Luminosity Data Research Articles

Investigating the Carbon Leakage Effect on the Environmental Kuznets Curve Using Luminosity Data

This paper studies the effect of carbon leakage on the environmental Kuznets curve (EKC) using satellite nighttime light data. I show that nighttime lighting is an important variable for estimating carbon dioxide emissions that is superior to other existing indicators and covers all countries in the world. I find evidence of an inverted-U shaped relationship between light and, thus, greenhouse gas emissions and income, with a turning point at approximately US $50,000. However, the relationship is primarily driven by changes in the structure of international trade, implying strong carbon leakage effects. Consequently, environmental regulations that become operative in only one part of the world may fail without global coordination.

Quantitative Estimation of the Velocity of Urbanization in China Using Nighttime Luminosity Data

Rapid urbanization with sizeable enhancements of urban population and built-up land in China creates challenging planning and management issues due to the complexity of both the urban development and the socioeconomic drivers of environmental change. Improved understanding of spatio-temporal characteristics of urbanization processes are increasingly important for investigating urban expansion and environmental responses to corresponding socioeconomic and landscape dynamics. In this study, we present an artificial luminosity-derived index of the velocity of urbanization, defined as the ratio of temporal trend and spatial gradient of mean annual stable nighttime brightness, to estimate the pace of urbanization and consequent changes in land cover in China for the period of 2000–2010. Using the Defense Meteorological Satellite Program–derived time series of nighttime light data and corresponding satellite-based land cover maps, our results show that the geometric mean velocity of urban dispersal at the country level was 0.21 km·yr−1 across 88.58 × 103 km2 urbanizing areas, in which ~23% of areas originally made of natural and cultivated lands were converted to artificial surfaces between 2000 and 2010. The speed of urbanization varies among urban agglomerations and cities with different development stages and urban forms. Particularly, the Yangtze River Delta conurbation shows the fastest (0.39 km·yr−1) and most extensive (16.12 × 103 km2) urban growth in China over the 10-year period. Moreover, if the current velocity holds, our estimates suggest that an additional 13.29 × 103 km2 in land area will be converted to human-built features while high density socioeconomic activities across the current urbanizing regions and urbanized areas will greatly increase from 52.44 × 103 km2 in 2010 to 62.73 × 103 km2 in China’s mainland during the next several decades. Our findings may provide potential insights into the pace of urbanization in China, its impacts on land changes, and accompanying alterations in environment and ecosystems in a spatially and temporally explicit manner.

Bringing ATLAS production to HPC resources - A use case with the Hydra supercomputer of the Max Planck Society

The possible usage of HPC resources by ATLAS is now becoming viable due to the changing nature of these systems and it is also very attractive due to the need for increasing amounts of simulated data.In recent years the architecture of HPC systems has evolved, moving away from specialized monolithic systems, to a more generic linux type platform. This change means that the deployment of non HPC specific codes has become much easier. The timing of this evolution perfectly suits the needs of ATLAS and opens a new window of opportunity.The ATLAS experiment at CERN will begin a period of high luminosity data taking in 2015. This high luminosity phase will be accompanied by a need for increasing amounts of simulated data which is expected to exceed the capabilities of the current Grid infrastructure.ATLAS aims to address this need by opportunistically accessing resources such as cloud and HPC systems. This paper presents the results of a pilot project undertaken by ATLAS and the MPP/RZG to provide access to the HYDRA supercomputer facility. Hydra is the supercomputer of the Max Planck Society, it is a linux based supercomputer with over 80000 cores and 4000 physical nodes located at the RZG near Munich.This paper describes the work undertaken to integrate Hydra into the ATLAS production system by using the Nordugrid ARC-CE and other standard Grid components. The customization of these components and the strategies for HPC usage are discussed as well as possibilities for future directions.

Stringent dilepton bounds on left-right models using LHC data

In canonical left-right symmetric models the lower mass bounds on the charged gauge bosons are in the ballpark of 3–4 TeV, resulting in much stronger limits on the neutral gauge boson ZR, making its production unreachable at the LHC. However, if one evokes different patterns of left-right symmetry breaking the ZR might be lighter than the WR± motivating an independent ZR collider study. In this work, we use the 8 TeV ATLAS 20.3 fb−1 luminosity data to derive robust bounds on the ZR mass using dilepton data. We find strong lower bounds on the ZR mass for different right-handed gauge couplings, excluding ZR masses up to ∼3.2 TeV. For the canonical LR model we place a lower mass bound of ∼2.5 TeV. Our findings are almost independent of the right-handed neutrino masses (∼2% effect) and applicable to general left-right models.

Lightning current and luminosity at and above channel bottom for return strokes and M‐components

We measured current and luminosity at the channel bottom of 12 triggered lightning discharges including 44 return strokes, 23 M-components, and 1 initial continuous current pulse. Combined current and luminosity data for impulse currents span a 10–90% risetime range from 0.15 to 192 µs. Current risetime and luminosity risetime at the channel bottom are roughly linearly correlated (τr,I = 0.71τr,L1.08). We observed a time delay between current and the resultant luminosity at the channel bottom, both measured at 20% of peak amplitude, that is approximately linearly related to both the luminosity 10–90% risetime (Δt20,b = 0.24τr,L1.12) and the current 10–90% risetime (Δt20,b = 0.35τr,I1.03). At the channel bottom, the peak current is roughly proportional to the square root of the peak luminosity (IP = 21.89LP0.57) over the full range of current and luminosity risetimes. For two return strokes we provide measurements of stroke luminosity vs. time for 11 increasing heights to 115 m altitude. We assume that measurements above the channel bottom behave similarly to those at the bottom and find that (1) one return stroke current peak decayed at 115 m to about 47% of its peak value at channel bottom, while the luminosity peak at 115 m decayed to about 20%, and for the second stroke 38% and 12%, respectively; and (2) measured upward return stroke luminosity speeds of the two strokes of 1.10 × 108 and 9.7 × 107 ms−1 correspond to current speeds about 30% faster. These results represent the first determination of return stroke current speed and current peak value above ground derived from measured return stroke luminosity data.

Towards the geometry of the Universe from data

We present a new algorithm that can reconstruct the full distributions of metric components within the class of spherically symmetric dust universes that may include a cosmological constant. The algorithm is capable of confronting this class of solutions with arbitrary data and opens a new observational window to determine the value of the cosmological constant. In this work we use luminosity and age data to constrain the geometry of the universe up to a redshift of $z = 1.75$. We show that, although current data are perfectly compatible with homogeneous models of the universe, simple radially inhomogeneous void models that are sometimes used as alternative explanations for the apparent acceleration of the late time universe cannot yet be ruled out. In doing so we reconstruct the density of cold dark matter out to $z = 1.75$ and derive constraints on the metric components when the universe was 10.5 Gyr old within a comoving volume of approximately 1 Gpc$^{3}$.

The informal economy of Rostov Oblast on the eve of the Ukrainian refugee crisis

Using a stochastic frontier production function at the raion (county) level of aggregation, Rostov Oblast rural economy's formal economic growth 2009–2013 is analyzed in conjunction with satellite luminosity data capturing both the formal and informal economy. Satellite luminosity data reveal a growing economy with higher levels of secondary education, access to a federal highway and availability of natural gas associated with wealthier raions. The region's ability to absorb unregistered Ukrainian refugees with both the wealthiest and one of the poorest performing raions right on the Ukrainian border is questionable though on the eve of the crisis most raions exhibited a growing informal and formal economy.

Selection biases in the gamma-ray burst Eiso – Lopt, X correlation

Abstract Gamma-ray burst (GRB) optical and X-ray afterglow luminosity is expected to correlate with the GRB isotropic equivalent kinetic energy of the outflow in the standard synchrotron model for GRB afterglows. Previous studies, using prompt GRB isotropic equivalent energy (Eiso) as a proxy for isotropic equivalent kinetic energy, have generally confirmed a correlation between X-ray and optical afterglow luminosities. Assuming that GRB afterglow luminosity does not evolve strongly with redshift, we identify a strong Malmquist bias in GRB optical and X-ray afterglow luminosity data. We show that selection effects dominate the observed Eiso–Lopt, X correlations, and have likely been underestimated in other studies. The bias is strongest for a subset of optically faint bursts m > 24 at 24 h with z > 2. After removing this optical selection bias, the Eiso–Lopt, X correlation for long GRBs is not statistically significant, but combining both long and short GRB luminosity data the correlation is significant. Using the median of the Eiso and Lopt, X distributions, we apply the synchrotron model assuming the same power-law index for short and long GRBs, but different microphysical parameter distributions. Comparing the ratio of optical and X-ray luminosities, we find tentative evidence that the fraction of post-shock energy in magnetic fields, ϵB, could be systematically higher in short GRBs compared to long GRBs.

Regional Inequality, Convergence, and its Determinants - A View from Outer Space

This paper provides a new data set of regional income inequalities within countries based on satellite nighttime light data. We first empirically study the relationship between luminosity data and regional incomes for those countries where regional income data are available. We subsequently use our estimation results for an out-ofsample prediction of regional incomes based on the luminosity data, which allows us to investigate regional income differentials in developing countries as well, where official income data are lacking. Based on the predicted incomes, we calculate commonly used measures of regional inequality within countries. Investigating changes in the dispersion of regional incomes over time reveals that approximately 71-80% of all countries face sigma-convergence. Finally, we study different major determinants of the level of regional inequality based on cross-section data. Panel regressions investigate the within-country changes in inequality, i.e., the determinants of the convergence process. We find evidence for an N-shaped relationship between development and regional inequality. Geography, mobility and trade openness are also highly important.

Statistics and Analysis of LEO Objects’ Luminosity

As one of basic properties of space objects, luminosity is frequently used for the identification of space objects, as well as for the calculation of their scattering cross sections. In general, space objects shine only by reflecting sunlight, their brightness observed by ground stations is affected by many factors. Since the multi-object photometric observation equipment operated five years ago, a large number of photometric data have been accumulated. This article estimates the overall accuracy of the data, and lists some typical situations in respect to the phase angle-magnitude (PA-m) relation for space objects. And the statistics are conducted on the luminosity data of more than two thousand low earth orbit (LEO) objects.

Prospects for Open Heavy Flavor Measurements in Heavy Ion andp+ACollisions in a Fixed-Target Experiment at the LHC

High luminosity data in a fixed-target experiment allow studying interactions of heavy quarks with nuclear matter in the intermediate energy range with extremely high precision. We present a feasibility study for open charm and bottom production measurements in the energy range of a fixed-target experiment at the LHC (AFTER@LHC). We demonstrate, that high-precision data from AFTER will allow answering two open questions: if there is a collective behavior of charm quarks inp+Acollisions at RHIC energy and if charm production is suppressed in the energy range ofsNN= 60–80 GeV. We argue that simultaneous measurement ofD0suppression as a function of traverse momentum at midrapidity and forward rapidity can help to pin down the mechanism of charm energy loss in the hot and dense nuclear medium.

Census from Heaven: An Estimate of Global Electricity Demand 'If Everyone Lived Like in OECD'

How much electricity does the world really need? Economic theory suggests that electricity demand depends on a number of factors such as per capita income, economic output, supply and cost of electricity. However, formal electricity demand models based on Gross Domestic Product (GDP), population growth and efficiency improvement assumptions may not capture the appropriate variables for responses at high geographical resolution level and, as a result, may be quite wrong about the prospective electricity need.This study proposed a method and then implemented it for the question of whether luminosity (measures of nighttime lights visible from space) could be used to improve estimates of electricity prospective demand in non-OECD countries at the high geographical resolution. Further, we investigated whether luminosity may serve as a proxy for electricity consumption. Luminosity data has an advantage over other proxies as night lights data are available over time and all space, but data on electricity consumption are unavailable for many lower income countries and generally are unavailable for most countries at sub-national levels. To the extent that luminosity is a good proxy for electricity consumption, we evaluated how much electricity the world would likely demand “if everyone lived like in OECD countries.”

Astrophysical Tests of Kinematical Conformal Cosmology in Fourth-Order Conformal Weyl Gravity

In this work we analyze kinematical conformal cosmology (KCC), an alternative cosmological model based on conformal Weyl gravity (CG), and test it against current type Ia supernova (SNIa) luminosity data and other astrophysical observations. Expanding upon previous work on the subject, we revise the analysis of SNIa data, confirming that KCC can explain the evidence for an accelerating expansion of the Universe without using dark energy or other exotic components. We obtain an independent evaluation of the Hubble constant, H_{0} = 67.53 km/s Mpc, very close to the current best estimates. The main KCC and CG parameters are re-evaluated and their revised values are found to be close to previous estimates. We also show that available data for the Hubble parameter as a function of redshift can be fitted using KCC and that this model does not suffer from any apparent age problem. Overall, KCC remains a viable alternative cosmological model, worthy of further investigation.

The Integrated Use of DMSP-OLS Nighttime Light and MODIS Data for Monitoring Large-Scale Impervious Surface Dynamics: A Case Study in the Yangtze River Delta

The timely and reliable estimation of imperviousness is essential for the scientific understanding of human-Earth interactions. Due to the unique capacity of capturing artificial light luminosity and long-term data records, the Defense Meteorological Satellite Program (DMSP)’s Operational Line-scan System (OLS) nighttime light (NTL) imagery offers an appealing opportunity for continuously characterizing impervious surface area (ISA) at regional and continental scales. Although different levels of success have been achieved, critical challenges still remain in the literature. ISA results generated by DMSP-OLS NTL alone suffer from limitations due to systemic defects of the sensor. Moreover, the majority of developed methodologies seldom consider spatial heterogeneity, which is a key issue in coarse imagery applications. In this study, we proposed a novel method for multi-temporal ISA estimation. This method is based on a linear regression model developed between the sub-pixel ISA fraction and a multi-source index with the integrated use of DMSP-OLS NTL and MODIS NDVI. In contrast with traditional regression analysis, we incorporated spatial information to the regression model for obtaining spatially adaptive coefficients at the per-pixel level. To produce multi-temporal ISA maps using a mono-temporal reference dataset, temporally stable samples were extracted for model training and validation. We tested the proposed method in the Yangtze River Delta and generated annual ISA fraction maps for the decade 2000–2009. According to our assessments, the proposed method exhibited substantial improvements compared with the standard linear regression model and provided a feasible way to monitor large-scale impervious surface dynamics.

The design and performance of the ATLAS jet trigger

The ATLAS jet trigger is an important element of the event selection process, providing data samples for studies of Standard Model physics and searches for new physics at the LHC. The ATLAS jet trigger system has undergone substantial modifications over the past few years of LHC operations, as experience developed with triggering in a high luminosity and high event pileup environment. In particular, the region-of-interest based strategy has been replaced by a full scan of the calorimeter data at the third trigger level, and by a full scan of the level-1 trigger input at level-2 for some specific trigger chains. Hadronic calibration and cleaning techniques are applied in order to provide improved performance and increased stability in high luminosity data taking conditions. In this note we discuss the implementation and operational aspects of the ATLAS jet trigger during 2011 and 2012 data taking periods at the LHC.

Jet-dominated quiescent states in black hole X-ray binaries: the case of V404 Cyg

Abstract The dynamical structure and radiative properties of the quiescent state (X-ray luminosity ≲1034 erg s−1) of black hole X-ray transients (BHXTs) remain unclear, mainly because of low luminosity and poor data quantity. We demonstrate that the simultaneous multi-wavelength (including radio, optical, ultraviolet and X-ray bands) spectrum of V404 Cyg in its bright quiescent state can be well described by the radiation from the companion star and more importantly, the compact jet. Neither the outer thin disc nor the inner hot accretion flow is important in the total spectrum. Together with recent findings, i.e. the power-law X-ray spectrum and the non-variable X-ray spectral shape (or constant photon index) in contrast to the dramatic change in the X-ray luminosity, we argue the quiescent state spectrum of BHXTs is actually jet-dominated. Additional observational properties consistent with this jet model are also discussed as supporting evidence.

A sharper image? Estimates of the precision of nighttime lights as a proxy for economic statistics

Much aggregate social-science analysis relies upon the standard national income and product accounts as a source of economic data. These are recognized to be defective in many poor countries, and are missing at the regional level for large parts of the world. Using updated luminosity (or nighttime lights) data, the present study examines whether such data contain useful information for estimating national and regional incomes and output. The bootstrap method is used for estimating the statistical precision of the estimates of the contribution of the lights proxy. We conclude that there may be substantial cross-sectional information in lights data for countries with low-quality statistical systems. However, lights data provide very little additional information for countries with high-quality data wherever standard data are available. The largest statistical concerns arise from uncertainties about the precision of standard national accounts data.

The Road Oft Taken: Highways to Spatial Development

Most estimates of the economic impacts of transit networks compare regions along network routes to neighboring regions away from such routes. However, in the presence of spatial spillovers in economic activity such a method will underestimate the true effect of roads and railways. In this paper, I take into account spatial spillovers in estimating the overall impacts of transit networks in India. I use an empirical strategy relying on the historical placement of major cities: by connecting nodal cities with straight lines, I instrument for the endogenous placement of these networks. Using night-time luminosity data as a measure of economic activity, I estimate the parameters of a predictive model that incorporates these spillovers, which then performs well in an out-of-sample exercise. I find that being close to transit networks between cities led to greater economic activity in the 1990s and that such activity spread to neighboring regions, substantially increasing the overall impacts. Ignoring the spillovers produces income elasticities that are only 27% of the true overall effects of such routes. These geographic externalities led to a rapid rate of convergence in incomes across regions, highlighting how transit networks and spatial spillovers together, strongly determined the geographic spread and temporal changes in the economic development of the region.

Luminosity–redshift (L−z) relation and the blazar sequence for low power blazars

This paper presents an alternative interpretation for the wide scatter and apparent lack of anti-correlation in the relationship between the spectral luminosity (Lν) and synchrotron peak frequency (νpeak) in a sample of BL Lac Objects contained in Wu et al. (Astron. Astrophys. 466:43, 2007) compilation. The apparent lack of correlation between the parameters contradicts the blazar sequence proposed by Fossati et al. (in Mon. Not. R. Astron. Soc. 299:433, 1998), which predicts a general decline in Lν with increasing νpeak. Analysis of the radio luminosity and synchrotron peak frequency data of the sample reveals a strong selection effect, due to Malmquist bias. We show that a clear anti-correlation (r∼−0.7) between the radio luminosity at synchrotron peak (Lpeak) and νpeak exists for the BL Lac sample above some redshift cut-off (zc=0.3), which may correspond to the flux limit of the sample. The results are not only in agreement with FRI–BL Lac unification, but also suggest that the present data is consistent with the blazar sequence.

Cold Nuclear Matter Effects and Heavy Quark Production in PHENIX

The PHENIX experiment uses semileptonic decay channels to measure open and closed heavy flavor cross sections across the rapidity range $-2.2 < y < 2.4$. High luminosity data are now available for p+p, d+Au, Cu+Cu and Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV, and for Au+Au collisions at $\sqrt{s_{NN}}$= 62 GeV. We discuss recent d+Au results for open heavy flavor and $J/\psi$ production, and discuss their implications for the cold nuclear matter contributions to heavy flavor production in heavy ion collisions.