2,547 research outputs found
Who Controls the Price Level?
Under the guidance of different theories and the problem of dominance and activeness, this study gives a survey of the rapidly growing literature on Fiscal Theory of Price Level, which opens up new horizons in a non–Ricardian world and questions the effectiveness of monetary policy on price level determination.inflation, FTPL, non-Ricardian
Who Controls the Price Level?
Under the guidance of monetarist theory and the issue of dominance, this study is a survey of a rapidly growing literature on Fiscal Theory of Price Level, which opens up new horizons in a non –Ricardian world and questions the effectiveness of monetary policy on price level determination.inflation, price level, FTPL, non Ricardian
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. 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
Industrialization in Animal Agriculture: A Kalman Filter Analysis
Studies discussing the effects of technological developments on (animal) agricultural production argue that the effective usage of chemicals and genetic engineering increase control over production processes, which in turn decreases seasonality (one significant factor defining agricultural production) significantly and brings standardization to production. Studies on broilery also show that production is not limited by nature determined seasons. Supply side changes accompanied by changes in demand have led to more healthier, standardized products. Using tools of economics and statistics, this study documents this transformation in animal agricultural production of beef, pork and milk. Results indicate decreasing seasonality, thus the industralization of animal agriculture
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 -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 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 -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 -ray emission via proton-proton interactions followed by a
subsequent 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
-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 J1826130: A Very Hard -Ray Spectrum Source in the Galactic Plane
HESS J1826130 is an unidentified hard spectrum source discovered by
H.E.S.S. along the Galactic plane, the spectral index being = 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
Discovery of the VHE gamma-ray source HESS J1641-463
A new TeV source, HESS J1641-463, has been serendipitously discovered in the
Galactic plane by the High Energy Stereoscopic System (H.E.S.S.) at a
significance level of 8.6 standard deviations. The observations of HESS
J1641-463 were performed between 2004 and 2011 and the source has a moderate
flux level of 1.7% of the Crab Nebula flux at E > 1 TeV. HESS J1641-463 has a
rather hard photon index of 1.99 +- 0.13_stat +- 0.20_sys. HESS J1641-463 is
positionally coincident with the radio supernova remnant SNR G338.5+0.1, but no
clear X-ray counterpart has been found in archival Chandra observations of the
region. Different possible VHE production scenarios will be discussed in this
contribution.Comment: 5 pages, 5 figures, 2012 Fermi Symposium proceedings - eConf C12102
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
- …