TY - JOUR
T1 - SUBARU HIGH-z EXPLORATION of LOW-LUMINOSITY QUASARS (SHELLQs). I. DISCOVERY of 15 QUASARS and BRIGHT GALAXIES at 5.7 < z < 6.9
AU - Matsuoka, Yoshiki
AU - Onoue, Masafusa
AU - Kashikawa, Nobunari
AU - Iwasawa, Kazushi
AU - Strauss, Michael A.
AU - Nagao, Tohru
AU - Imanishi, Masatoshi
AU - Niida, Mana
AU - Toba, Yoshiki
AU - Akiyama, Masayuki
AU - Asami, Naoko
AU - Bosch, James
AU - Foucaud, Sébastien
AU - Furusawa, Hisanori
AU - Goto, Tomotsugu
AU - Gunn, James E.
AU - Harikane, Yuichi
AU - Ikeda, Hiroyuki
AU - Kawaguchi, Toshihiro
AU - Kikuta, Satoshi
AU - Komiyama, Yutaka
AU - Lupton, Robert H.
AU - Minezaki, Takeo
AU - Miyazaki, Satoshi
AU - Morokuma, Tomoki
AU - Murayama, Hitoshi
AU - Nishizawa, Atsushi J.
AU - Ono, Yoshiaki
AU - Ouchi, Masami
AU - Price, Paul A.
AU - Sameshima, Hiroaki
AU - Silverman, John D.
AU - Sugiyama, Naoshi
AU - Tait, Philip J.
AU - Takada, Masahiro
AU - Takata, Tadafumi
AU - Tanaka, Masayuki
AU - Tang, Ji Jia
AU - Utsumi, Yousuke
N1 - Funding Information:
NK acknowledges support from the Japan Society for the Promotion of Science (JSPS) through Grant-in-Aid for Scientific Research 15H03645. KI acknowledges support by the Spanish MINECO under grant AYA2013-47447-C3-2-P and MDM-2014-0369 of ICCUB (Unidad de Excelencia Maria de Maeztu). TN acknowledges financial support from the JSPS (KAKENHI grant no. 25707010) and also from the JGC-S Scholarship Foundation.
Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - We report the discovery of 15 quasars and bright galaxies at 5.7 < z < 6.9. This is the initial result from the Subaru High-z Exploration of Low-Luminosity Quasars project, which exploits the exquisite multiband imaging data produced by the Subaru Hyper Suprime-Cam (HSC) Strategic Program survey. The candidate selection is performed by combining several photometric approaches including a Bayesian probabilistic algorithm to reject stars and dwarfs. The spectroscopic identification was carried out with the Gran Telescopio Canarias and the Subaru Telescope for the first 80 deg2 of the survey footprint. The success rate of our photometric selection is quite high, approaching 100% at the brighter magnitudes (zAB < 23.5 mag). Our selection also recovered all the known high-z quasars on the HSC images. Among the 15 discovered objects, six are likely quasars, while the other six with interstellar absorption lines and in some cases narrow emission lines are likely bright Lyman-break galaxies. The remaining three objects have weak continua and very strong and narrow Lyα lines, which may be excited by ultraviolet light from both young stars and quasars. These results indicate that we are starting to see the steep rise of the luminosity function of z ≥ 6 galaxies, compared with that of quasars, at magnitudes fainter than M1450 ∼ -22 mag or zAB ∼ 24 mag. Follow-up studies of the discovered objects as well as further survey observations are ongoing.
AB - We report the discovery of 15 quasars and bright galaxies at 5.7 < z < 6.9. This is the initial result from the Subaru High-z Exploration of Low-Luminosity Quasars project, which exploits the exquisite multiband imaging data produced by the Subaru Hyper Suprime-Cam (HSC) Strategic Program survey. The candidate selection is performed by combining several photometric approaches including a Bayesian probabilistic algorithm to reject stars and dwarfs. The spectroscopic identification was carried out with the Gran Telescopio Canarias and the Subaru Telescope for the first 80 deg2 of the survey footprint. The success rate of our photometric selection is quite high, approaching 100% at the brighter magnitudes (zAB < 23.5 mag). Our selection also recovered all the known high-z quasars on the HSC images. Among the 15 discovered objects, six are likely quasars, while the other six with interstellar absorption lines and in some cases narrow emission lines are likely bright Lyman-break galaxies. The remaining three objects have weak continua and very strong and narrow Lyα lines, which may be excited by ultraviolet light from both young stars and quasars. These results indicate that we are starting to see the steep rise of the luminosity function of z ≥ 6 galaxies, compared with that of quasars, at magnitudes fainter than M1450 ∼ -22 mag or zAB ∼ 24 mag. Follow-up studies of the discovered objects as well as further survey observations are ongoing.
KW - dark ages, reionization, first stars
KW - galaxies: active
KW - galaxies: high-redshift
KW - intergalactic medium
KW - quasars: general
KW - quasars: supermassive black holes
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U2 - 10.3847/0004-637X/828/1/26
DO - 10.3847/0004-637X/828/1/26
M3 - Article
AN - SCOPUS:84987925102
SN - 0004-637X
VL - 828
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 26
ER -