The ramp-up of interstellar medium enrichment at z > 4
Journal article, 2021

Fluorine is one of the most interesting elements for nuclear and stellar astrophysics1,2. Fluorine abundance was first measured for stars other than the Sun in 19921, then for a handful of metal-poor stars3, which are likely to have formed in the early Universe. The main production sites of fluorine are under debate and include asymptotic giant branch stars, the ν-process in core-collapse supernovae, and Wolf–Rayet stars4,5,6,7,8,9,10. Due to the difference in the mass and lifetime of progenitor stars, high-redshift observations of fluorine can help constrain the mechanism of fluorine production in massive galaxies. Here, we report the detection of HF (signal-to-noise ratio of 8) in absorption in a gravitationally lensed dusty star-forming galaxy at redshift z = 4.4 with NHF/NH2NH2 as high as ~2 × 10−9, indicating a very quick ramp-up of the chemical enrichment in this high-z galaxy. At z = 4.4, asymptotic giant branch stars of a few solar masses are very unlikely to dominate the enrichment. Instead, we show that Wolf–Rayet stars are required to produce the observed fluorine abundance at this time, with other production mechanisms becoming important at later times. These observations therefore provide an insight into the underlying processes driving the ramp-up phase of chemical enrichment alongside rapid stellar mass assembly in a young massive galaxy.


Maximilian Franco

University of Hertfordshire

K. E. K. Coppin

University of Hertfordshire

J. E. Geach

University of Hertfordshire

C. Kobayashi

University of Hertfordshire

S. C. Chapman

Herzberg Astronomy and Astrophysics, Dominion Radio Astrophysical Observatory (DRAO)

Dalhousie University

Chentao Yang

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

E. Gonzalez-Alfonso

University of Alcalá

Justin Spilker

The University of Texas at Austin

A. Cooray

University of California

M. J. Michalowski

Adam Mickiewicz University in Poznań

Nature Astronomy

23973366 (eISSN)

Vol. 5 1240-1246

Subject Categories

Analytical Chemistry

Astronomy, Astrophysics and Cosmology




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