Energy density of massive neutrinos

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Discussion Overview

The discussion centers on the current understanding of the energy density of massive neutrinos, specifically the value of the density parameter \Omega_{\nu}. Participants seek updated references and data regarding neutrino masses and their implications for cosmology.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant requests an up-to-date reference for the value of \Omega_{\nu}, noting that Dodelson's cosmology book cites \Omega_{\nu}\approx 10^{-3} but seeks more recent information.
  • Another participant suggests that current results may focus more on mass limits rather than translating those into a density parameter, mentioning that the best constraints likely come from the cosmic microwave background (CMB) and galaxy power spectrum data, specifically referencing the SDSS catalogue and a Tegmark paper from 2004.
  • A third participant provides a link to a resource that estimates \Omega_\nu < 0.0065 at 95% confidence, suggesting it may be the best current measure.
  • A later reply expresses gratitude for the information provided.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the most current value of \Omega_{\nu}, as multiple references and approaches are discussed without a definitive conclusion.

Contextual Notes

The discussion highlights the potential limitations in translating mass limits into density parameters and the reliance on specific datasets for constraints.

nicksauce
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Does anyone have an up-to-date reference for the best value of [itex]\Omega_{\nu}[/itex], given our current understanding of neutrino masses? Dodelson's cosmology book has [itex]\Omega_{\nu}\approx 10^{-3}[/itex], but something more recent would be nice.
 
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Not sure if the results get quoted like that these days, usually it's just the mass limits rather than translating that into a density parameter. I think the best constraints come from CMB plus galaxy power spectrum results, the biggest data set being the SDSS catalogue. I think there was a Tegmark paper in 2004 on this, though there is bound to be more recent work.
 
nicksauce said:
Does anyone have an up-to-date reference for the best value of [itex]\Omega_{\nu}[/itex], given our current understanding of neutrino masses? Dodelson's cosmology book has [itex]\Omega_{\nu}\approx 10^{-3}[/itex], but something more recent would be nice.
This is probably about the best current measure:
http://lambda.gsfc.nasa.gov/product/map/current/params/lcdm_sz_lens_mnu_wmap5_bao_snall.cfm

They estimate [itex]\Omega_\nu < 0.0065[/itex] at 95% confidence.
 
Last edited by a moderator:
Thanks a lot.
 

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