The failure of testing for cosmic opacity via the distance-duality relation (original) (raw)
Related papers
Journal of Cosmology and Astroparticle Physics, 2010
We update constraints on cosmic opacity by combining recent SN Type Ia data compilation with the latest measurements of the Hubble expansion at redshifts between 0 and 2. The new constraint on the parameter ǫ parametrising deviations from the luminosity-angular diameter distance relation (d L = d A (1 + z) 2+ǫ ), is ǫ = −0.04 +0.08 −0.07 (2-σ). For the redshift range between 0.2 and 0.35 this corresponds to an opacity ∆τ < 0.012 (95% C.L.), a factor of 2 stronger than the previous constraint. Various models of beyond the standard model physics that predict violation of photon number conservation contribute to the opacity and can be equally constrained. In this paper we put new limits on axion-like particles, including chameleons, and minicharged particles.
Model-independent constraints on the cosmic opacity
Journal of Cosmology and Astroparticle Physics, 2013
We use current measurements of the expansion rate H(z) and cosmic background radiation bounds on the spatial curvature of the Universe to impose cosmological model-independent constraints on cosmic opacity. To perform our analyses, we compare opacity-free distance modulus from H(z) data with those from two supernovae Ia compilations: the Union2.1 plus the most distant spectroscopically confirmed SNe Ia (SNe Ia SCP-0401 z = 1.713) and two Sloan Digital Sky Survey (SDSS) subsamples. The influence of different SNe Ia light-curve fitters (SALT2 and MLCS2K2) on the results is also verified. We find that a completely transparent universe is in agreement with the largest sample in our analysis (Union 2.1 plus SNe Ia SCP-0401). For SDSS sample a such universe it is compatible at < 1.5σ level regardless the SNe Ia light-curve fitting used.
Universe opacity and cosmic dynamics
arXiv: General Physics, 2019
Equations of cosmic dynamics for a model of the opaque Universe are derived and tested on supernovae (SNe) Ia observations. The model predicts a cyclic expansion/contraction evolution of the Universe within a limited range of scale factors. The maximum scale factor is controlled by the overcritical density of the Universe, the minimum scale factor depends on global stellar and dust masses in the Universe. During contraction due to gravitational forces, the extragalactic background light (EBL) and intergalactic opacity increase with time because of a smaller proper volume of the Universe. The radiation pressure produced by absorption of the EBL by dust steeply rises and counterbalances the gravitational forces. The maximum redshift, at which the radiation pressure is capable to stop the contraction and start a new expansion, is between 15 and 45. The model avoids the Big Bang and concepts of the non-baryonic dark matter and dark energy. The model successfully explains the existence o...
The Astrophysical Journal
In this paper, we present a cosmological model-independent test for the cosmic opacity at high redshifts (z ∼ 5). We achieve this with the opacity-dependent luminosity distances derived from nonlinear relation between X-ray and UV emissions of quasars, combined with two types of opacity-independent luminosity distances derived from the Hubble parameter measurements and simulated gravitational wave (GW) events achievable with the Einstein Telescope (ET). In the framework of two phenomenological parameterizations adopted to describe cosmic opacity at high redshifts, our main results show that a transparent universe is supported by the current observational data at 2σ confidence level. However, the derived value of the cosmic opacity is slightly sensitive to the parametrization of τ (z), which highlights the importance of choosing a reliable parametrization to describe the optical depth τ (z) in the early universe. Compared with the previous works, the combination of the quasar data and the H(z)/GW observations in similar redshift ranges provides a novel way to confirm a transparent universe (ǫ = 0 at higher redshifts z ∼ 5), with an accuracy of ∆ǫ ∼ 10 −2. More importantly, our findings indicate that a strong degeneracy between the cosmic opacity parameter and the parameters characterizing the L UV − L X relation of quasars, which reinforces the necessity of proper calibration for such new type of high-redshift standard candle (in a cosmological model-independent way).
An Empirical Determination of the EBL and the Gamma-ray Opacity of the Universe
I present the results of a new approach to the intensity and photon density spectrum of the intergalactic background light as a function of redshift using observational data obtained in many different wavelength bands from local to deep galaxy surveys. This enables an empirical determination of both the EBL and its observationally based uncertainties. Using these results one can place 68% confidence upper and lower limits on the opacity of the universe to {\gamma}-rays, free of the theoretical assumptions that were needed for past calculations. I compare our results with measurements of the extragalactic background light, upper limits obtained from observations made by the Fermi Gamma-ray Space Telescope, and new observationally based results from Fermi and H.E.S.S. using recent analyses of blazar spectra.
Monthly Notices of the Royal Astronomical Society
The observed extragalactic background light (EBL) is affected by light attenuation due to absorption of light by galactic and intergalactic dust in the Universe. Even galactic opacity of 10-20 per cent and minute universe intergalactic opacity of 0.01 mag h Gpc −1 at the local Universe have a significant impact on the EBL because obscuration of galaxies and density of intergalactic dust increase with redshift as (1 + z) 3. Consequently, intergalactic opacity increases and the Universe becomes considerably opaque at z > 3. Adopting realistic values for galactic and intergalactic opacity, the estimates of the EBL for the expanding dusty universe are close to observations. The luminosity density evolution fits well measurements. The model reproduces a steep increase of the luminosity density at z < 2, its maximum at z = 2-3, and its decrease at higher redshifts. The increase of the luminosity density at low z is not produced by the evolution of the star formation rate but by the fact that the Universe occupied a smaller volume in previous epochs. The decline of the luminosity density at high z originates in the opacity of the Universe. The calculated bolometric EBL ranges from 100 to 200 nW m −2 sr −1 and is within the limits of 40 and 200 nW m −2 sr −1 of current EBL observations. The model predicts 98 per cent of the EBL coming from radiation of galaxies at z < 3.5. Accounting for light extinction by intergalactic dust implies that the Universe was probably more opaque than dark for z > 3.5.
Current State of Astrophysical Opacities: A White Paper
arXiv: Solar and Stellar Astrophysics, 2018
Availability of reliable atomic and molecular opacity tables is essential in a wide variety of astronomical modeling: the solar and stellar interiors, stellar and planetary atmospheres, stellar evolution, pulsating stars, and protoplanetary disks, to name a few. With the advancement of powerful research techniques such as helio-seismology and asteroseismology, solar neutrino-flux measurements, exoplanet survey satellites, three-dimensional hydrodynamic atmospheric simulations (including non-LTE and granulation effects), high-performance computing of atomic and molecular data, and innovative plasma experiments the accuracy and completeness of opacity tables is being taken to an unprecedented level. The goal of the second Workshop on Astrophysical Opacities was to gather opacity data producers and consumers from both the atomic and molecular sectors to contribute to solving outstanding problems and to develop more effective and integrated interfaces. In this review we attempt to summa...
A test for cosmic distance duality
Journal of Cosmology and Astroparticle Physics, 2012
Testing the cosmic distance duality relation (CDDR) constitutes an important task for cosmology and fundamental physics since any violation of it would be a clear evidence of new physics. In this paper, we propose a new test for the CDDR using only current measurements of the gas mass fraction of galaxy clusters from Sunyaev-Zeldovich (fSZE) and X-ray surface brightness (fX−ray) observations. We show that the relation between fX−ray and fSZE observations is given by fSZE = ηfX−ray, where η quantifies deviations from the CDDR. Since this latter expression is valid for the same object in a given galaxy cluster sample, the method proposed removes possible contaminations from different systematics error sources and redshift differences involved in luminosity and angular diameter distance measurements. We apply this cosmological model-independent methodology to the most recent fX−ray and fSZE data and show that no significant violation of the CDDR is found.
Monthly Notices of the Royal Astronomical Society, 2018
A cosmological model, in which the cosmic microwave background (CMB) is a thermal radiation of intergalactic dust instead of a relic radiation of the big bang, is revived and revisited. The model suggests that a virtually transparent local Universe becomes considerably opaque at redshifts z > 2-3. Such opacity is hardly to be detected in the Type Ia supernova data, but confirmed using quasar data. The opacity steeply increases with redshift because of a high proper density of intergalactic dust in the previous epochs. The temperature of intergalactic dust increases as (1 + z) and exactly compensates the change of wavelengths due to redshift, so that the dust radiation looks apparently like the radiation of the blackbody with a single temperature. The predicted dust temperature is T D = 2.776 K, which differs from the CMB temperature by 1.9 per cent only, and the predicted ratio between the total CMB and extragalactic background light (EBL) intensities is 13.4 which is close to 12.5 obtained from observations. The CMB temperature fluctuations are caused by EBL fluctuations produced by galaxy clusters and voids in the Universe. The polarization anomalies of the CMB correlated with temperature anisotropies are caused by the polarized thermal emission of needle-shaped conducting dust grains aligned by large-scale magnetic fields around clusters and voids. A strong decline of the luminosity density for z > 4 is interpreted as the result of high opacity of the Universe rather than of a decline of the global stellar mass density at high redshifts.
The Astrophysical Journal
Since gravitational waves (GWs) propagate freely through a perfect fluid, coalescing compact binary systems as standard sirens allow to measure the luminosity distance directly and provide distance measurements unaffected by the cosmic opacity. DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO) is a future Japanese space gravitational-wave antenna sensitive to frequency range between target frequencies of LISA and ground-based detectors. Combining the predicted future GW observations from DECIGO and three current popular astrophysical probes (HII regions, SNe Ia Pantheon sample, quasar sample) in electromagnetic (EM) domains, one would be able to probe the opacity of the Universe at different redshifts. In this paper, we show that the cosmic opacity parameter can be constrained to a high precision (∆ǫ ∼ 10 −2) out to high redshifts (z ∼5). In order to reconstruct the evolution of cosmic opacity without assuming any particular functional form of it, the cosmic opacity tests should be applied to individual redshift bins independently. Therefore, we also calculate the optical depth at individual redshifts and averaged τ (z) within redshift bins. Our findings indicate that, compared with the results obtained from the HII galaxies and Pantheon SNe Ia, there is an improvement in precision when the quasar sample is considered. While non-zero optical depth is statistically significant only for redshift ranges 0 < z < 0.5, 1 < z < 2, and 2.5 < z < 3.5, such tendency is different from that obtained in the framework of its parametrized form. Therefore the importance of cosmic-opacity test without a prescribed phenomenological function should be emphasized.