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Hi-ho!
Astronom temukan tujuh Galaksi kerdil dengan teleskop baru
Hi-ho! Astronomers discover seven dwarf galaxies with new telescope
Date:
July 10,
2014
Source:
Yale University
Summary:
Meet the seven new dwarf galaxies. Astronomers, using
a new type of telescope made by stitching together telephoto lenses, recently discovered
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 signaling the discovery of a new class of objects in
space.
...........................
Meet the seven new dwarf galaxies.
Yale
University astronomers, using a new type of telescope made by stitching
together telephoto lenses, recently discovered 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
signaling the discovery of a new class of objects in space.
For now,
scientists know they have found a septuplet of new galaxies that were previously
overlooked because of their diffuse nature: The ghostly galaxies emerged from
the night sky as the team obtained the first observations from the
"homemade" telescope.
The
discovery came quickly, in a relatively small section of sky. "We got an
exciting result in our first images," said Allison Merritt, a Yale
graduate student and lead author of a paper about the discovery in The
Astrophysical Journal Letters. "It was very exciting. It speaks to the
quality of the telescope."
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, N.M. The telescope was named Dragonfly because the
lenses resemble the compound eye of an insect.
"We
knew there was a whole set of science questions that could be answered if we
could see diffuse objects in the sky," van Dokkum said. In addition to
discovering new galaxies, the team is looking for debris from long-ago galaxy
collisions.
"It's a
new domain. We're exploring a region of parameter space that had not been
explored before," van Dokkum said.
The Yale
scientists will tackle a key question next: 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."
Merritt
stressed that until they collect more data and determine the distances to the
objects, researchers won't know their true nature. But the possibilities are
intriguing enough that the team has been granted the opportunity to use the
Hubble Space Telescope for further study.
"I'm
confident that some of them will turn out to be a new class of objects,"
van Dokkum said. "I'd be surprised if all seven of them are satellites of
M101."
Meanwhile,
there is also more work to be done with the new telescope. "We are
collecting new data with the Dragonfly telescope every clear night. We're all
curious to see what other surprises the night sky has in store for us,"
Merritt said.
Story
Source:
The above
story is based on materials provided by Yale University. The original article was written by Jim Shelton. Note:
Materials may be edited for content and length.
Journal
Reference:
- Pieter G. van Dokkum, Roberto Abraham, Allison Merritt. FIRST RESULTS FROM THE DRAGONFLY TELEPHOTO ARRAY: THE APPARENT LACK OF A STELLAR HALO IN THE MASSIVE SPIRAL GALAXY M101. The Astrophysical Journal, 2014; 782 (2): L24 DOI: 10.1088/2041-8205/782/2/L24