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Opinion: Lighting for health (good or bad)
摘要： I have had the privilege to serve as Director of CIE Division 6 ‘Photobiology and Photochemistry’ since 2011. My two terms will end at the next CIE Quadrennial Session in Washington DC in 2019. Division 6 has historically concentrated on the adverse effects of optical radiation on people, publishing standards for the UV erythema action spectrum, non-melanoma skin cancer action spectrum and S009 on the photobiological safety of lamps and lamp systems (adopted by IEC as IEC 62471). During my tenure, although the concerns about harm have remained, there has been a greater focus on how light may be used to benefit humans, beyond vision. Manufacturers of lighting products, designers and installers all want to market their products or services to show how they can benefit the occupants of the lit space. It was becoming very clear that many claims were not supported by robust science.
关键词： Photobiology,Lighting for health,Optical radiation,Non-visual human responses,Photometry
更新于2025-09-23 15:21:01
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Calibrating the <i>James Webb Space Telescope</i> Filters as Star Formation Rate Indicators
摘要： We have calibrated the 6.5 m James Webb Space Telescope (JWST) mid-infrared (MIR) ?lters as star formation rate (SFR) indicators, using JWST photometry synthesized from Spitzer spectra of 49 low-redshift galaxies, which cover a wider luminosity range than most previous studies. We use Balmer-decrement-corrected Hα luminosity and synthesized MIR photometry to empirically calibrate the Spitzer, WISE, and JWST ?lters as SFR indicators. Our Spitzer and WISE calibrations are in good agreement with recent calibrations from the literature. While MIR luminosity may be directly proportional to SFR for high-luminosity galaxies, we ?nd a power-law relationship between MIR luminosity and SFR for low-luminosity galaxies (L ~ 1- ). We ?nd that for galaxies with an Hα luminosity of 10 erg s ), the corresponding JWST MIR ν Lν luminosity is between 1040.50 and 10. Power-law ?ts of JWST luminosity as a function of Hα luminosity have indices between 1.17 and 1.32. We ?nd that the scatter in the JWST ?lter calibrations decreases with increasing wavelength from 0.39 to 0.20 dex, although F1000W is an exception where the scatter is just 0.24 dex.
关键词： stars: formation,galaxies: general,galaxies: photometry,galaxies: evolution
更新于2025-09-23 15:19:57
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Photometric scaling relations of anti-truncated stellar discs in S0-Scd galaxies
摘要： Context. It has been recently found that the characteristic photometric parameters of anti-truncated discs in S0 galaxies follow tight scaling relations. Aims. We investigate whether similar scaling relations are satisfied by galaxies of other morphological types. Methods. We have analysed the trends in several photometric planes relating the characteristic surface brightness and scalelengths of the breaks and the inner and outer discs of local anti-truncated S0–Scd galaxies, using published data and fits performed to the surface brightness profiles of two samples of Type-III galaxies in the R and Spitzer 3.6 μm bands. We have performed linear fits to the correlations followed by different galaxy types in each plane, as well as several statistical tests to determine their significance. Results. We have found that 1) the anti-truncated discs of all galaxy types from Sa to Scd obey tight scaling relations both in R and 3.6 μm, as observed in S0s; 2) the majority of these correlations are significant accounting for the numbers of the available data samples; 3) the trends are clearly linear when the characteristic scalelengths are plotted on a logarithmic scale; and 4) the correlations relating the characteristic surface brightnesses of the inner and outer discs and the breaks with the various characteristic scalelengths significantly improve when the scalelengths are normalized to the optical radius of the galaxy. The observational uncertainties prevent us from discerning robustly whether the trends differ between the different types and bands, but we do not find statistical evidence of significant differences between the distributions of S0s and spirals or of barred and unbarred galaxies. These results suggest that the scaling relations of Type-III discs are independent of the morphological type and the presence (or absence) of bars within the observational uncertainties of the available datasets. However, larger and deeper samples are required to confirm this. Conclusions. The tight structural coupling implied by these scaling relations imposes strong constraints on the mechanisms proposed to explain the formation of anti-truncated stellar discs in the galaxies across the whole Hubble sequence.
关键词： galaxies: fundamental parameters,galaxies: spiral,galaxies: photometry,galaxies: structure,galaxies: evolution,galaxies: elliptical and lenticular, cD
更新于2025-09-19 17:15:36
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Frontier Fields: Combining HST, VLT, and <i>Spitzer</i> data to explore the <i>z</i> ~ 8 Universe behind the lensing cluster MACSJ0416.1?2403
摘要： Context. The Hubble Space Telescope (HST) Frontier Fields (HFFs) project started at the end of 2013 with the aim of providing extremely deep images of six massive galaxy clusters. One of the main goals of this program is to push several telescopes to their limits to provide the best current view of the earliest stages of the Universe. The analysis of the initial data has already demonstrated the huge capabilities of the program. Aims. We present a detailed analysis of z ～ 8 objects behind the HFFs lensing cluster, MACSJ0416.1-2403, combining 0.3?1.6 μm imaging from HST, ground-based Ks imaging from VLT HAWK-I, and 3.6 μm and 4.5 μm Spitzer Space Telescope. The images probe to 5σ depths of ≈29 AB for HST, 25.6 AB for HAWK-I, and ≈0.310 and 0.391 μJy at 3.6 and 4.5 μm, respectively. With these datasets, we assess the photometric properties of z ～ 8 galaxies in this ?eld, as well as their distribution in luminosity, to unprecedented sensitivity. Methods. We applied the classical Lyman break (LB) technique, which combines non detection criteria in bands blueward of the Lyman break at z ～ 8 and color-selection in bands redward of the break. To avoid contamination by mid-z interlopers, we required a strong break between optical and near-infrared data. We determined the photometric properties of z ～ 8 selected candidates using spectral energy distribution (SED)-?tting with standard library templates. The luminosity function at z ～ 8 is computed using a Monte-Carlo method taking advantage of the SED-?tting results. A piece of cautionary information is gleaned from new deep optical photometry of a previously identi?ed z ～ 8 galaxy in this cluster, which is now ?rmly detected as a mid-z interloper with a strong ≈1.5 mag Balmer break (between F606W and F125W). Using the SED of this interloper, we estimated the contamination rate of our MACSJ0416.1?2403 sample, and that of previous samples in Abell 2744 that were based on HFF data, we highlight the dangers of pushing the LB technique too close to the photometry limits. Results. Our selection reliably recovers four objects with mF160W ranging from 26.0 to 27.9 AB that are located in modest-ampli?cation regions (μ < 2.4). Two of the objects display a secondary break between the IRAC 3.6 μm and 4.5 μm bands, which could be associated to the Balmer break or emission lines at z ～ 8. The SED-?tting analysis suggests that all of these objects favor high-z solutions with no reliable secondary solutions. The candidates generally have star formation rates around ～10 M(cid:12)/yr and sizes ranging from 0.2 to 0.5 kpc, which agrees well with previous observations and expectations for objects in the early Universe. The sample size and luminosity distribution are consistent with previous ?ndings.
关键词： galaxies: formation,galaxies: photometry,galaxies: distances and redshifts,galaxies: evolution,galaxies: star formation,galaxies: high-redshift
更新于2025-09-19 17:15:36
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OmegaWINGS: OmegaCAM-VST observations of WINGS galaxy clusters
摘要： Context. Wide-field observations targeting galaxy clusters at low redshift are complementary to field surveys and provide the local benchmark for detailed studies of the most massive haloes in the local Universe. The Wide-field Nearby Galaxy-cluster Survey (WINGS) is a wide-field multi-wavelength survey of X-ray selected clusters at z = 0.04–0.07. The original 34' × 34' WINGS field of view has now been extended to cover a 1 deg2 field with both photometry and spectroscopy. Aims. We present the Johnson B- and V-band OmegaCAM at the VST observations of 46 WINGS clusters together with the data reduction, data quality, and Sextractor photometric catalogues. Methods. The data reduction was carried out with a modified version of the ESO-MVM (also known as ALAMBIC) reduction package, adding a cross-talk correction, the gain harmonisation, and a control procedure for problematic CCDs. The stray-light component was corrected for by employing our own observations of populated stellar fields. Results. With a median seeing of 1'' in both bands, our 25-min exposures in each band typically reach the 50% completeness level at V = 23.1 mag. The quality of the astrometric and photometric accuracy has been verified by comparison with the 2MASS and SDSS astrometry, and SDSS and previous WINGS imaging. Star-to-galaxy separation and sky-subtraction procedure were tested comparing them with previous WINGS data. Conclusions. The Sextractor photometric catalogues are publicly available at the CDS and will be included in the next release of the WINGS database on the Virtual Observatory together with the OmegaCAM reduced images. These data form the basis for a large ongoing spectroscopic campaign with AAOmega at the AAT and are being employed for a variety of studies.
关键词： galaxies: fundamental parameters,galaxies: clusters: general,galaxies: photometry,methods: observational,catalogs
更新于2025-09-19 17:15:36
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - The Possibilities of Using LED Photometry and Ellipsometry Technology for Monitoring the Aquatic Anvironment
摘要： This paper develops new information-instrumental tools for operative diagnostics of the water objects including a detection of negative processes in their functioning. These tools are based on the big data approach and use such instrumental means as multi-channel optical sensors using of which provides the e?ciency and reliability of the diagnostics results. The system consists of a LED spectrophotometer and a LED spectroellipsometer, an information interface, a set of algorithms for identifying spectral images, a database of spectral standards, algorithms for solving inverse problems of spectrophotometry, spectroellipsometry, and an algorithm for learning the recognition of spectral images. Information-modeling instrumental technology developed in this paper has adaptation function to the spatial water objects and provides their water quality diagnostics on the base of episodic in-situ measurements.
关键词： spectroellipsometer,spectrophotometer,ellipsometry,LED photometry,aquatic environment monitoring
更新于2025-09-19 17:13:59
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Quantification of Inflammation Following Nd:YAG Laser Capsulotomy and Assessing the Anti-inflammatory Effects of Nepafenac 0.1% and Betamethasone 0.1%
摘要： Purpose: To quantify the intraocular inflammation, measured using laser flare photometry (LFP), after Nd:YAG capsulotomy and compare the effects of different topical anti-inflammatory regimes. Methods: A single-center, prospective, randomized controlled study, which included 90 eyes of 90 patients with visually significant posterior capsular opacification. In all patients, Nd:YAG capsulotomy was done and was then randomized into three groups: (A) Topical betamethasone 0.1%; (B) Topical nepafenac 0.1%; and (C) Control group: did not receive any anti-inflammatory agent post capsulotomy. Results: There was a significant increase in the mean LFP values 2 h following laser capsulotomy (p < 0.001) and then declined gradually and came back to pre-laser values by 2 weeks in all three groups. The mean LFP values, central macular thickness, and best corrected visual acuity were comparable among groups. None developed central macular edema. Conclusion: Intraocular inflammation following Nd:YAG capsulotomies is minimal and transient. Routine use of prophylactic anti-inflammatory agents may be avoided.
关键词： posterior capsular opacification,laser flare photometry,Cataract surgery,YAG cap,YAG capsulotomy
更新于2025-09-19 17:13:59
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Depth-resolved fiber photometry with a single tapered optical fiber implant
摘要： Fiber photometry is increasingly utilized to monitor fluorescent sensors of neural activity in the brain. However, most implementations are based on flat-cleaved optical fibers that can only interface with shallow tissue volumes adjacent to the fiber. We exploit modal properties of tapered optical fibers (TFs) to enable light collection over an extent of up to 2 mm of tissue and multisite photometry along the taper. Using a single TF, we simultaneously observed distinct dopamine transients in dorsal and ventral striatum in freely moving mice performing a simple, operant conditioning task. Collection volumes from TFs can also be engineered in both shape and size by microstructuring the nonplanar surface of the taper, to optically target multiple sites not only in the deep brain but, in general, in any biological system or organ in which light collection is beneficial but challenging because of light scattering and absorption.
关键词： neural activity,tapered optical fibers,dopamine transients,fiber photometry,multisite photometry
更新于2025-09-16 10:30:52
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[IEEE 2019 Second Balkan Junior Conference on Lighting (Balkan Light Junior) - Plovdiv, Bulgaria (2019.9.19-2019.9.21)] 2019 Second Balkan Junior Conference on Lighting (Balkan Light Junior) - Influence of the Position of LED Luminaires on their Thermal Regimes in Photometrical Measurements with a Telecentric Photometer
摘要： The current paper experimentally obtained results for the heating of a LED luminaire put in different burning positions during photometric measurements. Two different goniophotometers are considered – telecentric, where the light distribution of the luminaire is measured while the luminaire is positioned with the light sources facing up (this is not its prescribed burning position) and mirror distributive gonio photometer (MDGP), where the light distribution is measured while the luminaire is in its prescribed burning position. The first equipment has the advantage, that although the luminaire is not in its burning position, the measurement is much faster than when MDGP is used, so the thermal regime of the luminaire under consideration remains normal.
关键词： telecentric photometer,LED luminaire photometry,burning position,heating of the luminaire
更新于2025-09-16 10:30:52
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Derivation and Experimental Verification of the near-field 2D and 3D optical intensities from a finite-size light emitting diode (LED)
摘要： We derive the near-field light intensity distributions of an inorganic LED on its surface and in volumetric space. Our closed-form solution for 3D intensity distribution for a finite-size LED is consistent with Lambert’s Cosine Law, which provides the 3D intensity distribution for an infinitesimal, flat light source. We also derive the formula for the 2D intensity distribution on a diode surface showing its similarity to a Gaussian function, which is typically used to approximate the surface light intensity profile for an LED and a laser diode. Our 2D intensity distribution function produces light propagation similar to the Gaussian beam propagation in space. However, unlike the Gaussian approximation, our formula invariably produces this behavior without assuming the refractive index inside the diode follows a quadratic function of the transverse spatial domains. Our 2D and 3D spatial intensity formulas in near-field for LEDs offer a unique way to calculate the peak intensity that occurs at the center of the flat LED source. We demonstrate, as expected, that the peak intensity increases with the size of the LED source as well as the brightness of each radiative electron-hole pair, which is a function of the drive current and quantum efficiency of the LED.
关键词： Near-field Photometry,Optical Waveguides,Display,Optical Wave Propagation,Closed-Form Solutions,and Lighting.,Lasers,Light Emitting Diodes,Mathematical Physics
更新于2025-09-16 10:30:52