Scientists investigate intergalactic space blob: What is it?
A schoolteacher discovered a blob of glowing hydrogen gas – called Hanny's Voorwerp in her honor – that astronomers say points to a nearly-invisible quenched quasar.
Astronomers hunt exotic objects – black holes, gamma-ray bursters, or mighty magnetars.Skip to next paragraph
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Now, some of them are tracking down the elusive Voorwerpjes.
Voorwerpjes is an informal moniker astronomers have given to odd blobs of glowing gas that appear to be floating free of any nearby galaxy – showing up in spots where no gas should glow, at least at visible wavelengths.
Recent observations of the Milky Way-sized structure, dubbed Hanny's Voorwerp (object), suggest that these blobs could serve as beacons, alerting astronomers to what may be the presence of a recently quenched quasar at the heart of a galaxy near the object.
Studying galaxies with newly-quenched quasars – galaxies that would be obscured by the brilliance of the quasar itself when it ws active – could yield fresh insights on the influence quasars have on the evolution of the galaxies they inhabit, says William Keel, an astronomer at the University of Arizona in Tucson who is deeply involved in the hunt.
So far, his team has confirmed an additional 18 "Voorwerpjes" out of a larger body of candidates that Galaxy Zoo participants identified after examining 18,000 images of galaxies with active quasars at their cores. Each of these 18 glowing expanses of gas span at least 32,000 light-years.
Some of these have been spotted before, Dr. Keel acknowledges, but others are new.
"One of the new ones is immense, fully half the size of Hanny's Voorwerp itself," he says.
The object is in the neighborhood of a galaxy known as IC 2497, a spiral galaxy, like the Milky Way. It lies 650 million light-years away from Earth in the constellation Leo Minor.
After Ms. van Arkel spotted the object, astronomers began observing it with different telescopes and at various wavelengths.
Radio observations revealed that the glowing blob of gas, located some 200,000 light-years beyond IC 2497, was part of a vast streamer of cold hydrogen gas that stretches some 300,000 light-years and tips the scales at 8 billion times the mass of the sun.
Researchers suspect that a close gravitational encounter or merger with another galaxy ripped the streamer away from IC 2497 at some point in its past. The galaxy's spiral arms also appear twisted, supporting this hypothesis.