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M64, the Black Eye Galaxy

A collision of two galaxies has left a merged star system with an unusual appearance as well as bizarre internal motions. Messier 64 (M64) has a spectacular dark band of absorbing dust in front of the galaxy's bright nucleus, giving rise to its nicknames of the "Black Eye" or "Evil Eye" galaxy. In a 1994 paper, astronomer Vera Rubin gave this non-threatening galaxy the name "Sleeping Beauty Galaxy."

More information on the discovery, physical structure and naming of M64.

1. What is notable about the motions of this galaxy?

At first glance, M64 appears to be a fairly normal pinwheel-shaped spiral galaxy. As in the majority of galaxies, all of the stars in M64 are rotating in the same direction, clockwise as seen in the Hubble image. However, the interstellar gas in the outer regions of M64 rotates in the opposite direction from the gas and stars in the inner regions.

2. What caused the backwards rotation of the gas in the center of this galaxy?

Astronomers believe that the oppositely rotating gas arose when M64 absorbed a satellite galaxy that collided with it, perhaps more than one billion years ago. This small galaxy has now been almost completely destroyed, but signs of the collision persist in the backward motion of gas at the outer edge of M64.

3. Are there new stars forming in this galaxy?

Active formation of new stars is occurring in the shear region where the oppositely rotating gases collide, are compressed, and contract. Particularly noticeable in the image are hot, blue young stars that have just formed, along with pink clouds of glowing hydrogen gas that fluoresce when exposed to ultraviolet light from newly formed stars.

4. What do the colors mean in the Hubble image?

M64 was taken with Hubble's Wide Field Planetary Camera 2 (WFPC2). The full detector image is shown at right overlayed on a ground-based image.The color filters isolate blue and near-infrared light (red), along with red light emitted by hydrogen atoms (pink in this image) and green light from Strömgren y.

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for NOAO ground view.

WFPC2 WFALL image credit: NASA and the Hubble Heritage Team (STScI/AURA).

Underlying Image Credit: NOAO/AURA/NSF and N.A. Sharp (NOAO). The underlying image of M64 is a color composite of CCD images from the 0.9-meter telescope of the Kitt Peak National Observatory, near Tucson, Arizona, taken in January 1997.

NICMOS image of M64

5. Has Hubble imaged M64 with any other filters or instruments?

M64 was imaged with Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) detector in 1999 as part of an infrared 'photo essay'of spiral galaxies. "By penetrating the dust clouds swirling around the centers of these galaxies, the telescope's infrared vision is offering fresh views of star birth." For more information, visit the STScI Press Release.