JWST FRESCO: a comprehensive census of H$\beta$+[OIII] emitters at 6.8<z<9.0 in the GOODS fields

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We present the census of H$\beta$+[OIII] 4960,5008 \AA emitters at 6.8<z<9.0 from the JWST FRESCO survey over 124 arcmin$^2$ in the GOODS-North and GOODS-South fields.

• Our unbiased spectroscopic search results in 137 spectroscopically-confirmed galaxies at $6.8<z<9.0$ with observed [OIII] fluxes $f_{[OIII]}\gtrsim 1\times 10^{-18}\ \rm{ergs}\ \rm{s}^{-1} \ \rm{cm}^{-2}$.
• The rest-frame optical line ratios of the median stacked spectrum (median $M_{\rm{UV}}=-19.65^{+0.59}_{-1.05}$) indicate negligible dust attenuation, low metallicity ($12+\log(\rm{O/H})= 7.2-7.7$) and a high ionisation parameter $\log_{10}U \simeq -2.5$.
• We find a factor $\times 1.3$ difference in the number density of $6.8<z<9.0$ galaxies between GOODS-South and GOODS-North, which is caused by a single overdensity at $7.0<z<7.2$ in GOODS-North.