suggested that bars may be a common stage in the formation of spiral galaxies and may indicate that a galaxy has reached full maturity.

Image Credit: ESA / NASA

NGC 613

A spiral galaxy’s brights and darksNGC 613 is a barred spiral galaxy about 65 million light-years away in the constellation of The Sculptor. It’s core looks bright and uniformly white in this image as a result of the combined light shining from the high concentration of stars packed into the core, but a massive black hole lurks at the center of this brilliance. Its mass is estimated at about 10 times that of the Milky Way’s supermassive black hole, and it is consuming stars, gas, and dust. As matter descends into the black hole’s, it radiates energy, but when looking at the galaxy in the optical and infrared wavelengths used to take this image, there is no trace of its dark heart.

Image Credit: ESA / NASA

The Case of the Missing Galaxy

Messier_91_(M91)Messier 91 is a barred spiral galaxy located in the constellation Coma Berenices. It’s part of the Virgo Cluster of galaxies and is about 63 million light-years away from the Earth. It was the last of a group of eight nebulae discovered by Charles Messier in 1781. Originally, M91 was a missing object in the Messier catalogue as the result a bookkeeping mistake by Messier. It was not until 1969 that amateur astronomer William C. Williams realized that M91 was the galaxy that had also be cataloged as NGC 4548.

Image Credit: (CC) Joseph D. Schulman

A Barred Spiral Galaxy

Hubble spies NGC 4394NGC 4394 is a barred spiral galaxy about 55 million light-years away. It’s a member of the Virgo Cluster and is an archetypal barred spiral galaxy, with bright spiral arms emerging from the ends of a bar that runs across the galaxy’s central bulge. The arms are filled with young blue stars, trails of dark cosmic dust, and regions of active star formation.

Image Credit: ESA / NASA