In this talk, I will shortly review some basic properties of the first stars. These first luminous objects form out of metal-free gas clouds in so-called minihaloes at high redshift. However, large-scale effects such as streaming velocities and Lyman-Werner radiation can delay their formation. I will give an overview over the literature and show results from my own cosmological simulations.
I summarize the remaining questions to uncover the first star formation and the initial mass function.
I present our resent efforts to understand key processes in the Pop III and low-metallicity star formation. One is the protostellar UV feedback, which is known to be strong enough to halt the accretion onto stars for Pop III cases. However, our knowledge on the UV feedback with non-zero metallicity is actually limited. Our recent radiation-hydrodynamic simulations show that, for cases with...
In massive star formation, the radiative feedback is a key process in general because it potentially halts the accretion flow to limit the stellar masses. Previous studies show that the UV feedback, the dynamical expansion of an HII region and photoevaporation of a circumstellar disk, plays such a role in the primordial star formation(e.g.,McKee & Tan 2008; Hosokawa et al.2016). However, it is...
It is expected that the first galaxies will be observed by the next generation telescopes, such as NASA's James Webb Space Telescope (JWST). The early star-forming galaxies are expected to brighten in the rest frame near-infrared. Understanding their spectra accurately is important to prepare future observations. In the conventional calculations of spectra of galaxies, Pre-main-sequence (PMS)...
The first stars are thought to have formed a few hundred million years after the big bang, lighting up the Universe for the first time and enriching the intergalactic medium with the first heavy elements. Since their properties depend sensitively on their masses, the holy grail has been to derive the initial mass function of the first stars from first principles. I will discuss recent progress...
