Massive stars in extremely metal-poor galaxies: A window into the past

Understand

Cosmic History has witnessed the lives and deaths of multiple generations of massive stars, all of them invigorating their host galaxies with ionizing photons, kinetic energy, fresh material and stellar-mass black holes.

• Ubiquitous engines as they are, Astrophysics needs a good understanding of their formation, evolution, properties and yields throughout the history of the Universe, and with decreasing metal content mimicking the environment at the earliest epochs.
• Ultimately, a physical model that could be extrapolated to zero metallicity would enable tackling long-standing questions such as "What did the First, very massive stars of the Universe look like?" or "What was their role in the re-ionization of the Universe?".
• Yet, most our knowledge of metal-poor massive stars is drawn from one single point in metallicity.