Tag infrared [at least 200 articles]

Abstract

We report on the first near-infrared observations obtained to date for Rotating RAdio Transients (RRATs). Using adaptive optics devices mounted on the ESO Very Large Telescope (VLT), we observed two objects of this class: RRAT J1819-1458, and RRAT J1317-5759. These observations have been performed in 2006 and 2008, in the J, H and Ks bands. We found no candidate infrared counterpart to RRAT J1317-5759, down to a limiting magnitude of Ks ~ 21. On the other hand, we found a possible candidate counterpart for RRAT J1819-1458, having ...

Abstract

This paper focuses on radio-frequency (RF) location determination characteristics and implementations. A presentation of RF transmission, propagation and reception characteristics is provided and a summary of some the major developments of RF-based location systems is also discussed. RF determination capabilities are typed and classified and outlined. Finally, examples of RF-based location systems are given. ...

Abstract

In 2006 ESO Council authorized a Phase B study of a European AO-telescope with a 42 m segmented primary with a 5-mirror design, the E-ELT. Several reports and working groups have already presented science cases for an E-ELT, specifically exploiting the new capabilities of such a large telescope. One of the aims of the design has been to find a balance in the performances between an E-ELT and the James Webb Space Telescope, JWST. Apart from the larger photon-collecting area, the strengths of the former is the ...

Abstract

The existence of submillimeter-selected galaxies (SMGs) at redshifts z>4 has recently been confirmed. Using simultaneously all the available data from UV to radio we have modeled the spectral energy distributions of the six known spectroscopically confirmed SMGs at z>4. We find that their star formation rates (average ~2500 MSun yr^-1), stellar (~3.6x10^11 MSun) and dust (~6.7x10^8 MSun) masses, extinction (A_V~2.2 mag), and gas-to-dust ratios (~60) are within the ranges for 1.7<z<3.6 SMGs. Our analysis suggests that infrared-to-radio luminosity ratios of SMGs do not change up to redshift ~5 ...

Abstract

An improved micro-reactor cell for IR spectroscopic studies of heterogeneous catalysis was built around a 5.8 GHz microwave cavity. The reactor can operate at 20 bars and with conventional heating up to 720 K, with reactant gas flows velocities (GHSV) from 25000 to 50000 h-1. The temperature of the sample under microwave irradiation was measured by time resolved IR emission spectroscopy. The first experiment performed was the IR monitoring of the desorption of carbonates induced by irradiating an alumina sample by ...

Abstract

We use a sample of 90 spectroscopically-confirmed Lyman Break Galaxies with H-alpha and 24 micron observations to constrain the relationship between rest-frame 8 micron luminosity, L(8), and star formation rate (SFR) for L* galaxies at z~2. We find a tight correlation with 0.24 dex scatter between L8 and L(Ha)/SFR for z~2 galaxies with L(IR)~10^10 - 10^12 Lsun. Employing this relationship with a larger sample of 392 galaxies with spectroscopic redshifts, we find that the UV slope can be used to recover the dust attenuation of the vast majority ...

Abstract

Atomic populations in a molecule have been defined via the Thomas–Reiche–Kuhn sum rule for oscillator strengths written within the acceleration gauge. These atomic populations are related to nuclear electric shieldings, i.e., to geometrical derivatives of electric dipole moment, and can therefore be connected with observable infrared intensities. A number of relationships can be considered to test a priori the quality of calculated electronic charges and to assess their physical meaning. It is shown via extended numerical tests on the first members ...

Abstract

The morphology, microstructure and chemical composition of pure as well as Ca and P doped TiO 2 films have been studied. The films were deposited using the aerosol–gel technique. After deposition as a liquid coating, subsequent evaporation of the solvent induces the polycondensation in the film. The final film densification was performed by heat-treatment at 80–500°C. The thickness of the titanium oxide layers was adjusted to be in the range of 10 to 100 nm by varying the deposition time. ...

Abstract

Guest molecules of typical clathrate hydrates are stabilized by weak nonspecific interactions with the cage walls of the host lattice. Despite their ability to form hydrogen bonds, this description also generally applies to encaged ether and other moderately strong proton acceptor molecules. However, on the basis of infrared spectroscopic and molecular dynamics results, an altered structure is indicated when guests such as HCN or SO2, capable of binding to oxygen lattice sites, occupy the small cages. During cooling from 140 to ...

Abstract

Dust-obscured star-formation becomes much more important with increasing intensity, and increasing redshift. We aim to reveal cosmic star-formation history obscured by dust using deep infrared observation with the AKARI. We construct restframe 8um, 12um, and total infrared (TIR) luminosity functions (LFs) at 0.15<z<2.2 using 4128 infrared sources in the AKARI NEP-Deep field. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24um) by the AKARI satellite allows us to estimate restframe 8um and 12um luminosities without using a large extrapolation ...

Abstract

We aim to reveal environmental dependence of infrared luminosity functions (IR LFs) of galaxies at z~0.8 using the AKARI satellite. We construct restframe 8um IR LFs in the cluster region RXJ1716.4+6708 at z=0.81, and compare them with a blank field using the AKARI North Ecliptic Pole deep field data at the same redshift. AKARI's wide field of view (10'x10') is suitable to investigate wide range of galaxy environments. AKARI's 15um filter is advantageous here since it directly probes restframe 8um at z~0.8, without relying on a large extrapolation ...

Abstract

A high-resolution, far ir lamellar grating interferometer that operates in either a single-beam or a double-beam differencing mode of operation is described. The instrument covers a frequency range of 10 cm-1 to 125 cm-1 (1000 µ to 80 µ). To illustrate the general performance of the instrument the pure rotational spectrum of water vapor between 15 cm-1 and 115 cm-1 is presented. It is estimated that the absorption line centers of strong isolated lines are measured to within ±0.008 cm-1. To ...

Abstract

A new silicon IR source and CO₂-chamber system for measurement of CO₂ concentration is presented. The micromachined IR-source, which consists of four groups of polysilicon filaments coated with silicon nitride suspended across a KOH-etched cavity, is used to generate two switched “sample” and “reference” beams. The electrically modulated sources present a modulation time of 10 ms and a power consumption of 1 W. The CO₂ chambers, placed beneath the reference sources, are used to produce a reference beam for long term ...

Abstract

PMID: 19441802 Spectral line shapes in a condensed phase contain information from various dynamic processes that modulate the transition energy, such as microscopic dynamics, inter- and intramolecular couplings, and solvent dynamics. Because nonlinear response functions are sensitive to the complex dynamics of chemical processes, multidimensional vibrational spectroscopies can separate these processes. In multidimensional vibrational spectroscopy, the nonlinear response functions of a molecular dipole or polarizability are measured using ultrashort pulses to monitor inter- and intramolecular vibrational motions. Because a complex profile ...

Abstract

PMID: 19754112 In aqueous solution, the basis of all living processes, hydrogen bonding exerts a powerful effect on chemical reactivity. The vibrational energy relaxation (VER) process in hydrogen-bonded complexes in solution is sensitive to the microscopic environment around the oscillator and to the geometrical configuration of the hydrogen-bonded complexes. In this Account, we describe the use of time-resolved infrared (IR) pump−probe spectroscopy to study the vibrational dynamics of (i) the carbonyl CO stretching modes in protic solvents and (ii) the OH ...

Abstract

PMID: 19469530 Water is the most extensively studied of liquids because of both its ubiquity and its anomalous thermodynamic and dynamic properties. The properties of water are dominated by hydrogen bonds and hydrogen bond network rearrangements. Fundamental information on the dynamics of liquid water has been provided by linear infrared (IR), Raman, and neutron-scattering experiments; molecular dynamics simulations have also provided insights. Recently developed higher-order nonlinear spectroscopies open new windows into the study of the hydrogen bond dynamics of liquid water. ...

Abstract

PMID: 19585982 Compared with other molecular liquids, water is highly structured because of its ability to form up to four hydrogen bonds, resulting in a tetrahedral network of molecules. However, this underlying intermolecular structure is constantly in motion, exhibiting large fluctuations and reorganizations on time scales from femtoseconds to picoseconds. These motions allow water to play a key role in a number of chemical and biological processes. By exploiting the fact that the OH stretching frequency of dilute HOD in liquid ...

Abstract

PMID: 19681584 For decades, the enigma of the hydrophobic force has captured the imagination of scientists. In particular, Frank and Evans’ idea that the hydrophobic effect was mainly due to some kind of “iceberg” formation around a hydrophobic solute stimulated many experiments and molecular dynamics simulation studies. A better understanding of hydrophobic interactions will aid understanding in many contexts including protein structural dynamics and functioning in biological systems. In this Account, we present results of two-dimensional infrared (2D IR) spectroscopy experiments ...

Abstract

We report that polarization-shaped mid-infrared (IR) pulses can be used to enhance the vibrational population of one mode over another in a coupled molecular system. A genetic algorithm and a new mid-IR polarization shaper were used to alter the relative vibrational excitation of the two carbonyl stretching modes in Mn(CO)5Br. One mode could be selectively enhanced over the other by 2-3 times. Control over the polarization leads to better optimization than phase-only control. Several possible mechanisms that indicate how polarization shaping ...

Abstract

The accessible time resolution in femtosecond infrared experiments is shorter than the typical phase relaxation time of a vibronic transition. Therefore, coherent interaction of the light pulses with the sample may disturb the observed absorbance signals. Coherence results in an artifact known as perturbed free induction decay, which may be misinterpreted as an intrinsic incoherent temporal evolution of the sample. In the present paper, a model is presented describing this effect for the general situation, where a complex molecule containing many ...

Abstract

A spectrometer system is presented for time-resolved probing in the midinfrared between 5 and 11 µm with a temporal resolution of better than 400 fs. Multichannel detection with HgCdTe detector arrays consisting of ten elements in combination with a high repetition rate permits one to record weak absorbance changes with an accuracy of 0.1 mOD. ...

Abstract

We report on an intense mid-infrared light source that provides femtosecond pulses on a microjoule energy level, broadly tunable in the 3–20-μm wavelength range with pulse durations as short as 50 fs at 5 μm. The pulses are generated by phase-matched difference-frequency mixing in GaSe of near-infrared signal and idler pulses of a parametric device based on a 1-kHz Ti:sapphire amplifier system. Pulse durations are characterized with different techniques including autocorrelation measurements in AgGaS2, two-photon absorption in InSb, and cross-correlation measurements ...

Abstract

Abstract: Location-aware applications for supporting the mobile user require reliable information about their position and the environment. Based on a critical review of solutions so far, a very cost effective solution of a local positioning system (LPS) is introduced for the need of positioning indoors as well as on a constrained outdoor campus with dynamic granularity. The simple and costeffective hybrid IR/RF (Infrared / Radio Frequency) technology fits into a suite of distributed Smart IP devices within a scalable and flexible ...

Abstract

[Abridged]We exploit a large homogeneous dataset to derive a self-consistent picture of IR emission based on the time-dependent 24, 15, 12 and 8micron monochromatic and bolometric IR luminosity functions (LF) over the 0<z<2.5 redshift range. Our analysis is based on the combination of data from deep Spitzer surveys in the VVDS-SWIRE and GOODS areas. To our limiting flux of S(24)=400microJy our derived sample in VVDS-SWIRE includes 1494 sources, and 666 and 904 sources brighter than S(24)=80microJy are catalogued in GOODS-S and GOODS-N, respectively, for a total area of ...

Abstract

A novel system for the location of people in an office environment is described. Members of staff wear badges that transmit signals providing information about their location to a centralized location service, through a network of sensors. The paper also examines alternative location techniques, system design issues and applications, particularly relating to telephone call routing. Location systems raise concerns about the privacy of an individual and these issues are also addressed. ...

Abstract

This paper describes a model-based approach to the unobtrusive monitoring of elders in their home environment to assess their health, daily activities, and cognitive function. We present a semi-Markov model representation with automated learning to characterize individual elder's mobility in the home environment. The assessed mobility can be used to characterize the elder's speed of walking and can serve as one of the predictors of future cognitive functionality and the ability of elders to live independently in their home environment. ...

Abstract

Elders live preferently in their own home, but with aging comes the loss of autonomy and associated risks. In order to help them live longer in safe conditions, we need a tool to automatically detect their loss of autonomy by assessing the degree of performance of activities of daily living. This article presents an approach enabling the activities recognition of an elder living alone in a home equipped with noninvasive sensors. ...

Abstract

(Abridged) We investigate the far-infrared properties of X-ray sources detected in the Chandra Deep Field-South (CDF-S) survey using the ultra-deep 70um and 24um Spitzer observations taken in this field. We rely on stacking analyses of the 70um data to characterise the average 70um properties of the X-ray sources. Using Spitzer-IRS data of the Swift-BAT sample of z~0 active galactic nuclei (hereafter, AGNs), we show that the 70um/24um flux ratio can distinguish between AGN-dominated and starburst-dominated systems out to z~1.5. From stacking analysis we find that both high redshift ...

Abstract

In this paper, we propose augmented reality (AR) applications for equipment maintenance. The system is based on the projection and detection of infrared markers. We use an infrared projector to project markers onto the surface of the equipment to be maintained. These markers are invisible to the human-eye, but they could be clearly identified by the infrared camera. As a proof of concept, we have implemented a prototype camera system consisting of a conventional camera (scene camera) and an infrared camera ...

Abstract

Abstract I came to the attention of astronomers through inventing the low temperature bolometer at Texas Instruments. I was quickly drawn into pioneering infrared (IR) astronomy. I soon transferred to the National Radio Astronomy Observatory and then to the University of Arizona to make astronomy my focus. Parallel programs were getting under way at the California Institute of Technology, Cornell, the Universities of Minnesota and of California, San Diego. Although our methods were crude, discoveries were easy and exciting. I was ...

Abstract

High-index-contrast compact microdisk resonators in thermally evaporated As2S3 and Ge17Sb12S71 chalcogenide glass films are designed and fabricated using standard UV lithography and characterized. Our pulley coupler configuration demonstrates coupling of the resonators to monolithically integrated photonic wire waveguides without resorting to demanding fine-line lithography. Microdisk resonators in As2S3 support whispering-gallery-mode with cavity quality factors (Q) exceeding 2×105, the highest Q value reported in resonator structures in chalcogenide glasses to the best of our knowledge. We have successfully demonstrated a lab-on-a-chip prototype ...

Abstract

Ultra-luminous infrared galaxies (ULIRGs) are interesting objects withdramatic properties. Much efforts have been made to understand the physics oftheir luminous infrared emission and evolutionary stages. However, a largeULIRG sample is still needed to study the properties of their central blackholes (BHs), the black hole-host galaxy relation and their evolution. Weidentified 308 ULIRGs from the Sloan Digital Sky Survey Data Release 6, andclassified them into the NL ULIRGs (with only narrow emission lines) and theType I ULIRGs (with broad emission lines). About ...

Abstract

Femtosecond high-order harmonic transient absorption spectroscopy is used to observe electromagnetically induced transparency-like behavior as well as induced absorption in the extreme ultraviolet by laser dressing of the He 2s2p ( 1 P o ) and 2p 2 ( 1 S e ) double excitation states with an intense 800 nm field. Probing in the vicinity of the 1s 2  → 2s2p transition at 60.15 eV reveals the formation of an Autler–Townes doublet due to coherent coupling of the double excitation states. Qualitative ...

Abstract

Applications of space-based microwave radiometry to precipitation retrieval is addressed, focusing on model-based inversion techniques and optimal combination with other satellite sensors. Statistical integration of microwave radiometers with space-borne radars and thermal infrared radiometers is sketched. Examples of measurements and products are shown to emphasize the physical background of combined techniques. The concept of the newly approved NASA/NASDA Global Precipitation Mission (GPM), considered to be the Tropical Rainfall Measuring Mission follow-on international space program on precipitation remote sensing, is finally illustrated ...

Abstract

Satellite data from the Atmospheric Infrared Sounder (AIRS) is analyzed to examine regions of the upper troposphere that are supersaturated: where the relative humidity (RH) is greater than 100%. AIRS data compare well to other in situ and satellite observations of RH and provide daily global coverage up to 200 hPa, though satellite observations of supersaturation are highly uncertain. The climatology of supersaturation is analyzed statistically to understand where supersaturation occurs and how frequently. Supersaturation occurs in humid regions of the ...

Abstract

A global climatology of height-resolved variance scaling within the troposphere is presented using derived temperature (T) and water vapor (q) profiles from the Atmospheric Infrared Sounder (AIRS). The power law exponent of T variance scaling approaches 1.0 outside of the Tropics at scales > 500–800 km, but is closer to 0.3 at scales < 500 km, similar to exponents obtained from aircraft campaigns, numerical modeling, and theoretical studies. The T exponents in the Tropics at all scales become less than 0.3, ...

Abstract

We derive a compact all-loop-order expression for the IR-divergent part of the N=4 SYM four-gluon amplitude, which includes both planar and all subleading-color contributions, based on the assumption that the higher-loop soft anomalous dimension matrices are proportional to the one-loop soft anomalous dimension matrix, as has been recently conjectured. We also consider the Regge limit of the four-gluon amplitude, and we present evidence that the leading logarithmic growth of the subleading-color amplitudes is less severe than that of the planar amplitudes. We obtain 1/N^2 corrections to the gluon Regge ...

Abstract

A fibre optic technique based on the Fresnel reflection from the fibre tip is used for measurements of the refractive indices of various liquids at wavelengths of 1310 and 1551 nm. Reflection signals from liquid-fibre interface are compared with reflection signals from air-fibre interface to obtain the refractive index. Values of refractive indices for distilled water measured by this technique compare very well with known values at both wavelengths only if the fibre effective waveguide index is used. Applying the double-pulse ...

Abstract

Midinfrared absorption can be locally measured using a detection combining an atomic force microscope and a pulsed excitation. This is illustrated for the midinfrared bulk GaAs phonon absorption and for the midinfrared absorption of thin SiO2 microdisks. We show that the signal given by the cantilever oscillation amplitude of the atomic force microscope follows the spectral dependence of the bulk material absorption. The absorption spatial resolution achieved with microdisks is around 50 nanometer for an optical excitation around 22 micrometer wavelength. ...

Abstract

Diffuse optical tomography, also known as near infrared tomography, has been under investigation, for non-invasive functional imaging of tissue, specifically for the detection and characterization of breast cancer or other soft tissue lesions. Much work has been carried out for accurate modeling and image reconstruction from clinical data. NIRFAST, a modeling and image reconstruction package has been developed, which is capable of single wavelength and multi-wavelength optical or functional imaging from measured data. The theory behind the modeling techniques as well ...

Abstract

Visibly fluorescent proteins (FPs) from jellyfish and corals have revolutionized many areas of molecular and cell biology, but the use of FPs in intact animals, such as mice, has been handicapped by poor penetration of excitation light. We now show that a bacteriophytochrome from Deinococcus radiodurans, incorporating biliverdin as the chromophore, can be engineered into monomeric, infrared-fluorescent proteins (IFPs), with excitation and emission maxima of 684 and 708 nm, respectively; extinction coefficient >90,000 M-1 cm-1; and quantum yield of 0.07. IFPs ...