We perform cosmological hydrodynamics simulations with non-equilibrium primordial chemistry to obtain 59 minihalos that host first stars. The obtained minihalos are used as initial conditions of local three dimensional radiation hydrodynamics simulations to investigate the formation of the first stars. We find two-thirds of the minihalos host multiple stars, while the rest of them have single stars. The mass of the stars found in our simulations are in the range of 1M ⊙ M 300M ⊙ , peaking at several×10M ⊙ . Most of the very massive stars of 140M ⊙ are born as single stars, although not all of the single stars are very massive. We also find a few stars of 1M ⊙ that are kicked by the gravitational three body interactions to the position distant from the center of mass. The frequency that a star forming minihalo contains a binary system is ∼ 50%. We also investigate the abundance pattern of the stellar remnants by summing up the contributions from the first stars in the simulations. Consequently, the pattern is compatible with that of the low metallicity Damped Lyman−α systems or the Extremely Metal Poor (EMP) stars , if the mass spectrum obtained in our experiment is shifted to the low mass side by 0.2 dex. If we consider the case that an EMP star is born in the remnant of the individual minihalo without mixing with others, the chemical signature of the pair instability supernova is more prominent, because most of them are born as single stars. Subject headings: early Universe-radiative transfer -first stars-metal poor stars

We present new large field observations of molecular clouds with NANTEN2 toward the super star cluster NGC3603 in the transitions 12 CO(J=2-1, J=1-0) and 13 CO(J=2-1, J=1-0). We suggest that two molecular clouds at 13 km s −1 and 28 km s −1 are associated with NGC3603 as evidenced by higher temperatures toward the H II region as well as morphological correspondence. The mass of the clouds is too small to gravitationally bind them, given their relative motion of ∼20 km s −1 . We suggest that the two clouds collided with each other a Myr ago to trigger the formation of the super star cluster. This scenario is able to explain the origin of the highest mass stellar population in the cluster which is as young as a Myr and is segregated within the central sub-pc of the cluster. This is the second super star cluster along side Westerlund2 where formation may have been triggered by a cloud-cloud collision. Subject headings: ISM: clouds -open clusters and associations -individual: (NGC3603)the large turbulence excited by the shock interaction. This is the second case of formation of a super star cluster by triggering in a cloud-cloud collision along side Westerlund2 NANTEN2 is an international collaboration of ten universities, Nagoya University,

We present distributions of two molecular clouds having velocities of 2 and 14 km s −1 toward RCW 38, the youngest super star cluster in the Milky Way, in the 12 CO J = 1-0 and 3-2 and 13 CO J = 1-0 transitions. The two clouds are likely physically associated with the cluster as verified by the high intensity ratio of the J = 3-2 emission to the J = 1-0 emission, the bridging feature connecting the two clouds in velocity, and their morphological correspondence with the infrared dust emission. The velocity difference is too large for the clouds to be gravitationally bound. We frame a hypothesis that the two clouds are colliding with each other by chance to trigger formation of the ∼20 O stars that are localized within ∼0.5 pc of the cluster center in the 2 km s −1 cloud. We suggest that the collision is currently continuing toward part of the 2 km s −1 cloud where the bridging feature is localized. This is the third super star cluster alongside Westerlund 2 and NGC 3603 where cloud-cloud collision has triggered the cluster formation. RCW 38 is the youngest super star cluster in the Milky Way, holding a possible sign of on-going O star formation, and is a promising site where we may be able to witness the moment of O star formation.

We present the SILVERRUSH program strategy and clustering properties investigated with ∼ 2, 000 Lyα emitters at z = 5.7 and 6.6 found in the early data of the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey exploiting the carefully designed narrowband filters. We derive angular correlation functions with the unprecedentedly large samples of LAEs at z = 6 − 7 over the large total area of 14 − 21 deg 2 corresponding to 0.3 − 0.5 comoving Gpc 2 . We obtain the average large-scale bias values of b avg = 4.1 ± 0.2 (4.5 ± 0.6) at z = 5.7 (z = 6.6) for > ∼ L * LAEs, indicating the weak evolution of LAE clustering from z = 5.7 to 6.6. We compare the LAE clustering results with two independent theoretical models that suggest an increase of an LAE clustering signal by the patchy ionized bubbles at the epoch of reionization (EoR), and estimate the neutral hydrogen fraction to be x HI = 0.15 +0.15 −0.15 at z = 6.6. Based on the halo occupation distribution models, we find that the > ∼ L * LAEs are hosted by the dark-matter halos with the average mass of log( M h /M ⊙ ) = 11.1 +0.2 −0.4 (10.8 +0.3 −0.5 ) at z = 5.7 (6.6) with a Lyα duty cycle of 1 % or less, where the results of z = 6.6 LAEs may be slightly biased, due to the increase of the clustering signal at the EoR. Our clustering analysis reveals the low-mass nature of > ∼ L * LAEs at z = 6 − 7, and that these LAEs probably evolve into massive super-L * galaxies in the present-day universe.

We compute the spherically-averaged power spectrum from four seasons of data obtained for the Epoch of Reionisation (EoR) project observed with the Murchison Widefield Array (MWA). We measure the EoR power spectrum over k = 0.07 − 3.0 hMpc −1 at redshifts z = 6.5 − 8.7. The largest aggregation of 110 hours on EoR0 high-band (3,340 observations), yields a lowest measurement of (43 mK) 2 = 1.8×10 3 mK 2 at k=0.14 hMpc −1 and z = 6.5 (2σ thermal noise plus sample variance). Using the Real-Time System to calibrate and the CHIPS pipeline to estimate power spectra, we select the best observations from the central five pointings within the 2013-2016 observing seasons, observing three independent fields and in two frequency bands. This yields 13,591 2-minute snapshots (453 hours), based on a quality assurance metric that measures ionospheric activity. We perform another cut to remove poorly-calibrated data, based on power in the foreground-dominated and EoR-dominated regions of the twodimensional power spectrum, reducing the set to 12,569 observations (419 hours). These data are processed in groups of 20 observations, to retain the capacity to identify poor data, and used to analyse the evolution and structure of the data over field, frequency, and data quality. We subsequently choose the cleanest 8,935 observations (298 hours of data) to form integrated power spectra over the different fields, pointings and redshift ranges.