Keck Spectroscopy of Lyman-break Galaxies and Its Implications for the UV-continuum and Lyα Luminosity Functions at z > 6

December 2011 • 2011ApJ...743...65J

Authors • Jiang, Linhua • Egami, Eiichi • Kashikawa, Nobunari • Walth, Gregory • Matsuda, Yuichi • Shimasaku, Kazuhiro • Nagao, Tohru • Ota, Kazuaki • Ouchi, Masami

Abstract • We present Keck spectroscopic observations of z > 6 Lyman-break galaxy (LBG) candidates in the Subaru Deep Field (SDF). The candidates were selected as i'-dropout objects down to z' = 27 AB magnitudes from an ultra-deep SDF z'-band image. With the Keck spectroscopy we identified 19 LBGs with prominent Lyα emission lines at 6 <= z <= 6.4. The median value of the Lyα rest-frame equivalent widths (EWs) is ~50 Å, with four EWs >100 Å. This well-defined spectroscopic sample spans a UV-continuum luminosity range of -21.8 <= M _UV <= -19.5 (0.6 ~ 5 L*_UV) and a Lyα luminosity range of (0.3-3) × 10⁴³ erg s^-1 (0.3-3 L*_Lyα). We derive the UV and Lyα luminosity functions (LFs) from our sample at langzrang ~ 6.2 after we correct for sample incompleteness. We find that our measurement of the UV LF is consistent with the results of previous studies based on photometric LBG samples at 5 < z < 7. Our Lyα LF is also generally in agreement with the results of Lyα-emitter surveys at z ~ 5.7 and 6.6. This study shows that deep spectroscopic observations of LBGs can provide unique constraints on both the UV and Lyα LFs at z > 6.

Links

• PREPRINT http://arxiv.org/abs/1109.0023
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2011ApJ...743...65J
• ELECTR https://doi.org/10.1088%2F0004-637X%2F743%2F1%2F65
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2011ApJ...743...65J
• PDF https://iopscience.iop.org/article/10.1088/0004-637X/743/1/65/pdf
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• DATA https://hst.esac.esa.int/ehst/#/pages/search;bibcode=2011ApJ...743...65J