5,632 research outputs found
Charting the TeV Milky Way: H.E.S.S. Galactic plane survey maps, catalog and source populations
Very-high-energy (VHE, E>100 GeV) gamma-rays provide a unique view of the
non-thermal universe, tracing the most violent and energetic phenomena at work
inside our Galaxy and beyond. The latest results of the H.E.S.S. Galactic Plane
Survey (HGPS) undertaken by the High Energy Stereoscopic System (H.E.S.S.), an
array of four imaging atmospheric Cherenkov telescopes located in Namibia, are
described here. The HGPS aims at the detection of cosmic accelerators with
environments suitable for the production of photons at the highest energies and
has led to the discovery of an unexpectedly large and diverse population of
over 60 sources of TeV gamma rays within its current range of l = 250 to 65
degrees in longitude and |b|<3.5 degrees in latitude. The data set of the HGPS
comprises 2800 hours of high-quality data, taken in the years 2004 to 2013. The
sensitivity for the detection of point-like sources, assuming a power-law
spectrum with a spectral index of 2.3 at a statistical significance of 5 sigma,
is now at the level of 2% Crab or better in the core HGPS region. The latest
maps of the inner Galaxy at TeV energies are shown alongside an introduction to
the first H.E.S.S. Galactic Plane Survey catalog. Finally, in addition to an
overview of the H.E.S.S. Galactic source population a few remarkable, recently
discovered sources will be highlighted.Comment: 8 pages, 6 figures, in Proceedings of the 48th Rencontres de Moriond
(2013), La Thuile (Italy
Detection of very-high-energy gamma-ray emission from the vicinity of PSR B1706-44 with H.E.S.S
The energetic pulsar PSR B1706-44 and the adjacent supernova remnant (SNR)
candidate G 343.1-2.3 were observed by H.E.S.S. during a dedicated
observational campaign in 2007. A new source of very-high-energy (VHE; E > 100
GeV) gamma-ray emission, HESS J1708-443, was discovered with its centroid at
RA(J2000) = 17h08m10s and Dec(J2000) = -44d21', with a statistical error of 3
arcmin on each axis. The VHE gamma-ray source is significantly more extended
than the H.E.S.S. point-spread function, with an intrinsic Gaussian width of
0.29 +/- 0.04 deg. Its energy spectrum can be described by a power law with a
photon index Gamma = 2.0 +/- 0.1 (stat) +/- 0.2 (sys). The integral flux
measured between 1-10 TeV is ~17% of the Crab Nebula flux in the same energy
range. The possible associations with PSR B1706-44 and SNR G343.1-2.3 are
discussed.Comment: 4+ pages, 2 figures; v1 submitted to ICRC Proceedings on 15 May 2009;
v2 has additional references and minor change
New unidentified H.E.S.S. Galactic sources
H.E.S.S. is one of the most sensitive instruments in the very high energy
(VHE; > 100 GeV) gamma-ray domain and has revealed many new sources along the
Galactic Plane. After the successful first VHE Galactic Plane Survey of 2004,
H.E.S.S. has continued and extended that survey in 2005-2008, discovering a
number of new sources, many of which are unidentified. Some of the unidentified
H.E.S.S. sources have several positional counterparts and hence several
different possible scenarios for the origin of the VHE gamma-ray emission;
their identification remains unclear. Others have so far no counterparts at any
other wavelength. Particularly, the lack of an X-ray counterpart puts serious
constraints on emission models. Several newly discovered and still unidentified
VHE sources are reported here.Comment: ICRC 2009 proceeding
Bound vortex states and exotic lattices in multi-component Bose-Einstein condensates: The role of vortex-vortex interaction
We numerically study the vortex-vortex interaction in multi-component
homogeneous Bose-Einstein condensates within the realm of the Gross-Pitaevskii
theory. We provide strong evidences that pairwise vortex interaction captures
the underlying mechanisms which determine the geometric configuration of the
vortices, such as different lattices in many-vortex states, as well as the
bound vortex states with two (dimer) or three (trimer) vortices. Specifically,
we discuss and apply our theoretical approach to investigate intra- and
inter-component vortex-vortex interactions in two- and three-component
Bose-Einstein condensates, thereby shedding light on the formation of the
exotic vortex configurations. These results correlate with current experimental
efforts in multi-component Bose-Einstein condensates, and the understanding of
the role of vortex interactions in multiband superconductors.Comment: Published in PR
Produção de frutos e estimativas de parâmetros genéticos em pimenta-de-cheiro.
O objetivo deste trabalho foi avaliar a produção de dez acessos de pimenta-de-cheiro e estimar parâmetros genéticos importantes para o melhoramento genético
Antimicrobial activity of essential oils from Piper hispidum and Piper hispidinervum.
The objective of this work was to evaluate the antimicrobial activities of the plants Piper hispidum and P. hispidinervum
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