Energy density of massive neutrinos

In summary, the conversation was about finding an up-to-date reference for the best value of \Omega_{\nu}, given our current understanding of neutrino masses. Dodelson's cosmology book suggests a value of \Omega_{\nu}\approx 10^{-3}, but something more recent would be preferred. It was mentioned that the best constraints come from CMB plus galaxy power spectrum results, with the SDSS catalogue being the biggest data set. A 2004 Tegmark paper was suggested, although there is likely more recent work available. The conversation then concludes with a link to a current measure which estimates \Omega_\nu < 0.0065 at 95% confidence.
  • #1
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.
 
  • #3
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.
 
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  • #4
Thanks a lot.
 

FAQ: Energy density of massive neutrinos

1. What is the energy density of massive neutrinos?

The energy density of massive neutrinos refers to the amount of energy contained in a given volume of space due to the presence of massive neutrinos. It is typically measured in units of joules per cubic meter.

2. How is the energy density of massive neutrinos calculated?

The energy density of massive neutrinos can be calculated using the standard formula for energy density, which is mass divided by volume. In this case, the mass is the total mass of all the massive neutrinos present in the volume, and the volume is the size of the region of space being considered.

3. What is the significance of the energy density of massive neutrinos in cosmology?

The energy density of massive neutrinos is significant in cosmology because it contributes to the overall energy budget of the universe. It affects the expansion rate of the universe and can impact the formation and evolution of large-scale structures, such as galaxies and galaxy clusters.

4. How does the energy density of massive neutrinos compare to other types of matter in the universe?

The energy density of massive neutrinos is relatively low compared to other types of matter in the universe, such as dark matter and baryonic matter. However, it is still significant and plays a role in shaping the structure and evolution of the universe.

5. Can the energy density of massive neutrinos change over time?

Yes, the energy density of massive neutrinos can change over time. As the universe expands, the energy density of neutrinos decreases, but it can also be affected by interactions with other particles and the environment. In certain scenarios, the energy density of massive neutrinos may even increase over time.

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