منابع مشابه
A Hubble Diagram for Quasars
The cosmological model is at present not tested between the redshift of the farthest observed supernovae (z ∼ 1.4) and that of the Cosmic Microwave Background (z ∼1,100). Here we introduce a new method to measure the cosmological parameters: we show that quasars can be used as “standard candles” by employing the non-linear relation between their intrinsic UV and X-ray emission as an absolute di...
متن کاملQuasars and the Hubble Relation
If active galaxies are defined as extragalactic objects with appreciably non thermal spectra then a continuity exists in redshift from the highest redshift quasars to low redshift Seyferts, AGNs and allied galaxies. Evidence is discussed for this sequence to be an evolutionary track with objects evolving from high to low intrinsic redshift with time. At the end of this evolution the objects are...
متن کاملHubble Diagram Dispersion From Large-Scale Structure
We consider the effects of large structures in the Universe on the Hubble diagram. This problem is treated non-linearly by considering a Swiss Cheese model of the Universe in which under-dense voids are represented as negatively curved regions of space-time. Exact expressions for luminosity distances and redshifts are used to investigate the non-linear effects of structure on the magnitudes of ...
متن کاملAn updated Gamma Ray Bursts Hubble diagram
Gamma ray bursts (GRBs) have recently attracted much attention as a possible way to extend the Hubble diagram to very high redshift. To this aim, the luminosity (or isotropic emitted energy) of a GRB at redshift z must be evaluated from a correlation with a distance independent quantity so that one can then solve for the luminosity distance DL(z) and hence the distance modulus μ(z). Averaging o...
متن کامل(An)isotropy of the Hubble diagram: comparing hemispheres
Aims. We test the isotropy of the Hubble diagram. At small redshifts, this is possible without assumptions on the cosmic inventory and provides a fundamental test of the cosmological principle. At higher redshift we check for the self-consistency of the ΛCDM model. Methods. At small redshifts, we use public supernovae (SNe) Ia data to determine the deceleration parameter q0 and the SN calibrati...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1977
ISSN: 0252-9211
DOI: 10.1017/s0252921100053689