Hubble Sees Spirals in Galaxy Cluster Abell 428

Two bright objects in this Hubble Space Telescope image are massive spiral galaxies in the galaxy cluster known as Abell 428, in the constellation of Eridanus, about one billion light-years away.

The large object captured in the left half of this Hubble image is the edge-on spiral galaxy LEDA 97372.

Also known as LO95 0313-192, this galaxy has a spiral shape similar to that of our own Milky Way Galaxy. It has a large central bulge, and arms speckled with brightly glowing gas mottled by a thick lane of dark dust.

According to astronomers, “the dust lane is thick with rich vertical structure, as seen in edge-on spirals with brisk star formation.”

“Clouds and filaments reach to almost 2,600 light-years from the plane. The dust is warped by about 3 degrees from the stellar disk, allowing us to peek around to some pieces of the blue thin-disk component. Dust spans the whole radial extent of the stellar disk.”

LEDA 97372 is an unusual, and in many respects unique, object. It is the first confirmed disk/spiral galaxy with huge radio jets and double-lobed radio morphology.

Jets — outbursts of superheated gas moving at close to the speed of light — have been found coming from thousands of galaxies across the Universe, but always from giant elliptical galaxies or galaxies in the process of merging.

However, in an unexpected discovery, Gemini Observatory astronomer Michael Ledlow and his colleagues found LEDA 97372 to have intense radio jets spewing out from its center.

“Aside from being intrinsically interesting in itself,” the scientists said, “LEDA 97372 offers a potential test bed for understanding the whole issue of why spirals generally do not produce powerful jets and double radio sources, which could have an impact on black hole, jet, and AGN (active galactic nuclei) physics from many different angle.”

“The loose-knit nature of Abell 428 may play a part in allowing this particular spiral galaxy to produce jets.”

The discovery of these giant jets in the 2000s has been followed by the unearthing of a further three spiral galaxies containing radio-emitting jets in recent years.

LEDA 97372’s companion, sitting pretty in the right of the frame, is known as [LOY2001] J031549.8-190623.

This composite image includes infrared and optical observations from Hubble’s Advanced Camera for Surveys (ACS).

Astronomer Judy Schmidt submitted a version of the image to the Hubble’s Hidden Treasures image processing competition.