Timeline for Bullet Cluster and MOND
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 8, 2016 at 23:04 | comment | added | xi45 | Are these active (SM) neutrinos, or sterile ones added to fit the data? | |
| Oct 4, 2015 at 19:36 | comment | added | user32023 | I'm almost there, but I still can't get past this one last thing: the Ideal Gas Law. if we measure a temperature, T, in the Coma Cluster and then use a formula involving the volume to arrive at a number of hydrogen atoms, n, won't those exact same atoms glow with 2T if we double the pressure? I can't get over the fact that pressure isn't considered anywhere in the calculation. | |
| Oct 4, 2015 at 15:46 | comment | added | ProfRob | @DonaldRoyAirey The second one. | |
| Oct 4, 2015 at 12:33 | comment | added | user32023 | @RobJeffries I'm having some trouble interpreting Table 5 from Ota et al. Is the gas fraction the fraction of total baryonic mass - Gas Mass + Stellar Mass - or the total of all mass Dark Halo Mass + Gas Mass + Stellar Mass? | |
| Oct 4, 2015 at 7:30 | comment | added | ProfRob | @DonaldRoyAirey Ota et al find the average gas to total mass is 20 per cent. The value for the bullet cluster is a little lower. No assumptions about $\Lambda$CDM required for this. | |
| Oct 4, 2015 at 1:18 | comment | added | user32023 | @GaryGodfrey - Again, I'm not sure how you came to this number (90%), but Ota & al studied 79 clusters and came up with a ratio of roughly %20. astro.isas.jaxa.jp/~ota/Cluster_Catalog_files/om04_aa_all.pdf | |
| Oct 3, 2015 at 18:08 | comment | added | user32023 | @Gary - "The visible mass is measured by x-rays to be ~90% gas and by light ~10% stars." I'm looking for a reference for this that doesn't assume a ΛCDM model. | |
| Oct 3, 2015 at 17:11 | comment | added | Gary Godfrey | @Peter: The present wisdom is that warm dark matter (eg: 1 eV neutrinos) would delay/prevent structure formation in the early universe. However, the MOND force law is stronger than Newton and warm dark matter may well be needed to slow down structure formation. As for how these neutrinos would eventually get trapped in the Fermi-Dirac distribution of a galactic cluster. Good point. I don't know. Will think about it. | |
| Oct 3, 2015 at 16:20 | comment | added | Peter Shor | Are you saying that neutrinos are slow enough to be captured by the mass of a galaxy cluster? | |
| Oct 3, 2015 at 4:29 | history | edited | Gary Godfrey | CC BY-SA 3.0 |
added 99 characters in body
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| Oct 3, 2015 at 4:24 | history | edited | Gary Godfrey | CC BY-SA 3.0 |
added 99 characters in body
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| Oct 3, 2015 at 4:14 | history | answered | Gary Godfrey | CC BY-SA 3.0 |