scholarly journals Gamma-rays from SS433: evidence for periodicity

2019 ◽  
Vol 485 (2) ◽  
pp. 2970-2975 ◽  
Author(s):  
Kajwan Rasul ◽  
Paula M Chadwick ◽  
Jamie A Graham ◽  
Anthony M Brown
Keyword(s):  
Energy Range ◽  
Photon Energy ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Temporal Analysis ◽  
Photon Energy Range ◽  
X Ray ◽  
Relativistic Jet ◽  
Gamma Ray Emission

ABSTRACT In this paper we present our study of the gamma-ray emission from the microquasar SS433. Integrating over 9 yr of Fermi-LAT Pass 8 data, we detect SS433 with a significance of ∼13σ in the 200 to 500 MeV photon energy range, with evidence for an extension in the direction of the w1 X-ray ‘hotspot’. A temporal analysis reveals evidence for modulation of SS433’s gamma-ray emission with the precession period of its relativistic jet. This suggests that at least some of SS433’s gamma-ray emission originates close to the object rather than from the jet termination regions.

scholarly journals Radio jets and gamma-ray emission in radio-silent narrow-line Seyfert 1 galaxies

2018 ◽  
Vol 614 ◽  
pp. L1 ◽  
Author(s):  
A. Lähteenmäki ◽  
E. Järvelä ◽  
V. Ramakrishnan ◽  
M. Tornikoski ◽  
J. Tammi ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Spiral Galaxies ◽  
Narrow Line ◽  
Radio Jets ◽  
Relativistic Jet ◽  
Gamma Ray Emission

We have detected six narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz that were previously classified as radio silent and two that were classified as radio quiet. These detections reveal the presumption that NLS1 galaxies labelled radio quiet or radio silent and hosted by spiral galaxies are unable to launch jets to be incorrect. The detections are a plausible indicator of the presence of a powerful, most likely relativistic jet because this intensity of emission at 37 GHz cannot be explained by, for example, radiation from supernova remnants. Additionally, one of the detected NLS1 galaxies is a newly discovered source of gamma rays and three others are candidates for future detections.

A scanning transmission X-ray microscope at the Pohang Light Source

2018 ◽  
Vol 25 (3) ◽  
pp. 878-884 ◽  
Author(s):  
Hyun-Joon Shin ◽  
Namdong Kim ◽  
Hee-Seob Kim ◽  
Wol-Woo Lee ◽  
Chae-Soon Lee ◽  
...  
Keyword(s):  
Energy Range ◽  
Light Source ◽  
Photon Energy ◽  
Chemical State ◽  
Photon Energy Range ◽  
X Rays ◽  
X Ray ◽  
Space Resolution ◽  
Scanning Transmission ◽  
Pohang Light Source

A scanning transmission X-ray microscope is operational at the 10A beamline at the Pohang Light Source. The 10A beamline provides soft X-rays in the photon energy range 100–2000 eV using an elliptically polarized undulator. The practically usable photon energy range of the scanning transmission X-ray microscopy (STXM) setup is from ∼150 to ∼1600 eV. With a zone plate of 25 nm outermost zone width, the diffraction-limited space resolution, ∼30 nm, is achieved in the photon energy range up to ∼850 eV. In transmission mode for thin samples, STXM provides the element, chemical state and magnetic moment specific distributions, based on absorption spectroscopy. A soft X-ray fluorescence measurement setup has been implemented in order to provide the elemental distribution of thicker samples as well as chemical state information with a space resolution of ∼50 nm. A ptychography setup has been implemented in order to improve the space resolution down to 10 nm. Hardware setups and application activities of the STXM are presented.

scholarly journals Centaurus A at Hard X-Rays and Soft Gamma-Rays

2010 ◽  
Vol 27 (4) ◽  
pp. 431-438 ◽  
Author(s):  
H. Steinle
Keyword(s):  
Energy Range ◽  
Spatial Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Spectral Energy ◽  
X Rays ◽  
Satellite Mission ◽  
X Ray

AbstractCen A, at a distance of less than 4 Mpc, is the nearest radio-loud AGN. Its emission is detected from radio to very-high energy gamma-rays. Despite the fact that Cen A is one of the best studied extragalactic objects the origin of its hard X-ray and soft gamma-ray emission (100 keV <E< 50 MeV) is still uncertain. Observations with high spatial resolution in the adjacent soft X-ray and hard gamma-ray regimes suggest that several distinct components such as a Seyfert-like nucleus, relativistic jets, and even luminous X-ray binaries within Cen A may contribute to the total emission in the MeV regime that has been detected with low spatial resolution. As the Spectral Energy Distribution of Cen A has its second maximum around 1 MeV, this energy range plays an important role in modeling the emission of (this) AGN. As there will be no satellite mission in the near future that will cover this energies with higher spatial resolution and better sensitivity, an overview of all existing hard X-ray and soft gamma-ray measurements of Cen A is presented here defining the present knowledge on Cen A in the MeV energy range.

Reducing the thermal deformation of InSb crystal by using double-bounce HHRMs in the TPS tender X-ray absorption spectroscopy beamline

2021 ◽  
Vol 28 (4) ◽  
Author(s):  
Din-Goa Liu ◽  
Ming-Han Lee ◽  
Ying-Jui Lu ◽  
Jyh-Fu Lee ◽  
Chi-Liang Chen
Keyword(s):  
Energy Range ◽  
Photon Energy ◽  
Absorption Spectroscopy ◽  
Thermal Load ◽  
Incident Angle ◽  
Silicon Surfaces ◽  
Photon Energy Range ◽  
Double Crystal ◽  
X Ray ◽  
X Ray Absorption

The Taiwan Photon Source (TPS) with high brightness and energy tunability is suitable for applications in spectroscopy. The tender X-ray absorption beamline will be optimized for X-ray absorption spectroscopy measurements using a bending-magnet source in a unique photon energy range (1.7–10 keV) and two crystal pairs [InSb(111) and Si(111)] separated using back-to-back double-crystal monochromators (DCMs). InSb crystals are typically used in the lower photon energy range of 1.7–3.5 keV. However, the poor thermal conductivity of InSb crystals leads to severe deformation. This factor should be considered when the monochromator is installed on a tender X-ray beamline in a storage ring with a high power density. There are many approaches to reducing the thermal load on the first crystal of a DCM. Double-bounce high harmonics rejection mirrors in front of the DCM serve not only to reduce the high-order harmonics but also to absorb considerable quantities of heat. Two coating stripes on the silicon surfaces with a variable incident angle will be key to solving the thermal load on this beamline.

scholarly journals Physics of Reflective Optics for the Soft Gamma-Ray Photon Energy Range

2013 ◽  
Vol 111 (2) ◽  
Author(s):  
Mónica Fernández-Perea ◽  
Marie-Anne Descalle ◽  
Regina Soufli ◽  
Klaus P. Ziock ◽  
Jennifer Alameda ◽  
...  
Keyword(s):  
Energy Range ◽  
Photon Energy ◽  
Gamma Ray ◽  
Photon Energy Range ◽  
Reflective Optics

MGNS experiment science investigations during BepiColombo cruise

2020 ◽  
Author(s):  
Alexander Kozyrev ◽  
Maxim Litvak ◽  
Anton Sanin ◽  
Alexey Malakhov ◽  
Igor Mitrofanov ◽  
...  
Keyword(s):  
Energy Range ◽  
Energy Resolution ◽  
Gamma Rays ◽  
Time Resolution ◽  
Solar Flares ◽  
Gamma Ray ◽  
Galactic Cosmic Rays ◽  
Wide Energy Range ◽  
Gamma Ray Emission ◽  
Mars Odyssey

&lt;p&gt;The Mercurian Gamma-ray and Neutron Spectrometer (MGNS) is a scientific instrument developed to study the elementary composition of the Mercury&amp;#8217;s sub-surface by measurements of neutron and gamma-ray emission of the planet. MGNS measures neutron fluxes in a wide energy range from thermal energy up to 10 MeV and gamma-rays in the energy range of 300 keV up to 10 MeV with the energy resolution of 5% FWHM at 662 keV and of 2% at 8 MeV. The innovative crystal of CeBr3 is used for getting such a good energy resolution for a scintillation detector of gamma-rays.&lt;/p&gt; &lt;p&gt;During the BC long cruise to Mercury, it is planned that the MGNS instrument will operate practically continuously to perform measurements of neutrons and gamma-ray fluxes for achieving two main goals of investigations.&lt;/p&gt; &lt;p&gt;The first goal is monitoring of the local radiation background of the prompt spacecraft emission due to bombardment by energetic particles of Galactic Cosmic Rays. This data will be taken into account at the mapping phase of the mission on the orbit around Mercury. Detailed knowledge of the spacecraft background radiation during the cruise will help to derive the data for neutron and gamma-ray emission of the planet at the mapping stage of the mission because many elements, like Mg, Na, O and others, the abundance of which at the uppermost layer of the planet is studied, are also present in the material of the spacecraft. Indeed, the nuclear lines of Al, Mg and O are well-pronounced in the spectrum, which are also expected to be detectable in the gamma-ray spectrum of the Mercury emission.&lt;/p&gt; &lt;p&gt;The second goal of MGNS cruise operations is the participation in the Inter Planetary Network (IPN) program for the localization of sources of Gamma-Ray Bursts in the sky. In fact, the localization accuracy by the interplanetary triangulation technique is inversely proportional to the distance between the spacecrafts that jointly detected a GRB. Before the launch of BepiColombo, the IPN network included a group of spacecrafts in the near-to-Earth orbit (e.g. Konus-Wind, Fermi-GBM, INTEGRAL, Insight-HXMT) and the Mars Odyssey spacecraft on the orbit around Mars. Now, MGNS provides another interplanetary location, potentially increasing the accuracy of GRBs localization. During the first 13 months of continuous operation, MGNS detected 24 GRB's. Pre-set value of time resolution for continuous measurements of profiles of GRBs is 20 seconds. Since of November 14, 2019, the BC Mission Operation Centre has allocated downlink resources to run MGNS continuously in a 1 sec time resolution for GRB measurements. The GRB detection rate, based on data with a time resolution of 1 sec is about 2-3 GRB's per month.&lt;/p&gt; &lt;p&gt;Gamma-rays of solar flares are also detectable by MGNS. Solar flares are nonstationary and anisotropic processes and the ability to observe them from different directions in the Solar system is crucial for further understanding their developments and propagation, as it was demonstrated in the case of HEND instrument on board Mars Odyssey. The Sun cycle is presently around its minimum, and MGNS has not detected any solar events during its first 7 months of the cruise, but the flight to Mercury is long enough and many future flares are expected to be detected.&lt;/p&gt; &lt;p&gt;The MGNS instrument will also perform special sessions of measurements during flybys of Earth, Venus and Mercury with the objective to measure neutron and gamma-ray albedo of the upper atmosphere of Earth and Venus and of the surface of Mercury. Another objective is to test the computational model of the local background of the spacecraft using the data measured at different orbital phases of flyby trajectories. The low altitude flybys (such as the 700 km flyby for Venus and three 200 km flybys for Mercury) would be the most useful for such tests being BC maximally shadowed for cosmic radiation by the actual planet. Neutron and gamma-ray measurements during Earth flybys enable investigation of interaction between solar wind and Earth environments as well as studies of spacecraft neutron and gamma-ray background upon its passage through the Earth's radiation belts.&lt;/p&gt;

A REVIEW OF PARTICLE-INDUCED X-RAY EMISSION IN GEOLOGY

1991 ◽  
Vol 01 (04) ◽  
pp. 311-338 ◽  
Author(s):  
J. D. MACARTHUR ◽  
XIN-PEI MA
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Light Element ◽  
X Rays ◽  
Geological Samples ◽  
Geological Material ◽  
Element Analysis ◽  
X Ray ◽  
Gamma Ray Emission

Particle-induced X-ray emission is very well suited for the analysis of geological samples. This review discusses the characteristics for such analyses. For light-element analysis, the complimentary technique of particle-induced gamma ray emission is also discussed since the emission of gamma rays occurs simultaneously with the X-rays. Not only are exploratory investigations of PIXE's capabilities presented but also synopses of studies aimed at answering geological questions. The latter have become more and more common in the last few years, an indication of PIXE's maturity as a technique for clement analysis of geological material.

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