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Published byVirgil Harrison Modified over 9 years ago
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Beam profile sensitivity of WMAP CMB power spectrum Utane Sawangwit & Tom Shanks Durham University
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Standard CDM Model - Issues! Dark matter – exotic particles as yet undetected! ⇒ 1 in 10 100 fine-tuning coincidence – anthropic? Even though inflation was set up to get rid of fine-tuning! has wrong sign for string theory – Anti-de Sitter v. de Sitter Standard inflation model ⇒ 10^10 77 Universes! Wrong mass function for galaxies! Downsizing observed v. bottom-up hierarchy predicted Feedback - more energy now used in preventing stars form than in forming them under gravity
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WMAP 5-Year CMB Map
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WMAP 5-Year Power Spectrum Universe comprises: ~72% Dark Energy ~24% CDM ~4% Baryons (Hinshaw et al. 2003, 2006, 2008, Spergel et al. 2003, 2006, 2008)
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And yet…….
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Sensitivity of WMAP C l to beam Raw C l result Final C l result
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WMAP beams (Page et al 2003)
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WMAP5 point sources 390 sources detected (5sigma) in K/Ka/Q/V/W Complete down to ~1Jy 373/390 have 5GHz counterparts Flat spectrum, = -0.09 We only use compact sources (5 GHz GB6/PMN) Wright et al. (2009)
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WMAP5 Radio Source Profiles Gaussian Jupiter beam Radio sources
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Comparison with ground-based fluxes
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Potential problems with RS beam Radio Source Clustering? Estimate based on bright NVSS source clustering... …suggests clustering is unlikely explanation But what about the CMB fluctuations – Eddington effect? - referee
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New: “CMB-free” point sources CMB-free WMAP5 source detection, Chen & Wright 2009
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New: NVSS 1.4GHz point sources
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New: Monte Carlo Simulations
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Simulations: known source positions
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Source detection Filter the weighted map with (Wright et al. 2009, Tegmark et al. 1998) W V Q Ka K
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Simulations: after source detection
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WMAP5 Radio Source Profiles Gaussian Jupiter beam Radio sources
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De-beamed power spectra Gaussian Radio sources Jupiter
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WMAP peak moved to l=330
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A diy beam that works!
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Conclusions CDM assumes “undiscovered physics” + very finely- tuned + problems in many other areas Model gained overwhelming support from WMAP But WMAP power spectra highly sensitive to beam Radio sources indicate wider beams than expected Systematic errors on WMAP C l may therefore increase May reduce constraints on simpler models
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Example simpler model: low H 0, baryon =1 Shanks (1985) - if H o <40kms -1 Mpc -1 then: X-ray gas → DM in Coma, M vir /M X =15h 1.5 Inflationary baryon =1 model in better agreement with nucleosynthesis Light element abundances baryon h 2 <0.06 baryon 1 starts to be allowed for low h Inflation+EdS => =1 => Globular Cluster Ages of 13- 16Gyr require H o <40kms -1 Mpc -1 But the first acoustic peak is at l=330, not l=220
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‘Do it Yourself’ (DIY) WMAP beam b S ( ) is the beam and b l is the beam transfer function To get the “true” power spectrum, C l, divide the raw power spectrum, C l ’, by b l 2 Alternatively to get the beam function b l 2, divide raw by true power spectum!
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Beam transfer functions diy beam functions – divide low H 0 C l by raw WMAP C l & square root Power-law radio source beam fits give too much power at l>300 Need spike in b l
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Ed Witten -“Strings 2001” http://theory.tifr.res.in/strings /Proceedings/witten/22.html String theory prefers a negative (anti-de Sitter!) rather than the observed positive
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