scholarly journals Spectropolarimetric analysis of prompt emission of GRB 160325A: jet with evolving environment of internal shocks

2020 ◽  
Vol 493 (4) ◽  
pp. 5218-5232 ◽  
Author(s):  
Vidushi Sharma ◽  
Shabnam Iyyani ◽  
Dipankar Bhattacharya ◽  
Tanmoy Chattopadhyay ◽  
Santosh V Vadawale ◽  
...  
Keyword(s):  
Confidence Level ◽  
Activity Period ◽  
Opening Angle ◽  
First Episode ◽  
Polarization Spectrum ◽  
Inverse Compton Scattering ◽  
Poynting Flux ◽  
Thin Region ◽  
Inverse Compton ◽  
Prompt Emission

ABSTRACT GRB 160325A is the only bright burst detected by AstroSat CZT Imager in its primary field of view to date. In this work, we present the spectral and polarimetric analysis of the prompt emission of the burst using AstroSat, Fermi, and Niel Gehrels Swift observations. The prompt emission consists of two distinct emission episodes separated by a few seconds of quiescent/ mild activity period. The first emission episode shows a thermal component as well as a low polarization fraction of $PF \lt 37\, {{\ \rm per\ cent}}$ at $1.5\, \sigma$ confidence level. On the other hand, the second emission episode shows a non-thermal spectrum and is found to be highly polarized with $PF \gt 43\, {{\ \rm per\ cent}}$ at 1.5σ confidence level. We also study the afterglow properties of the jet using Swift/XRT data. The observed jet break suggests that the jet is pointed towards the observer and has an opening angle of 1.2° for an assumed redshift, z = 2. With composite modelling of polarization, spectrum of the prompt emission, and the afterglow, we infer that the first episode of emission originates from the photosphere with localized dissipation happening below it, and the second from the optically thin region above the photosphere. The photospheric emission is generated mainly by inverse Compton scattering, whereas the emission in the optically thin region is produced by the synchrotron process. The low radiation efficiency of the burst suggests that the outflow remains baryonic dominated throughout the burst duration with only a subdominant Poynting flux component, and the kinetic energy of the jet is likely dissipated via internal shocks which evolves from an optically thick to optically thin environment within the jet.

scholarly journals Gamma-ray emission from pulsar binaries

2012 ◽  
Vol 8 (S291) ◽  
pp. 418-418
Author(s):  
John Kirk ◽  
Iwona Mochol
Keyword(s):  
Magnetic Field ◽  
Binary Systems ◽  
Gamma Ray ◽  
High Energy ◽  
Low Density ◽  
Inverse Compton Scattering ◽  
Poynting Flux ◽  
Inverse Compton ◽  
Shock Precursor ◽  
The Waves

AbstractPulsar winds, containing charged particles, waves and a net (phase-averaged) magnetic field, are thought to fuel the high-energy emission from several gamma-ray binaries. They terminate where the ram pressure matches that of the surroundings - which, in binaries, is provided by the wind of the companion. Before termination, pulsed emission can be produced by inverse Compton scattering of photons from the companion by particles in the waves. After termination, both the bulk kinetic energy of the particles and the Poynting flux in the waves are dissipated into an energetic particle population embedded in the surviving phase-averaged magnetic field. Pulsed emission is no longer possible, but a substantial flux of unpulsed high-energy photons can be produced. I will present results showing that the physical conditions at the termination shock can be divided into two regimes: a high density one, where current sheets in the wind are first compressed by an MHD shock and subsequently dissipate by reconnection, and a low density one, where the wind can first convert into an electromagnetic wave in the shock precursor, which then damps and merges into the wind nebula. The shocks surrounding isolated pulsars fall into the low-density category, but those around pulsars in binary systems, may transit from one regime to the other according to binary phase. The implications of the shock-structure dichotomy for these objects will be discussed.

Visualization of microvessels by angiography using inverse-Compton scattering X-rays in animal models

2014 ◽  
Vol 21 (6) ◽  
pp. 1327-1332 ◽  
Author(s):  
Toshiharu Fujii ◽  
Naoto Fukuyama ◽  
Chiharu Tanaka ◽  
Yoshimori Ikeya ◽  
Yoshiro Shinozaki ◽  
...  
Keyword(s):  
Compton Scattering ◽  
Photon Number ◽  
High Gain ◽  
Image Sensor ◽  
Clinical Settings ◽  
X Rays ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Small Vessels ◽  
Inverse Compton

The fundamental performance of microangiography has been evaluated using the S-band linac-based inverse-Compton scattering X-ray (iCSX) method to determine how many photons would be required to apply iCSX to human microangiography. ICSX is characterized by its quasi-monochromatic nature and small focus size which are fundamental requirements for microangiography. However, the current iCSX source does not have sufficient flux for microangiography in clinical settings. It was determined whether S-band compact linac-based iCSX can visualize small vessels of excised animal organs, and the amount of X-ray photons required for real time microangiography in clinical settings was estimated. The iCSX coupled with a high-gain avalanche rushing amorphous photoconductor camera could visualize a resolution chart with only a single iCSX pulse of ∼3 ps duration; the resolution was estimated to be ∼500 µm. The iCSX coupled with an X-ray cooled charge-coupled device image sensor camera visualized seventh-order vascular branches (80 µm in diameter) of a rabbit ear by accumulating the images for 5 and 30 min, corresponding to irradiation of 3000 and 18000 iCSX pulses, respectively. The S-band linac-based iCSX visualized microvessels by accumulating the images. An iCSX source with a photon number of 3.6 × 103–5.4 × 104times greater than that used in this study may enable visualizing microvessels of human fingertips even in clinical settings.

scholarly journals Relativistic inverse Compton scattering of photons from the early universe

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Siddharth Malu ◽  
Abhirup Datta ◽  
Sergio Colafrancesco ◽  
Paolo Marchegiani ◽  
Ravi Subrahmanyan ◽  
...  
Keyword(s):  
Compton Scattering ◽  
Early Universe ◽  
Inverse Compton Scattering ◽  
Inverse Compton

scholarly journals Nested Kirkpatrick–Baez (Montel) optics for hard X-rays

2015 ◽  
Vol 48 (2) ◽  
pp. 558-564 ◽  
Author(s):  
Giacomo Resta ◽  
Boris Khaykovich ◽  
David Moncton
Keyword(s):  
Ray Tracing ◽  
Compton Scattering ◽  
Analytical Procedure ◽  
X Rays ◽  
Multilayer Mirrors ◽  
Comprehensive Description ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Proper Orientation

A comprehensive description and ray-tracing simulations are presented for symmetric nested Kirkpatrick–Baez (KB) mirrors, commonly used at synchrotrons and in commercial X-ray sources. This paper introduces an analytical procedure for determining the proper orientation between the two surfaces composing the nested KB optics. This procedure has been used to design and simulate collimating optics for a hard-X-ray inverse Compton scattering source. The resulting optical device is composed of two 12 cm-long parabolic surfaces coated with a laterally graded multilayer and is capable of collimating a 12 keV beam with a divergence of 5 mrad (FWHM) by a factor of ∼250. A description of the ray-tracing software that was developed to simulate the graded multilayer mirrors is included.

scholarly journals The versatile X-ray beamline of the Munich Compact Light Source: design, instrumentation and applications

2020 ◽  
Vol 27 (5) ◽  
pp. 1395-1414 ◽  
Author(s):  
Benedikt Günther ◽  
Regine Gradl ◽  
Christoph Jud ◽  
Elena Eggl ◽  
Juanjuan Huang ◽  
...  
Keyword(s):  
Light Source ◽  
Phase Contrast ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
University Of Munich ◽  
Inverse Compton ◽  
Compact Light Source

Inverse Compton scattering provides means to generate low-divergence partially coherent quasi-monochromatic, i.e. synchrotron-like, X-ray radiation on a laboratory scale. This enables the transfer of synchrotron techniques into university or industrial environments. Here, the Munich Compact Light Source is presented, which is such a compact synchrotron radiation facility based on an inverse Compton X-ray source (ICS). The recent improvements of the ICS are reported first and then the various experimental techniques which are most suited to the ICS installed at the Technical University of Munich are reviewed. For the latter, a multipurpose X-ray application beamline with two end-stations was designed. The beamline's design and geometry are presented in detail including the different set-ups as well as the available detector options. Application examples of the classes of experiments that can be performed are summarized afterwards. Among them are dynamic in vivo respiratory imaging, propagation-based phase-contrast imaging, grating-based phase-contrast imaging, X-ray microtomography, K-edge subtraction imaging and X-ray spectroscopy. Finally, plans to upgrade the beamline in order to enhance its capabilities are discussed.

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