Weighing the universe : baryons, dark matter, and dark energy

Transcription

1 Weighing the universe : baryons, dark matter, and dark energy Department of Physics The University of Tokyo Yasushi Suto The 21 st century COE program of Tohoku University International symposium Exploring New Science by Bridging Particle-Matter Hierarchy March 5-9, 2004

2 What is the universe made of? Microscopic world origin of matter Identifying the hierarchy in the material world: molecules atoms nuclei (baryons) elementary particles (quarks and leptons) particle physics in the 20 th century was so successful and established the standard model any other matter hierarchy in the microscopic world beyond the standard model? Macroscopic world origin of the universe hierarchy in the universe: planets stars galaxies clusters of galaxies large-scale structure of the universe Is the universe really dominated by matters that are fully described in the standard model of particle physics? Weighing the universe 2

3 Universe bridges microscopic and macroscopic worlds Universe galaxies elementary particles nuclei stars planetary systems Earth atoms mountains human beings based on a plot in Interaction (S.Glashaw) Weighing the universe 3

4 Hierarchical structure in the universe Solar system Dwarf galaxy Galaxy group Large-scale structure Star cluster Galaxy Galaxy cluster Weighing the universe 4

5 Looking into the past /PR/96/01.html Weighing the universe 5

6 Distant universe observed by Subaru telescope Weighing the universe 6

7 Widest-separation separation gravitationally lensed quasar images Subaru 8.2m telescope Subaru image Inada et al. Nature 426(2003)810 gravitational bending lensing cluster of light path (6.2 billion yrs away) QSO J1004 (9.8 billion yrs Zoomed Subaru image away) 1 SDSS 2.5m telescope ,000 light yrs apart SDSS image Weighing the universe 7

8 General relativistic mirage from the universe 10Gyrs ago Weighing the universe 8

9 Exploring the edge of the universe NASA/WMAP Science Team Weighing the universe 9

10 13.7Gyr 0.2Gyr CMB: Cosmic Microwave Background time 0.38Myr 3min sec relic thermal photons from the ancient universe the present reionization CMB photons recombination Big-bang history large-scale structure galaxy cluster galaxy formation first objects light element synthesis generation of quantum fluctuations Recombination of protons and electrons = decoupling of baryons and photons Weighing the universe 10

11 From the infant universe to the present NASA/WMAP Science Team Weighing the universe 11

12 WMAP: Wilkinson Microwave Anisotropy Probe NASA/WMAP Science team Weighing the universe 12

13 Progress in mapping the CMB sky Weighing the universe 13

14 Sound waves in the CMB sky seed fluctuations acoustic oscillations CMB anisotropy pattern NASA/WMAP Science team Weighing the universe 14

15 Geometry of the universe from the CMB sky curvature changes the characteristic angular scale of the CMB anisotropy pattern NASA/WMAP Science team Weighing the universe 15

16 ancient document in cipher CMB all-sky map a cipher key spherical harmonics δt θ, ϕ ) T ( = a lm Y lm ( θ, ϕ ) l, m deciphered data temperature spectrum C = grammar to understand the universe cold dark matter model imprinted information age, geometry, and composition of the universe l a lm a * lm Weighing the universe 16

17 age of the universe: 13.7 Gyr universe is spatially flat universe reionized at 0.2Gyr after Big-bang cosmic matter is dominated by dark matter cosmic energy is dominated by dark energy Weighing the universe 17

18 Results: weighing the universe baryons ordinary matter makes up merely 4 percent of the entire mass of the universe dark matter dark energy galaxies and clusters are surrounded by invisible mass an order-of-magnitude more massive than their visible part unknown elementary particles? universe is dominated by even more exotic component! homogeneously fills the universe (unclustered) repulsive force (negative pressure; equation of state:p= ) Einstein s cosmological constant? Weighing the universe 18

19 More intriguingly, most of the cosmic baryon dark matter dark energy is also dark baryons composition of cosmic baryons stars hot gas Cosmic Baryon Budget: Fukugita, Hogan & Peebles ApJ 503 (1998) 518 Weighing the universe 19

20 hydrodynamical simulation with gas A (30h -1 Mpc) 3 box around a massive cluster at z=0 CDM SPH simulation Yoshikawa et al. 2001) Galaxy (cold clump) Dark matter All gas particles Hot gas (T>10 7 K) Warm gas (10 5 K<T<10 7 K) Weighing the universe 20

21 Searching for cosmic dark baryons with DIOS (Diffuse Intergalactic Oxygen Surveyor) Weighing the universe 21

22 DIOS: Diffuse Intergalactic Oxygen Surveyor A Japanese proposal of a dedicated X-ray mission to search for dark baryons PI: Takaya Ohashi (Tokyo Metropolitan Univ.) + Univ. of Tokyo, JAXA/ISAS, Nagoya Univ., Tokyo Metro. Univ. A dedicated small satellite with cost < 40M USD. Proposed launch in 2008 (not yet approved). Unprecedented energy spectral resolution: E=2eV in soft X-ray band (0.1-1keV) Aim at detection of 30 percent of the total cosmic baryons via Oxygen emission lines. Weighing the universe 22

23 Searching for dark baryons with DIOS (Diffuse Intergalactic Oxygen Surveyor) Mock simulations PASJ 55 (2003) 879 astro-ph/ , Univ of Tokyo: K. Yoshikawa Y.Suto JAXA/ISAS: N. Yamasaki K. Mitsuda Tokyo Metropolitan Univ.: T. Ohashi Nagoya Univ.: Y. Tawara A. Furuzawa Weighing the universe 23

24 Conclusion: 99% of the universe is DARK Quite frustrating We have not yet understood 99% of the universe at all! (dark baryons 3%) cosmological observations in the 20 th century have identified previously unknown hierarchy of matter beyond the standard model of particle physics Provides an ultimate goal of science in the 21 st century cosmology promises to bridge particle-matter hierarchy keep funding Tohoku University s s COE program Weighing the universe 24