Seven new dwarf galaxies discovered

This color composite image released Thursday April 7, 2005 by NASA of nearby galaxy NGC 300 combines the visible-light pictures from Carnegie Institution of Washington's 100-inch telescope at Las Campanas Observatory (colored red and yellow), with ultraviolet views from NASA's Galaxy Evolution Explorer. Galaxy Evolution Explorer detectors image far ultraviolet light (colored blue). This composite image traces star formation in progress. Young hot blue stars dominate the outer spiral arms of the galaxy, while the older stars congregate in the center regions which appear yellow-green. Gases heated by hot young stars and shocks due to winds from massive stars and supernova explosions appear in pink, as revealed by the visible-light image of the galaxy. Located nearly 7 million light years away, NGC 300 is a member of a nearby group of galaxies known as the Sculptor Group. It is a spiral galaxy like our own Milky Way. (AP Photo/NASA)

Astronomers have used a new type of telescope to discover seven new dwarf galaxies.

Yale University astronomers used a new type of telescope made by stitching together telephoto lenses and discovered the seven celestial surprises while probing a nearby spiral galaxy.

The previously unseen galaxies may yield important insights into dark matter and galaxy evolution, while possibly signalling the discovery of a new class of objects in space, researchers said.

Pieter van Dokkum, chair of Yale’s astronomy department, designed the robotic telescope with University of Toronto astronomer Roberto Abraham.

Their Dragonfly Telephoto Array uses eight telephoto lenses with special coatings that suppress internally scattered light.

This makes the telescope uniquely adept at detecting the very diffuse, low surface brightness of the newly discovered galaxies.

“These are the same kind of lenses that are used in sporting events like the World Cup. We decided to point them upward instead,” van Dokkum said.

He and Abraham built the compact, oven-sized telescope in 2012 at New Mexico Skies, an observatory in Mayhill. The telescope was named Dragonfly because the lenses resemble the compound eye of an insect.

The Yale scientists will now tackle a key question: Are these seven newly found objects dwarf galaxies orbiting around the M101 spiral galaxy, or are they located much closer or farther away, and just by chance are visible in the same direction as M101?

If it’s the latter, Merritt said, these objects represent something entirely different.

“There are predictions from galaxy formation theory about the need for a population of very diffuse, isolated galaxies in the universe,” Merritt said.

“It may be that these seven galaxies are the tip of the iceberg, and there are thousands of them in the sky that we haven’t detected yet,” he said.

“I’m confident that some of them will turn out to be a new class of objects. I’d be surprised if all seven of them are satellites of M101,” van Dokkum added.