Estimates of the cosmic star formation rate and of cluster metallicities independently imply that at z 0.5 the gas in the universe has substantial average metallicity: 1/10 Z/Z☉ 1/3 for Ωgas = 0.05. This metal density probably cannot be contained in known solar-metallicity galaxies of density parameter Ω* ≈ 0.004, implying significant enrichment of the intergalactic medium (IGM) by ejection of metals and dust from galaxies via winds, in mergers or in dust efflux driven by radiation pressure. Galaxies have a dust-to-metal ratio of ~0.5 in their interstellar media, but some fraction (1 - f) > 0 of this must be destroyed in the IGM or during the ejection process. Assuming the Draine & Lee dust model and preferential destruction of small grains (as destruction by sputtering would provide), I calculate the reddening and extinction of a uniform cosmological dust component in terms of f and the minimum grain size amin. Very small grains provide most of the reddening but less than half of the opacity for optical extinction. For f 0.3 and amin 0.1 μm, the intergalactic dust would be too gray to have been detected by its reddening, yet dense enough to be cosmologically important: it could account for the recently observed Type Ia supernova dimming at z ~ 0.5 without cosmic acceleration. It would also have implications for galaxy counts and evolutionary studies and would contribute significantly to the cosmic infrared background (CIB). The importance of gray intergalactic dust of the described type can be tested by observations of z = 0.5 supernovae in (rest) R-band or longer wavelengths and by the fluxes of a large sample of supernovae at z > 1.

https://iopscience.iop.org/article/10.1086/307945/pdf

Intergalactic Dust and Observations of Type Ia Supernovae

A preliminary discussion is presented of recent results obtained as part of the extension of the Center of Astrophysics redshift survey. Several features of the results are striking. The distribution of galaxies in the sample, which contains 1100 galaxies in a 6 deg x 117 deg strip going through the Coma cluster, looks like a slice through the suds in the kitchen sink. It appears that the galaxies are on the surfaces of bubble-like structures with diameters of 25-50/h-Mpc. The largest bubble in the survey has a diameter comparable with the most recent estimates of the diameter of the void in Bootes. This topology poses serious challenges for current models for the formation of large-scale structure. The best available model for generating these structures is the explosive galaxy formation theory of Ostriker and Cowie (1981).

A Slice of the Universe

Morphological Analysis in Inventive Engineering

Fritz Zwicky is identified commonly as the discoverer o f dark matter, the unobservable mass that is believed to occupy about 90 percent of the universe. In 1933 Zwicky found a mass discrepancy in the Coma cluster o f galaxies, and in 1936 a similar discrepancy was found in the Virgo cluster. The startling news of a mass discrepancy in clusters did not raise many eyebrows. In fact, the astronomical community did not address the problem until the occasion of two conferences held in 1961. and it only gained astronomical prestige at the end of the 1970s, forty years after the initial postulation. Zwicky’s role in the history o f this most important subject in astronomy is significant in tracing the progression of the understanding of extragalactic dynamics and observations. It also shows that it is not only scientific evidence that defines theories, but that social interactions are also of vital importance.

Lunatic on a mountain : Fritz Zwicky and the early history of dark matter

A general relativistic cosmological model is presented which has closed space sections and mass density below a critical density similar to that of Friedmann's models. The model may predict double images of cosmic sources: a hint is made at a qualitative application to quasar astronomy.

A cosmological model with compact space sections and low mass density

We used theIRAS All Sky Maps in order to search for infrared emission in the direction of the Okroy Cloud (R.A.=12h50m, δ=22°). An enhancement of 100 μm diffuse emission is evident in such a region, with an anomalous value of the ratioIv (100 μm)/Av; hydrogen 21 cm emission is also present with low radial speed, thus suggesting that the cloud could be a satellite of our Galaxy.

Far-infrared emission from an intergalactic dust cloud?

Testing cosmological models is worthwhile as long as the theoretical assumptions, on which these models are based, are true In this report observational material testing the Cosmological Principle separately for geometry and substratum, is discussed without referring to any given model of the Universe

Observational Foundations for Assumptions in Cosmology

Fritz Zwicky as a conscious Goetheanist. Johann Wolfgang Goethe as a natural philosopher and methodologist. Goetheanist theory of knowledge — a theory essentially different from the theory of Kant, from which the contemporary concept of paradigms has originated. Pre-scientific character of theory of knowledge. The principal thought experiment. The role of thinking in Goetheanism. Fundamental phenomena. Morphological approach. The ‘shape’ (µoρφή) of a problem. Morphological box. Individual hypothesis versus classes of hypotheses. Theory and reality.

Philosophical foundations of Zwicky's morphological approach in science

Observational data on the intergalactic dust.

The suitability of different mathematical methods with respect to particular problems is shown.

Konrad Rudnicki

Papers

Far-infrared emission from an intergalactic dust cloud?

Observational Foundations for Assumptions in Cosmology

Philosophical foundations of Zwicky's morphological approach in science

Observational data on the intergalactic dust.

Comparison of different mathematical methods for the investigation of object distributions