Results 61 to 70 of about 219,246 (225)
Fast Radio Burst Energy Function in the Presence of DMhost Variation
UniverseFast radio bursts (FRBs) have been found in great numbers, but the physical mechanism of these sources is still a mystery. The redshift evolutions of the FRB energy distribution function and the volumetric rate shed light on the origin of FRBs.
Ji-Guo Zhang +5 more
doaj +1 more source
The Angular Diameter-Redshift Test for Large Redshift Quasars [PDF]
Symposium - International Astronomical Union, 1977 Complete samples of quasars in the 3CR and 4C catalogues have been observed with a resolution of 2″ arc in RA and 2″ cosecδ in dec with the Cambridge 5-km telescope at 5 GHz (Riley & Pooley 1975; Jenkins et al 1977), from which it has been possible to determine the overall angular sizes of their radio structures (LAS). The angular diameter-redshift
J. M. Riley, A. Hooley, M. S. Longair
openaire +2 more sources
A Note on the Inverse Problem with LTB Universes
, 2010 The inverse problem with Lema\^itre-Tolman-Bondi (LTB) universe models is discussed. The LTB solution for the Einstein equations describes the spherically symmetric dust-filled spacetime. The LTB solution has two physical functional degrees of freedom of
Yoo, Chul-Moon
core +1 more source
Redshift-space distortions [PDF]
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2011 Comparing measurements of redshift-space distortions (RSDs) with geometrical observations of the expansion of the Universe offers tremendous potential for testing general relativity on very large scales. The basic linear theory of RSDs in the distant-observer limit has been known for 25 years and the effect has been conclusively observed ...
Percival W. J. +4 more
openaire +5 more sources
ASTROMETRIC REDSHIFTS FOR QUASARS [PDF]
The Astronomical Journal, 2009 The wavelength dependence of atmospheric refraction causes differential chromatic refraction (DCR), whereby objects imaged at different optical/UV wavelengths are observed at slightly different positions in the plane of the detector. Strong spectral features induce changes in the effective wavelengths of broad-band filters that are capable of producing
Gordon T. Richards +3 more
openaire +3 more sources
Comparative study on zinc oxide nanocrystals synthesized by two precipitation methods
CerâmicaZinc oxide nanocrystals were synthesized by two precipitation methods successfully. The nanocrystals prepared via method I (zinc acetate dihydrate precipitation with KOH) were smaller in crystallite size (~20 nm) as compared to method II (zinc nitrate ...
M. R. Bodke, Y. Purushotham, B. N. Dole
doaj +1 more source
Electrostatic time dilation and redshift
Physics Letters B, 2020 We first present the salient features of the gravitational time dilation and redshift effects in two ways; by considering the oscillation frequencies/rates of clocks at different heights/potentials and by considering the photons emitted by these clocks ...
Murat Özer
doaj +1 more source
The K20 survey. IV. The redshift distribution of Ks<20 galaxies: a test of galaxy formation models [PDF]
, 2002 We present the redshift distribution of a complete sample of 480 galaxies with Ks1 and z>1.5 respectively. A ``blind'' comparison is made with the predictions of a set of the most recent LambdaCDM hierarchical merging and pure luminosity evolution (PLE ...
Arimoto +27 more
core +2 more sources
1.4-GHz Luminosity Function of Galaxies from the Las Campanas Redshift Survey
, 1998 A preliminary 1.4 GHz RLF at redshift of about 0.14 is derived from the Las Campanas Redshift Survey (LCRS) and the NVSS radio data. No significant evolution has been found at this redshift in comparison to the 'local' RLF.Comment: 2 pages including 2 ...
Godlowski, W., Machalski, J.
core +1 more source
Morpho-photometric redshifts [PDF]
Monthly Notices of the Royal Astronomical Society, 2019 ABSTRACT Machine learning (ML) is one of two standard approaches (together with SED fitting) for estimating the redshifts of galaxies when only photometric information is available. ML photo-z solutions have traditionally ignored the morphological information available in galaxy images or partly included it in the form of hand-crafted ...
openaire +2 more sources