The ramp-up of interstellar medium enrichment at z>4

Abstract

Fluorine is one of the most interesting elements for nuclear and stellar astrophysics. Fluorine abundance was first measured for stars other than the Sun in 1992, then for a handful metal-poor stars, which are likely to have formed in the early Universe. The main production sites of fluorine are under debate and include asymptotic giant branch (AGB) stars, $\nu$-process in core-collapse supernovae, and Wolf-Rayet (WR) stars. 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 (S/N = 8) in absorption in a gravitationally lensed dusty star-forming galaxy at redshift z=4.4 with $N_{\mathrm{HF}}$/$N_{{\mathrm{H}}_2}$ as high as $\sim 2\times 10^{-9}$, indicating a very quick ramp-up of the chemical enrichment in this high-z galaxy. At z=4.4, AGB stars of a few solar masses are very unlikely to dominate the enrichment. Instead, we show that WR 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.

21 pages, 4 figures, published in Nature Astronomy

References in corpus (11)

• Multi-Scale CLEAN deconvolution of radio synthesis images
• SHARC-2 350 Micron Observations of Distant Submillimeter Selected Galaxies
• Molecular outflows in local ULIRGs: energetics from multi-transition OH analysis
• ALMA observations of atomic carbon in z~4 dusty star-forming galaxies
• The space density of luminous dusty star-forming galaxies at $z>4$: SCUBA-2 and LABOCA imaging of ultrared galaxies from $Herschel$-ATLAS
• The most distant, luminous, dusty star-forming galaxies: redshifts from NOEMA and ALMA spectral scans
• Modeling the H2O submillimeter emission in extragalactic sources
• The Chemical Evolution of Fluorine in the Bulge - High-resolution K-band spectra of giants in three fields
• Atomic Carbon in APM 08279+5255 at z=3.91
• Fluorine in the solar neighborhood: modelling the Galactic thick and thin discs
• Origin of hydrogen fluoride emission in the Orion Bar: An excellent tracer for CO-dark H2 gas clouds

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• From Dust to Nanodust: Resolving Circumstellar Dust from the Colliding-Wind Binary Wolf-Rayet (WR) 140
• Fluorine abundances in CEMP stars at the lowest metallicity: Hints on the nature of the first stars
• First detection of CF${}^{+}$ in the Large Magellanic Cloud
• Nuclear astrophysics