comoving distance to the source. We adopt a phenomenological model for the rate of GRBs that occur at redshift z per unit comoving volume of the form proposed by Rowan-Robinson for the star formation rate [10]. In this model, the GRB rate is given by R GRB (z;P, Q) =R 0 t(...
To demonstrate numerically (I'm too tired at the moment to plot another diagram), let DC be comoving distance and DL be the look-back time, D L = 1 Gyr, D C = 1.038 Gly D L = 2 Gyr, D C = 2.156 Gly D L = 3 Gyr, D C = 3.365 Gly D L = 4 Gyr, D C = 4.678 Gly...
By using the comoving distance, we derive an analytic expression forthe optical depth of gravitational lensing, which depends on theredshift to the source ... ZHU,ZONG-HONG - 《Modern Physics Letters A》 被引量: 32发表: 2000年 Mapping the ionised gas around the luminous QSO HE?1029-1401...
Transformations of the coordinates between the co-moving, the de Sitter and the standard systems of coordinates are given. The Poynting vector giving the intensity of light emitted by the distant receding galaxy and observed on earth has different forms in these systems of coordinates. As a first...
I was looking at the answer to this question: The difference between comoving and proper distances in defining the observable universe and wanted to reproduce the chart in order to better understand the relationship between the Hubble Sphere and the Particle Horizon, but I'm stuck w...
Whereas then the ambulance goes past you and moves away, the sound waves are spread across an increasing distance thus reducing the frequency you hear so the pitch seems lower. This principle of the Doppler effect applies to light as well as sound. American astronomer Edwin Hubble (who the ...
Homework Statement Consider a point in the intergalactic medium at some cosmic time ## t_{obs}##, the time of arrival of a photon of wavelength ##λ_{obs}## as seen by a hydrogen atom at that location. The source of this photon a comoving distance ##r## away emitted it at wavele...
, for the subsample that we use to 6 dV/dz = 4π (c/H 0 ) d 2 c (z)/ p (1 +z) 3 Ωm +Ω Λ , where dc is the comoving distance, Ωm = 0.3, Ω Λ = 0.7, and H 0 = 70 km/s/Mpc. 0 1 2 3 4 5 6 7 8 z 10 49 10 50 10 51 10 52 10 53 L i...
However, we cannot actually obtain the comoving distance from observations. In fact, the cosmological distances we observe are luminosity or angular diameter distances. The dimensionless curvature k=−1,0,+1 corresponds to open, flat and closed universes, respectively. With such a metric, the ...
We investigate a high-z cosmological model to compute the comoving sound horizon rat baryon-velocity freeze-out towards the end of hydrogen recombination. This model assumes a replacement of the conventional cosmic microwave background (CMB) photon gas by deconfining SU(2) Yang-Mills thermodynamics...