Are you one of the authors of this paper? Email us from your institutional or work email address mentioning this article's arXiv ID and we'll verify you and give you edit access to this page.
Are you an author who sees something we missed or got wrong? Write to us — the subject line already carries the paper id. We read every note and correct the write-up.
The supernova SN Eos exploded when the universe was only a billion years old. Its light traveled 13 billion years to reach us, and along the way, the spacetimecurvature of the cluster deflected it, creating multiple images. The flash's spectrum, its broken-down light, revealed that the progenitor star contained almost no elements heavier than helium. Astronomers call such elements "metals" (not iron or copper, but anything heavier than helium). This is the first direct evidence that massive stars were born in the metal-poor young universe.
SN Eos is the most distant supernova with a spectrum obtained. It flared up just after the "dark ages," when the universe was becoming transparent to ultraviolet light.
Each such discovery is another lens through which we see the early epoch more clearly. It allows us to calculate how often the first stars ignited and how quickly galaxies grew.
