Galaxies Inside Stromgren Spheres of Luminous Quasars at z>6: Detection of The First Galaxies

The intrinsic Lyman-alpha emission lines of normal galaxies before reionization are much absorbed by the damping wing of the Gunn-Peterson trough, rendering their direct detection nearly impossible, if their intrinsic line widths are less than ~100km/s. High redshift luminous quasars prior to the completion of cosmological reionization at z~6, on the other hand, are capable of producing large HII regions around them (Stromgren spheres) to allow their intrinsic Lyman-alpha emission lines to be transmitted without overwhelming absorption (Cen & Haiman 2000). We suggest that targeted observations at the Stromgren spheres of known luminous quasars at z >= 6 would be able to detect Lyman-alpha emission lines of galaxies inside the Stromgren spheres largely unattenuated. A tunable, very narrowband filter of \Delta\lambda\over \lambda ~ 0.1% or a narrowband filter of \Delta\lambda\over \lambda ~1% with follow-up spectroscopic identifications will be required. Such observations could directly observe the sources of cosmological reionization including possibly the Pop III galaxies at z=6-20 by JWST. Possible applications include determinations of the ionization state of the intergalactic medium, the sizes of the Stromgren spheres, the ages of the quasars, the luminosity function of high redshift galaxies and its evolution, the spatial distribution of galaxies and its evolution, the biased distribution of galaxies around quasars and the anisotropy of quasar emission. Observations using Keck-class telescopes may already be made to enable a differentiation between a fully neutral and a 10% neutral intergalactic medium at z>6.Comment: Submitted to ApJ Letters, 10 page

Assessment of the behavior of vertical ties in RC structures under progressive collapse

Despite the recent amount of theoretical and technological developements, structural robustness is still an issue of controversy being underlined by serveral progressive collapses in te past. Current design codes point out different strategies, among which strategies to limit progressive structual damage by applying prescriptive design and detailing rules. For example, for consequence class 2 structures, EN1991-1-7 defines a risk class CC2b for which also vertical ties are required. However, te background of the design values of vertical ties in current code is not clear and their adequacy should be validated. Moreover, effects such as membrane action and Vierendeel action are important to consider when assessing structural robustness and are difficult to incorporate when applying only traditional design methodologies. To this extent, a set of numerical simulations have been executed in this contribution in order to verify and investigate the progressive collapse behavior of RC frames including the redistribution of internal forces and the response of the vertical ties in columns

Pengaruh Media Periklanan terhadap Pengambilan Keputusan Siswa Smu untuk Mendaftar di Universitas Kristen Maranatha: Sikap Konsumen sebagai Variabel Moderasi (Studi Kasus Siswa Smu di Bandung)

Advertising is one of the indicators to build a brand image in consumers' minds. Advertisingcan evolve through feedback or consumer attitudes toward advertising displayed and the brandimage the company itself. Consumer's acceptance or rejection of advertising will be veryinfluential on the goods or services offered. Advertising is used as a stimulus to bring the responsefrom consumers. Response referred in this research is the consumer attitude. In this case can beseen that the advertising is basically intended to build an customer's attitude (affective andcognitive). Purpose of this research is to view the relationship between the effectiveness ofpromotions that have been conducted Maranatha Christian University with purchasing decisionsof high school students in Bandung, which is moderated by consumer attitudes. The resultsobtained show that high school students' attitudes toward advertising and Maranatha ChristianUniversity itself have a good results as well as feelings of respondents toward advertising showsthat advertising is able to remind, made an impression and encouraging respondents to continuetheir education at Maranatha Christian University

Evolution of the Luminosity Function and Colors of Galaxies in a Lambda-CDM Universe

The luminosity function of galaxies is derived from a cosmological hydrodynamic simulation of a Lambda cold dark matter (CDM) universe with the aid of a stellar population synthesis model. At z=0, the resulting B band luminosity function has a flat faint end slope of \alpha \approx -1.15 with the characteristic luminosity and the normalization in a fair agreement with observations, while the dark matter halo mass function is steep with a slope of \alpha \approx -2. The colour distribution of galaxies also agrees well with local observations. We also discuss the evolution of the luminosity function, and the colour distribution of galaxies from z=0 to 5. A large evolution of the characteristic mass in the stellar mass function due to number evolution is compensated by luminosity evolution; the characteristic luminosity increases only by 0.8 mag from z=0 to 2, and then declines towards higher redshift, while the B band luminosity density continues to increase from z=0 to 5 (but only slowly at z>3).Comment: 6 pages, including 4 figures, mn2e style. Accepted to MNRAS pink page

Where Are the Baryons? II: Feedback Effects

Numerical simulations of the intergalactic medium have shown that at the present epoch a significant fraction (40-50%) of the baryonic component should be found in the (T~10^6K) Warm-Hot Intergalactic Medium (WHIM) - with several recent observational lines of evidence indicating the validity of the prediction. We here recompute the evolution of the WHIM with the following major improvements: (1) galactic superwind feedback processes from galaxy/star formation are explicitly included; (2) major metal species (O V to O IX) are computed explicitly in a non-equilibrium way; (3) mass and spatial dynamic ranges are larger by a factor of 8 and 2, respectively, than in our previous simulations. Here are the major findings: (1) galactic superwinds have dramatic effects, increasing the WHIM mass fraction by about 20%, primarily through heating up warm gas near galaxies with density 10^{1.5}-10^4 times the mean density. (2) the fraction of baryons in WHIM is increased modestly from the earlier work but is ~40-50%. (3) the gas density of the WHIM is broadly peaked at a density 10-20 times the mean density, ranging from underdense regions to regions that are overdense by 10^3-10^4. (4) the median metallicity of the WHIM is 0.18 Zsun for oxygen with 50% and 90% intervals being (0.040,0.38) and (0.0017,0.83).Comment: 44 pages, 17 figures, high res version at http://www.astro.princeton.edu/~cen/baryonII.ps.g

Massive galaxies in cosmological simulations: UV-selected sample at redshift z=2

We study the properties of galaxies at z=2 in a Lambda CDM universe, using two different types of hydrodynamic simulation methods (Eulerian TVD and SPH) and a spectrophotometric analysis in the Un, G, R filter set. The simulated galaxies at z=2 satisfy the color-selection criteria proposed by Adelberger et al. (2004) when we assume Calzetti extinction with E(B-V)=0.15. We find that the number density of simulated galaxies brighter than R<25.5 at z=2 is about 2e-2 h^3/Mpc^3, roughly one order of magnitude larger than that of Lyman break galaxies at z=3. The most massive galaxies at z=2 have stellar masses >~1e11 Msun, and their observed-frame G-R colors lie in the range 0.0<G-R<1.0. They typically have been continuously forming stars with a rate exceeding 30 Msun/yr over a few Gyrs from z=10 to z=2, although the TVD simulation indicates a more sporadic star formation history than the SPH simulations. Of order half of their stellar mass was already assembled by z~4. The reddest massive galaxies at z=2 with G-R >= 1.0 and Mstar>1e10 Msun/h finished the build-up of their stellar mass by z~3. Interestingly, our study suggests that the majority of the most massive galaxies at z=2 should be detectable at rest-frame UV wavelengths, contrary to some recent claims made on the basis of near-IR studies of galaxies at the same epoch, provided the median extinction is less than E(B-V)<0.3. However, our results also suggest that the fraction of stellar mass contained in galaxies that pass the color-selection criteria could be as low as 50% of the total stellar mass in the Universe at z=2. Our simulations suggest that the missing stellar mass is contained in fainter (R>25.5) and intrinsically redder galaxies. Our results do not suggest that hierarchical galaxy formation fails to account for the massive galaxies at z>=1. (abridged)Comment: 35 pages, 11 figures. Submitted to ApJ. Error in AB magnitude calculation corrected. Higher resolution version available at http://cfa-www.harvard.edu/~knagamine/redgal.ps.g

FORMATION OF GLOBULAR CLUSTERS IN ATOMIC-COOLING HALOS VIA RAPID GAS CONDENSATION AND FRAGMENTATION DURING THE EPOCH OF REIONIZATION

We investigate the formation of metal-poor globular clusters (GCs) at the center of two dark matter halos with $\textit{M}_{halo}$ ~ 4 $\times$ 10$^7$ $\textit{M}_\odot$ at $\textit{z}$ > 10 using cosmological radiation-hydrodynamics simulations. We find that very compact ($\lesssim$1 pc) and massive (~ 6 $\times$ 10$^5$ $\textit{M}_\odot$) clusters form rapidly when pristine gas collapses isothermally with the aid of efficient Ly$\alpha$ emission during the transition from molecular-cooling halos to atomic-cooling halos. Because the local free-fall time of dense star-forming gas is very short ($\ll$1 Myr), a large fraction of the collapsed gas is turned into stars before stellar feedback processes blow out the gas and shut down star formation. Although the early stage of star formation is limited to a small region of the central star-forming disk, we find that the disk quickly fragments due to metal enrichment from supernovae. Sub-clusters formed in the fragmented clouds eventually merge with the main cluster at the center. The simulated clusters closely resemble the local GCs in mass and size but show a metallicity spread that is much wider than found in the local GCs. We discuss a role of pre-enrichment by Pop III and II stars as a potential solution to the latter issue. Although not without shortcomings, it is encouraging that a naive blind (not tuned) cosmological simulation presents a possible channel for the formation of at least some massive GCs.The research is supported in part by NSF grant AST-1108700 and NASA grant NNX12AF91G and in part by the ERC Advanced Grant 320596 “The Emergence of Structure during the epoch of Reionization.” JR was funded by the European Research Council under the European Unions Seventh Framework Programme (FP7/2007- 2013)/ERC Grant agreement 278594-GasAroundGalaxies, and the Marie Curie Training Network CosmoComp (PITN-GA- 2009-238356). SKY acknowledges support from the Korean National Research Foundation (Doyak 2014003730).This is the final version of the article. It first appeared from the Institute of Physics via http://dx.doi.org/10.3847/0004-637X/823/1/5

Rewritable nanoscale oxide photodetector

Nanophotonic devices seek to generate, guide, and/or detect light using structures whose nanoscale dimensions are closely tied to their functionality. Semiconducting nanowires, grown with tailored optoelectronic properties, have been successfully placed into devices for a variety of applications. However, the integration of photonic nanostructures with electronic circuitry has always been one of the most challenging aspects of device development. Here we report the development of rewritable nanoscale photodetectors created at the interface between LaAlO3 and SrTiO3. Nanowire junctions with characteristic dimensions 2-3 nm are created using a reversible AFM writing technique. These nanoscale devices exhibit a remarkably high gain for their size, in part because of the large electric fields produced in the gap region. The photoconductive response is gate-tunable and spans the visible-to-near-infrared regime. The ability to integrate rewritable nanoscale photodetectors with nanowires and transistors in a single materials platform foreshadows new families of integrated optoelectronic devices and applications.Comment: 5 pages, 5 figures. Supplementary Information 7 pages, 9 figure