Lecture 16 - PowerPoint Presenta

Document Sample
Lecture 16 - PowerPoint Presenta Powered By Docstoc
					SDSS slideshow
Welcome
to 8.902!
  Welcome
  to 8.902!

Alan Guth
      MIT Course 8.902, Fall 2009, Lecture 16
                                 Max Tegmark
Practical stuff:
• ps5 due moments ago
• ps6 due on Tuesday




Today’s topics: The universe to 0th order, cont’d
• Angular diameter distance
• Luminosity distance
• 13 confusing cosmology questions
• Inflation
                                                 Brief History of
            Fluctuation generator                our Universe
                                    Fluctuation amplifier




                         400



Summary
  of last
 lecture                            (Graphics from Gary Hinshaw/WMAP team)
Summary
  of last
 lecture
Summary
  of last
 lecture
    0th order:
 Measuring
Expansion:
 a(t) <=> H(z)
Figure from WMAP team
                   -dimmed
Distant light is
                   -redshifted
Luminosity distance (on board)
                   -dimmed
Distant light is
                   -redshifted




                      Redshift



                                 Dimming
                      -dimmed
   Distant light is
                      -redshifted




                         Redshift



                                    Dimming
Standard candles,
rulers or clocks
From Saul Perlmutter’s web site



                                        QuickTime™ an d a
                                   YUV420 codec decompressor
                                  are need ed to see this p icture .
What we’ve learned about H(z) from
SN Ia, CMB, BAO, BBN, etc:
                                 Assumes k=0


                                 SN Ia+CMB+LSS constraints
                        Yun Wang & MT 2004, PRL 92, 241302




Vanilla rules OK!
What we’ve learned about H(z) from SN Ia




            Riess et al, astro-ph/0611572
                                           DO ANY OF THESE QUESTIONS CONFUSE YOU?
              QuickTime™ and a
                                           1.   What is the Universe expanding into?
                 decompressor
        are need ed to see this picture.

                                           2.    How can stuff be more than 14 billion light years away when
                                                the Universe is only 14 billion light years old?
                                           3.   Where in space did the Big Bang explosion happen?
                                           4.   Did the Big Bang happen at a single point?
                                           5.    How could a the Big Bang create an infinite space in a finite
                                                time?
                                           6.   How could space not be infinite?
Let’s argue!                               7.   If the Universe is only 10 billion years old, how can we see
                                                objects that are now 30 billion light years away?
                                           8.    Don’t galaxies receeding faster than c violate relativity
                                                theory?
                                           9.   Are galaxies really moving away from us, or is space just
                                                expanding?
       Quic kTim e™ and a
         decompress or
                                           10. Is the Milky Way expanding?
are needed to s ee this pic ture.
                                           11. Do we have evidence for a Big Bang singularity?
                                           12. What came before the Big Bang?
                                           13. Should I feel insignificant?
How did it all begin?
         Big Bang Zoom




Graphics from WMAP team
Figure from STScI
Some things to ponder…
Ned Wright
Ned Wright
MATHFEST
Got to here
Evidence #1 for inflation:
Space is very flat
tot=1.003 ±0.010
                  MT et al 2006,
                  astro-ph 0608632
How flat is space?
How flat is space?
How flat is space? Somewhat.
How flat is space? tot=1.003
Party on!
1st order:
measuring
clustering
Foreground-cleaned WMAP map from Tegmark, de Oliveira-Costa & Hamilton, astro-ph/0302496

                                                                     CMB
z = 1000
Mathis, Lemson, Springel, Kauffmann, White & Dekel 2001
                                                  z = 2.4
Mathis, Lemson, Springel, Kauffmann, White & Dekel 2001
                                                  z = 0.8
Mathis, Lemson, Springel, Kauffmann, White & Dekel 2001
                                                  z=0
CMB                                             Clusters




                             LSS                       Lensing




                                                            Lya

Tegmark & Zaldarriaga, astro-ph/0207047 + updates
Galaxy power spectrum measurements 1999
(Based on compilation by Michael Vogeley)
LSS
                                                Clusters




                             LSS




Tegmark & Zaldarriaga, astro-ph/0207047 + updates
CMB                                             Clusters




                             LSS




Tegmark & Zaldarriaga, astro-ph/0207047 + updates
(Figure from Wayne Hu)




         (Figure from WMAP team)
Foreground-cleaned WMAP map from Tegmark, de Oliveira-Costa & Hamilton, astro-ph/0302


                                                                CMB
                                       Inflation              Open      3
Guth & Kaiser 2005 (Science) + WMAP3    with                universe




                                               Inflation
                                               without 


                                                       Cosmic strings
CMB                                             Clusters




                             LSS




Tegmark & Zaldarriaga, astro-ph/0207047 + updates
CMB                                             Clusters




                             LSS

                                                           Lya

Tegmark & Zaldarriaga, astro-ph/0207047 + updates
             Lyman Alpha Forest Simulation: Cen et al 2001



LyaF
                                                     Quasar



       You
CMB                                             Clusters




                             LSS

                                                           Lya

Tegmark & Zaldarriaga, astro-ph/0207047 + updates
CMB                                             Clusters




                             LSS                       Lensing




                                                            Lya

Tegmark & Zaldarriaga, astro-ph/0207047 + updates
         GRAVITATIONAL LENSING:
A1689 imaged by Hubble ACS, Broadhurst et al 2004
Lensing
CMB                                             Clusters




                             LSS                       Lensing




                                                            Lya

Tegmark & Zaldarriaga, astro-ph/0207047 + updates
Galaxy power spectrum measurements 1999
(Based on compilation by Michael Vogeley)
CMB                                             Clusters




                             LSS                       Lensing




                                                            Lya

Tegmark & Zaldarriaga, astro-ph/0207047 + updates
But the best is
yet to come…
   Precision, 21cm tomography, …
      Our observable
        universe

LSS
 Measuring
cosmological
 parameters
par movies
             Ordinary Matter    75%
Using        Dark Energy
             Cold Dark Matter
WMAP3 +      Hot Dark Matter
             Photons
SDSS LRGs:   Budget Deficit
                                                        Cold Dark Matter
                                      Ordinary Matter
                                                              23%
                                      4% 5%                21%
386



      430



            13.8
 Standard model parameters:
Cosmology
                  Particle physics




       C = h = G = kb = qe = 1
How flat is space?

                 Why are we
                 cosmologists
                 so excited?
How flat is space?
How flat is space? Somewhat.
How flat is space? tot=1.003
Cosmological
   data




               75%


Cosmological
 Parameters
                     4%   21%
Cosmological
   data




               75%


Cosmological
 Parameters
                     4%   21%




                ARE WE
                DONE?
Cosmological
   data




               75%


Cosmological
 Parameters
                     4%       21%




                                           Why these particular values?


                                    Nature of dark matter?
Fundamental
   theory
                          ?         Nature of dark energy?

                                    Nature of early Universe?
Cosmological
   data




               75%


Cosmological
 Parameters
                     4%       21%




                                           Why these particular values?


                                    Nature of dark matter?
                                                                   Map our
Fundamental
   theory
                          ?         Nature of dark energy?

                                    Nature of early Universe?
                                                                   universe!
Physics with
   21 cm
tomography
Foreground-cleaned WMAP map from Tegmark, de Oliveira-Costa & Hamilton, astro-ph/030



                                                               CMB
                                                                      History
                                                                          universe
                                                                        Our observable
      Our observable
        universe

LSS
The time
frontier

 LSS
Cmbgg OmOl
Cmbgg OmOl
LSS   The
      scale
      frontier
  Physics of the 21 cm Line:




MWA = Murchison Widefield Array
Experiment                 GMRT            PAST/21CMA              LOFAR                          MWA                  PAPER     SKA

# of Antennas(Total)       30 dishes       10,000                                                 8,192                16 (4)

# of Antennas(Installed)   30 dishes        2,000 (4 Tiles)                      512 (32 Tiles)                8 (0)
# of Tiles                 NA              20 (1 Tile=500 ant)   96(1 Tile=16 ant)       512 (1 Tile=16 ant)           NA

                                                                   96 V crossed Dipoles

Effective Area (m 2)       5.104           7.0.104                1.0.105                         ~ 104                1.0.104   1.0.106

Imaging Field of View                      2o                      3o - 7.5o                      ~ 5o                           30o - 1o

Angular Resolution         3.8o - 0.4o     3’                      25” - 3.5”                     ~ 15’                          < 0.1’

Frequency Range (MHz)      50 - 1420       50 - 200                10 - 240                       80 - 300 110 - 200

Mapping Sensitivity                15mK/(day)1/2

Site                       India           China                   Netherlands                    Australia USA/AUS    AUS(?)

Year                       2007            2007                    2007          2008                      2008        2015(?)