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Observações fundamentais da cosmologia

Observações fundamentais da cosmologia

Aula do curso de "Introdução à cosmologia" para graduação, Prof. Rodrigo Nemmen, IAG USP.

https://rodrigonemmen.com/teaching/introducao-a-cosmologia/

Rodrigo Nemmen

August 07, 2017
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  1. Big news: primeiros resultados cosmológicos do Dark Energy Survey 23

    Planck No Lensing DES Y1 DES Y1+Planck No Lensing DES Y1+Planck+BAO+JLA 0.60 0.66 0.72 0.78 0.84 h 1.6 1.3 1.0 0.7 0.4 w 0.24 0.30 0.36 0.42 m 0.75 0.80 0.85 0.90 S8 0.60 0.66 0.72 0.78 0.84 h 1.6 1.3 1.0 0.7 0.4 w 0.75 0.80 0.85 0.90 S8 https://arxiv.org/pdf/1708.01530.pdf
  2. Big news: primeiros resultados cosmológicos do Dark Energy Survey .

    68% confidence levels on three cosmological parameters from the joint DES Y1 probes and other experiments for w context of this model. These factors degrade of the value w = 1.34+0 . 08 0 . 15 returned by th combination. The addition of BAO, SNe, and Planck the DES+Planck combination yields the red c ure 14, shifting the solution substantially al degeneracy direction, demonstrating (i) the tioned above with the DES+Planck (no lensin and (ii) that these problems are resolved when are introduced that restrict the Hubble param able values. The Bayes factor for combination the low-z suite of DES+BAO+SNe in the w R = 699, substantially more supportive of t of experiments than the case for Planck and D DES+Planck+BAO+SNe solution shows good the ⌦m –w–S 8 subspace and yields our final c dark energy equation of state: w = 1.00+0 . 04 0 . 05 . DES Y1 reduces the width of the allowed 68% percent. The evidence ratio Rw = 0.08 for Planck with no lensing (green), bined (red) in the ⌦m, h plane. in the CMB constrain ⌦mh3 ex- nation of ⌦m breaks the degen- h than inferred from Planck only to test the ⇤CDM prediction fer the issue of parameter de- ions. However, there is one ts combined with DES that is ta do not constrain the Hubble shown in Figure 12, the DES bined with Planck’s measure- n the inference of the Hubble l measurements [119]). Since ed value of h moves up. As atively in Table II, the shift is Table II, this shift in the value FIG. 13. ⇤CDM constraints from all three two within DES and BAO, JLA, and Planck (with lens S8 plane. Combining all of these leads to the tightest on ⇤CDM parameters, shown in Table II. Hig of these: at 68% C.L., the combination of D external data sets yields ⌦m = 0.301+0 . 006 0 . 008 . This value is about 1 lower than the value wi with comparable error bars. The clustering am constrained at the percent level: 8 = 0.801 ± 0.014 S 8 = 0.799+0 . 014 0 . 009 . h = 0.682+0 . 006 0 . 006 (D s in the CMB constrain ⌦mh ex- mination of ⌦m breaks the degen- h than inferred from Planck only is to test the ⇤CDM prediction efer the issue of parameter de- ctions. However, there is one ents combined with DES that is ata do not constrain the Hubble s shown in Figure 12, the DES mbined with Planck’s measure- in the inference of the Hubble cal measurements [119]). Since rred value of h moves up. As itatively in Table II, the shift is Table II, this shift in the value are added in. arameters in ⇤CDM FIG. 13. ⇤CDM constraints from all three tw within DES and BAO, JLA, and Planck (with le S8 plane. Combining all of these leads to the tightes on ⇤CDM parameters, shown in Table II. H of these: at 68% C.L., the combination of external data sets yields ⌦m = 0.301+0 . 006 0 . 008 . This value is about 1 lower than the value w with comparable error bars. The clustering a constrained at the percent level: 8 = 0.801 ± 0.014 S 8 = 0.799+0 . 014 0 . 009 . Note that fortuitously, because ⌦m is so clos ference in the central values of 8 and S 8 is combined result is about 1 lower than the in https://arxiv.org/pdf/1708.01530.pdf
  3. Tamanhos angulares θ 1° = 1/360 de um círculo =

    2π/360 rad 1 minuto de arco = 1' = 1/60 de um ° = 2.9×10-4 rad 1 segundo de arco = 1" = 1/60 de um ' = 4.8×10-6 rad 0.5° ≈ 30’ 0.5° ≈ 30’ 4” 3° Galáxia de Andrômeda
  4. Unidades de medida na cosmologia Distância, tempo e massa MKS

    parsec (pc) = 3.1×1016 m usaremos comumente Mpc, Gpc M⦿ (massa solar) = 2×1030 kg Distância Massa Tempo Gano = 109 anos = 3.2×1016 s Energia eV = 1.6×10-19 J elétron: mec2 = 0.511 MeV próton: mpc2 = 938.3 MeV ~ 1 GeV Luminosidade solar L⦿ = 3.8×1026 W = 3.8×1033 erg/s
  5. 1 ano-luz = 9 trilhões de km = 60.000 a

    distância Terra-Sol X 25.000 anos-luz de distância Sistema Solar
  6. Figure 2.4: Edwin Hubble’s original plot of the relation between

    redshift (vertical axis) and distance (horizontal axis). Note that the vertical axis Hubble. 1929, PNAS cz
  7. 2.3. REDSHIFT PROPORTIONAL TO DISTANCE 17 Figure 2.5: A more

    modern version of Hubble’s plot, showing cz versus Freedman et al. 2001, ApJ H0 = 70 km s-1 Mpc-1 cz
  8. t1

  9. t2

  10. t3

  11. t4

  12. t5

  13. t = 0 obs. a b c d Evolução do

    tamanho do horizonte do universo observável
  14. t1

  15. t2

  16. t3

  17. t4

  18. t5

  19. partícula símbolo energia de repouso (MeV) carga próton p 938.3

    +1 nêutron n 939.6 0 elétron e- 0.511 -1 neutrino νe, νμ, ντ ? 0 fóton γ 0 0 matéria escura ? ? 0 Propriedades das partículas
  20. partícula símbolo energia de repouso (MeV) carga próton p 938.3

    +1 nêutron n 939.6 0 elétron e- 0.511 -1 neutrino νe, νμ, ντ ? 0 fóton γ 0 0 matéria escura ? ? 0 Propriedades das partículas
  21. partícula símbolo energia de repouso (MeV) carga próton p 938.3

    +1 nêutron n 939.6 0 elétron e- 0.511 -1 neutrino νe, νμ, ντ ? 0 fóton γ 0 0 matéria escura ? ? 0 Propriedades das partículas
  22. partícula símbolo energia de repouso (MeV) carga próton p 938.3

    +1 nêutron n 939.6 0 elétron e- 0.511 -1 neutrino νe, νμ, ντ ? 0 fóton γ 0 0 matéria escura ? ? 0 Propriedades das partículas aula 20
  23. Arno Penzias Robert Wilson Cientistas que descobriram a radiação cósmica

    de fundo em microondas Cosmic microwave background (CMB)
  24. Propriedades da CMB corpo negro T0 = 2.725 ± 0.001

    K Tipo de espectro Temperatura Densidade 
 de energia u = 4.2×10-14 J m-3 Densidade 
 de fótons ⟨E⟩ dos fótons 0.26 MeV m-3 (0.5 mec2) 2 fótons de raios gama n = 4.1×108 m-3 411 fótons cm-3 ¯ E = 6.34 ⇥ 10 4eV energia de ionização H: 13.6 eV 2 mm (microondas) ¯ E = h¯ ⌫ ) ¯ ⌫ =
  25. Universo jovem, T≫104 K: plasma quente e completamente ionizado Fótons

    interagindo fortemente com elétrons livres. Por quê?
  26. http://nickstravelbug.com/travel-photos/fotofriday-golden-gate-bridge/ Fótons saem do cárcere: Universo transparente Radiação cósmica de

    fundo de microondas T ⇠ 3000 K Universo se expande e esfria, elétrons e prótons recombinam, formando átomos de H neutros
  27. http://www.gadventures.com/blog/pics-of-the-week-structures/ Fótons saem do cárcere: Universo transparente Radiação cósmica de

    fundo de microondas T ⇠ 3000 K Universo se expande e esfria, elétrons e prótons recombinam, formando átomos de H neutros
  28. T 104 K T 3000 K T0 = 2.73 K

    Universo se torna transparente época da recombinação
  29. • em inglês: cosmic microwave background (CMB) radiation • “fóssil”

    mais antigo do universo • traz consigo a foto mais antiga do cosmos (infância do universo) • é a coisa mais fria do universo • maior parte dos fótons no universo são da radiação cósmica de fundo de microondas (>99%) • está aqui nesta sala, e em todo lugar: 
 400 fótons/cm3 㱺 estática na TV Radiação cósmica de fundo em microondas