"I would be a little more risky and say that [the newfound blob is] pretty clear evidence for massive galaxies forming very early," said Carilli, who was not involved with the study.
Richard Ellis, an astronomy professor at the California Institute of Technology, said Himiko could be a galaxy that is collapsing in on itself, a never before observed stage of galactic development.
Such a collapse would create an enormous burst of star formation, which would heat up the remaining hydrogen around the galaxy, creating a charged cloud like that seen around Himiko.
Alternatively, Ouchi suggested, the hydrogen cloud could be gases from the surrounding environment that are cooling and gravitating toward what is actually a mature galaxy inside Himiko.
But if the blob is a stable, mature galaxy at its core, astronomers should be seeing other similar galaxies from the same time period, Caltech's Ellis noted.
"I much prefer the spectacular argument that we're seeing an object at a very special time in its history," he said.
Ouchi hopes to resolve some of these issues by solving the mystery of Himiko's energy source, which he described as "the most difficult question."
"It could be a supermassive black hole or the cooling radiation powered by gravitational energy or outflow from starbursts ," he said.
Understanding what's driving the blob's development should help determine what kind of object it is.
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