Jun’ichi Yokoyama (RESCEU) (As of 2002, just before WMAP data came.)

Photon density Black body radiation with temperature dominated by Cosmic Microwave Background (CMB) Neutrino Background for 3 species in the standard model (massless)

Baryon density Luminosity density of galaxies solar luminosity Mass-to-Light ratio Density of Visible Matter (It simply means that our Sun is a typical star.)

Baryon density Big bang Nucleosynthesis (BBN) theory and Observations of light elements (D, He4, Li…) constrain Baryon-to-Photon ratio. All Baryon density BBN is one of the most important subjects of the standard cosmology. But I do not discuss it here any further, since it will be covered by lectures on Nuclear Physics III.

前ページと左図は ApJ600(2004)544 右図は astro-ph/ による。

Total Matter (Baryon + Cold Dark Matter) Rotation curve of a spiral galaxy 渦巻き銀河の回転曲線 Mass within radius r Rotation curve remain constant even beyond the size of the galactic disk, which indicates the existence of dark matter.

Random velocities of galaxies in a group of galaxies Cluster baryon fraction from X-ray emissivity and baryon density from primordial nucleosynthesis Shape parameter of the transfer function of CDM scenario of structure formation Many others Total Matter (Baryon + Cold Dark Matter) Virial Theorem gives an estimate of gravitational potential energy Mass.

2Mpc Hubble`s discovery The Greatest Blunder Current data

Luminosity Distance Angular Diameter Distance Absolute Luminosity Absolute Size

Before turning into observations, some terminologies… Band central wavelength (μm) band width (μm) 0 mag flux (Jy) U B V R I Apparent magnitude grizgriz

Absolute magnitude Apparent magnitude seen 10pc away from the star. Measure of the absolute luminosity Color, Colours, … e.g. Distance modulus in parsec in Mpc Extinction by dusts etc. = Reddening Light with shorter wavelength is more likely absorbed/scattered. (1pc = 3.26ly = ×10 18 cm).

Color excess e.g. Extinction is proportional to color excess. standard text-book value K correction When we observe high-redshift objects, we observe at a longer wavelength than the rest-frame counterpart. Hence depending on the spectral shape of the object, we must correct the flux or the apparent magnitude of each band.

Cepheids H 0 =75 ± 10km/s/Mpc SNIa H 0 =71±2(stat) ± 6(syst)km/s/Mpc Tully-Fisher H 0 =71±3 ± 7km/s/Mpc Surface Brightness Fluctuation H 0 =70±5 ± 6km/s/Mpc SNII H 0 =72±9 ± 7km/s/Mpc Fundamental Plane of Elliptical Galaxies H 0 =82±6 ± 9km/s/Mpc Summary H 0 =72±8km/s/Mpc HST Key Project (Freedman et al ApJ 553(2001)47) A suffix 0 denotes the present value.

Cepheid 動径脈動型変光星 They change their size with a certain constant period P=5-70 days. Their absolute magnitude M is proportional to logP. distance to LMC = 51kpc (46kpc previously). Hubble space telescope (HST) measured 20 cepheids in M100 galaxy, for example. H 0 =75 ± 10km/s/Mpc This method is used to measure the distance to relatively close galaxies and it serves as the second step to the cosmic distance ladder. This distance is also determined using variable stars (Mira type). NB. Parallax distance can be determined only up to 100pc or so.

Tully Fisher relation Rotation velocity of a spiral galaxy is correlated with its absolute luminosity. Line broadening by Doppler effect=Observable

Surface Brightness Fluctuations Nearby Mountains =Trees can be resolved. Distant Mountains =Looks homogeneous. Galaxies consist of stars. Distant galaxies looks more homogeneous with smaller pixel-to-pixel fluctuations of surface brightness.

Cepheids H 0 =75 ± 10km/s/Mpc SNIa H 0 =71±2(stat) ± 6(syst)km/s/Mpc Tully-Fisher H 0 =71±3 ± 7km/s/Mpc Surface Brightness Fluctuation H 0 =70±5 ± 6km/s/Mpc SNII H 0 =72±9 ± 7km/s/Mpc Fundamental Plane of Elliptical Galaxies H 0 =82±6 ± 9km/s/Mpc Summary H 0 =72±8km/s/Mpc HST Key Project (Freedman et al ApJ 553(2001)47) A suffix 0 denotes the present value.

Type I : No H lines, Type II : H lines Gravitational Collapse and Bounce

Type Ia Supernovae Accretion to a C+O white dwarf in a binary system Radius of the white dwarf drops rapidly with increased central temperature, leading to the ignition of Carbon It approaches Chandrasekhar mass (1.38 M  ), the maximum mass that can be supported by degenerate electron pressure. Deflagration and Detonation

Type Ia Supernovae SN1994D in NGC4526 Theoretical studies including numerical simulations have been in difficult situations to realize explosion… Large luminosity ～ whole galaxy Measurable at cosmological distances Observations of nearby SNIa indicate that they can be used as a standard candle whose absolute luminosity can be found from the light curve shape and color..

Phillips (1993) Astrophys J 413, L105 Measured B, V, I absolute magnitudes of 9 SNIa using host-galaxy distances estimated by the surface-brightness fluctuations or Tully-Fisher relation. Light curve observed for > 20 days after the maximum. Scatter in the maximum absolute magnitudes are quite large: ±0.79mag in B, ±0.59mag in V, ±0.46mag in V They cannot be used as a standard candle as they are. But a strong correlation was found between the maximum magnitudes and decline rate of the light curve., drop in the B magnitude during the first 15 days after the maximum is strongly correlated to the maximum absolute magnitude.

MBMB 0 15 days Peak luminosity-decline rate relation

The light curve of SNIa is powered by the radiative decay of 56 Ni  56 Co  56 Fe, so its luminosity depends on the amount of 56 Ni synthesized in the explosion. More 56 Ni →larger luminosity → higher temperature → higher opacity → broader light curve

Perlmutter et al (1997) Astrophys J 483, 565 (Supernova Cosmology Project) Light curve width – Luminosity relation The stretch factor linearly broadens or narrows the rest-frame time scale of an average template light curve. Related to as. Corrected magnitude From 6 distant supernovae with z= they found no evidence for the dark energy.

Perlmutter et al (1999) Astrophys J 517, 565 (Supernova Cosmology Project) 42 SNIa at z= and are nuisance parameters to be integrated out

Distant SN and closer SN have the same property.

Type Ia Supernovae m-z relation log(d L ) z

various tests

Location of 1 st peak in the angular power spectrum of CMB anisotropy The angular scale subtending the sound horizon at decoupling depends on spatial geometry. in accordance with (standard) Inflation What makes up the rest of the Universe?

SNIa

SNIa+CMB

+Matter density

as predicted by Inflation Cosmic age H 0 =72±8km/s/Mpc, centered around Observation: from globular cluster from cosmological nuclear chronology

Expected accuracy of MAP satellite Present status will make it possible to determine cosmological parameters much more accurately. Perturbation spectrum as well.

as predicted by Inflation good news bad news