相关论文: Diffuse Background Radiation

Here is reviewed our current understanding of Galactic and extragalactic diffuse gamma-ray emission. The spectrum of the extragalactic gamma-ray background above 30 MeV can be well described by a power law with photon index s=2.1. In the…

We re-examine {\em Voyager} Ultraviolet Spectrograph data used to establish upper limits to the $\lambda$ 500-900 \AA and $\lambda$ 900-1100 \AA cosmic diffuse background. The measurement of diffuse flux with the {\em Voyager} UVS data…

The cosmic far-infrared background is now well measured from 140 micron to 1 mm. Uncertainties remain at 100 micron (and even more at 60 micron). These are dominated by limitations of the zodiacal model. The nature of sources dominating the…

I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet…

It has recently become apparent that the background level of diffuse radio emission on the sky is significantly higher than the level that can result from known extragalactic radio source classes or our Galaxy given our current…

We describe an ongoing experiment to search for the meta-galactic Lyman-continuum background at z~2-3. We are obtaining one of the deepest optical spectra ever, using LRIS/Keck-II to search for the fluorescent Ly-alpha emission from…

We study the annihilating dark matter contribution to the extra-galactic diffuse gamma-ray background spectrum, motivated by the recent observations of cosmic-ray positron/electron anomalies. The observed diffuse gamma-ray flux provides…

It is shown that a collection of photons with nearly the same frequency exhibits a Bose "condensation" type of phenomenon at about 3 degrees K corresponding to a peak intensity at a wave length of about 0.4cm. This could give a mechanism…

The H-alpha luminosity density of galaxies is used to calculate the local diffuse radiation field at the Lyman limit as resulting from star formation in the universe. The fraction of Lyman continuum radiation leaking out from galaxies…

Diffuse ultrahigh energy gamma-radiation can arise from a variety of astrophysical sources, including the interaction of extremely high energy cosmic rays with the 3K microwave background radiation or the collapse of topological defects…

The recent detection of the "cosmic dawn" redshifted 21 cm signal at 78 MHz by the EDGES experiment differs significantly from theoretical predictions. In particular, the absorption trough is roughly a factor of two stronger than the most…

It is argued that if extragalactic magnetic fields are smaller than 2x10^{-12} G the flux of ultra-high energy photons of (a few)x10^{-1} eV cm^{-2}s^{-1}sr^{-1} predicted in the top-down models of UHE CR implies similar flux of the diffuse…

Dark matter particle annihilation or decay can produce monochromatic gamma-ray lines and contribute to the diffuse gamma-ray background. Flux upper limits are presented for gamma-ray spectral lines from 7 to 200 GeV and for the diffuse…

Understanding diffuse Galactic radio emission is interesting both in its own right and for minimizing foreground contamination of cosmological measurements. Cosmic Microwave Background experiments have focused on frequencies > 10 GHz,…

... A strict lower-limit flux for the evolving extragalactic background light (and in particular the cosmic infrared background) has been calculated up to redshift of 5. The computed flux is below the existing upper limits from direct…

Very high energy gamma-ray data obtained by CAT and HEGRA from active galactic nucleus Mkn 501 are used to constrain the cosmic Mid-Infrared background. While the entire infrared and submillimeter spectrum shape based on models has been…

Galactic diffuse continuum gamma-ray emission is intricately related to cosmic-ray physics and radio astronomy. We describe recent results from an approach which endeavours to take advantage of this. Information from cosmic-ray composition…

The propagation of very high energy gamma-rays ($E>100$~GeV) over cosmological distances is suppressed by pair-production processes with the ubiquitous extra-galactic soft photon background, mainly in the optical to near infra-red. The…

Based on the Sloan Digital Sky Survey Data Release 16, we have detected the large-scale structure of Ly$\alpha$ emission in the Universe at redshifts $z = 2$--3.5 by cross-correlating quasar positions and Ly$\alpha$ emission imprinted in…

The first measurement of the diffuse background spectrum at 0.8-1.7 $\mu \rm{m}$ from the CIBER experiment has revealed a significant excess of the cosmic infrared background (CIB) radiation compared to the theoretically expected spectrum.…