SILVERRUSH. II. First Catalogs and Properties of ~2,000 Lya Emitters and
  Blobs at z~6-7 Identified over the 14-21 deg2 Sky
  We present an unprecedentedly large catalog consisting of 2,230 > L* Lya
emitters (LAEs) at z=5.7 and 6.6 on the 13.8 and 21.2 deg2 sky, respectively,
that are identified by the SILVERRUSH program with the first narrowband imaging
data of the Hyper Suprime-Cam (HSC) survey. We confirm that the LAE catalog is
reliable on the basis of 96 LAEs whose spectroscopic redshifts are already
determined by this program and the previous studies. This catalogue is also
available on-line. Based on this catalogue, we derive the rest-frame Lya
equivalent-width distributions of LAEs at z~5.7-6.6 that are reasonably
explained by the exponential profiles with the scale lengths of ~120-170A,
showing no significant evolution from z~5.7 to z~6.6. We find that 275 LAEs
with a large equivalent width (LEW) of >240A are candidates of young-metal poor
galaxies and AGNs. We also find that the fraction of LEW LAEs to all ones is 4%
and 21% at z~5.7 and z~6.6, respectively. Our LAE catalog includes 11 Lya blobs
(LABs) that are LAEs with spatially extended Lya emission whose profile is
clearly distinguished from those of stellar objects at the >~ 3sigma level. The
number density of the LABs at z=6-7 is ~ 10^-7-10^-6 Mpc^-3, being ~ 10-100
times lower than those claimed for LABs at z~ 2-3, suggestive of disappearing
LABs at z>~6, albeit with the different selection methods and criteria for the
low and high-z LABs.
