Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

The Electromagnetic Spectrum02:37

The Electromagnetic Spectrum

65.2K
The electromagnetic spectrum consists of all the types of electromagnetic radiation arranged according to their frequency and wavelength. Each of the various colors of visible light has specific frequencies and wavelengths associated with them, and you can see that visible light makes up only a small portion of the electromagnetic spectrum. Because the technologies developed to work in various parts of the electromagnetic spectrum are different, for reasons of convenience and historical...
65.2K
The Electromagnetic Spectrum01:24

The Electromagnetic Spectrum

33.7K
Electromagnetic waves are categorized according to their wavelengths and frequencies, giving the electromagnetic spectrum. These waves are classified as radio, infrared, ultraviolet, etc. Radio waves refer to electromagnetic radiation with wavelengths ranging from millimeters to kilometers. Radio waves are commonly used for audio communications (i.e., radios) and typically result from an alternating current in the wires of a broadcast antenna. They cover a broad wavelength range and are used...
33.7K
X-ray Crystallography02:18

X-ray Crystallography

26.2K
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
26.2K
IR Spectrum01:19

IR Spectrum

2.2K
When infrared (IR) radiation passes through a molecule, the bonds stretch or bend by absorbing the radiation. This absorption creates the molecule's absorption spectrum, which is the plot of its percentage transmittance versus wavenumber.
Transmittance is defined as the ratio of the radiant power passing through a sample to that from the radiation's source. Multiplying the transmittance by 100 gives the percent transmittance (%T), which varies between 100% (no absorption) and 0%...
2.2K
Angular Momentum01:21

Angular Momentum

810
Angular momentum characterizes an object's rotational motion and is defined as the moment of its linear momentum about a specified point O. When a particle moves along a curved path in the x-y plane, the scalar formulation calculates the magnitude of its angular momentum, utilizing the moment arm (d), representing the perpendicular distance from point O to the line of action of the linear momentum. Despite being scalar in formulation, angular momentum is inherently a vector quantity. Its...
810
Angular Velocity and Displacement01:08

Angular Velocity and Displacement

22.8K
Uniform circular motion is motion in a circle at a constant speed. Although this is the simplest case of rotational motion, it is very useful for many situations and is used to introduce rotational variables. When a particle is moving in a circle, the coordinate system is fixed and serves as a frame of reference to define the particle’s position. Its position vector from the origin of the circle to the particle sweeps out the angle θ, which increases in the counterclockwise direction...
22.8K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

ERBB2/HER2 landscape and prognostic impact: large-scale, real-world analysis across solid cancers.

ESMO open·2026
Same author

Evidence for a Spectral Break or Curvature in the Spectrum of Astrophysical Neutrinos from 5 TeV to 10 PeV.

Physical review letters·2026
Same author

Patient Reported Satisfaction Outcomes After Breast Radiation Using Intraoperative Radiation Therapy vs. External Beam Radiation Therapy.

European journal of breast health·2026
Same author

Search for Extremely-High-Energy Neutrinos and First Constraints on the Ultrahigh-Energy Cosmic-Ray Proton Fraction with IceCube.

Physical review letters·2025
Same author

Measurement of Atmospheric Neutrino Oscillation Parameters Using Convolutional Neural Networks with 9.3 Years of Data in IceCube DeepCore.

Physical review letters·2025
Same author

High-Statistics Measurement of the Cosmic-Ray Electron Spectrum with H.E.S.S.

Physical review letters·2024
Same journal

Erratum: Bacterial Turbulence at Compressible Fluid Interfaces [Phys. Rev. Lett. 136, 138301 (2026)].

Physical review letters·2026
Same journal

Unveiling Light-Quark Yukawa Flavor Structure via Dihadron Fragmentation at Lepton Colliders.

Physical review letters·2026
Same journal

Adaptable Route to Fast Coherent State Transport via Bang-Bang-Bang Protocols.

Physical review letters·2026
Same journal

Topological Transition and Emergence of Elasticity of Dislocation in Skyrmion Lattice: Beyond Kittel's Magnetic-Polar Analogy.

Physical review letters·2026
Same journal

Pound-Drever-Hall Method for Superconducting-Qubit Readout.

Physical review letters·2026
Same journal

Coupling a ^{73}Ge Nuclear Spin to an Electrostatically Defined Quantum Dot in Silicon.

Physical review letters·2026
See all related articles

Related Experiment Video

Updated: Jan 31, 2026

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera
06:28

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera

Published on: January 30, 2020

13.2K

Unresolved Gamma-Ray Sky through its Angular Power Spectrum.

M Ackermann, M Ajello, L Baldini

  • 1Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy.

Physical Review Letters
|January 5, 2019
PubMed
Summary
This summary is machine-generated.

Fermi-LAT observations reveal the unresolved gamma-ray background (UGRB) likely originates from two distinct source populations. This finding enhances our understanding of the high-energy Universe and its constituents.

More Related Videos

Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes
07:51

Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes

Published on: August 24, 2017

7.7K
Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles
10:00

Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles

Published on: July 5, 2016

12.4K

Related Experiment Videos

Last Updated: Jan 31, 2026

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera
06:28

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera

Published on: January 30, 2020

13.2K
Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes
07:51

Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes

Published on: August 24, 2017

7.7K
Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles
10:00

Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles

Published on: July 5, 2016

12.4K

Area of Science:

  • High-energy astrophysics
  • Gamma-ray astronomy
  • Cosmic background radiation

Background:

  • The Fermi Large Area Telescope (LAT) has provided unprecedented accuracy in observing the gamma-ray sky.
  • The unresolved gamma-ray background (UGRB) contains information about high-energy sources below the detection threshold.
  • Characterizing UGRB fluctuations is key to understanding the composition of the high-energy Universe.

Purpose of the Study:

  • To measure the autocorrelation angular power spectrum of the UGRB.
  • To investigate the number of source populations contributing to the UGRB.
  • To enhance sensitivity to subthreshold sources compared to previous measurements.

Main Methods:

  • Analysis of eight years of Fermi-LAT Pass 8 data products.
  • Measurement of the UGRB autocorrelation angular power spectrum.
  • Robust analysis techniques to mitigate contamination from resolved sources and noise systematics.

Main Results:

  • Evidence (∼3.7σ significance) favoring a scenario with two contributing source classes over a single class for the UGRB.
  • A double power law with exponential cutoff accurately describes the anisotropy energy spectrum.
  • Photon indices for the two populations are determined to be 2.55±0.23 and 1.86±0.15.

Conclusions:

  • The UGRB is likely composed of at least two distinct populations of high-energy sources.
  • This study significantly improves sensitivity to subthreshold sources contributing to the UGRB.
  • The findings provide crucial insights into the nature and origin of the high-energy Universe.