Two neutron stars slammed together far away from Earth. The energy of their collision lit up their corner of the sky with a brief flash of gamma radiation, followed by a softer, longer-lasting glow across the electromagnetic spectrum. Peering into that fading light, researchers spotted an unusual infrared signal — the first-ever recorded signature, they believe, of a newborn cosmic behemoth, a magnetar.
A magnetar is a neutron star with an unusually strong magnetic field. Astronomers have spotted magnetars elsewhere in the universe, but they’ve never before seen one being born. This time, researchers suspected they’d spotted a newborn magnetar because of an unusual pattern of flashing light. First, there was a short, ultrabright burst of gamma radiation (GRB). Then there was a longer-lasting, glowing “kilonova,” a telltale sign of neutron stars colliding. And that glow was much brighter than usual, suggesting a phenomenon astronomers had never seen before.