A Subaru Search for Lyman$\alpha$ Emitters at z = 5.8 with an Intermediate-Band Filter

We present the results of a survey for Ly $$\alpha$$ emitters at $$z \approx 5.8$$ using a new intermediate-band filter centered at $$\lambda_\mathrm{c} \approx 8275 \,{Å$$ with $$\Delta\lambda_\mathrm{FWHM} \approx 340 \,{Å$$ (i.e., spectroscopic resolution is $$R \approx 24$$ ) and a combination with a traditional narrow-band centered at $$\lambda_\mathrm{c} \approx 8150 \,{Å$$ with $$\Delta\lambda_\mathrm{FWHM} \approx 120 \,{Å$$ ( $$R \approx 68$$ ). Our observations were made using the Subaru Prime Focus Camera, Suprime-Cam, on the 8.2m Subaru telescope in a sky area surrounding the high-redshift quasar SDSSp J104433.04 $$-$$ 012522.2 at $$z = 5.74$$ , covering an effective sky area of $$\approx 720 \;\mathrm{arcmin}^2$$ . In this survey, we have found four Ly $$\alpha$$ -emitter candidates from the intermediate-band image ( $$z \approx 5.8$$ with $$\Delta z \approx 0.3$$ ). Combined with our previous results based on the NB816 imaging, we discuss the star-formation activity in galaxies between $$z \approx 5.7$$ and $$z \approx 5.9$$ .