NGC 5101 and friends


This sharp telescopic field of view holds two bright galaxies. Barred spiral NGC 5101 (top right) and nearly edge-on system NGC 5078 are separated on the sky by about 0.5 degrees or about the apparent width of a full moon. Found within the boundaries of the serpentine constellation Hydra, both are estimated to be around 90 million light-years away and similar in size to our own large Milky Way galaxy. In fact, if they both lie at the same distance their projected separation would be only 800,000 light-years or so. That’s easily less than half the distance between the Milky Way and the Andromeda Galaxy. NGC 5078 is interacting with a smaller companion galaxy, cataloged as IC 879, seen just below and left of the larger galaxy’s bright core. Even more distant background galaxies are scattered around the colorful field. Some are even visible right through the face-on disk of NGC 5101. But the prominent spiky stars are in the foreground, well within our own Milky Way.

Image credit & Copyright: Martin Pugh


Centaurus A


Only 11 million light-years away, Centaurus A is the closest active galaxy to planet Earth. Spanning over 60,000 light-years, the peculiar elliptical galaxy, also known as NGC 5128, is featured in this sharp color image. Centaurus A is apparently the result of a collision of two otherwise normal galaxies resulting in a fantastic jumble of star clusters and imposing dark dust lanes. Near the galaxy’s center, left over cosmic debris is steadily being consumed by a central black hole with a billion times the mass of the Sun. As in other active galaxies, that process likely generates the radio, X-ray, and gamma-ray energy radiated by Centaurus A.

Credit: Tim Carruthers

The Whale Galaxy


NGC 4631 is a big beautiful spiral galaxy. Seen edge-on, it lies only 25 million light-years away in the well-trained northern constellation Canes Venatici. The galaxy’s slightly distorted wedge shape suggests to some a cosmic herring and to others its popular moniker, The Whale Galaxy. Either way, it is similar in size to our own Milky Way. In this gorgeous color image, the galaxy’s yellowish core, dark dust clouds, bright blue star clusters, and red star forming regions are easy to spot. A companion galaxy, the small elliptical NGC 4627, is just above the Whale Galaxy. Out of view, off the lower edge of the picture lies another distorted galaxy, hockey stick-shaped NGC 4656. The distortions and mingling trails of gas and dust detected at other wavelengths suggest that all three galaxies have had close encounters with each other in their past. The Whale Galaxy is also known to have spouted a halo of hot gas glowing in x-rays.

Credit & CopyrightAdam BlockMt. Lemmon SkyCenterU. Arizona
Guest Astronomers: Tom Bash and Craig Gates

Galactic Fling


This Hubble Space Telescope image shows galaxy NGC 4485. Located about 25 million light-years away in the constellation Canes Venatici, this galaxy was once a spiral. Now it has an irregular shape, the result of interactions with nearby NGC 4490, which lies out of image to the bottom right of the frame. The pair of galaxies, together known as Arp 269, are putting distance between themselves now, having made their closest approach to each other long ago.

In addition to the warped shape this spiral took on from this close passage with NGC 4490, it sports a trail of bright stars and clumps of gas and dust to the lower right. It is a tenuous bridge stretching some 24,000 light-years across space, the last loose connection between the pair.

There are other vestiges from this cosmic fling. As they passed by each other, vast fields of hydrogen gas were shared between them. The intermixing clouds created waves of new star formation, the progeny of this cosmic romance. The starburst activity is ongoing, with the newest stars forming within the orange knots of gas and dust.

Image credit: ESA/Hubble & NASA

A Tidal Galaxy


A previously unsuspected tidal dwarf galaxy candidate appears only in the ultraviolet, indicating the presence of many hot young stars as seen in this cool space Image. IC 4970, the small disk galaxy interacting with NGC 6872, is located above the spiral’s central region. The spiral is 522,000 light-years across from the tip of one outstretched arm to the tip of the other, which makes it about five times the size of our home galaxy, the Milky Way.

Credit: NASA’s Goddard Space Flight Center/ESO/JPL-Caltech/DSS/via