Diffuse extragalactic background radiation: Difference between revisions

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{{Short description|Photon field that fills our universe}}

The '''diffuse extragalactic background radiation''' (DEBRA) refers to the diffuse photon field from extragalactic origin that fill our Universe. It contains photons over ∼ 20 decades of energy from ~10⁻⁷ eV to ~100 GeV. The origin and the physical processes involved are different within every wavelength range. There are plenty of observational evidences that support the existence of the DEBRA.<ref>Hauser M. G., Dwek E., 2001, Annual Review of Astronomy and Astrophysics, 39, 249</ref> Figure 1 shows a schematic picture, based on many different data sets, of the spectral intensity (also called spectral radiance) multiplied by wavelength of the DEBRA over all the electromagnetic spectrum. This representation is convenient because the area inside the curve is the energy. The nature and history of the universe is coded in this radiation field and any realistic cosmological model must be able to describe it. Understanding the DEBRA is a major challenge of modern cosmology with huge consequences in other fields of astrophysics, therefore extraordinary efforts are being put by theoreticians, observers, and instrumentalists to do so.

{{one source |date=March 2024}}

[[Image:Extragalactic-background-power-density.jpg|Figure 1: thumb|321px|right|Schematic representation of the spectral energy distribution of the DEBRA. The dependent quantity is the [[spectral radiometric quantity|spectral]] [[spectral radiance|radiance]] multiplied by [[wavelength]], i.e. ''λL''_e''λ''.

Legend: gamma-ray background (CGB), [[cosmic X-ray background]] (CXB), cosmic ultraviolet/optical background (CUVOB), [[cosmic infrared background]] (CIB), [[cosmic microwave background]] (CMB), and cosmic radio background (CRB)]]

[[Image:Extragalactic-background-power-density.jpg|Figure 1: Schematic representation of the spectral energy distribution of the DEBRA.]]

The '''diffuse extragalactic background radiation''' (DEBRA) refers to the photon field of extragalactic origin that fills our Universe. It contains photons whose energies span more than twenty orders of magnitude, from 10⁻⁷ eV to more than 100 GeV. This range covers everything from the [[Microwave|microwaves]] emitted by free hydrogen atoms to [[Ultra-high-energy gamma ray|ultra high-energy gamma rays]], which can only be emitted by the most powerful physical processes in the modern universe such as [[Kilonova|kilonovas]] and [[Binary black hole|merging black holes]].

The origin and the physical processes involved are different within every wavelength range. There is plenty of observational evidence that support the existence of the DEBRA.<ref>{{cite journal

| author1 = Hauser M. G.

| author2 = Dwek E.

| title = THE COSMIC INFRARED BACKGROUND: Measurements and Implications

| journal = Annual Review of Astronomy and Astrophysics

| volume = 39

| issue = 1

| pages = 249–307

| doi = 10.1146/annurev.astro.39.1.249

| date = September 2001

|arxiv = astro-ph/0105539 |bibcode = 2001ARA&A..39..249H | s2cid = 45573664

}}</ref>

The '''diffuse extragalactic background radiation''' (DEBRA) refers to the diffuse photon field from extragalactic origin that fill our Universe. It contains photons over ∼ 20 decades of energy from ~10⁻⁷ eV to ~100 GeV. The origin and the physical processes involved are different within every wavelength range. There are plenty of observational evidences that support the existence of the DEBRA.<ref>Hauser M. G., Dwek E., 2001, Annual Review of Astronomy and Astrophysics, 39, 249</ref> Figure 1figure shows a schematic picture, based on many different data sets, of the spectral intensity (also called spectral radiance) multiplied by wavelength of the DEBRA over all the electromagnetic spectrum. This representation is convenient because the area inside the curve is the energy. The nature and history of the universe is coded in this radiation field and any realistic cosmological model must be able to describe it. Understanding the DEBRA is a major challenge of modern cosmology with huge consequences in other fields of astrophysics, therefore extraordinary efforts are being put by theoreticians, observers, and instrumentalists to do so.

==Regions of the DEBRA==

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* [[Cosmic radio background]]

== See also ==

* [[Photon underproduction crisis]]

==References==

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* [http://ned.ipac.caltech.edu/level5/bcg_radiation.html Caltech papers]

[[Category:Extragalactic astronomy]]

{{Astronomy-stub}}

[[Category:Astronomy]]

[[Category:Astronomy articles needing expert attention]]

[[Category:Astronomy articles needing attention]]

[[Category:Cosmic rays]]

[[Category:Cosmic background radiation]]

[[Category:Unsolved problems in astronomy]]

{{AstronomyAstrophysics-stub}}