Results 11 to 20 of about 926 (266)
The galaxy luminosity function and the redshift-distance controversy (A Review) [PDF]
Proceedings of the National Academy of Sciences, 1986 The mean relation between distance and redshift for galaxies is reviewed as an observational question. The luminosity function for galaxies is an important ingredient and is given explicitly. We discuss various observational selection effects that are important for comparison of the linear and quadratic distance-redshift laws. Several lines of evidence
E E, Salpeter, G L, Hoffman
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Do Multi-Structural One-Off FRBs Trace Similar Cosmology History with Repeaters?
Universe, 2023 Fast Radio Bursts (FRBs) are millisecond-duration transient events that are typically observed at radio wavelengths and cosmological distances but their origin remains unclear.
Yuhao Zhu +9 more
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Luminosity distance and redshift in the Szekeres inhomogeneous cosmological models [PDF]
Journal of Cosmology and Astroparticle Physics, 2011 The Szekeres inhomogeneous models can be used to model the true lumpy universe that we observe. This family of exact solutions to Einstein's equations was originally derived with a general metric that has no symmetries. In this work, we develop and use a framework to integrate the angular diameter and luminosity distances in the general Szekeres models.
Nwankwo, Anthony +2 more
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Understanding the Fundamental Plane and the Tully Fisher Relation
Frontiers in Astronomy and Space Sciences, 2020 The relation between early type galaxy size, surface brightness and velocity dispersion, “the fundamental plane,” has long been understood as resulting from equilibrium in their largely pressure supported stellar dynamics.
Jeremy Mould
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Weighing Cosmological Models with SNe Ia and Gamma Ray Burst Redshift Data
Universe, 2019 Many models have been proposed to explain the intergalactic redshift using different observational data and different criteria for the goodness-of-fit of a model to the data. The purpose of this paper is to examine several suggested models using the same
Rajendra P. Gupta
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The Astrophysical Journal, 2023 We perform a rigorous cosmology analysis on simulated Type Ia supernovae (SNe Ia) and evaluate the improvement from including photometric host galaxy redshifts compared to using only the “ z _spec ” subset with spectroscopic redshifts from the host or SN.
Ayan Mitra +4 more
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SNe Ia Redshift in a Nonadiabatic Universe
Universe, 2018 By relaxing the constraint of adiabatic universe used in most cosmological models, we have shown that the new approach provides a better fit to the supernovae Ia redshift data with a single parameter, the Hubble constant H0, than the standard ΛCDM
Rajendra P. Gupta
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The local redshift-distance relation and spatial uniformity [PDF]
Proceedings of the National Academy of Sciences, 1987 Regrettably, the review of the redshift-distance relation in the review by Salpeter and Hoffman [Salpeter, E. E. & Hoffman, G. L., Jr. (1986) Proc. Natl. Acad. Sci. USA 83, 3056-3063], appears flawed. In particular, the logically inconclusive and uncertain hypothesis of local extragalactic spatial uniformity is ...
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Constraints on the CMB temperature-redshift dependence from SZ and distance measurements [PDF]
Journal of Cosmology and Astroparticle Physics, 2012 The relation between redshift and the CMB temperature, $T_{CMB}(z)=T_0(1+z)$ is a key prediction of standard cosmology, but is violated in many non-standard models. Constraining possible deviations to this law is an effective way to test the $ $CDM paradigm and search for hints of new physics. We present state-of-the-art constraints, using both direct
A. Avgoustidis +3 more
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Galaxies, 2019 We have shown that the Hubble constant H 0 embodies the information about the evolutionary nature of the cosmological constant Λ , gravitational constant G , and the speed of light c .
Rajendra P. Gupta
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