slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
How can CMB help constraining dark energy? PowerPoint Presentation
Download Presentation
How can CMB help constraining dark energy?

Loading in 2 Seconds...

play fullscreen
1 / 18

How can CMB help constraining dark energy? - PowerPoint PPT Presentation


  • 85 Views
  • Uploaded on

How can CMB help constraining dark energy?. Licia Verde ICREA & Institute of space Sciences (ICE CSIC-IEEC). The standard cosmological model.  CDM model. . Spatially flat Universe. Power-law, primordial power spectrum. Only 6 parameters: WMAP5yr analysis. recombination.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'How can CMB help constraining dark energy?' - vartouhi


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

How can CMB help constraining dark energy?

Licia Verde

ICREA & Institute of space Sciences (ICE CSIC-IEEC)

slide2

The standard cosmological model

CDM model

Spatially flat Universe

Power-law, primordial power spectrum

Only 6 parameters: WMAP5yr analysis

slide4

Hot and cold spots 

Tiny ripples in density  seeds of galaxies

Detailed statistical properties of these ripples tell us a lot about the Universe

slide5

How’s that?

The Universe back then was made of a very hot and dense “gas”,

so it was emitting radiation

This is the radiation we see when we look at the CMB

Uniform , but with tiny (contrast x 100000) density (and temperature) ripples

Ripples in a gas? SOUND WAVES!

Truly a cosmic symphony…

We are seeing sound!

These tiny fluctuations, quantitatively, give rise galaxies

We try to listen to the sound and figure out how the instrument is made

Fundamental scale Fundamental mode and overtones

like blowing on a pipe….

slide6

Even for LCDM CMB alone does NOT imply >0

How many of you really believe H0=30?

slide7

Dark energy

WMAP5

Komatsu et al (2008)

slide9

Why so weak dark energy constraints from CMB?

The limitation of the CMB in

constraining dark energy

is that the CMB is located

at z=1090.

WMAP5

Dunkley et al (2008)

We need to look at the expansion history (I.e. more than one snapshot of the Universe)

Several options….

slide10

THE SYMPTOMS

Or OBSERVATIONAL EFFECTS of DARK ENERGY

Recession velocity vs brightness of standard candles: dL(z)

CMB acoustic peaks: Da to last scattering

Da to zsurvey

LSS: perturbations amplitude today, to be compared with CMB

Perturbation amplitude at zsurvey

slide11

Leading observational techniques to go after dark energy

(expansion history)

Supernovae

(mostly growth of structure)

Galaxy clusters number counts

Weak Lensing

(growth of structure and expansion history)

Baryonic Acoustic Oscillations (BAO)

(expansion history)

Q: A combination of techniques will be best for

at least two reasons

slide12

weak dark energy constraints from CMB?

BUT The CMB encloses information about the growth of

foreground structures: secondary CMB!

A

Integrated Sachs Wolfe effect

Secondary effects: Sunyaev Zeldovich(SZ), Kintetic SZ,

Rees-Sciama, Lensing.

What if one could see the peaks pattern

also at lower redshifts?

B

(and get other things for free)

C

… resort to other probes (CMB serves as anchor point)

slide13

USE the CMB as BACKLIGHT,

illuminating the foreground universe

  • First galaxies
  • Universe is reionized
  • Ostriker-Vishniac
  • Diffuse thermal SZ
  • Cluster formation: Sunyaev-Zel’dovich (SZ)
  • Kinematic SZ
  • Lensing of the CMB

Cosmic Microwave Background

  • The growth of structure is sensitive to dark energy
  • Rich additional science from correlations among effects
  • Extraction of cosmological parameters
  • Initial conditions for structure formation

High z

mid z

low z

sunyaev zel dovich sz clusters
Sunyaev-Zel’dovich (SZ) clusters

Coma Cluster

Telectron = 108 K

e-

e-

e-

e-

e-

e-

e-

Cosmic Microwave Background

e-

e-

X-ray Flux:

Mass

Optical:

Redshift and Mass

mm-Wave: SZ –

Compton Scattering

slide15

http://www.physics.princeton.edu/act/

Barcelona, Cardiff, Columbia, Haverford, Inaoe, KwaZulu-Natal, NASA, NIST,UPenn,

Princeton, U. Pittsburgh, Rutgers, Toronto, UBC, Cape Town, Universidad Catolica,

York College

slide16

The south pole telescope

http://pole.uchicago.edu/public/

slide17

Summary: Much ado about nothing

The standard cosmological model is extremely successful, but….

Observations indicate that nothing weighs something (but much less than

expected) and make the universe accelerate (other options are still

Possible, inhomogeneities, gravity, but the result must “look like ”).

What would it take to discriminate?

discussion

Heroic observational effort is on going

(we’ll learn not only about dark energy from it)

The“Accelerating universe challenge”