On the determination of the cosmic infrared background radiation from the high-energy spectrum of extragalactic gamma-ray sources

1994 ◽  
Vol 436 ◽  
pp. 696 ◽  
Author(s):  
Eli Dwek ◽  
Jonathan Slavin
Keyword(s):  
Energy Spectrum ◽  
Gamma Ray ◽  
Background Radiation ◽  
High Energy ◽  
Infrared Background ◽  
Cosmic Infrared Background

scholarly journals Latest Cosmic Ray Results from IceTop and IceCube

2019 ◽  
Vol 210 ◽  
pp. 03005
Author(s):  
Karen Andeen ◽  
Matthias Plum
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Low Energy ◽  
South Pole ◽  
Air Showers ◽  
Future Plans

The IceCube Neutrino Observatory at the geographic South Pole, with its surface array IceTop, detects three different components of extensive air showers: the total signal at the surface, low energy muons on the periphery of the showers, and high energy muons in the deep In Ice array of IceCube. These measurements enable determination of the energy spectrum and composition of cosmic rays from PeV to EeV energies, the anisotropy in the distribution of cosmic ray arrival directions, the muon density of cosmic ray air showers, and the PeV gamma-ray flux. Furthermore, IceTop can be used as a veto for the neutrino measurements. The latest results from these IceTop analyses will be presented along with future plans.

scholarly journals The COBE DIRBE Search for the Cosmic Infrared Background

1996 ◽  
Vol 168 ◽  
pp. 99-108
Author(s):  
Michael G. Hauser
Keyword(s):  
Spectral Range ◽  
Background Radiation ◽  
Spectral Band ◽  
Current Approach ◽  
Cosmic Background ◽  
Infrared Background ◽  
Cosmic Infrared Background

The Diffuse Infrared Background Experiment (DIRBE) on the Cosmic Background Explorer (COBE) satellite is designed to conduct a sensitive search for isotropic cosmic infrared background radiation over the spectral range from 1.25 to 240 μm. The cumulative emissions of pregalactic, protogalactic, and evolving galactic systems are expected to be recorded in this background. The DIRBE instrument has mapped the full sky with high redundancy at solar elongation angles ranging from 64°to 124°to facilitate separation of interplanetary, Galactic, and extragalactic sources of emission. Conservative limits on the isotropic infrared background are given by the minimum observed sky brightnesses in each DIRBE spectral band during the 10 months of cryogenic operation. Extensive modeling of the foregrounds is under way to isolate or strongly limit the extragalactic infrared component. The current approach to these modeling efforts is described and representative present residuals are reported.

Energy spectrum from single TGFs detected by ASIM

2020 ◽  
Author(s):  
Anders Lindanger ◽  
Martino Marisaldi ◽  
Nikolai Østgaard ◽  
Andrey Mezentsev ◽  
Torstein Neubert ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Spectral Analysis ◽  
Energy Spectrum ◽  
Monte Carlo Simulations ◽  
Energy Range ◽  
Gamma Ray ◽  
High Energy ◽  
Energy Calibration ◽  
Energy Detector ◽  
Instrumental Effects

<p>Terrestrial Gamma-ray Flashes (TGFs) are sub milliseconds bursts of high energy photons associated with lightning flashes in thunderstorms. The Atmosphere-Space Interactions Monitor (ASIM), launched in April 2018, is the first space mission specifically designed to detect TGFs. We will mainly focus on data from the High Energy Detector (HED) which is sensitive to photons with energies from 300 keV to > 30 MeV, and include data from the Low Energy Detector (LED) sensitive in 50 keV to 370 keV energy range. Both HED and LED are part of the Modular X- and Gamma-ray Sensor (MXGS) of ASIM.<br><br>The energy spectrum of TGFs, together with Monte Carlo simulations, can provide information on the production altitude and beaming geometry of TGFs. Constraints have already been set on the production altitude and beaming geometry using other spacecraft and radio measurements. Some of these studies are based on cumulative spectra of a large number of TGFs (e.g. [1]), which smooth out individual variability. The spectral analysis of individual TGFs has been carried out up to now for Fermi TGFs only, showing spectral diversity [2]. Crucial key factors for individual TGF spectral analysis are a large number of counts, an energy range extended to several tens of MeV, a good energy calibration as well as knowledge and control of any instrumental effects affecting the measurements.</p><p>We strive to put stricter constraints on the production altitude and beaming geometry, by comparing Monte Carlo simulations to energy spectra from single ASIM TGFs. We will present the dataset and method, including the correction for instrumental effects, and preliminary results on individual TGFs.</p><p>Thanks to ASIM’s large effective area and low orbital altitude, single TGFs detected by ASIM have much more count statistics than observations from other spacecrafts capable of detecting TGFs. ASIM has detected over 550 TGFs up to date (January 2020), and ~115 have more than 100 counts. This allows for a large sample for individual spectral analysis.</p><p>References:</p><ol><li>Dwyer, J. R., and D. M. Smith (2005), A comparison between Monte Carlo simulations of runaway breakdown and terrestrial gamma-ray flash observations, Geophys. Res. Lett., 32, L22804, doi:10.1029/2005GL023848.</li> <li>Mailyan et al. (2016), The spectroscopy of individual terrestrial gamma-ray flashes: Constraining the source properties, J. Geophys. Res. Space Physics, 121, 11,346–11,363, doi:10.1002/2016JA022702.</li> </ol>

scholarly journals Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow

Science ◽  
2021 ◽  
Vol 372 (6546) ◽  
pp. 1081-1085
Author(s):  
◽  
H. Abdalla ◽  
F. Aharonian ◽  
F. Ait Benkhali ◽  
E. O. Angüner ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
X Ray ◽  
Photon Index ◽  
Very High Energy ◽  
Stereoscopic System ◽  
Very High ◽  
Intrinsic Energy

Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera–electron volts, this spectrum is described by a power law with photon index of 2.07 ± 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma-ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios.

scholarly journals A Satellite Experiment to Measure the Intensity and the Energy Spectrum of Gamma Rays from Solar Flares in the Range 50–500 MeV

1971 ◽  
Vol 41 ◽  
pp. 44-44
Author(s):  
G. F. Bignami ◽  
C. J. Bland ◽  
O. Citterio ◽  
A. J. Dean ◽  
P. Inzani
Keyword(s):  
Energy Spectrum ◽  
Solar Flare ◽  
Gamma Rays ◽  
Solar Flares ◽  
Gamma Ray ◽  
High Energy ◽  
Measurement Capability ◽  
Satellite Experiment

A high energy solar gamma-ray telescope incorporating a lenticular Čerenkov for directional measurement and an energy calorimeter is described. The instrument is included in the payload of the TD-1 ESRO spacecraft to be launched into a sun-pointing orbit during spring 1972. The results of laboratory and accelerator tests are presented and the sensitivity and measurement capability to solar flare gamma rays is discussed.

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