http://arxiv.org/abs/1612.00902
Recent observations have suggested that the CIII]$\lambda1907/1909$ emission lines could be alternative diagnostic lines for galaxies in the reionization epoch. We use F128N narrowband filter on the Hubble Space Telescope’s ($\it{HST}$) Wide Field Camera 3 (WFC3) to search for CIII] emission in a sample of five galaxies at z = 5.7 in the Subaru Deep Field and the Subaru/XMM-Newton Deep Field. Using the F128N narrowband imaging, together with the broadband imaging, we report a CIII] flux of $3.34\pm1.81 \times 10^{-18}$ $\mathrm{erg\ s^{-1}\ cm^{-2}}$ in J132416.13+274411.6, the brightest galaxy in our sample (z = 5.70, $J_{\rm{AB}} = 24.10$), which places a stringent 3-$\rm\sigma$ upper limit of 6.57 \AA\ on the CIII] equivalent width for this galaxy. We do not detect CIII] emission for the rest of 4 galaxies with $J_{\rm{AB}}$ ranging from 25.00 — 27.00. Using the stacked image, we put a 3-$\rm\sigma$ upper limit on the mean CIII] flux of $\mathrm{2.85\times10^{-18}\ erg\ s^{-1}\ cm^{-2}}$, and a 3-$\rm\sigma$ upper limit on the mean CIII] equivalent width of 3.63 $\mathrm{\AA}$ for this sample of galaxies at z = 5.70. Combined with strong CIII] detection reported among high-z galaxies in the literature, our observations suggest that the equivalent widths of CIII] from galaxies at z $>$ 5.70 exhibit a wide range of distribution. Our strong limits on CIII] emission could be used as a guide for future observations in the reionization epoch.
J. Ding, Z. Cai, X. Fan, et. al.
Tue, 6 Dec 16
15/71
Comments: N/A
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