15 research outputs found
High-energy and very high-energy gamma-ray emission from the magnetar SGR 1900+14 neighbourhood
Magnetar wind nebulae (MWNe), created by new-born millisecond magnetars, and
magnetar giant flares are PeVatron candidates and even potential sources of
ultra high energy () cosmic rays (UHECRs). Nonthermal
high-energy (HE, ) and very high-energy (VHE, ) -ray emission from magnetars' neighbourhoods should be
a promising signature of acceleration processes. We investigate a possibility
of explaining HE and VHE -ray emission from the vicinity of the
magnetar SGR 1900+14 by cosmic rays accelerated in a Supernova remnant of a
magnetar-related Supernova and/or in a MWN. Simulation of the observed HE (the
extended Fermi-LAT source 4FGL J1908.6+0915e) and VHE (the extended H.E.S.S.
source candidate HOTS J1907+091 and the point-like HAWC TeV source 3HWC
J1907+085) -ray emission, spatially coincident with the magnetar SGR
1900+14, was carried out in the framework of hadronic (pp collisions with a
subsequent pion decay) and leptonic (inverse Compton scattering of low energy
background photons by ultrarelativistic electrons) models. We show that under
reasonable assumptions about parameters of the circumstellar medium the
observed -ray emission of Fermi-LAT 4FGL J1908.6+0915e, H.E.S.S.
HOTSJ1907+091 and 3HWC J1907+085 sources may be explained or at least
considerably contributed by a (still undetected) magnetar-connected Hypernova
remnant and/or a MWN created by new-born millisecond magnetar with a large
reserve of rotational energy .Comment: 13 pages, 7 figure
Combined application of microbial preparation, mineral fertilizer and bioadhesive in production of leek
The research deals with additional fertilizing of leek cultivars Goliath and Tango with
bacterial preparation Organic-balance and mineral fertilizer DripFert N20P20K20 + Ме in
combination with adhesive agent of a natural origin Liposam. Field research was performed on
the experimental plots of the Department of Vegetable Growing of Uman National University of
Horticulture. The research focused on microbiological processes and formation of productivity
in the leek crops depending on the combination of preparations.
It has been established that the number of bacteria Azotobacter in the rhizosphere of leek
increased 2.8 times after a four-time fertilizing with bacterial preparation Organic-balance and
bioadhesive Liposam during vegetation. The maximum number of bacteria, including
Azotobacter, in the rhizosphere of leek, was recorded after a four-time fertilization with DripFert
N20P20K20 + Ме in combination with Organic-balance and Liposam. The share of influence of
additional fertilization on the microbiota of the rhizosphere made up 77–97%.
Leek cultivar Tango produced a larger assimilative leaf surface. Depending on the fertilizing the
maximum leaf surface and photosynthetic potential of leek cultivars Tango and Goliath were
recorded under combination of Organic-balance + DripFert N20P20K20 + Ме + Liposam. The
yielding capacity of variety Goliath was better than that one of the variety Tango regardless of
fertilizing. To make the growing technology of leek more environmental friendly it is advisable
to introduce in the growing technology bacterial preparation Organic-balance together with
Liposam. Utilization of these preparations improves crop yield, which makes up 0.6–0.7 t ha-1
for
variety Goliath and 1.1–2.7 t ha-1
for variety Tango correspondingly. The investigated leek
varieties had the maximum yields under combined application of Organic-balance + Liposam
with fertilizer DripFert N20P20K20 + Ме, which is by 18–24% higher than provided by plants
grown without fertilization
The Technology and Construction Methods of Digital Terrain Models
Using of digital maps in simulators will dynamically change the tasks options and improve the quality of military professionals. The paper said existing ways to get digital maps and focuses on the most promising of them.
Also identified the main stages of the automated vectorization process and analyzed algorithms used to implement them
Galactic transient sources with the Cherenkov Telescope Array
International audienceA wide variety of Galactic sources show transient emission at soft and hard X-ray energies: low-mass and high-mass X-ray binaries containing compact objects (e.g., novae, microquasars, transitional millisecond pulsars, supergiant fast X-ray transients), isolated neutron stars exhibiting extreme variability as magnetars as well as pulsar wind nebulae. Although most of them can show emission up to MeV and/or GeV energies, many have not yet been detected in the TeV domain by Imaging Atmospheric Cherenkov Telescopes. In this paper, we explore the feasibility of detecting new Galactic transients with the Cherenkov Telescope Array (CTA) and the prospects for studying them with Target of Opportunity observations. We show that CTA will likely detect new sources in the TeV regime, such as the massive microquasars in the Cygnus region, low-mass X-ray binaries with low-viewing angle, flaring emission from the Crab pulsar-wind nebula or other novae explosions, among others. We also discuss the multi-wavelength synergies with other instruments and large astronomical facilities
Galactic transient sources with the Cherenkov Telescope Array
International audienceA wide variety of Galactic sources show transient emission at soft and hard X-ray energies: low-mass and high-mass X-ray binaries containing compact objects (e.g., novae, microquasars, transitional millisecond pulsars, supergiant fast X-ray transients), isolated neutron stars exhibiting extreme variability as magnetars as well as pulsar wind nebulae. Although most of them can show emission up to MeV and/or GeV energies, many have not yet been detected in the TeV domain by Imaging Atmospheric Cherenkov Telescopes. In this paper, we explore the feasibility of detecting new Galactic transients with the Cherenkov Telescope Array (CTA) and the prospects for studying them with Target of Opportunity observations. We show that CTA will likely detect new sources in the TeV regime, such as the massive microquasars in the Cygnus region, low-mass X-ray binaries with low-viewing angle, flaring emission from the Crab pulsar-wind nebula or other novae explosions, among others. We also discuss the multi-wavelength synergies with other instruments and large astronomical facilities
Galactic transient sources with the Cherenkov Telescope Array
International audienceA wide variety of Galactic sources show transient emission at soft and hard X-ray energies: low-mass and high-mass X-ray binaries containing compact objects (e.g., novae, microquasars, transitional millisecond pulsars, supergiant fast X-ray transients), isolated neutron stars exhibiting extreme variability as magnetars as well as pulsar wind nebulae. Although most of them can show emission up to MeV and/or GeV energies, many have not yet been detected in the TeV domain by Imaging Atmospheric Cherenkov Telescopes. In this paper, we explore the feasibility of detecting new Galactic transients with the Cherenkov Telescope Array (CTA) and the prospects for studying them with Target of Opportunity observations. We show that CTA will likely detect new sources in the TeV regime, such as the massive microquasars in the Cygnus region, low-mass X-ray binaries with low-viewing angle, flaring emission from the Crab pulsar-wind nebula or other novae explosions, among others. We also discuss the multi-wavelength synergies with other instruments and large astronomical facilities
Galactic transient sources with the Cherenkov Telescope Array
International audienceA wide variety of Galactic sources show transient emission at soft and hard X-ray energies: low-mass and high-mass X-ray binaries containing compact objects (e.g., novae, microquasars, transitional millisecond pulsars, supergiant fast X-ray transients), isolated neutron stars exhibiting extreme variability as magnetars as well as pulsar wind nebulae. Although most of them can show emission up to MeV and/or GeV energies, many have not yet been detected in the TeV domain by Imaging Atmospheric Cherenkov Telescopes. In this paper, we explore the feasibility of detecting new Galactic transients with the Cherenkov Telescope Array (CTA) and the prospects for studying them with Target of Opportunity observations. We show that CTA will likely detect new sources in the TeV regime, such as the massive microquasars in the Cygnus region, low-mass X-ray binaries with low-viewing angle, flaring emission from the Crab pulsar-wind nebula or other novae explosions, among others. We also discuss the multi-wavelength synergies with other instruments and large astronomical facilities
Dark Matter Line Searches with the Cherenkov Telescope Array
International audienceMonochromatic gamma-ray signals constitute a potential smoking gun signature for annihilating or decaying dark matter particles that could relatively easily be distinguished from astrophysical or instrumental backgrounds. We provide an updated assessment of the sensitivity of the Cherenkov Telescope Array (CTA) to such signals, based on observations of the Galactic centre region as well as of selected dwarf spheroidal galaxies. We find that current limits and detection prospects for dark matter masses above 300 GeV will be significantly improved, by up to an order of magnitude in the multi-TeV range. This demonstrates that CTA will set a new standard for gamma-ray astronomy also in this respect, as the world's largest and most sensitive high-energy gamma-ray observatory, in particular due to its exquisite energy resolution at TeV energies and the adopted observational strategy focussing on regions with large dark matter densities. Throughout our analysis, we use up-to-date instrument response functions, and we thoroughly model the effect of instrumental systematic uncertainties in our statistical treatment. We further present results for other potential signatures with sharp spectral features, e.g.~box-shaped spectra, that would likewise very clearly point to a particle dark matter origin
Dark Matter Line Searches with the Cherenkov Telescope Array
International audienceMonochromatic gamma-ray signals constitute a potential smoking gun signature for annihilating or decaying dark matter particles that could relatively easily be distinguished from astrophysical or instrumental backgrounds. We provide an updated assessment of the sensitivity of the Cherenkov Telescope Array (CTA) to such signals, based on observations of the Galactic centre region as well as of selected dwarf spheroidal galaxies. We find that current limits and detection prospects for dark matter masses above 300 GeV will be significantly improved, by up to an order of magnitude in the multi-TeV range. This demonstrates that CTA will set a new standard for gamma-ray astronomy also in this respect, as the world's largest and most sensitive high-energy gamma-ray observatory, in particular due to its exquisite energy resolution at TeV energies and the adopted observational strategy focussing on regions with large dark matter densities. Throughout our analysis, we use up-to-date instrument response functions, and we thoroughly model the effect of instrumental systematic uncertainties in our statistical treatment. We further present results for other potential signatures with sharp spectral features, e.g.~box-shaped spectra, that would likewise very clearly point to a particle dark matter origin