JADES: Physical properties of Ly$\alpha$ and non-Ly$\alpha$ emitters at z ~ 4.8-9.6

Nimisha Kumari; Renske Smit; Joris Witstok; Marco Sirianni; Roberto Maiolino; Andrew J. Bunker; Rachana Bhatawdekar; Kristan Boyett; Alex J. Cameron; Stefano Carniani; Stephane Charlot; Mirko Curti; Emma Curtis-Lake; Francesco D'Eugenio; Daniel J. Eisenstein; Kevin Hainline; Zhiyuan Ji; Gareth C. Jones; Brant Robertson; Aayush Saxena; Jan Scholtz; Charlotte Simmonds; Christina C. Williams; Christopher N. A. Willmer

arXiv · 2406.11997

JADES: Physical properties of Ly$\alpha$ and non-Ly$\alpha$ emitters at z ~ 4.8-9.6

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Abstract

We investigate the physical properties of Lyman-alpha emitters (LAEs) and non-Lyman-alpha emitters (non-LAEs) at z$\sim$4.8--9.6 via a stacking analysis of 253 JWST/NIRSpec spectra of galaxies observed as part of the JWST Advanced Deep Extragalactic Survey (JADES). We identify a sample of 42 LAEs with the equivalent width of Ly$\alpha$ $\gtrsim$20\AA and a sample of 211 non-LAEs, divide each sample further via the median redshift of the LAEs (z~6.3), and create composite spectra using the low and medium resolution spectra from NIRSpec. We estimate physical quantities such as dust extinction, UV continuum slope $\beta$, electron temperatures, ionization parameter, escape fraction of Ly$\alpha$ and Lyman Continuum, and the photon production rate for each bin/stack. The existing dust-extinction laws do not appear to be valid at these epochs. The emission line ratio analyses show that active galactic nuclei might dominate all sub-samples, irrespective of Ly$\alpha$ emission. LAEs show much higher [OIII]/[OII] and low [OII]/H$\delta$ at z$\lesssim$6.3 compared to non-LAEs, but these line ratios are not sufficient to distinguish the two populations at z$>$6.3. However, the LAEs samples show large EW([OIII]4959, 5007) ($>$1000\AA) compared to the non-LAEs sample at all redshifts. CIV/Ly$\alpha$ and CIV/CIII] for LAE population at z$\lesssim$6.3 is $\sim$a factor of 5 larger than that for LAE population at z$>$6.3. The ionizing radiation for LAEs is hard, as revealed from several diagnostics, including CIV detection, high [OIII]/[OII] ($>$8), and large values of $\xi^{\star}_{ion}$.

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Nimisha Kumari, Renske Smit, Joris Witstok, Marco Sirianni, Roberto Maiolino, Andrew J. Bunker, Rachana Bhatawdekar, Kristan Boyett, Alex J. Cameron, Stefano Carniani, Stephane Charlot, Mirko Curti, Emma Curtis-Lake, Francesco D'Eugenio, Daniel J. Eisenstein, Kevin Hainline, Zhiyuan Ji, Gareth C. Jones, Brant Robertson, Aayush Saxena, Jan Scholtz, Charlotte Simmonds, Christina C. Williams, Christopher N. A. Willmer. 2024-06-17. JADES: Physical properties of Ly$\alpha$ and non-Ly$\alpha$ emitters at z ~ 4.8-9.6. https://arxiv.org/abs/2406.11997

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