scholarly journals Extragalactic background light measurements and applications

2016 ◽  
Vol 3 (3) ◽  
pp. 150555 ◽  
Author(s):  
Asantha Cooray
Keyword(s):  
Solar System ◽  
Galaxy Formation ◽  
Interplanetary Dust ◽  
Absorption Feature ◽  
Electromagnetic Spectrum ◽  
Zodiacal Light ◽  
Small Aperture ◽  
Extragalactic Background Light ◽  
Background Light ◽  
Optical Background

This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.

scholarly journals Fitting Zodiacal Models

2001 ◽  
Vol 204 ◽  
pp. 157-160 ◽  
Author(s):  
Edward L. Wright
Keyword(s):  
Solar System ◽  
Radiation Field ◽  
Measured Data ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Zodiacal Light ◽  
Extragalactic Background Light ◽  
Background Light

Models of the zodiacal light are necessary to convert measured data taken from low Earth orbit into the radiation field outside the Solar System. The uncertainty in these models dominates the overall uncertainty in determining the extragalactic background light for wavelengths λ < 100 μm.

scholarly journals The Contribution of Kuiper Belt Dust Grains to the Inner Solar System

1996 ◽  
Vol 150 ◽  
pp. 163-166
Author(s):  
Jer-Chyi Liou ◽  
Herbert A. Zook ◽  
Stanley F. Dermott
Keyword(s):  
Solar System ◽  
Interstellar Dust ◽  
Numerical Study ◽  
Kuiper Belt ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Dust Grains ◽  
Zodiacal Light ◽  
Interplanetary Dust Particles ◽  
The Earth

AbstractThe recent discovery of the so-called Kuiper belt objects has prompted the idea that these objects produce dust grains that may contribute significantly to the interplanetary dust population at 1 AU. We have completed a numerical study of the orbital evolution of dust grains, of diameters 1 to 9 μm, that originate in the region of the Kuiper belt. Our results show that about 80% of the grains are ejected from the Solar System by the giant planets while the remaining 20% of the grains evolve all the way to the Sun. Surprisingly, these dust grains have small orbital eccentricities and inclinations when they cross the orbit of the Earth. This makes them behave more like asteroidal than cometary-type dust particles. This also enhances their chances to be captured by the Earth and makes them a possible source of the collected interplanetary dust particles (IDPs); in particular, they represent a possible source that brings primitive/organic materials from the outer Solar System to the Earth.When collisions with interstellar dust grains are considered, however, Kuiper belt dust grains larger than about 9 μm appear likely to be collisionally shattered before they can evolve to the inner part of the Solar System. Therefore, Kuiper belt dust grains may not, as they are expected to be small, contribute significantly to the zodiacal light.

scholarly journals Observations of the Extragalactic Background Light

1990 ◽  
Vol 139 ◽  
pp. 257-268 ◽  
Author(s):  
K. Mattila
Keyword(s):  
Galaxy Formation ◽  
Basic Problem ◽  
Dark Cloud ◽  
Extragalactic Background Light ◽  
Background Light ◽  
Galaxy Formation And Evolution ◽  
Intergalactic Space ◽  
Formation And Evolution ◽  
Night Sky ◽  
Observational Techniques

We present a review of the presently available observations of the extragalactic background light (EBL) obtained by means of night sky photometry. The EBL is a quantity of great cosmological importance; areas which are directly affected include galaxy formation and evolution, the appropriateness of different cosmological models, and the local luminosity density due to galaxies and other matter in intergalactic space. The basic problem in measuring the EBL is its separation from other, much stronger components of the light of the night sky. None of the different observational techniques have succeeded in providing a generally accepted measurement of the EBL. After a review of available methods, we present new results from an experiment by Mattila and Schnur (1989) utilizing the dark cloud technique in the area of L1642, a high-latitude dark nebula in the galactic anticentre direction.

scholarly journals 21. Light of the Night Sky / Lumière du Ciel Nocturne

1997 ◽  
Vol 23 (1) ◽  
pp. 231-236
Author(s):  
Christoph Leinert
Keyword(s):  
Interstellar Dust ◽  
Thermal Emission ◽  
Scattered Light ◽  
Diffuse Radiation ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Zodiacal Light ◽  
Interplanetary Dust Particles ◽  
Extragalactic Background Light ◽  
Night Sky

The light of the night sky is a difficult to disentangle mixture of tropospherically scattered light, airglow, zodiacal light (including the thermal emission by interplanetary dust particles), unresolved stellar light, diffuse scattering and emission by interstellar dust and gas, and finally an extragalactic component. It has the reputation of being a very traditional field of astronomy, which certainly is true if we look at the long history of the subject. The recent renewed interest in this topic, which continued during this triennium, appears mainly to come from three sources: - first from the impressive results of the IRAS and COBE infrared satellites. They brought to general consciousness the fact that the infrared sky is characterised by strong emission from interplanetary and interstellar dust, and made clear that this emission may interfere with the study of faint interesting sources. - then from the development of sensitive detectors and arrays for essentially all of the wavelength range to be covered in this report, from the Lyman limit to ≈ 300 μm. Now the difficult measurements of the ultraviolet diffuse radiation and of the extragalactic background light in the infrared cosmological windows around 3 μm and 200 μm have become feasible and state of the art projects. - finally, the threat to astronomical observations arising from man-made development and lighting has become important enough to further studies of uncontaminated and contaminated night sky brightnesses. This report will refer mainly to those areas and is meant to highlight noteworthy developments. It was prepared with the help of Drs. Bowyer and Mattila.

scholarly journals Normalization of the extragalactic background light from high-energy γ-ray observations

2019 ◽  
Vol 627 ◽  
pp. A110
Author(s):  
B. Biasuzzi ◽  
O. Hervet ◽  
D. A. Williams ◽  
J. Biteau
Keyword(s):  
Galaxy Formation ◽  
A Priori ◽  
Diffuse Radiation ◽  
Far Infrared ◽  
High Energy ◽  
Extragalactic Background Light ◽  
Background Light ◽  
Spectrum Radio ◽  
High Energy Absorption ◽  
The Impact

Extragalactic background light (EBL) plays an important role in cosmology since it traces the history of galaxy formation and evolution. Such diffuse radiation from near-UV to far-infrared wavelengths can interact with γ-rays from distant sources such as active galactic nuclei (AGNs), and is responsible for the high-energy absorption observed in their spectra. However, probing the EBL from γ-ray spectra of AGNs is not trivial due to internal processes that can mimic its effect. Such processes are usually taken into account in terms of curvature of the intrinsic spectrum. Hence, an improper choice of parametrization for the latter can seriously affect EBL reconstruction. In this paper, we propose a statistical approach that avoids a priori assumptions on the intrinsic spectral curvature and that, for each source, selects the best-fit model on a solid statistical basis. By combining the Fermi-LAT observations of 490 blazars, we determine the γ-ray-inferred level of EBL for various state-of-the-art EBL models. We discuss the EBL level obtained from the spectra of both BL Lacs and flat spectrum radio quasars (FSRQ) in order to investigate the impact of internal absorption in different classes of objects. We further scrutinize constraints on the EBL evolution from γ-ray observations by reconstructing the EBL level in four redshift ranges, up to z ∼ 2.5. The approach implemented in this paper, carefully addressing the question of the modeling of the intrinsic emission at the source, can serve as a solid stepping stone for studies of hundreds of high-quality spectra acquired by next-generation γ-ray instruments.

scholarly journals Physical Modeling of the Zodiacal Dust Cloud

2001 ◽  
Vol 204 ◽  
pp. 17-34 ◽  
Author(s):  
Leonid M. Ozernoy
Keyword(s):  
Solar System ◽  
Physical Modeling ◽  
Interstellar Dust ◽  
Extrasolar Planets ◽  
Dust Cloud ◽  
Interplanetary Dust ◽  
Asteroid Belt ◽  
Dust Particles ◽  
Resonant Structure ◽  
Zodiacal Light

This review is based on extensive work done in collaboration with N. Gorkavyi, J. Mather, and T. Taidakova, which aimed at physical modeling of the interplanetary dust (IPD) cloud in the Solar System, i.e., establishing a link between the observable characteristics of the zodiacal cloud and the dynamical and physical properties of the parent minor bodies. Our computational approach permits one to integrate the trajectories of hundreds of particles and to effectively store up to 1010–11 positions with modest computer resources, providing a high fidelity 3D distribution of the dust. Our numerical codes account for the major dynamical effects that govern the motion of IPD particles: Poynting-Robertson (P-R) drag and solar wind drag; solar radiation pressure; particle evaporation; gravitational scattering by the planets; and the influence of mean-motion resonances. The incorporation of secular resonances and collisions of dust particles (both mutual and with interstellar dust) is underway. We have demonstrated the efficacy of our codes by performing the following analyses: (i) simulation of the distribution of Centaurs (comets scattered in their journey from the Kuiper belt inward in the Solar System) and revealing the effects of the outer planets in producing ‘cometary belts’; (ii) detailed inspection of a rich resonant structure found in these belts, which predicts the existence of gaps similar to the Kirkwood gaps in the main asteroid belt; (iii) a preliminary 3-D physical model of the IPD cloud, which includes three dust components – asteroidal, cometary, and kuiperoidal – and is consistent with the available data of Pioneer and Voyager dust detectors; (iv) modeling of the IPD cloud, which provides a zodiacal light distribution in accord, to the order of 1%, with a subset of the COBE/DIRBE observations; and (v) showing that the resonant structure in dusty circumstellar disks of Vega and Epsilon Eridani is a signature of embedded extrasolar planets. Further improvements of our modeling and their importance for astronomy and cosmology are outlined.

scholarly journals The intrinsic gamma-ray spectrum of TXS 0506+056: intergalactic propagation effects

2020 ◽  
Vol 500 (2) ◽  
pp. 2188-2195
Author(s):  
Andrey Saveliev ◽  
Rafael Alves Batista
Keyword(s):  
Gamma Ray ◽  
Recent Observation ◽  
High Energy ◽  
Spectral Energy ◽  
Electromagnetic Spectrum ◽  
Extragalactic Background Light ◽  
Background Light ◽  
Propagation Effects ◽  
Very High Energy ◽  
Energy Gamma

ABSTRACT The recent observation of high-energy neutrinos from the 2017 flare of the blazar TXS 0506+056, together with counterparts across the whole electromagnetic spectrum, opens up new possibilities for investigating the properties of this class of objects as well as the traversed medium. Propagation effects such as the attenuation of the very-high-energy gamma-ray component by the extragalactic background light are well known, and usually taken into account when fitting spectral energy distributions of objects. Other effects such as those of intergalactic magnetic fields are, however, often neglected. In this work, we present a comprehensive study of the influence of these fields and the extragalactic background light on the determination of the intrinsic gamma-ray spectrum of this blazar.

scholarly journals EXTRAGALACTIC BACKGROUND LIGHT FROM HIERARCHICAL GALAXY FORMATION: GAMMA-RAY ATTENUATION UP TO THE EPOCH OF COSMIC REIONIZATION AND THE FIRST STARS

2013 ◽  
Vol 768 (2) ◽  
pp. 197 ◽  
Author(s):  
Yoshiyuki Inoue ◽  
Susumu Inoue ◽  
Masakazu A. R. Kobayashi ◽  
Ryu Makiya ◽  
Yuu Niino ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Gamma Ray ◽  
Extragalactic Background Light ◽  
First Stars ◽  
Background Light ◽  
Gamma Ray Attenuation

scholarly journals Spectrophotometric measurement of the Extragalacic Background Light

2011 ◽  
Vol 7 (S284) ◽  
pp. 429-436 ◽  
Author(s):  
Kalevi Mattila ◽  
Kimmo Lehtinen ◽  
Petri Väisänen ◽  
Gerhard von Appen-Schnur ◽  
Christoph Leinert
Keyword(s):  
Scattered Light ◽  
Spectral Lines ◽  
Spectral Signature ◽  
Zodiacal Light ◽  
Differential Measurement ◽  
Extragalactic Background Light ◽  
Background Light ◽  
The Difference ◽  
Lower Limits ◽  
Night Sky Brightness

AbstractThe Extragalactic Background Light (EBL) at UV, optical and NIR wavelengths consists of the integrated light of all unresolved galaxies along the line of sight plus any contributions by intergalactic matter including hypothetical decaying relic particles. The measurement of the EBL has turned out to be a tedious problem. This is because of the foreground components of the night sky brightness, much larger than the EBL itself: the Zodiacal Light (ZL), Integrated Starlight (ISL), Diffuse Galactic Light (DGL) and, for ground-based observations, the Airglow (AGL) and the tropospheric scattered light. We have been developing a method for the EBL measurement which utilises the screening effect of a dark nebula on the EBL. A differential measurement in the direction of a high-latitude dark nebula and its surrounding area provides a signal that is due to two components only, i.e. the EBL and the diffusely scattered ISL from the cloud. We present a progress report of this method where we are now utilising intermediate resolution spectroscopy with ESO's VLT telescope. We detect and remove the scattered ISL component by using its characteristic Fraunhofer line spectral signature. In contrast to the ISL, in the EBL spectrum all spectral lines are washed out. We present a high quality spectrum representing the difference between an opaque position within our target cloud and several clear OFF positions around the cloud. We derive a preliminary EBL value at 400 nm and an upper limit to the EBL at 520 nm. These values are in the same range as the EBL lower limits derived from galaxy counts.Unit: We will use in this paper the abbreviation 1 cgs = 10−9erg s−1cm−2sr−1Å−1

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