Upper limits on the mass and luminosity of Population III-dominated galaxies

Hidenobu Yajima, Sadegh Khochfar

Research output: Contribution to journalArticlepeer-review


We here derive upper limits on the mass and luminosity of Population III (POPIII) dominated proto-galaxies based on the collapse of primordial gas under the effect of angular momentum loss via Lyα radiation drag and the gas accretion on to a galactic centre. Our model predicts that POPIII-dominated galaxies at z ∼ 7 are hosted by haloes with Mh ∼ 1.5 × 108-1.1 × 109 M⊙, that they have Lyα luminosities of LLyα ∼ 3.0 × 1042-2.1 × 1043 erg s- 1, stellar mass of Mstar ∼ 0.8 × 105-2.5 × 106 M⊙ and outflowing gas with velocities Vout ∼ 40 km s- 1 due to Lyα radiation pressure. We show that the POPIII galaxy candidate CR7 violates the derived limits on stellar mass and Lyα luminosity and thus is unlikely to be a POPIII galaxy. POPIII-dominated galaxies at z ∼ 7 have He ii line emission that is ∼1-3 orders of magnitude lower than that of Lyα, they have high Lyα equivalent width of ≳ 300 Å and should be found close to bright star-forming galaxies. The He ii 1640 Å line is in comfortable reach of next generation telescopes, like the James Webb Space Telescope (JWST) or Thirty Meter Telescope (TMT).
Original languageEnglish
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
Publication statusPublished - 13 Dec 2016


  • radiative transfer
  • stars: Population III
  • galaxies: evolution
  • galaxies: formation
  • galaxies: high-redshift


Dive into the research topics of 'Upper limits on the mass and luminosity of Population III-dominated galaxies'. Together they form a unique fingerprint.

Cite this