Stardustin the

Early Universe

Erik ElfgrenLuleå University of Technology

Swedish National GraduateSchool of Space Technology

Acknowledgements

Supervisors

Sverker FredrikssonJohnny Ejemalm

Collaborators

François-Xavier Désert – Grenoble

Bruno Guiderdoni – Lyon

History of the Universe

Cosmic Microwave Background

Dust

My Research

Conclusions

Early historyHistory of the Universe

• Big Bang13.7 billion years agoRapid expansion

• First atoms formed1 min after the BB75% H25% He<1% D, Li, He-3Duration: 3 min No heavier elements

?

History of the UniverseDecoupling• Plenty of high E photons

Photons ionize H

• When T ~ 3000 KPhotons can’t ionize No interaction Photons unchanged

until today Cosmic Microwave Background (CMB)300,000 years after Big Bang

History of the UniverseThe Dark Ages

• Photons cool

• Matter contract through gravitation

• First Generation of Stars~1 billion years after Big Bang~100 times heavier than the Sun~1 million years before they dieFinish as supernovae Dust

• Galaxy formation10 times more Dark Matter Dark Matter shepherds normal matter

History of the UniverseStructure Formation

History of the UniverseStructure Formation

History of the UniverseStructure Formation

Star birthStar death

Supernova

Dust

Dust ejection

Dust accretion

History of the UniverseSummary

• Big Bangrapid expansion

• First atoms1 min

• Decoupling300,000 years

• First stars & galaxies1 billion years

• Today13.7 billion years

CMB

Dust

Cosmic Microwave BackgroundCMB

• 300,000 years after BB:T ~ 3000 K

• 13.7 billion years after BB:T ~ 3 K

• Everywhere

• Black Body radiationlike the Sun

• T = 2.725 K = Microwaves

Cosmic Microwave BackgroundWhy is the CMB interesting?

• Expansion rate Age of the Universe

• Amount of Dark Matter, Dark Energy Shape of the Universe

• Matter distribution at t = 300,000 years Closing in on the Big Bang

• Structure formation How the first galaxiesand stars form

Stephen Hawking: “It is the discovery of the century, if not of all time.”

Cosmic Microwave BackgroundHow?

• Temperature map(whole sky)

Power Spectrum= angularcorrelations

DustWhy is the dust interesting?

• Absorbs CMB light

• Absorbs star light

• Emits radiation similar to the CMB

• Comes from the first stars

Star light

CMB light

Dust emission

Supernova

• Supernovae ejects heavierelements such as C, Si, O, N, Fewhich condense into dust:CO, SiO2, Al2O3, …

DustCreation

• Friction with Gas and Dust• High energy photons• Cosmic rays

Mean life timeΔt = 30 million – 10 billion years

Destruction

• Dust life timesΔt = 108, 109 and 1010 years

• Dust production Star formation

• Dust distribution Dark Matter distribution

My ResearchModel

My Research

• IntensityLike CMB but also

Dust Spectrum

2

(CMB)In

tens

ity

Observed wavelength

My Research

• Temporal distribution

Dust Distribution

13.5 billion years ago

12.5 billion years ago

Rel

ativ

e du

st d

ensi

ty

Time from now

My Research

• Spatial distribution

Dust Distribution

Ang

ular

co

rrel

atio

n

180º/angle

ConclusionsDetection with Planck

Ang

ular

co

rrel

atio

n

180º/angle

• Seems possible

ConclusionsSummary

• First stars star dust• Star dust emit radiation• The radiation might be detected with Planck

Outlook• Collaboration with Lyon• Simulation of the first galaxies• Dust influence on their properties

Supernova Star light

CMB light

Dust emission

Planck detector

1st stars Dust