First stars and the extragalactic background light: how recent<i>γ</i>-ray observations constrain the early universe

Kneiske, T.; Mazin, D.

doi:10.1051/0004-6361/200810396

Cited by 38 publications

(42 citation statements)

References 84 publications

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“…If the EBL excess arises mainly from high-redshift objects, it obviously conflicts with the gamma-ray transparency of the intergalactic medium (IGM) corresponding to the number of EBL photons for the electron-positron pair creation, as discussed by many authors on previous EBL results ( Aharonian et al 2006;Raue et al 2009; H.E.S.S. Collaboration 2013).…”

Section: Discussionmentioning

confidence: 99%

New Spectral Evidence of an Unaccounted Component of the Near-infrared Extragalactic Background Light from the CIBER

Matsuura

Arai

Bock

et al. 2017

ApJ

107

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The Extragalactic Background Light (EBL) captures the total integrated emission from stars and galaxies throughout the cosmic history. The amplitude of the near-infrared EBL from space absolute photometry observations has been controversial and depends strongly on the modeling and subtraction of the Zodiacal light foreground. We report the first measurement of the diffuse background spectrum at 0.8-1.7 µm from the CIBER experiment. The observations were obtained with an absolute spectrometer over two flights in multiple sky fields to enable the subtraction of Zodiacal light, stars, terrestrial emission, and diffuse Galactic light. After subtracting foregrounds and accounting for systematic errors, we find the nominal EBL brightness, assuming the Kelsall Zodiacal light model, is 42.7 +11.9 −10.6 nW m −2 sr −1 at 1.4 µm. We also analyzed the data using the Wright Zodiacal light model, which results in a worse statistical fit to the data and an unphysical EBL, falling below the known background light from galaxies at λ <1.3 µm. Using a model-independent analysis based on the minimum EBL brightness, we find an EBL brightness of 28.7+5.1 −3.3 nWm −2 sr −1 at 1.4 µm. While the derived EBL amplitude strongly depends on the Zodiacal light model, we find that we cannot fit the spectral data to Zodiacal light, Galactic emission, and EBL from solely integrated galactic light from galaxy counts. The results require a new diffuse component, such as an additional foreground or an excess EBL with a redder spectrum than that of Zodiacal light.

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Section: Discussionmentioning

confidence: 99%

New Spectral Evidence of an Unaccounted Component of the Near-infrared Extragalactic Background Light from the CIBER

Matsuura

Arai

Bock

et al. 2017

ApJ

107

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“…galaxy clusters described in Chelouche et al 2007) or other faint sources (e.g. population III stars as shown in Raue et al 2009).…”

Section: Introductionmentioning

confidence: 99%

A lower-limit flux for the extragalactic background light

Kneiske¹,

Dole

2010

A&A

220

268

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Context. The extragalactic background light (EBL) contains information about the evolution of galaxies from very early times up to the present. The spectral energy distribution is not known accurately, especially in the near-and mid-infrared range. Upper limits and absolute measurements come from direct observations which might be be polluted by foreground emission, while indirect upper limits can also be set by observations of high energy gamma-ray sources. Galaxy number counts integrations of observable galaxies, missing possible faint sources, give strict lower limits. Aims. A model is constructed, which reproduces the EBL lower limit flux. This model can be used for a guaranteed minimum correction of observed spectra of extragalactic gamma-ray sources for extragalactic absorption. Methods. A forward evolution model for the metagalactic radiation field is used to fit recent observations of satelites like Spitzer, ISO, Hubble and GALEX. The model is applied to calculate the Fazio-Stecker relation, and to compute the absorption factor at different redshifts and corrected blazar spectra. Results. A strict lower-limit flux for the evolving extragalactic background light (and in particular the cosmic infrared background) has been calculated up to a redshift of five. The computed flux is below the existing upper limits from direct observations, and agrees with all existing limits derived from very-high energy gamma-ray observations. The corrected spectra still agree with simple theoretical predictions. The derived strict lower-limit EBL flux is very close to the upper limits from gamma-ray observations. This is true for the present day EBL, but also for the diffuse flux at higher redshift. Conclusions. If future detections of high redshift gamma-ray sources require a lower EBL flux than derived here, the physics assumptions used to derive the upper limits have to be revised. The lower-limit EBL model is not only needed for absorption features in active galactic nuclei and other gamma-ray sources, but is also essential when alternative particle processes are tested, which could prevent the high energy gamma-rays from being absorbed. It can also be used for a guaranteed interaction of cosmic-ray particles. The model is available online.

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“…Further contributions may come from diffuse emission from galaxy clusters (Chelouche et al 2007), unresolved active galactic nuclei (Matute et al 2006), Population III stars (e.g. Santos et al 2002;Raue et al 2009), or exotic sources like dark matter powered stars in the early universe (Maurer et al 2011). The SED of the EBL at z = 0 comprises information about the star and galaxy formation rates and the dust content of galaxies.…”

Section: Introductionmentioning

confidence: 99%

Limits on the extragalactic background light in theFermiera

Meyer

Raue

Mazin

et al. 2012

A&A

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Very high energy (VHE, energy E < ∼ 100 GeV) γ-rays from cosmological sources are attenuated due to the interaction with photons of the extragalactic background light (EBL) in the ultraviolet to infrared wavelength band. The EBL, thus, leaves an imprint on the observed energy spectra of these objects. In the last four years, the number of extragalactic VHE sources discovered with imaging atmospheric Cherenkov telescopes (IACTs), such as MAGIC, H.E.S.S., and VERITAS, has doubled. Furthermore, the measurements of the Fermi satellite brought new insights into the intrinsic spectra of the sources at GeV energies. In this paper, upper limits on the EBL intensity are derived by considering the most extensive VHE source sample ever used in this context. This is accomplished by constructing a large number of generic EBL shapes and combining spectral informations from Fermi and IACTs together with minimal assumptions about the source physics at high and very high γ-ray energies. The evolution of the EBL with redshift is accounted for and the possibility of the formation of an electromagnetic cascade and the implications on the upper limits are explored. The EBL density at z = 0 is constrained over a broad wavelength range between 0.4 and 100 μm. At optical wavelengths, the EBL density is constrained below 24 nW m −2 sr −1 and below 5 nW m −2 sr −1 between 8 μm and 31 μm.

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First stars and the extragalactic background light: how recentγ-ray observations constrain the early universe

Cited by 38 publications

References 84 publications

New Spectral Evidence of an Unaccounted Component of the Near-infrared Extragalactic Background Light from the CIBER

New Spectral Evidence of an Unaccounted Component of the Near-infrared Extragalactic Background Light from the CIBER

A lower-limit flux for the extragalactic background light

Limits on the extragalactic background light in theFermiera

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