HESS J1641-463, a very hard spectrum TeV gamma-ray source in the Galactic plane

HESS J1641-463 is a unique source discovered by the High Energy Stereoscopic System (H.E.S.S.) telescope array in the multi-TeV domain. The source had been previously hidden in the extended tail of emission from the bright nearby source HESS J1640-465. However, the analysis of the very-high-energy (VHE) data from the region at energies above 4 TeV revealed this new source at a significance level of 8.5$\sigma$. HESS J1641-463 showed a moderate flux level F(E > 1 TeV) = (3.64 +/- 0.44_stat +/- 0.73_sys) 10^-13 cm^-2s^-1, corresponding to 1.8% of the Crab Nebula flux above the same energy, and a hard spectrum with a photon index Gamma = 2.07 +/- 0.1_stat +/- 0.20_sys. The light curve was investigated for evidence of variability, but none was found on both short (28-min observation) and long (yearly) timescales. HESS J1641-463 is positionally coincident with the radio supernova remnant (SNR) G338.5+0.1. There is no clear X-ray counterpart of the SNR, although Chandra and XMM-Newton data reveal some weak emission that may be associated. If the emission from HESS J1641-463 is produced by cosmic ray protons colliding with the ambient gas, then the proton spectrum extends up to 0.1 PeV (99% confidence level) and likely to higher energies, > 0.27 PeV (90% confidence level). If this is the case, then HESS J1641-463 may be a member of a larger source population contributing to the Galactic cosmic-ray flux around the knee.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherland

Application of Customer Lifetime Value Model in Make-to-Order Manufacturing

PURPOSE: The applicability of the customer life time value (CLV) concept goes beyond consumer markets. Specifically, the purpose of this paper is to show how a make-to-order manufacturing company in a supply chain can set customer-focus manufacturing strategies using CLV. DESIGN/METHODOLOGY/APPROACH: Data from an integrated steel plant is used to calculate the life time value of customers based on the past value, the potential value, and their loyalty. The past value of a customer is based on the historical data and the future value of a customer is then forecasted. The loyalty index of a customer is determined by survey results. FINDINGS: In general, it was found that the CLV for the most valuable customers increases exponentially and the top 28 percent of customers constitute 80 percent of the total value of all customers. RESEARCH LIMITATIONS/IMPLICATIONS: This study focuses on make-to-order manufacturing organizations and the three strategies suggested for business process improvement need to be re-evaluated for make-to-stock or mass production. PRACTICAL IMPLCATIONS: Based on these results, the authors suggest three strategies for business process improvement and revenue growth for the plant. ORIGINALITY/VALUE: This study constitutes an initial effort to develop a CLV model for make-to-order manufacturing organizations for improving plant performance. The model links customers with not only the front office functions but also with ERP systems. Organizations that are part of value chains can benefit significantly from CLV applications

Very high energy emission from the hard spectrum sources HESS J1641-463, HESS J1741-302 and HESS J1826-130

A recent study of the diffuse $\gamma$-ray emission in the Central Molecular Zone using very high energy (VHE, E $>$ 0.1 TeV) H.E.S.S. data suggests that the Galactic Center (GC) is the most plausible supplier of Galactic ultra-relativistic cosmic-rays (CRs) up to the knee at about 10$^{15}$ eV (PeV). However, the GC might not be the only source capable to accelerate CRs up to PeV energies in the Galaxy. Here we present H.E.S.S. data analysis results and interpretation of three H.E.S.S. sources, with spectra extending beyond 10 TeV and relatively hard spectral indices compared with the average spectral index of H.E.S.S. sources, namely HESS J1641-463, HESS J1741-302 and HESS J1826-130. Although the nature of these VHE $\gamma$-ray sources is still open, their spectra suggest that the astrophysical objects producing such emission must be capable of accelerating the parental particle population up to energies of at least several hundreds of TeV. Assuming a hadronic scenario, dense gas regions can provide rich target material for accelerated particles to produce VHE $\gamma$-ray emission via proton-proton interactions followed by a subsequent $\pi^{0}$ decay. Thus, detailed investigations of the interstellar medium along the line of sight to all of these sources have been performed by using data from available atomic and molecular hydrogen surveys. The results point out the existence of dense interstellar gas structures coincident with the best fit positions of these sources. One can find possible hadronic models with CRs being accelerated close to the PeV energies to explain the $\gamma$-ray emission from all of these sources, which opens up the possibility that a population of PeV CR accelerators might be active in the Galaxy.Comment: 8 pages, 2 figures, in Proceedings of 35th ICRC, Busan (Korea) 201

HESS J1826−-130: A Very Hard γ\gamma-Ray Spectrum Source in the Galactic Plane

HESS J1826$-$130 is an unidentified hard spectrum source discovered by H.E.S.S. along the Galactic plane, the spectral index being $\Gamma$ = 1.6 with an exponential cut-off at about 12 TeV. While the source does not have a clear counterpart at longer wavelengths, the very hard spectrum emission at TeV energies implies that electrons or protons accelerated up to several hundreds of TeV are responsible for the emission. In the hadronic case, the VHE emission can be produced by runaway cosmic-rays colliding with the dense molecular clouds spatially coincident with the H.E.S.S. source.Comment: 6 pages, 3 figures, Proceedings of the 6th International Symposium on High Energy Gamma-Ray Astronomy (Gamma2016), Heidelberg, German

Estimating the Leverage Parameter of Continuous-time Stochastic Volatility Models Using High Frequency S&P 500 VIX

This paper proposes a new method for estimating continuous-time stochastic volatility (SV) models for the S&P 500 stock index process using intraday high-frequency observations of both the S&P 500 index and the Chicago Board of Exchange (CBOE) implied (or expected) volatility index (VIX). Intraday high-frequency observations data have become readily available for an increasing number of financial assets and their derivatives in recent years, but it is well known that attempts to estimate the parameters of popular continuous-time models can lead to nonsensical estimates due to severe intraday seasonality. A primary purpose of the paper is to estimate the leverage parameter, , that is, the correlation between the two Brownian motions driving the diffusive components of the price process and its spot variance process, respectively. We show that, under the special case of Heston’s (1993) square-root SV model without measurement errors, the “realized leverage”, or the realized covariation of the price and VIX processes divided by the product of the realized volatilities of the two processes, converges to in probability as the time intervals between observations shrink to zero, even if the length of the whole sample period is fixed. Finite sample simulation results show that the proposed estimator delivers accurate estimates of the leverage parameter, unlike existing methods

MWL observations of VHE blazars in 2006

In 2006 the MAGIC telescope observed the well known very high energy (VHE, > 80 GeV) blazars Mrk 421 and Mrk 501 in the course of multi-wavelength campaigns, comprising measurements in the optical, X-ray and VHE regime. MAGIC performed additional snapshot observations on Mrk 421 around the MWL campaigns and detected the source each night with high significance, establishing once more flux variability on nightly scales for this object. For certain nights, the integral flux exceeded the one of Crab significantly, whereas the truly simultaneous observations have been conducted in a rather low flux state. The MAGIC observations contemporaneous to XMM-Newton revealed clear intra-night variability. No significant correlation between the spectral index and the flux could be found for the nine days of observations. The VHE observations of Mrk 501 have been conducted during one of the lowest flux states ever measured by MAGIC for this object. The VHE and optical light curves do not show significant variability, whereas the flux in X-rays increased by about 50 %. In this contribution, the results of the MAGIC observations will be presented in detail.Comment: Contribution to the 31st ICRC, Lodz, Poland, July 200

Multicomponent bi-superHamiltonian KdV systems

It is shown that a new class of classical multicomponent super KdV equations is bi-superHamiltonian by extending the method for the verification of graded Jacobi identity. The multicomponent extension of super mKdV equations is obtained by using the super Miura transformation