Milky Way has two new neighbours

The dwarf galaxy in Canes VenaticiUK astronomers have found two new galaxies right in our own cosmic backyard.
The clusters of thousands of stars are companions of our own Milky Way. But they previously went undetected because they are extremely faint.
The first (pictured here) was found in the constellation Canes Venatici – the Hunting Dogs – by Daniel Zucker as he studied photos of the night sky taken for the Sloan Digital Sky Survey.
Zucker, of Cambridge University, said he was poring over a pattern of distant stars when he spotted they looked particularly dense in one region.
He said: “It proved to be a previously unknown dwarf galaxy. It’s about 640,000 light years from the Sun. This makes it one of the most remote of the Milky Way’s companion galaxies.”
Zucker emailed university colleague Vasily Belokurov to tell him the news and just hours later Belokurov emailed back to announce he had discovered an even fainter dwarf galaxy. He named it Boo after the constellation in which he found it – Bootes, the Herdsman.
Boo, which is a similar distance from us as Zucker’s galaxy, is the faintest companion known. It shows a distorted structure that suggests it is being disrupted by the Milky Way’s gravitational pull.
“Something really bashed Boo about,” said Belokurov.
The new finds bring the known number of dwarf galaxy companions to the Milky Way to twelve.
Zucker and Belokurov have constructed a new map of the heavens from the Sloan images taken with a telescope in New Mexico.
It reveals a night sky criss-crossed with streams of stars, left behind by satellite galaxies and star clusters spiralling to their deaths.
The pair found so many trails of stars on their map that they named the area the Field of Streams.

Paul Sutherland

Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.
Paul Sutherland

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Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.

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