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This paper is devoted to the experimental study of the characteristics of a continuous optical discharge (COD) sustained by high power continuous wave laser radiation at a wavelength λ = 1.08 μ m in high pressure argon. New data on the COD threshold laser power dependence of argon pressure in the range 20–50 bar is obtained. The COD threshold laser power is shown to be in good agreement with the data obtained by other authors and theoretical evaluations provided the contribution of plasma energy loss due to thermal radiation is taken into account properly. The maximum plasma temperature was estimated to be 20–21 kk or higher, favorable to obtain high UV spectral radiance. A study of the convective plume oscillations around COD in argon has been carried out. It is found that in the pressure range 25–35 bars the growth of the laser radiation power leads to a decrease in convection oscillation frequency from 33 to 29 Hz, while the radius of the convective plume grows accordingly. The oscillation frequency ν and characteristic radius of the convective plume r 0 were found to obey the similarity relation ν = 0.5 g / 2 r 0 previously established in experiments with COD in xenon. These results are promising for using COD in argon as a high brightness broadband UV radiation source. [ABSTRACT FROM AUTHOR]

In this study, we introduce a theoretical model designed to explore both the photochemical and photothermal behavior of arc plasma radiation-induced ablation in gassing materials. We employ time-dependent density functional theory to analyze the photochemical behavior, while reactive force field molecular dynamics are used to explore the photothermal behavior. The phenomena, behavior and consequences of valence shell electronic excitation are analyzed in terms of ultraviolet (UV) absorption, electron-hole distribution, and Mayer bond order. Based on the photochemical findings, we apply a periodic electric field that corresponds to the vibration frequency of the permanent dipole moment to simulate infrared radiation, and convert UV photon energy into atomic kinetic energy to analyze UV radiation. This atomic-scale insight into photothermal behavior enables us to identify the final composition of ablation gases, including H2, CO, H2O, NH3, as well as specific cyanides, amines, and hydrocarbons. The results of the theoretical model and physical properties indicate that the concentration of hydrogen-containing gases in the ablation gas significantly affects the arc extinguishing capabilities of different polymers. Finally, we propose modification schemes suitable for polymers in power circuit breakers, considering UV absorption and smoke black production. Additionally, we present the potential application of theoretical models for calculating the ablation rate, necessitating further in-depth re-search. [ABSTRACT FROM AUTHOR]

The mid-infrared emission mechanism of line-and-space structures of metallic plates on dielectric materials is substantiated using high conductive n-doped (n++-) GaN–semi-insulating (SI-) GaN microstripe structures on an SI-GaN epitaxial layer, which was veiled when using line-and-space structures of Au plates. The present structure exhibits a few thermal emission lines originating from electric dipoles resonating with the coherent longitudinal optical (LO) phonon-like lattice vibration, which are formed by the local depolarization electric field in the surface n++-GaN/SI-GaN/n++-GaN regions. The energies of the LO-phonon-like modes shift from the original LO-phonon energy of GaN to the lower energy region, which contrasts with the LO-phonon resonant emission from the microstructures on GaAs. These emission lines have another notable feature, i.e. the observed peak energies are independent of the polar emission angle for both s- and p-polarizations, unlike the emissions by surface phonon polaritons showing a significant directive nature of peak energies. The results show that each peak energy of the present emission lines is positioned at the zero-point of the real part of the electric permittivity comprising the components of the transverse optical phonon and other electric dipoles induced by the LO-like modes, excluding the target mode. The significant peak-energy shift of the LO-like phonons is applicable to materials with wide Reststrahlen bands, which contrasts with that of the nearly LO-phonon resonating feature of materials with narrow Reststrahlen bands, such as GaAs. The peak energy shift depending on the emission direction is observed for Au–GaN stripe structures. This property is ascribed to the imperfect Au/GaN interface with surface states through the theoretical analysis of the modified electric permittivity in the surface region, numerical simulation of the local electric field via finite-difference time-domain calculation, and experimental studies on a Ti–GaN structure and emission peaks originating from an LO-like phonon of the α -Al2O3 substrate. [ABSTRACT FROM AUTHOR]

In this paper, based on split resonant ring (SRR) and NaCl solution (NS), a conformal and low thermal infrared radiation (LTIR) broadband metamaterial absorber (MA) with double SRRs and NS resonant cavity is proposed. Through simulation and measurement, it is proved that the proposed absorber has electromagnetic (EM) wave absorptivity of more than 90% under different polarization angles and different conformal conditions at 9.58â€"24.42 GHz. By introducing microfluidic channels, coupled electromagnetic thermal and coupled heat transfer simulations demonstrate that the design MA can maintain the thermal stability and LTIR characteristics under different power EM waves irradiation with low flow velocity (0.05 m sâˆ'1). Based on its good absorption performance and LTIR performance, it can be predicted that the proposed MA will have great application value in non-planar surface EM wave stealth and infrared stealth. [ABSTRACT FROM AUTHOR]

To meet the global energy demand, rapid growth in fossil fuel consumption has significantly contributed to global warming. Judicious utilization of renewable energy resources could help to combat this global challenge. Here, we present a comparative study on the designs of static and electro-tunable ‘smart’ windows that could help to reduce the energy need of typical air-conditioning systems deployed in buildings and motor vehicles. Our design comprises insulatorâ€"metalâ€"insulator multi-layered thin-films deposited over a silica glass substrate to filter visible and infrared solar radiation selectively. For static windows, we optimize our design to operate in diverse climatic conditions by choosing different combinations and thicknesses of metal and insulator layers. Whereas for electro-tunable windows, we use an electroâ€"optic polymer as the insulator layers to dynamically control portions of transmitted solar radiation over a voltage range of âˆ'12 to +12 V. Through size-dependence analysis, we could safely assume that the performance of smart windows is less likely to degrade during experimental realization. Our designs are lithography-free, large-area compatible, polarization-independent, angle-insensitive, and robust to fabrication imperfections. The analytical results show a near-perfect match with the simulation findings. The theoretically calculated figure of merit indicates that our proposed smart windows can outperform industry-standard commercial windows. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) and immunotherapy have been often adopted for ovarian cancer therapy, yet their application is limited by the high recurrence rate and toxic side effects. Intriguingly, nanoparticles contribute to enhancing the performance of PDT. Here, we investigated the synthesis of HER-2-Nanobody (Nb)-conjugated human serum albumin (HSA) incorporated with chlorin (Ce6) and catalase (CAT) (Nb@HCC), and analyzed the synergic effect of Nb@HCC-mediated PDT and immunotherapy for SK-OV-3 tumors. The Ce6 and CAT were incorporated into HSA to construct the HCC nanoparticles. HER-2-Nanobody was the purified bacterial crude extract, and conjugated with HCC to prepare Nb@HCC via heterodisulfide. The effects of Nb@HCC with near infrared ray (NIR) irradiation on moderating hypoxia and hypoxia inducible factor-1α (HIF-1α) expression were evaluated in the SK-OV-3 cells and tumor tissues. A SK-OV-3 tumor-bearing model was developed, where the synergistic effect of Nb@HCC-mediated PDT and anti-CTLA-4 therapy was investigated. Nb@HCC with a 660 nm laser irradiation could induce massive reactive oxygen species and trigger apoptosis in SK-OV-3 cells. Nb@HCC and PDT promoted danger-associated molecular patterns (DAMPs), which indicated immunogenic cell death and maturation of dendritic cells in the SK-OV-3 cells. Irradiated by NIR, Nb@HCC alleviated the hypoxia and decreased the expression of HIF-1α. The Nb@HCC-mediated PDT and anti-CTLA-4 therapy synergically inhibited the progression of distant tumor, and induced T cell infiltration. Biosafety tests suggested that Nb@HCC would not cause damage to the major organs with less toxicity and side effects. To conclude, a combination of Nb@HCC-mediated PDT and anti-CTLA-4 therapy could inhibit the progression of distant tumor to attain remarkable therapeutic outcomes. [ABSTRACT FROM AUTHOR]

Metasurfaces based on metal-dielectric-metal structures have been an effective means to comprehensively suppress infrared radiation. In this paper, we propose the idea of discretization to divide the circular resonator into countless rectangular elements and establish a complex equivalent LC circuit model, which provides a rapid design method for broadband absorption metasurfaces. The metasurface composed of two circle-shaped metal-dielectric-metal resonators were preliminarily designed based on impedance matching, and the geometric parameters and materials were optimally decided through numerical simulation. To validate the simulated result, we experimentally prepared a sample of the designed metasurface, the measured spectrum has revealed the radiative cooling ability (60% absorption over a range of 5–8 μm) and achieved infrared stealth (nearly 90% reflectance in the two atmospheric windows). Furthermore, the method provides potential applications to other requirements of thermal radiation regulation and theoretical support for establishing the model of metasurfaces with other configurations. [ABSTRACT FROM AUTHOR]

Silicon quantum dots (Si-QDs) are excellent luminescent material due to its unique optoelectronic properties and have huge application potential in the field of photodetection. Recently, there has been much research interests in developing low-cost, facile and environmentally friendly methods to prepare the nanomaterials in addition to yielding excellent performances. In this article, we developed a novel preparation method of producing Si-QDs film based on carbon–silicon composite. The film was synthesized by co-sputtering using magnetron sputtering technique and studied at different annealing temperatures. Upon annealing, the film was transformed from an amorphous state to a crystalline state leading to Si-QDs precipitation, which can be observed at a low temperature of 600 °C. A Si-QDs thin film/n-Si photodetector was then prepared and characterized. The device exhibited a high specific detection rate (D*) of 1.246 × 1012 cm Hz1/2 W−1 under 940 nm (1.1 mW cm−2) infrared radiation at 5 V bias. It also demonstrated good responsiveness and stability. [ABSTRACT FROM AUTHOR]

TianQin is a proposed space-borne gravitational wave observatory in high geocentric orbits, exposed to radiating heat sources in space. Due to the stringent thermal stability requirements from the key payloads, the analysis of space thermal environment is of great importance. This paper studies the incident thermal radiation onto the TianQin satellites from the Sun–Earth–Moon system. The solar constant fluctuation (SCF) and the Earth's land-type features, based on the meteorological data, are considered, and an analytic function of lunar surface temperature is used. The analysis includes the solar radiation, the infrared radiation, and the albedo. The results are discussed in both time and frequency domains. The spectral analysis indicates that in the target frequency band of 0.1 mHz–1 Hz, the SCF plays a dominant role, and that the associated incident thermal disturbance is ∼5 W m−2 Hz−1/2 for TianQin, at the same level of the LISA in heliocentric orbits. In addition, the power spectra of the Earth's and Moon's heating fluctuation are given, both order-of-magnitude weaker than that of the solar radiation. The results may contribute to the thermal design and the noise analysis for TianQin. [ABSTRACT FROM AUTHOR]

A gliding arc discharge is a typical method of producing non-equilibrium plasma, presenting excellent advantages in the field of enhanced combustion. In this study, a rotating gliding arc (RGA) plasma was combined with an aero-engine combustor dome to develop a RGA plasma-enhanced combustion dome. Experiments were conducted to investigate discharge, spectral, and infrared radiation temperature characteristics in the RGA plasma-enhanced combustion dome. Experimental results showed that two different discharge modes occurred during the RGA discharge process, the breakdown gliding mode and the steady arc gliding mode. The results had major implications for understanding the effects of the airflow rate and input voltage on the arc gliding mode transformation. The breakdown voltage, the average power, and the gliding arc rotational velocity increased with an increase in the airflow rate and a decrease of the input voltage. The spectral emission intensities of OH, O2, and O and vibrational temperature of N2 (C3Πu→B3Πg) were relatively high at a high airflow rate. Additionally, the RGA discharge had a weak temperature rise effect on electrode, which had no obvious impact on the discharge process. These characteristics could be important for future applications for controlling plasma-enhanced combustion process. [ABSTRACT FROM AUTHOR]

Stellar feedback is needed to produce realistic giant molecular clouds and galaxies in simulations, but due to limited numerical resolution, feedback must be implemented using sub-grid models. Observational work is an important means to test and anchor these models, but limited studies have assessed the relative dynamical role of multiple feedback modes, particularly at the earliest stages of expansion when H ii regions are still deeply embedded. In this paper, we use multiwavelength (radio, infrared, and X-ray) data to measure the pressures associated with direct radiation (Pdir), dust-processed radiation (PIR), photoionization heating (PH II ), and shock-heating from stellar winds (PX) in a sample of 106 young, resolved H ii regions with radii ≲0.5 pc to determine how stellar feedback drives their expansion. We find that the PIR dominates in 84% of the regions and that the median Pdir and PH II are smaller than the median PIR by factors of ≈6 and ≈9, respectively. Based on the radial dependences of the pressure terms, we show that H ii regions transition from PIR-dominated to PH II -dominated at radii of ∼3 pc. We find a median trapping factor of ftrap ∼ 8 without any radial dependence for the sample, suggesting this value can be adopted in sub-grid feedback models. Moreover, we show that the total pressure is greater than the gravitational pressure in the majority of our sample, indicating that the feedback is sufficient to expel gas from the regions. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of pollutants has been proved to be an effective strategy for wastewater treatment. Herein, TiO2 nanoparticles were synthesized on a Ti3C2 matrix by in situ growth, forming Z-scheme TiO2@Ti3C2/Cd0.5Zn0.5S (TO/CZS) multilevel structured nanocomposites via one-step hydrothermal route. The effects of hydrothermal temperature and Cd0.5Zn0.5S content on microstructure and properties of composites were assessed. TO/CZS nanocomposites were probed into phase composition, morphological and optical properties with x-ray diffractometer, infrared radiation, scanning electron microscope and UV–vis reflective spectra. Following the hydrothermal reaction at 160 °C for 12 h, TiO2 nanoparticles of 30 nm in diameter were generated in situ on Ti3C2 lamina and Cd0.5Zn0.5S particles were evenly distributed on the Ti3C2 matrix. The photocatalytic activity of TO/CZS composites were evaluated, which found that degradation rate constant (k = 0.028 min−1) of TO/CZS-40 on Rhodamine B was 5.19 times that of pure TiO2 and 4.48 times that of Cd0.5Zn0.5S. Through anchoring Ti3C2 as an electron transition mediator and combination with TiO2 and Cd0.5Zn0.5S, the new Z-scheme between TiO2 oxidized by Ti3C2 and Cd0.5Zn0.5S establishes a multilevel structure of separating electron-hole pairs. This work demonstrates a valid way to control electrons and hole transfer directions efficiently through designing multilevel semiconductor structural designs. [ABSTRACT FROM AUTHOR]

A convective heat flux model for perturbed plasmas, based on guiding center ion drift in vacuum fields (Wingen, et al 2014 Phys. Plasmas 21 012509), has been updated. The old model only considered ion heat flux, while here also electron heat flux is included. The updated model predicts divertor heat flux distributions in non-axisymmetric (3D) plasmas with applied resonant magnetic perturbation fields, and includes electric scalar potentials. It is found that a radial electric field in the near scrape-off layer can considerably shift the footprints toroidally, leading to a smearing out effect of the incident heat flux, while a simple model for sheath potential has little impact on footprints. Various approaches to model electron heat flux are studied. A convective electron model, based on collisionless free streaming, is found to yield the best agreement with measurements, while a conductive model requires a flat temperature gradient inside lobes to yield acceptable peak heat flux values. A heuristic heat flux layer approach, based on a fixed layer width also requires a limited heat flux inside the last closed flux surface (LCFS); by selecting various locations of the LCFS, the results of the conductive or convective model can be recovered respectively. The sum of ion and electron heat fluxes, both obtained by the convective model, is compared to experimental data for multiple time slices in DIII-D. Strike point splitting is observed with peak heat fluxes and layer widths that compare well to infrared camera measurements. [ABSTRACT FROM AUTHOR]

Observations of debris disks, the products of the collisional evolution of rocky planetesimals, can be used to trace planetary activity across a wide range of stellar types. The most common end points of stellar evolution are no exception, as debris disks have been observed around several dozen white dwarf stars. But instead of planetary formation, post-main-sequence debris disks are a signpost of planetary destruction, resulting in compact debris disks from the tidal disruption of remnant planetesimals. In this work, we present the discovery of five new debris disks around white dwarf stars with gaseous debris in emission. All five systems exhibit excess infrared radiation from dusty debris, emission lines from gaseous debris, and atmospheric absorption features indicating ongoing accretion of metal-rich debris. In four of the systems, we detect multiple metal species in emission, some of which occur at strengths and transitions previously unseen in debris disks around white dwarf stars. Our first year of spectroscopic follow-up hints at strong variability in the emission lines that can be studied in the future, expanding the range of phenomena these post-main-sequence debris disks exhibit. [ABSTRACT FROM AUTHOR]

We present arepo-mcrt , a novel Monte Carlo radiative transfer radiation-hydrodynamics (RHD) solver for the unstructured moving-mesh code arepo. Our method is designed for general multiple scattering problems in both optically thin and thick conditions. We incorporate numerous efficiency improvements and noise reduction schemes to help overcome efficiency barriers that typically inhibit convergence. These include continuous absorption and energy deposition, photon weighting and luminosity boosting, local packet merging and splitting, path-based statistical estimators, conservative (face-centered) momentum coupling, adaptive convergence between time steps, implicit Monte Carlo algorithms for thermal emission, and discrete-diffusion Monte Carlo techniques for unresolved scattering, including a novel advection scheme. We primarily focus on the unique aspects of our implementation and discussions of the advantages and drawbacks of our methods in various astrophysical contexts. Finally, we consider several test applications including the levitation of an optically thick layer of gas by trapped infrared radiation. We find that the initial acceleration phase and revitalized second wind are connected via self-regulation of the RHD coupling, such that the RHD method accuracy and simulation resolution each leave important imprints on the long-term behavior of the gas. [ABSTRACT FROM AUTHOR]

Studies of excess infrared radiation around white dwarfs provide important constraints on the evolution of planetary systems and low-mass companions beyond the main-sequence stage. In this paper series, we focus on identifying and characterizing bright white dwarfs with an infrared excess. Here, we present 188 infrared excess candidates from Gaia and unWISE, 147 of which are new discoveries. Further characterization of this sample can significantly increase the current list of white dwarf debris disks and white dwarfs with low-mass companions. [ABSTRACT FROM AUTHOR]

The detection of dusty winds dominating the infrared emission of active galactic nuclei (AGNs) on parsec scales has revealed the limitations of traditional radiative transfer models based on a toroidal distribution of dusty gas. A new, more complex, dynamical structure is emerging and the physical origin of such dusty winds has to be critically assessed. We present a semi-analytical model to test the hypothesis of radiatively accelerated dusty winds launched by the AGN and by the heated dust itself. The model consists of an AGN and an infrared radiating dusty disk, the latter being the primary mass reservoir for the outflow. We calculate the trajectories of dusty gas clumps in this environment, accounting for both gravity and the AGN radiation as well as the re-radiation by the hot, dusty gas clouds themselves. We find that the morphology consists of a disk of material that orbits with sub-Keplerian velocities and a hyperboloid polar wind launched at the inner edge of the dusty disk. This is consistent with high-angular resolution infrared and sub-mm observations of some local Seyfert AGN. The strength of the wind and its orientation depend on the Eddington ratio and the column density of the dusty clumps, which is in agreement with proposed radiation regulated obscuration models developed for the X-ray obscuring material around AGNs. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to deriving far-infrared (FIR) photometric redshifts for galaxies based on their reprocessed emission from dust at rest-frame FIR through millimeter wavelengths. FIR photometric redshifts ("FIR-z") have been used over the past decade to derive redshift constraints for highly obscured galaxies that lack photometry at other wavelengths like the optical/near-IR. Most literature FIR-z fits are performed through minimization to a single galaxy's FIR template spectral energy distribution (SED). The use of a single galaxy template, or modest set of templates, can lead to an artificially low uncertainty estimate on FIR-z's because real galaxies display a wide range in intrinsic dust SEDs. I use the observed distribution of galaxy SEDs (for well-constrained samples across) to motivate a new FIR through millimeter photometric redshift technique called MMpz. The MMpz algorithm asserts that galaxies are most likely drawn from the empirically observed relationship between rest-frame peak wavelength, , and total IR luminosity, L ; the derived photometric redshift accounts for the measurement uncertainties and intrinsic variation in SEDs at the inferred L , as well as heating from the cosmic microwave background at. The MMpz algorithm has a precision of , similar to single-template fits, while providing a more accurate estimate of the FIR-z uncertainty with reduced chi-squared of order , compared to alternative FIR photometric redshift techniques (with). [ABSTRACT FROM AUTHOR]

We present submillimeter spectra of the (proto-)super star cluster (SSC) candidates in the starbursting center of the nearby galaxy NGC 253 identified by Leroy et al. The 2.5 pc resolution of our Atacama Large Millimeter/submillimeter Array cycle 3 observations approaches the size of the SSCs and allows for the study of physical and chemical properties of the molecular gas in these sources. In the 14 SSC sources and in the frequency ranges 342.0–345.8 GHz and 353.9–357.7 GHz, we detect 55 lines belonging to 19 different chemical species. The SSCs differ significantly in chemical complexity, with the richest clusters showing 19 species and the least complex showing four species. We detect HCN isotopologues and isomers (H13CN, HC15N, H15NC), abundant HC3N, SO and S18O, SO2, and H2CS. The gas ratios CO/HCN, CO/HCO+ are low, ∼1–10, implying high dense gas fractions in the SSCs. Line ratio analyses suggests chemistry consistent with photon-dominated regions and mechanical heating. None of the SSCs near the galaxy center show line ratios that imply an X-ray-dominated region, suggesting that heating by any (still unknown) active galactic nucleus does not play a major role. The gas temperatures are high in most sources, with an average rotational temperature of ∼130 K in SO2. The widespread existence of vibrationally excited HCN and HC3N transitions implies strong infrared radiation fields, potentially trapped by a greenhouse effect due to high continuum opacities. [ABSTRACT FROM AUTHOR]

Metal-insulator-semiconductor (MIS) structures were fabricated by depositing an Al2O3 dielectric on top of the contact layer of a mid-wave infrared nBn detector based on n-Hg1-xCdxTe grown by molecular beam epitaxy on GaAs (013) substrates. It is shown that when creating a backward electrode on the absorbing layer, the form of the capacitance–voltage characteristics depends not only on the properties of the contact layer, but also on the properties of the barrier and absorbing layers. An equivalent circuit of MIS structure based on nBn detector with mesa configuration is proposed. It is shown that measurements of the admittance of MIS structures with mesa configuration allow one to study the properties of the barrier layer in the nBn structure. The influence of infrared radiation on the temperature dependence of the barrier layer resistance is studied. [ABSTRACT FROM AUTHOR]

The measurement of precise absolute fluxes for stellar sources has been pursued with increased vigor since the discovery of dark energy and the realization that its detailed understanding requires accurate spectral energy distributions (SEDs) of redshifted la supernovae in the rest frame. The flux distributions of spectrophotometric standard stars were initially derived from the comparison of stars to laboratory sources of known flux but are now mostly based on calculated model atmospheres. For example, pure hydrogen white dwarf (WD) models provide the basis for the MST CALSPEC archive of flux standards. The basic equations for quantitative spectrophotometry and photometry are explained in detail. Several historical lab-based flux calibrations are reviewed; and the SEDs of stars in the major online astronomical databases are compared to the CALSPEC reference standard spectrophotometry. There is good evidence that relative fluxes from the visible to the near-IR wavelength of ~2.5 μm are currently accurate to 1% for the primary reference standards, and new comparisons with lab flux standards show promise for improving that precision. [ABSTRACT FROM AUTHOR]

Propyl-1,2,3-triazole was synthesized within the nanostructure of Nafion giving a Nafion -- propyl-1,2,3-triazole composite, which was confirmed by IR and NMR. TEM images of the material revealed that the cluster structure of the composite membrane is smaller than that of Nafion. Analysis of the mechanical properties of the composite membrane showed that propyl-1,2,3-triazole might contribute to improve the strength of the network. A maximum conductivity of 0.07 S/cm and current density of 760 mA/cm² at 0.6V were obtained under cell conditions of 70°C, RH = 100%. [ABSTRACT FROM AUTHOR]

In this paper, the effect of an environmental temperature change on multilayer diffractive optical elements (MLDOEs) is studied in terms of the diffraction efficiency and the polychromatic integral diffraction efficiency (PIDE). The relation between the diffraction efficiency of MLDOEs and environmental temperature is analyzed theoretically, and examples of different MLDOEs are discussed in the visible and infrared wavebands. The result shows that the diffraction efficiency reduction is no more than 5% and the PIDE reduction is less than 1.5% for optical plastic MLDOEs in the visible waveband when the environmental temperature ranges from −62 to 71 °C, and that the decrease of both the diffraction efficiency and PIDE for MLDOEs is more significant in the mid-wave infrared than in the long-wave infrared. The analysis result can be considered during optical engineering design with MLDOEs. [ABSTRACT FROM AUTHOR]

We present Herschel/HIFI observations of the light hydride H2S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the Herschel Observations of EXtra-Ordinary Sources GT (guaranteed time) key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H232S, H234S, and H233S, respectively. We only analyze emission from the so-called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H2S follow straight lines given the uncertainties and yield Trot = 141 ± 12 K. This indicates H2S is in local thermodynamic equilibrium and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (Eup ≳ 1000 K) are likely populated primarily by radiation pumping. We derive a column density, Ntot(H232S) = 9.5 ± 1.9 × 1017 cm–2, gas kinetic temperature, Tkin = 120 K, and constrain the H2 volume density, ≳ 9 × 10 7 cm–3, for the H2S emitting gas. These results point to an H2S origin in markedly dense, heavily embedded gas, possibly in close proximity to a hidden self-luminous source (or sources), which are conceivably responsible for Orion KL's high luminosity. We also derive an H2S ortho/para ratio of 1.7 ± 0.8 and set an upper limit for HDS/H2S of <4.9 × 10 –3. [ABSTRACT FROM AUTHOR]

We show that the ghost-free models of massive gravity and their multi-graviton extensions follow from considering higher dimensional General Relativity in Einstein–Cartan form on a discrete extra dimension, according to the dimensional deconstruction paradigm. We show that dimensional deconstruction is equivalent to a truncation of the Kaluza–Klein tower at the nonlinear level. Higher dimensional gravity is not recovered from a lower dimensional multi-graviton theory in the limit of a continuous extra dimension (infinite Kaluza–Klein tower) due to the appearance of a low strong coupling scale that depends on IR physics. This strong coupling scale, which is associated with the mass of the lowest Kaluza–Klein mode, controls the onset of the Vainshtein mechanism and is crucial to the theoretical and observational viability of the truncated theory. [ABSTRACT FROM AUTHOR]

Ultrafast and sensitive room temperature NH3 gas sensors based on chemically reduced graphene oxide (rGO) are demonstrated in this work. rGO, which was prepared via the reduction of graphene oxide by pyrrole, exhibited excellent responsive sensitivity and selectivity to ammonia (NH3) gas. The high sensing performance of these rGO sensors with resistance change as high as 2.4% and response time as fast as 1.4 s was realized when the concentration of NH3 gas was as low as 1 ppb. Furthermore, the rGO sensors could rapidly recover to their initial states with IR illumination. The devices also showed excellent repeatability and selectivity to NH3. These rGO sensors, with low cost, low power, and easy fabrication, as well as scalable properties, showed great potential for ultrasensitive detection of NH3 gas in a wide variety of fields. [ABSTRACT FROM AUTHOR]

Young stars with masses 2-8 times solar, the Herbig Ae and Be stars, often show a near-infrared excess too large to explain with a hydrostatically supported circumstellar disk of gas and dust. At the same time, the accretion flow carrying the circumstellar gas to the star is thought to be driven by magnetorotational turbulence, which, according to numerical MHD modeling, yields an extended low-density atmosphere supported by the magnetic fields. We demonstrate that the base of the atmosphere can be optically thick to the starlight and that the parts lying near 1 AU are tall enough to double the fraction of the stellar luminosity reprocessed into the near-infrared. We generate synthetic spectral energy distributions (SEDs) using Monte Carlo radiative transfer calculations with opacities for submicron silicate and carbonaceous grains. The synthetic SEDs closely follow the median Herbig SED constructed recently by Mulders & Dominik and, in particular, match the large near-infrared flux, provided the grains have a mass fraction close to interstellar near the disk's inner rim. [ABSTRACT FROM AUTHOR]

The interaction of water clusters that adsorbed methane molecules with infrared radiation is studied by molecular dynamics. The presence of methane molecules in the disperse water system leads to an increase in absorption and emission of infrared radiation and a strong depletion of the Raman spectrum. In this case, the reflection coefficient of a monochromatic plane electromagnetic wave increases and its frequency spectrum significantly changes. The comparison of experimental data for similar characteristics of water, methane, or their mixtures is presented. [ABSTRACT FROM AUTHOR]

We present measurements of the microlensing optical depth and event rate toward the Galactic Bulge (GB) based on two years of the MOA-II survey. This sample contains ∼1000 microlensing events, with an Einstein radius crossing time of tE ⩽ 200 days in 22 bulge fields covering ∼42 deg2 between –5° < l < 10° and –7° < b < –1°. Our event rate and optical depth analysis uses 474 events with well-defined microlensing parameters. In the central fields with |l| < 5°, we find an event rate of Γ = [2.39 ± 1.1]e[0.60 ± 0.05](3 – |b|) × 10–5 star–1 yr–1 and an optical depth (for events with tE ⩽ 200 days) of τ200 = [2.35 ± 0.18]e[0.51 ± 0.07](3 – |b|) × 10–6 for the 427 events, using all sources brighter than Is ⩽ 20 mag. The distribution of observed fields is centered at (l, b) = (0.°38, –3.°72). We find that the event rate is maximized at low latitudes and a longitude of l ≈ 1°. For the 111 events in 3.2 deg2 of the central GB at |b| ⩽ 3.°0 and 0.°0 ⩽ l ⩽ 2.°0, centered at (l, b) = (0.°97, –2.°26), we find star–1 yr–1 and . We also consider a red clump giant (RCG) star sample with Is < 17.5, and we find that the event rate for the RCG sample is slightly lower than but consistent with the all-source event rate. The main difference is the lack of long duration events in the RCG sample due to a known selection effect. Our results are consistent with previous optical depth measurements, but they are somewhat lower than previous all-source measurements, and slightly higher than previous RCG optical depth measurements. This suggests that the previously observed difference in optical depth measurements between all-source and RCG samples may largely be due to statistical fluctuations. These event rate measurements toward the central GB are necessary to predict the microlensing event rate and to optimize the survey fields in future space missions such as Wide Field Infrared Space Telescope. [ABSTRACT FROM AUTHOR]

We combine Herschel Photodetector Array Camera and Spectrometer and Spectral and Photometric Imaging Receiver maps of the full 2 deg2 Cosmic Evolution Survey (COSMOS) field with existing multi-wavelength data to obtain template and model-independent optical-to-far-infrared spectral energy distributions (SEDs) for 4218 Herschel-selected sources with log(LIR/L☼) = 9.4-13.6 and z = 0.02-3.54. Median SEDs are created by binning the optical to far-infrared (FIR) bands available in COSMOS as a function of infrared luminosity. Herschel probes rest-frame wavelengths where the bulk of the infrared radiation is emitted, allowing us to more accurately determine fundamental dust properties of our sample of infrared luminous galaxies. We find that the SED peak wavelength (λpeak) decreases and the dust mass (Mdust) increases with increasing total infrared luminosity (LIR). In the lowest infrared luminosity galaxies (log(LIR/L☼) = 10.0-11.5), we see evidence of polycyclic aromatic hydrocarbon (PAH) features (λ ∼ 7-9 μm), while in the highest infrared luminosity galaxies (LIR > 1012L☼) we see an increasing contribution of hot dust and/or power-law emission, consistent with the presence of heating from an active galactic nucleus (AGN). We study the relationship between stellar mass and star formation rate of our sample of infrared luminous galaxies and find no evidence that Herschel-selected galaxies follow the SFR/M* “main sequence” as previously determined from studies of optically selected, star-forming galaxies. Finally, we compare the mid-infrared to FIR properties of our infrared luminous galaxies using the previously defined diagnostic, IR8 ≡ LIR/L8, and find that galaxies with LIR ≳ 1011.3L☼ tend to systematically lie above (× 3-5) the IR8 “infrared main sequence,” suggesting either suppressed PAH emission or an increasing contribution from AGN heating. [ABSTRACT FROM AUTHOR]

Directly imaged exoplanets are unexplored laboratories for the application of the spectral and temperature retrieval method, where the chemistry and composition of their atmospheres are inferred from inverse modeling of the available data. As a pilot study, we focus on the extrasolar gas giant HR 8799b, for which more than 50 data points are available. We upgrade our non-linear optimal estimation retrieval method to include a phenomenological model of clouds that requires the cloud optical depth and monodisperse particle size to be specified. Previous studies have focused on forward models with assumed values of the exoplanetary properties; there is no consensus on the best-fit values of the radius, mass, surface gravity, and effective temperature of HR 8799b. We show that cloud-free models produce reasonable fits to the data if the atmosphere is of super-solar metallicity and non-solar elemental abundances. Intermediate cloudy models with moderate values of the cloud optical depth and micron-sized particles provide an equally reasonable fit to the data and require a lower mean molecular weight. We report our best-fit values for the radius, mass, surface gravity, and effective temperature of HR 8799b. The mean molecular weight is about 3.8, while the carbon-to-oxygen ratio is about unity due to the prevalence of carbon monoxide. Our study emphasizes the need for robust claims about the nature of an exoplanetary atmosphere to be based on analyses involving both photometry and spectroscopy and inferred from beyond a few photometric data points, such as are typically reported for hot Jupiters. [ABSTRACT FROM AUTHOR]

We present the results of a pilot survey to find dust-reddened quasars by matching the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) radio catalog to the UKIDSS near-infrared survey and using optical data from Sloan Digital Sky Survey to select objects with very red colors. The deep K-band limit provided by UKIDSS allows for finding more heavily reddened quasars at higher redshifts as compared with previous work using FIRST and Two Micron All Sky Survey (2MASS). We selected 87 candidates with K ⩽ 17.0 from the UKIDSS Large Area Survey (LAS) First Data Release (DR1), which covers 190 deg2. These candidates reach up to ∼1.5 mag below the 2MASS limit and obey the color criteria developed to identify dust-reddened quasars. We have obtained 61 spectroscopic observations in the optical and/or near-infrared, as well as classifications in the literature, and have identified 14 reddened quasars with E(B – V) > 0.1, including 3 at z > 2. We study the infrared properties of the sample using photometry from the Wide-Field Infrared Survey Explorer and find that infrared colors improve the efficiency of red quasar selection, removing many contaminants in an infrared-to-optical color-selected sample alone. The highest-redshift quasars (z ≳ 2) are only moderately reddened, with E(B – V) ∼ 0.2-0.3. We find that the surface density of red quasars rises sharply with faintness, comprising up to 17% of blue quasars at the same apparent K-band flux limit. We estimate that to reach more heavily reddened quasars (i.e., E(B – V) ≳ 0.5) at z > 2 and a depth of K = 17, we would need to survey at least ∼2.5 times more area. [ABSTRACT FROM AUTHOR]

We present WISE All-Sky mid-infrared (IR) survey detections of 55% (17/31) of the known QSOs at z > 6 from a range of surveys: the SDSS, the CFHT-LS, FIRST, Spitzer, and UKIDSS. The WISE catalog thus provides a substantial increase in the quantity of IR data available for these sources: 17 are detected in the WISE W1 (3.4 μm) band, 16 in W2 (4.6 μm), 3 in W3 (12 μm), and 0 in W4 (22 μm). This is particularly important with Spitzer in its warm-mission phase and no faint follow-up capability at wavelengths longward of 5 μm until the launch of James Webb Space Telescope (JWST). WISE thus provides a useful tool for understanding QSOs found in forthcoming large-area optical/IR sky surveys using PanSTARRS, SkyMapper, VISTA, DES, and LSST. The rest-UV properties of the WISE-detected and the WISE-non-detected samples differ: the detections have brighter i/z-band magnitudes and redder rest-UV colors. This suggests that a more aggressive hunt for very high redshift QSOs by combining WISE W1 and W2 data with red, observed optical colors could be effective at least for a subset of dusty candidate QSOs. Stacking the WISE images of the WISE-non-detected QSOs indicates that they are, on average, significantly fainter than the WISE-detected examples, and are thus not narrowly missing detection in the WISE catalog. The WISE catalog detection of three of our sample in the W3 band indicates that their mid-IR flux can be detected individually, although there is no stacked W3 detection of sources detected in W1 but not W3. Stacking analyses of WISE data for large active galactic nucleus samples will be a useful tool, and high-redshift QSOs of all types will be easy targets for JWST. [ABSTRACT FROM AUTHOR]

This paper presents a study of the rate and efficiency of star formation in the NGC 6334 star-forming region. We obtained observations at J, H, and Ks taken with the NOAO Extremely Wide-Field Infrared Imager and combined them with observations taken with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope at wavelengths = 3.6, 4.5, 5.8, and 8.0 μm. We also analyzed previous observations taken at 24 μm using the Spitzer MIPS camera as part of the MIPSGAL survey. We have produced a point source catalog with >700, 000 entries. We have identified 2283 young stellar object (YSO) candidates, 375 Class I YSOs, and 1908 Class II YSOs using a combination of existing IRAC-based color classification schemes that we have extended and validated to the near-IR for use with warm Spitzer data. We have identified multiple new sites of ongoing star formation activity along filamentary structures extending tens of parsecs beyond the central molecular ridge of NGC 6334. By mapping the extinction, we derived an estimate for the gas mass, 2.2 × 105M☼. The heavy concentration of protostars along the dense filamentary structures indicates that NGC 6334 may be undergoing a “mini-starburst” event with ΣSFR > 8.2 M☼ Myr–1 pc–2 and SFE > 0.10. We have used these estimates to place NGC 6334 in the Kennicutt-Schmidt diagram to help bridge the gap between observations of local low-mass star-forming regions and star formation in other galaxies. [ABSTRACT FROM AUTHOR]

This study brings initial insight into the characterization of the gas chemical composition in a dielectric barrier discharge (DBD) by Fourier-transformed infrared absorption spectroscopy. Capitalizing on a double path of the IR beam, measurements were performed in 5 cm long, 2 mm gap plasma. As the IR beam cross-section in the plasma was 2 × 2 mm2, a translation system was used to scan the plasma along the direction of the gas flow with a 2 mm spatial resolution.In the case of Ar–SiH4(67 ppm)–NH3(133 ppm) glow-mode DBD, all IR spectra peaks from 6000 to 800 cm−1 are related to vibrations of Si–H from SiH4 and N–H from NH3. Here, the N–H vibration is observable but non-quantifiable.At 50 kHz excitation, the absolute concentration of SiH4 was measured at different positions and different power values in continuous and modulated modes. In the absence of powder formation in the plasma and for an initial density of 1.6 × 1015 cm−3, all the measurements are fitted by the same exponential decay leading to an energy of 38 eV per dissociated molecule of SiH4. The presence of powders in the plasma reduces SiH4 dissociation rate by a factor larger than 4. [ABSTRACT FROM AUTHOR]

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint US/German project operating a 2.7 m infrared airborne telescope onboard a modified Boeing 747-SP in the stratosphere at altitudes up to 13.7 km. SOFIA covers a spectral range from 0.3 µm to 1.6 mm, with an average atmospheric transmission greater than 80%. After successfully completing its commissioning, SOFIA commenced regular astronomical observation in spring 2013, and will ramp up to more than one hundred 8 to 10 h flights per year by 2015. The observatory is expected to operate until the mid 2030s. SOFIA's initial complement of seven focal plane instruments includes broadband imagers, moderate-resolution spectrographs and high-resolution spectrometers. SOFIA also includes an elaborate program for Education and Public Outreach. We describe the SOFIA facility together with its first light instrumentation and include some of its first scientific results. In addition, the education and public outreach program is presented. [ABSTRACT FROM AUTHOR]

The photoelectron angular distributions (PADs) have been investigated for infrared (IR) ionization of He atoms excited to Rydberg states by extreme ultraviolet free-electron laser pulses. The experiment was carried out with two pulses which do not overlap in time. Depending on the intensity of the IR pulses, one IR photon ionization or additionally two-photon above-threshold ionization is observed. For low IR intensity, the PAD is well described by a contribution of s and d partial waves in accordance with early experiments. At high IR intensity, the PAD for two IR photon ionization clearly shows the contribution of higher partial waves. The experimental data are compared with the results of theoretical calculations based on solving the time-dependent Schrödinger equation. [ABSTRACT FROM AUTHOR]

We present Herschel observations of 6 fine-structure lines in 25 ultraluminous infrared galaxies at z < 0.27. The lines, [O III]52 μm, [N III]57 μm, [O I]63 μm, [N II]122 μm, [O I]145 μm, and [C II]158 μm, are mostly single Gaussians with widths <600 km s–1 and luminosities of 107-109L☼. There are deficits in the [O I]63/LIR, [N II]/LIR, [O I]145/LIR, and [C II]/LIR ratios compared to lower luminosity systems. The majority of the line deficits are consistent with dustier H II regions, but part of the [C II] deficit may arise from an additional mechanism, plausibly charged dust grains. This is consistent with some of the [C II] originating from photodissociation regions or the interstellar medium (ISM). We derive relations between far-IR line luminosities and both the IR luminosity and star formation rate. We find that [N II] and both [O I] lines are good tracers of the IR luminosity and star formation rate. In contrast, [C II] is a poor tracer of the IR luminosity and star formation rate, and does not improve as a tracer of either quantity if the [C II] deficit is accounted for. The continuum luminosity densities also correlate with the IR luminosity and star formation rate. We derive ranges for the gas density and ultraviolet radiation intensity of 101 < n < 102.5 and 102.2 < G0 < 103.6, respectively. These ranges depend on optical type, the importance of star formation, and merger stage. We do not find relationships between far-IR line properties and several other parameters: active galactic nucleus (AGN) activity, merger stage, mid-IR excitation, and SMBH mass. We conclude that these far-IR lines arise from gas heated by starlight, and that they are not strongly influenced by AGN activity. [ABSTRACT FROM AUTHOR]

The authors report on advanced metalorganic chemical vapor deposition (MOCVD) grown HgCdTe device structure for an ambient temperature long wavelength infrared radiation (LWIR) detector application. MOCVD technology with a wide range of composition and donor/acceptor doping and without post grown annealing seems to be an excellent tool for HgCdTe heterostructure epitaxial growth structure. The N+ /G/π/G/P+ /G/n+ (where G denotes graded interface region) HgCdTe photovoltaic device concept of a specific barrier bandgap architecture integrated with Auger-suppression is a good solution for high operating temperature (HOT) infrared detectors. Selected problems of photodiode designing are indicated. Theoretical modelling using APSYS platform supports design and better understanding of the carrier transport mechanism in the photodiode structures. SIMS profiles allowed comparing projected and obtained structures and revealed diffusion processes in the structures. The negative differential resistance, clearly visible on current-voltage characteristics, evidences for Auger-suppression due to exclusion and extraction phenomena. It is shown that the thickness and arsenic doping of the active region influence the reverse bias dark current minimum and the response time of LWIR HOT HgCdTe photodiodes. Reverse bias highly (up to 50 times) increases responsivity that could reach 6 A/W at 300 K. [ABSTRACT FROM AUTHOR]

This paper describes a set of demonstration school experiments where infrared radiation is detected using thermal sensitive foils. The possibility of using standard glass lenses for infrared imaging is discussed in detail. It is shown that with optic components made from glass, infrared radiation up to 2.5 μm of wavelength can be detected. The effect of surface emissivity is studied qualitatively where in different experimental arrangements lower or higher detected irradiance from a low emissivity surface can be obtained. [ABSTRACT FROM AUTHOR]

Interference of several identical laser beams allows for the fabrication of periodical structures over large areas. We present two complementary techniques for the patterning of thin films using the laser beam interference and direct ablation of material. The first one is based on precise control of the laser fluence relative to the ablation threshold of the film. Additional means for pattern management are provided by separate control of the intensity and phase of the interfering laser beams. Interference of four or six laser beams permits fabrication of periodical arrays of circular holes. Flexibility and sensitivity to the process parameters of the method beyond of simple hole arrays are shown for the thin Cr film ablation. Another versatile means for pattern generation in the films is the scanning of the periodic laser beam distribution over a workpiece in a sub-period area. By translation of the sample in small steps between laser shots, the structures with their shape independent of the interfering beam intensity distribution can be fabricated by overlapping the ablated holes. Slit- and cross-shaped periodical structures were fabricated using direct structuring with interfering nanosecond and femtosecond pulses. The thin-film structures fabricated by both techniques can be used as spectrally-selective elements for terahertz and infrared radiation. [ABSTRACT FROM AUTHOR]

We have observed the dwarf galaxy IC 1613, at multiple epochs in the mid-infrared using Spitzer and contemporaneously in the near-infrared using the new FourStar near-infrared camera on Magellan. We have constructed Cepheid period–luminosity relations in the J, H, Ks, [3.6] and [4.5] bands and have used the run of their apparent distance moduli as a function of wavelength to derive the line-of-sight reddening and distance to IC 1613. Using a nine-band fit, we find E(B − V ) = 0.05 ± 0.01 mag and an extinction-corrected distance modulus of μ0 = 24.29 ± 0.03statistical ± 0.03systematic mag. By comparing our multi-band and [3.6] distance moduli to results from the tip of the red giant branch and red clump distance indicators, we find that metallicity has no measurable effect on Cepheid distances at 3.6μm in the metallicity range −1.0 ⩽ [Fe/H] ⩽ 0.2, hence derivations of the Hubble constant at this wavelength require no correction for metallicity. [ABSTRACT FROM AUTHOR]

Under high pressure, a cagelike diamondoid nitrogen structure was lately discovered by first-principles structure researches. This newly proposed structure is very unique and has not been observed in any other element. Using density-functional calculations, we study the pressure effect on its vibrational properties. The Born effective charges are calculated, and the resulting LO—TO splittings of certain infrared active modes are beyond 20 cm−1. We depict the Γ-point vibrational modes and find the breathing mode, rotational mode, and shearing mode. Frequencies of all the optical modes increase with pressure increasing. Moreover, the relation between the breathing mode frequency and the nitrogen cage diameter is discussed in detail. Our calculation results give a deeper insight into the vibrational properties of the cagelike diamondoid nitrogen. [ABSTRACT FROM AUTHOR]

We have obtained JHK near-IR images and JH band low-resolution spectra of candidate members of the southern region of the young open cluster NGC 2264.We have determined spectral types from H-band spectra for 54 sources, 25 of which are classified for the first time. The stars in our sample cover a large range of spectral types (A8-M8). Using a cluster distance of 780 pc, we determined a median age of 1Myr for this region of NGC 2264, with 90% of the stars being 5 Myr or younger. To improve the statistical significance of our sample, we included 66 additional cluster members within our field of view with optical spectral classification in the literature. We derived infrared excesses using stellar properties to model the photospheric emission for each source and the extinction to correct FLAMINGOS near-IR and Spitzer mid-IR photometry, and obtained a disk fraction of 51% ± 5% for the region. Binning the stars by stellar mass, we find a disk fraction of 38% ± 9% for the 0.1-0.3 solar mass group, 55% ± 6% for 0.3-1 solar masses, and 58% ± 10% for the higher than 1 solar mass group. The lower disk fraction for the lower mass stars is similar to the results found in non-cluster regions like Taurus and Chamaeleon, but differs from the older 3 Myr cluster IC 348 in which the disk fraction is lower for the higher mass stars. This mass-dependent disk fraction is accentuated in the sample with isochrone ages younger than 2 Myr. Here, we find that 45% ± 11% of the 0.1-0.3 solar mass stars have disks, 60% ± 7% of the 0.3-1 solar mass stars have disks, and all 1-3 solarmass stars have disks. Stellar masses might be an important factor in the ability of a system to form or retain a disk early on. However, regardless of the stellar mass, the large infrared excesses expected from optically thick disks disappear within the first 2 Myr for all stars in our study and small excesses from optically thin disks are found mostly in sources younger than 4 Myr. [ABSTRACT FROM AUTHOR]

We present Herschel far-infrared (FIR) photometry of 11 quasars at redshiftz > 5 that have previously been detected at 1.2 mm. We perform full spectral energy distribution (SED) fits over the wavelength range λrest ~ 0.1-400 μm for those objects with good Herschel detections. These fits reveal the need for an additional FIR component besides the emission from a dusty active galactic nucleus (AGN)-powered torus. This additional FIR component has temperatures of TFIR ~ 40-60 K with luminosities of L8-1000 μm ~ 1013 L⊙ (accounting for 25%-60% of the bolometric FIR luminosity). If the FIR dust emission is due to star formation it would suggest star formation rates in excess of 1000 solar masses per year. We show that at long wavelengths (λrest ≳ 50 μm) the contribution of the AGN-powered torus emission is negligible. This explains how previous FIR studies of high-redshift quasars that relied on single-component fits to (ground-based) observations at λobs ≳ 350 μm reached TFIR and LFIR values similar to our complete SED fits. Stacking the Herschel data of four individually undetected sources reveals a significant average signal in the PACS bands but not in SPIRE. The average SED of sources with individual Herschel detections shows a striking surplus in near- and mid-infrared (MIR) emission when compared to common AGN templates. The comparison between two average SEDs (sources with and without individual Herschel detections) matched in the UV/optical indicates that for these objects the strength of the MIR emission may correlate with the strength of the FIR emission. [ABSTRACT FROM AUTHOR]

Poly(o-phenylenediamine-co-o-aminophenol) (PoPDoAP) was firstly synthesized via the electrochemical copolymerization of o-phenylenediamine (o-PD) and o-aminophenol (o-AP) in aqueous H2SO4 solution. The monomer concentration ratio strongly affected the electrochemical properties of the copolymer. The results from electrochemical impedance spectroscopy (EIS) indicated a copolymerization reaction took place between o-PD and o-AP. Compared to poly(o-phenylenediamine) (PoPD), the copolymer exhibited novel and improved electrical properties. The effect of the scan rate on the redox activity was also studied, indicating the electrochemical process of the copolymer is diffusion-controlled. A possible copolymerization mechanism was deduced from the IR spectrum of the copolymer. [ABSTRACT FROM AUTHOR]

We present measurements of the auto- and cross-frequency power spectra of the cosmic infrared background (CIB) at 250, 350, and 500μm (1200, 860, and 600 GHz) from observations totaling ~70 deg² made with the SPIRE instrument aboard the Herschel Space Observatory. We measure a fractional anisotropy δI/I = 14%±4%, detecting signatures arising from the clustering of dusty star-forming galaxies in both the linear (2-halo) and nonlinear (1-halo) regimes; and that the transition from the 2- to 1-halo terms, below which power originates predominantly from multiple galaxies within dark matter halos, occurs at kθ ~ 0.10-0.12 arcmin-1 (⨏ ~ 2160-2380), from 250 to 500μm. New to this paper is clear evidence of a dependence of the Poisson and 1-halo power on the flux-cut level of masked sources-suggesting that some fraction of the more luminous sources occupy more massive halos as satellites, or are possibly close pairs. We measure the cross-correlation power spectra between bands, finding that bands which are farthest apart are the least correlated, as well as hints of a reduction in the correlation between bands when resolved sources are more aggressively masked. In the second part of the paper, we attempt to interpret the measurements in the framework of the halo model. With the aim of fitting simultaneously with one model the power spectra, number counts, and absolute CIB level in all bands, we find that this is achievable by invoking a luminosity-mass relationship, such that the luminosity-to-mass ratio peaks at a particular halo mass scale and declines toward lower and higher mass halos. Our best-fit model finds that the halo mass which is most efficient at hosting star formation in the redshift range of peak star-forming activity, z ~ 1-3, is log(Mpeak/M☉) ~ 12.1±0.5, and that the minimum halo mass to host infrared galaxies is log(Mmin/M☉) ~ 10.1 ± 0.6. [ABSTRACT FROM AUTHOR]

We have made the first detection of a near-infrared counterpart associated with the disk around Radio Source "I," a massive protostar in the Kleinmann-Low nebula in Orion, using imaging with laser guide star adaptive optics on the Keck II telescope. The infrared emission is evident in images acquired using L' (3.8 μm) and Ms (4.7 μm) filters and is not detectable at K' (2.1 μm). The observed morphology strongly suggests that we are seeing some combination of scattered and thermal light emanating from the disk. The disk is also manifest in the L' /Ms flux ratio image. We interpret the near-infrared emission as the illuminated surface of a nearly edge-on disk, oriented so that only the northern face is visible; the opposite surface remains hidden by the disk. We do not see infrared radiation associated directly with the star proposed to be associated with Source "I." The data also suggest that there is a cavity above and below the disk that is oriented perpendicular to the disk and is sculpted by the known, strong outflow from the inner disk of Source I. We compare our data to models of a protostar with a surrounding disk, envelope, and wind-blown cavity in order to elucidate the nature of the disk around Radio Source I. [ABSTRACT FROM AUTHOR]

Metal-poor massive stars typically end their lives as blue supergiants (BSGs). Gamma-ray bursts (GRBs) from such progenitors could have an ultra-long duration of relativistic jets. For example, Population III (Pop III) GRBs at z ~ 10-20 might be observable as X-ray-rich events with a typical duration of T90 ~ 104(1 + z) s. The recent GRB111209A at z = 0.677 has an ultra-long duration of T90 ~ 2.5 × 104 s and it has been suggested that its progenitor might have been a metal-poor BSG in the local universe. Here, we suggest that luminous UV/optical/infrared emission is associated with this new class of GRBs from metal-poor BSGs. Before the jet head breaks out of the progenitor envelope, the energy injected by the jet is stored in a hot plasma cocoon, which finally emerges and expands as a baryon-loaded fireball.We show that the photospheric emissions from the cocoon fireball could be intrinsically very bright (Lpeak ~ 1042-1044 erg s-1) in UV/optical bands (εpeak ~ 10 eV) with a typical duration of ~100 days in the rest frame. Such cocoon emissions from Pop III GRBs might be detectable in infrared bands at ~years after Pop III GRBs at up to z ~ 15 by upcoming facilities such as the James Webb Space Telescope. We also suggest that GRB111209A might have been rebrightening in UV/optical bands up to an AB magnitude of ≲26. The cocoon emission from local metal-poor BSGs might have been observed previously as luminous supernovae without GRBs since they can be seen from the off-axis direction of the jet. [ABSTRACT FROM AUTHOR]

Molecular hydrogen is now understood to be the main coolant of the primordial gas clouds leading to the formation of the very first stars and galaxies. The line emissions associated with molecular hydrogen should then be a good tracer of the matter distribution at the onset of the reionization of the universe. Here, we propose intensity mapping of H2 line emission in rest-frame mid-infrared wavelengths to map out the spatial distribution of gas at redshifts z > 10. We calculate the expected mean intensity and clustering power spectrum for several H2 lines. We find that the 0-0S(3) rotational line at a rest wavelength of 9.66μm is the brightest line over the redshift range of 10-30 with an intensity of about 5-10 Jy sr-1 at z ~ 15. To reduce astrophysical and instrumental systematics, we propose the cross-correlation between multiple lines of the H2 rotational and vibrational line emission spectrum. Our estimates of the intensity can be used as guidance in planning instruments for future mid-IR spectroscopy missions such as SPICA. [ABSTRACT FROM AUTHOR]