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[1302.5308] Interpretation of the Hubble diagram in a non-homogeneous universe - 0 views

arxiv.org/1302.5308 cosmology lensing
shared by Phil Bull on 22 Feb 13 - No Cached
  • Phil Bull on 22 Feb 13
     
    Abstract: In the standard cosmological framework, the Hubble diagram is interpreted by assuming that the light emitted by standard candles propagates in a spatially homogeneous and isotropic spacetime. However, the light from "point sources" -- such as supernovae -- probes the universe on scales where the homogeneity principle is no longer valid.
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Intrinsic uncertainty on the nature of dark energy - 1 views

voxcharta.org/...y-on-the-nature-of-dark-energy cosmology lensing inhomogeneity
shared by Phil Marshall on 28 Feb 13 - No Cached
  • Phil Marshall on 28 Feb 13
     
    Valkenburg et al look at the way inhomogeneities in the universe introduce apparent uncertainty in dark energy measurements, if one assumes a homogeneous world model when interpreting distance measurements. They also point out that cosmic variance will lead to bias in w(a). Modeling the structure in the universe is important! My question: is weak lensing immune from these worries, since it involves treatment of all the inhomogeneities?
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Cosmic Censorship: Formation of a Shielding Horizon Around a Fragile Horizon - 0 views

arxiv.org/1302.6658 black holes
shared by Tessa Baker on 01 Mar 13 - No Cached
  • Tessa Baker on 01 Mar 13
     
    The Cosmic Censorship hypothesis suggests that gravitational singularities will always be hidden from the view of an external observer by an event horizon. It's sometimes given the status of a 'fundamental principle of the universe', though there's no particularly solid reasoning behind this (as far as I'm aware, at least). This short paper explores a gedanken experiment that attempts to violate cosmic censorship.
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Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars - 2 views

arxiv.org/1211.2616 cosmology dark energy
shared by Graeme Addison on 13 Nov 12 - No Cached
  • Graeme Addison on 13 Nov 12
     
    BAO detected at z > 2 using BOSS quasars
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Galaxy-Cluster Masses via 21st-Century Measurements of Lensing of 21-cm Fluctuations - 1 views

arxiv.org/1210.3041 cosmology lensing
shared by Phil Bull on 12 Oct 12 - No Cached
  • Phil Bull on 12 Oct 12
     
    "Observations of lensing of the 21-cm background from the dark ages will be capable of detecting M>~10^12 Msun/h mass halos, but will require futuristic experiments to overcome the contaminating sources."
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Dark Matter Substructure Detection Using Spatially Resolved Spectroscopy of Lensed Dust... - 1 views

voxcharta.org/...scopy-of-lensed-dusty-galaxies lensing ALMA Herschel darkmatter
shared by Phil Marshall on 19 Oct 12 - No Cached
  • Phil Marshall on 19 Oct 12
     
    Hezaveh et al simulate ALMA cycle 1 (ie 0.16" resolution) observations of Herschel/SPT sub mm lensed galaxies, and claim that the magnification is high enough, and the sources likely to be complex enough, to enable the detection of at least one DM subhalo of mass 10^8 or greater *in every system*
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