The galactic center shines too brightly, like the glow of a metropolis at night where maps show only a town. To mend their cosmic cartography, astrophysicists have spent years debating what could be powering this excess of energetic light. In 2015 the arguments appeared to swing decisively in favor of a somewhat prosaic explanation — that a large population of dim neutron stars was responsible. But a new examination of that work, posted on the scientific preprint site arxiv.org earlier this month, revealed a likely flaw in those analyses. “There’s something happening in the data we don’t understand,” said Rebecca Leane, a theoretical physicist at the Massachusetts Institute of Technology and co-author of the paper.

The new study, along with two others that came out in March, reopens the possibility that space-based instruments have found the first direct evidence of the elusive “dark matter” thought to pervade the universe.

The problem first appeared in 2009, when Dan Hooper, an astrophysicist at the University of Chicago, and Lisa Goodenough, then a graduate student at New York University, noticed that NASA’s Fermi Gamma-ray Space Telescope appeared to be picking up too many of the energetic photons known as gamma rays.

He suggested the anomaly could originate from a theoretical jumbling throng of dark matter particles in the galaxy’s center. While dark matter doesn’t shine or fraternize with known particles, in the right sort of collision these particles could annihilate in a shower of familiar matter and antimatter that would then go out with a puff of gamma rays. A measurement of these offshoots would represent the first evidence of dark matter that wasn’t exclusively gravitational in nature.

Yet dark matter wasn’t the only thing that could be generating the excess gamma rays. They could shine from cosmic lighthouses known as millisecond pulsars — magnetically charged neutron stars that make a thousand turns each second. A group of undiscovered pulsars too dim to be picked out individually could be bathing the center of the galaxy in extra gamma rays.

Ultimately, two studies released in 2015 leaned toward the mundane. The Fermi data looked grainy. It had bright pixels suggestive of multiple millisecond pulsars, and dim pixels suggestive of no pulsars. If dark matter was the culprit, it should have colored all pixels more evenly. The dark matter interpretation, it seemed, was dying.

Now Leane and Tracy Slatyer, a theoretical physicist at MIT and a co-author of one of those 2015 pulsar studies, have breathed some life back into the dark matter option.

First, the duo cooked up a digital representation of the Milky Way galaxy. They added the known ingredients: stars, gas, dust and known pulsars. Then they included the hypothetical ingredients — not only a sizable helping of dark matter but also some additional small pulsars that were unaccounted for in the initial mockup. They studied this fake Milky Way using the same methods from 2015, to see if they could find the dark matter. Ultimately they learned that the unexpected pulsars threw off the analysis, leading to the erroneous conclusion that this dark matter–stuffed galaxy had little dark matter.