687 research outputs found
Sub-millimetre galaxies in cosmological hydrodynamic simulations: Source number counts and the spatial clustering
We use large cosmological Smoothed-Particle-Hydrodynamics simulations to
study the formation and evolution of sub-millimetre galaxies (SMGs). In our
previous work, we studied the statistical properties of ultra-violet selected
star-forming galaxies at high redshifts. We populate the same cosmological
simulations with SMGs by calculating the reprocess of stellar light by dust
grains into far-infrared to millimetre wavebands in a self-consistent manner.
We generate light-cone outputs to compare directly the statistical properties
of the simulated SMGs with available observations. Our model reproduces the
submm source number counts and the clustering amplitude. We show that bright
SMGs with flux mJy reside in halos with mass of and have stellar masses greater than .
The angular cross-correlation between the SMGs and Lyman- emitters is
significantly weaker than that between the SMGs and Lyman-break galaxies. The
cross-correlation is also weaker than the auto-correlation of the SMGs. The
redshift distribution of the SMGs shows a broad peak at , where
Bright SMGs contribute significantly to the global cosmic star formation rate
density. Our model predicts that there are hundreds of SMGs with mJy
at per 1 square degree field. Such SMGs can be detected by ALMA.Comment: 11 pages, 13 figures, submitted to MNRA
Physical Properties of UDF12 Galaxies in Cosmological simulations
We have performed a large cosmological hydrodynamics simulation tailored to
the deep survey with the Hubble Space Telescope made in 2012, the so-called
UDF12 campaign. After making a light-cone output, we have applied the same
color selection criteria as the UDF12 campaign to select galaxies from our
simulation, and then, have examined the physical properties of them as a proxy
of the real observed UDF12 galaxies at . As a result, we find that the
halo mass is almost linearly proportional to the observed ultraviolet (UV)
luminosity ( at ). The dust
attenuation and UV slope well correlates with the observed UV
luminosity, which is consistent with observations quantitatively. The star
formation rate (SFR) is also linearly proportional to the stellar mass and the
specific SFR shows only a weak dependency on the mass. We also find an
increasing star formation history with a time-scale of Myr in the
high- galaxies. An average metallicity weighted by the Lyman continuum
luminosity reaches up to Solar even at , suggesting a rapid
metal enrichment. We also expect mJy at 350 GHz of the dust thermal
emission from the galaxies with , which can be detectable with
the Atacama Large Milimetre-submilimetre Array. The galaxies selected by the
UDF12 survey contribute to only of the cosmic SFR density from to , respectively. The James Webb Space Telescope will push
the detection fraction up to .Comment: re-Submitted to MNRAS; 16 pages; 14 figures; 1 tables
Insulin-like and IGF-like peptides in the silkmoth Bombyx mori: discovery, structure, secretion, and function
A quarter of a century has passed since bombyxin, the first insulin-like peptide identified in insects, was discovered in the silkmoth Bombyx mori. During these years, bombyxin has been studied for its structure, genes, distribution, hemolymph titers, secretion control, as well as physiological functions, thereby stimulating a wide range of studies on insulin-like peptides in other insects. Moreover, recent studies have identified a new class of insulin family peptides, IGF-like peptides, in B. mori and Drosophila melanogaster, broadening the base of the research area of the insulin-related peptides in insects. In this review, we describe the achievements of the studies on insulin-like and IGF-like peptides mainly in B. mori with short histories of their discovery. Our emphasis is that bombyxins, secreted by the brain neurosecretory cells, regulate nutrient-dependent growth and metabolism, whereas the IGF-like peptides, secreted by the fat body and other peripheral tissues, regulate stage-dependent growth of tissues
An Analysis on Influence of Regional and Individual Conditions to Intended Needs and Actual Demands of Bus Service
Shock-induced star cluster formation in colliding galaxies
We studied the formation process of star clusters using high-resolution
N-body/smoothed particle hydrodynamcs simulations of colliding galaxies. The
total number of particles is 1.2x10^8 for our high resolution run. The
gravitational softening is 5 pc and we allow gas to cool down to \sim 10 K.
During the first encounter of the collision, a giant filament consists of cold
and dense gas found between the progenitors by shock compression. A vigorous
starburst took place in the filament, resulting in the formation of star
clusters. The mass of these star clusters ranges from 10^{5-8} Msun. These star
clusters formed hierarchically: at first small star clusters formed, and then
they merged via gravity, resulting in larger star clusters.Comment: 4 pages, 3 figures, Proceedings of IAU Symposium 270, Computational
Star Formatio
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