scholarly journals Gamma ray burst studies with THESEUS

2021 ◽  
Author(s):  
G. Ghirlanda ◽  
R. Salvaterra ◽  
M. Toffano ◽  
S. Ronchini ◽  
C. Guidorzi ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Wide Energy Range ◽  
Spectral Evolution ◽  
Imaging Spectrometer ◽  
X Ray ◽  
Compact Binaries ◽  
Wide Energy ◽  
First Time ◽  
Intermediate Redshifts ◽  
Prompt Emission

AbstractGamma-ray Bursts (GRBs) are the most powerful transients in the Universe, over–shining for a few seconds all other γ-ray sky sources. Their emission is produced within narrowly collimated relativistic jets launched after the core–collapse of massive stars or the merger of compact binaries. THESEUS will open a new window for the use of GRBs as cosmological tools by securing a statistically significant sample of high-z GRBs, as well as by providing a large number of GRBs at low–intermediate redshifts extending the current samples to low luminosities. The wide energy band and unprecedented sensitivity of the Soft X-ray Imager (SXI) and X-Gamma rays Imaging Spectrometer (XGIS) instruments provide us a new route to unveil the nature of the prompt emission. For the first time, a full characterisation of the prompt emission spectrum from 0.3 keV to 10 MeV with unprecedented large count statistics will be possible revealing the signatures of synchrotron emission. SXI spectra, extending down to 0.3 keV, will constrain the local metal absorption and, for the brightest events, the progenitors’ ejecta composition. Investigation of the nature of the internal energy dissipation mechanisms will be obtained through the systematic study with XGIS of the sub-second variability unexplored so far over such a wide energy range. THESEUS will follow the spectral evolution of the prompt emission down to the soft X–ray band during the early steep decay and through the plateau phase with the unique ability of extending above 10 keV the spectral study of these early afterglow emission phases.

scholarly journals Recent X-ray Observations of Pulsar Nebulae

1996 ◽  
Vol 160 ◽  
pp. 367-374 ◽  
Author(s):  
Nobuyuki Kawai ◽  
Keisuke Tamura
Keyword(s):  
Spectral Characteristics ◽  
High Spectral Resolution ◽  
Wide Energy Range ◽  
Emission Sources ◽  
Diffuse Emission ◽  
X Ray ◽  
Diffuse Sources ◽  
Vela Pulsar ◽  
Wide Energy ◽  
First Time

AbstractResults from the X-ray observations of pulsars with ASCA are presented. The surroundings of pulsars are investigated in detail taking advantage of ASCA’s unique capabilities; high spectral resolution and a high throughput over a wide energy range from 0.4 keV to 10 keV. The spectral characteristics of the nebulae of PSR B1509—58 and the Vela pulsar are spectroscopically investigated. A jet-like feature is found from PSR B1509—58. We detected diffuse emission sources in the vicinity of many pulsars. The high probability of finding such diffuse sources for many pulsars suggests that they exist universally for all the active pulsars, and that they are powered by the pulsars. SNR Kes 32 was imaged in X-ray for the first time. Its X-ray properties can be used to examine its association with the nearby pulsar PSR B1610—50.

scholarly journals ARGO-YBJ: STATUS AND HIGHLIGHTS

2013 ◽  
Vol 53 (A) ◽  
pp. 646-651
Author(s):  
Giuseppe Di Sciascio
Keyword(s):  
Energy Range ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Current Status ◽  
Wide Energy Range ◽  
Open Problems ◽  
Direct Measurements ◽  
Wide Energy ◽  
First Time ◽  
Gathering Data

The ARGO-YBJ experiment has been gathering data steadily since November 2007 at the YangBaJing Cosmic Ray Laboratory (Tibet, P.R. China, 4300m a.s.l., 606 g/cm2). ARGO-YBJ is confronting various open problems in Cosmic Ray (CR) physics. The search for CR sources is carried out by observing TeV gamma-ray sources, both galactic and extra-galactic. The CR spectrum, composition and anisotropy are measured in a wide energy range (TeV ÷ PeV), thus overlapping direct measurements for the first time. This paper summarizes the current status of the experiment and describes some of the scientific highlights since 2007.

scholarly journals Interpreting the X-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars

2020 ◽  
Vol 499 (4) ◽  
pp. 5986-5992
Author(s):  
Nikhil Sarin ◽  
Paul D Lasky ◽  
Gregory Ashton
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Dipole Radiation ◽  
X Ray ◽  
Radiative Efficiency ◽  
Central Engine ◽  
Radiative Losses ◽  
Wave Emission ◽  
Prompt Emission

ABSTRACT The spin-down energy of millisecond magnetars has been invoked to explain X-ray afterglow observations of a significant fraction of short and long gamma-ray bursts. Here, we extend models previously introduced in the literature, incorporating radiative losses with the spin-down of a magnetar central engine through an arbitrary braking index. Combining this with a model for the tail of the prompt emission, we show that our model can better explain the data than millisecond-magnetar models without radiative losses or those that invoke spin-down solely through vacuum dipole radiation. We find that our model predicts a subset of X-ray flares seen in some gamma-ray bursts. We can further explain the diversity of X-ray plateaus by altering the radiative efficiency and measure the braking index of newly born millisecond magnetars. We measure the braking index of GRB061121 as $n=4.85^{+0.11}_{-0.15}$ suggesting the millisecond-magnetar born in this gamma-ray burst spins down predominantly through gravitational-wave emission.

scholarly journals Discovery of recombining plasma inside the extended gamma-ray supernova remnant HB9

2019 ◽  
Vol 489 (3) ◽  
pp. 4300-4310 ◽  
Author(s):  
A Sezer ◽  
T Ergin ◽  
R Yamazaki ◽  
H Sano ◽  
Y Fukui
Keyword(s):  
Supernova Remnant ◽  
Gamma Ray ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Large Area ◽  
Imaging Spectrometer ◽  
X Ray ◽  
East Region ◽  
X Ray Imaging ◽  
Collisional Ionization

ABSTRACT We present the results from the Suzaku X-ray Imaging Spectrometer observation of the mixed-morphology supernova remnant (SNR) HB9 (G160.9+2.6). We discovered recombining plasma (RP) in the western Suzaku observation region and the spectra here are well described by a model having collisional ionization equilibrium (CIE) and RP components. On the other hand, the X-ray spectra from the eastern Suzaku observation region are best reproduced by the CIE and non-equilibrium ionization model. We discuss possible scenarios to explain the origin of the RP emission based on the observational properties and concluded that the rarefaction scenario is a possible explanation for the existence of RP. In addition, the gamma-ray emission morphology and spectrum within the energy range of 0.2–300 GeV are investigated using 10 yr of data from the Fermi Large Area Telescope (LAT). The gamma-ray morphology of HB9 is best described by the spatial template of radio continuum emission. The spectrum is well fit to a log-parabola function and its detection significance was found to be 25σ. Moreover, a new gamma-ray point source located just outside the south-east region of the SNR’s shell was detected with a significance of 6σ. We also investigated the archival H i and CO data and detected an expanding shell structure in the velocity range of $-10.5$ and $+1.8$ km s−1 that is coinciding with a region of gamma-ray enhancement at the southern rim of the HB9 shell.

Design of an ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline

2013 ◽  
Vol 21 (1) ◽  
pp. 273-279 ◽  
Author(s):  
L. Xue ◽  
R. Reininger ◽  
Y.-Q. Wu ◽  
Y. Zou ◽  
Z.-M. Xu ◽  
...  
Keyword(s):  
Energy Range ◽  
Energy Resolution ◽  
Wide Energy Range ◽  
Ultrahigh Energy ◽  
Exit Slit ◽  
Shanghai Synchrotron Radiation Facility ◽  
X Ray ◽  
Variable Line ◽  
Line Spacing ◽  
Wide Energy

A new ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline has been designed and is under construction at the Shanghai Synchrotron Radiation Facility. The beamline has two branches: one dedicated to angle-resolved photoemission spectroscopy (ARPES) and the other to photoelectron emission microscopy (PEEM). The two branches share the same plane-grating monochromator, which is equipped with four variable-line-spacing gratings and covers the 20–2000 eV energy range. Two elliptically polarized undulators are employed to provide photons with variable polarization, linear in every inclination and circular. The expected energy resolution is approximately 10 meV at 1000 eV with a flux of more than 3 × 1010 photons s−1at the ARPES sample positions. The refocusing of both branches is based on Kirkpatrick–Baez pairs. The expected spot sizes when using a 10 µm exit slit are 15 µm × 5 µm (horizontal × vertical FWHM) at the ARPES station and 10 µm × 5 µm (horizontal × vertical FWHM) at the PEEM station. The use of plane optical elements upstream of the exit slit, a variable-line-spacing grating and a pre-mirror in the monochromator that allows the influence of the thermal deformation to be eliminated are essential for achieving the ultrahigh-energy resolution.

XAFS and X-MCD spectroscopies with undulator gap scan

1998 ◽  
Vol 5 (3) ◽  
pp. 989-991 ◽  
Author(s):  
Andrei Rogalev ◽  
Vincent Gotte ◽  
Jose´ Goulon ◽  
Christophe Gauthier ◽  
Joel Chavanne ◽  
...  
Keyword(s):  
Energy Range ◽  
Absorption Spectroscopy ◽  
Emission Peak ◽  
Photon Statistics ◽  
Wide Energy Range ◽  
X Ray ◽  
Polarization Rate ◽  
Spin Polarized ◽  
Wide Energy ◽  
X Ray Absorption

The first experimental applications of the undulator gap-scan technique in X-ray absorption spectroscopy are reported. The key advantage of this method is that during EXAFS scans the undulator is permanently tuned to the maximum of its emission peak in order to maximize the photon statistics. In X-MCD or spin-polarized EXAFS studies with a helical undulator of the Helios type, the polarization rate can also be kept almost constant over a wide energy range.

ASCA Observations of White Dwarfs, Neutron Stars and Black Holes

1996 ◽  
Vol 165 ◽  
pp. 321-331
Author(s):  
H. Inoue
Keyword(s):  
Black Holes ◽  
Focal Plane ◽  
Thin Foil ◽  
Effective Area ◽  
Wide Energy Range ◽  
Ccd Cameras ◽  
X Ray ◽  
Different Types ◽  
Wide Energy ◽  
Large Effective Area

ASCA, the fourth Japanese X-ray astronomy satellite, was launched by the Institute of Space and Astronautical Science (ISAS) on 1993 February 20. ASCA is designed to be a high-capability X-ray observatory (Tanaka et al. 1994). It is equipped with nested thin-foil mirrors which provide a large effective area over a wide energy range from 0.5 to 10 keV. Two different types of detectors, CCD cameras (SIS) and imaging gas scintillation proportional counters (GIS) are employed as the focal plane instruments.

scholarly journals X-ray Spectral Evolution of High Energy Peaked Blazars

Galaxies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Haritma Gaur
Keyword(s):  
High Energy ◽  
Energy Interval ◽  
Spectral Studies ◽  
Parabolic Model ◽  
Spectral Evolution ◽  
Spectral Variability ◽  
Spectral Parameters ◽  
X Ray ◽  
Wide Energy ◽  
Energy Dependent

The synchrotron hump of the high energy peaked blazars generally lies in the 0.1–10 keV range and such sources show extreme flux and spectral variability in X-ray bands. Various spectral studies showed that the X-ray spectra of high energy peaked blazars are curved and better described by the log-parabolic model. The curvature is attributed to the energy dependent statistical acceleration mechanism. In this work, we review the X-ray spectral studies of high energy peaked blazars. It is found that the log-parabolic model well describes the spectra in a wide energy interval around the peak. The log-parabolic model provides the possibility of investigating the correlation between the spectral parameters derived from it. Therefore, we compiled the studies of correlations between the various parameters derived from the log-parabolic model and their implications to describe the variability mechanism of blazars.

scholarly journals Study of the process $$e^+e^- \rightarrow \eta \pi ^0\gamma $$ in the energy range $$\sqrt{s} = {1.05-2.00}$$ GeV with the SND detector

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
M. N. Achasov ◽  
A. Yu. Barnyakov ◽  
A. A. Baykov ◽  
K. I. Beloborodov ◽  
A. V. Berdyugin ◽  
...  
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Center Of Mass ◽  
Wide Energy Range ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
Wide Energy ◽  
Radiation Processes ◽  
Using Data ◽  
First Time

AbstractThe process $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ is studied in the center-of-mass energy range 1.05–2.00 GeV using data with an integrated luminosity of 94.5 $$\hbox {pb}^{-1}$$ pb - 1 collected by the SND detector at the VEPP-2000 $$e^{+}e^{-}$$ e + e - collider. The $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ cross section is measured for the first time. It is shown that the dominant mechanism of this reaction is the transition through the $$\omega \eta $$ ω η intermediate state. The measured cross section of the subprocess $$e^+e^-\rightarrow \omega \eta \rightarrow \eta \pi ^0\gamma $$ e + e - → ω η → η π 0 γ is consistent with previous measurements in the $$e^+e^-\rightarrow \pi ^+\pi ^-\pi ^0\eta $$ e + e - → π + π - π 0 η mode. It is found, with a significance of $$5.6\sigma $$ 5.6 σ , that the process $$e^+e^-\rightarrow \eta \pi ^0\gamma $$ e + e - → η π 0 γ is not completely described by hadronic vector-pseudoscalar intermediate states. The cross section of this missing contribution, which can originate from radiation processes, e. g. $$e^+e^-\rightarrow a_{0}(1450)\gamma $$ e + e - → a 0 ( 1450 ) γ , is measured. It is found to be 15–20 pb in the wide energy range from 1.3 to 1.9 GeV.

scholarly journals Multiwavelength observations of PSR J2032+4127 during the 2017 periastron passage

2020 ◽  
Vol 495 (1) ◽  
pp. 365-374 ◽  
Author(s):  
M Chernyakova ◽  
D Malyshev ◽  
P Blay ◽  
B van Soelen ◽  
S Tsygankov
Keyword(s):  
Gamma Ray ◽  
Broad Band ◽  
Joint Analysis ◽  
Spectral Evolution ◽  
Optical Telescope ◽  
X Ray ◽  
Broad Band Emission ◽  
Band Emission ◽  
Mass Outflow ◽  
Be Star

ABSTRACT PSR J2032+4127 is only the second known gamma-ray binary where it is confirmed that a young radio pulsar is in orbit around a Be-star. The interaction of the pulsar wind with the mass outflow from the companion leads to broad-band emission from radio up to TeV energies. In this paper we present results of optical monitoring of the 2017 periastron passage with the Nordic Optical Telescope. These observations are complemented by X-ray (Swift/XRT, NuSTAR) and GeV (Fermi/LAT) monitoring. Joint analysis of the evolution of the parameters of the H α line and the broad-band (X-ray to TeV) spectral shape allows us to propose a model linking the observed emission to the interaction of the pulsar and Be-star winds under the assumption of the inclined disc geometry. Our model allows the observed flux and spectral evolution of the system to be explained in a self-consistent way.

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