2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Monsters in Early Universe

Myungshin Im

Dept. of Physics and Astronomy

Astronomy Program

Seoul National University

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

History of the Universe

Early Universe

Unexplored Epoch of the Cosmic History

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

H

Proto-Galactic

Gas

Theoretical Story of Early Universe I

Cosmic

Microwave

Background

(Nobel Prizes)

H

H

H

He

First Stars

(~100 M⊙)

Re-ionization of

the Universe

H H

Supernovae

(超新星, GRB)

~3-6 Myr

Heavy elements

(Ingredients of life!)

Proto-Galactic

Gas

+H

+

--

Black Holes

(~10 M⊙)

+ +- -

Proton (+)

Electron (-)

Photons (N)

+ +

- -

Dark

Age

+

Proto-Galactic

Gas

H

+

-

-

~3x105 yrs ~3x108 yrs

~(3-10)x108 yrs

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Theoretical Story of Early Universe II

~1x109 yrs

~2x109 yrs

Quasar

(> 1012 L⊙)

Quasar +

Galaxy

Galaxy

Cluster

Supermassive

Black Holes

(~106 - 109 M⊙)

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Is This Story Right?

• Monsters in the Universe can answer

the question!

Enormous Explosion:

Gamma Ray Burst (GRB)

Ghosts of Star:

Supermassive Black Holes

The Most Massive Astronomical Object:

Proto-clusters of Galaxies

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Gamma Ray Bursts:The Most Energetic Event in the Universe

• γ-ray: high energy photons (> 100 keV, nuclear bomb)

• Discovered first by spy satellites (1973)

• Duration of 0.001 – 1000 sec

• Luminosity: ~1054 erg/sec

The Sun: 2 x 1033 erg/sec

Galaxy ~ 1043 erg/sec

All galaxies in the Universe

~ 1054 erg/sechttp://science.nasa.gov

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Optical Afterglow

• Can be as bright as 6 mag (Naked-eye burst) even at billions of light-years away

• GRB can be studied at very high redshift (early universe ~ 0.5 billion years old)

ΔT=0.5 days ΔT=5.5 days ΔT=8.5 days

GRB 071010B (Urata, Huang, Im, et al. 2009; Lee, Im, et al. 2010)

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Origin of GRB

• Long GRB (> 2 sec):

Hypernova (Extreme Supernova; e.g., Woosley & Bloom 2006) First stars (Belczynski et al. 2010; 10x)

• Short GRB (< 2 sec):

Neutron star-neutron star merging, neutron star-black hole merging (e.g., Nakar 2007)

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

GRBs at High Redshift

• GRB 090423 (z ~ 8.2; Tanvir et al. 2009, Salvattera et al. 2009)

• GRB 100905A (z ~ 7.5; Im et al. 2011, prep)

• GRB 080930 (z ~ 6.8; Greiner et al. 2009)

• GRB 050904 (z ~ 6.29; Kawai et al. 2006; Totani et al. 2006)

Lyman break (13.6 keV ~ 121.6 nm)

Age (Gyr)

GRB 100905A at z ~ 7.5

0.6

0.7

0.8

0.9

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

GRBs in Early Universe…

• GRBs in early universe long GRB? No!

• All three GRBs at z > 6.5 Short GRBs!

• Great Mystery….

BZ process? (Blandford-Znajek 1977)

Short

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Supermassive Black Holes (SMBH)

• What are they?

- Black Holes with masses ~ 106 – 1010 M⊙

• Where are they ?

- Centers of massive spheroids/bulges or quasars

Elliptical galaxy Bulges of Spirals Quasars/AGNs

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Quasars

• Looks like a star (QUAsi-StellAR radio sources)

• Shines via accretion of matters around SMBHs

• Highest redshift QSO at z=6.43 (Willott et al. 2009)

Lee, Im, et al. 2008

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

When Did They Appear?

• 1010 M⊙ SMBHs are stilll forming at z ~ 6 (0.95 Gyr)

• What Happened before? Quasar Cliff?

AKARI points

(Our result)Quasar Cliff?

Present day Early Universe

Mass o

f B

H

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Growth of SMBHs• E= ε M c2, L = dE/dt ~ ε dM/dt c2

• dM/dt = L(Edd)/c2/ ε = M/τ, where τ ~ 4.5 x 107 (ε/0.1) yrs

M(t) = M(seed) exp(t/τ), exponential growth

Between z=15 to z=6, only 0.5 Gyr difficult to make SMBHs

Volonteri & Rees (2006)

Sijacki, Springel,& Haehnelt (2009)

ε=0.1

ε=0.2

ε=0.4

Super-critical

Age

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Galaxy Clusters

• The most massive, gravitationally bound object in the Universe (~1015 M⊙)

• 100-1000 member galaxies

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Recent proto-cluster studies

• Abundance: Sensitive to cosmological parameters, initial conditions

• Search for proto-clusters (Miley et al. 2004; Overzier et al. 2008, Matsuda et al. 2011; Kajisawa et al. 2006; Capak et al. 2011,…; 1 < z < 5.3)

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Proto-clusters in Early Universe

• Discovered a proto-cluster at z=3.7 (t ~ 1.7 billion years)

• Mass: 1014 M⊙

• Also proto-clusters at z=3.1 (Matsuda, Yamada et al.), z=4.1 (Miley et al. 2004), z=5.3 (Capak et al. 2011)

Kang & Im (2009)

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Implication

• Too many massive proto-clusters at high redshift! another mystery

Ph.D Thesis

Kang, E. (2010)

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

What Have We Learned?

Proto-clusters in Early Universe

Theory Observation ?

Rare 100x more Strange

Death of First Stars - GRB

Theory Observation ?

Long GRB Short GRB Why?

Supermassive BH Growth

Theory Observation ?

~1 Gyr Rapid Growth How?

2011. 2.16-2.18 GCOE International Symposium

(Tohoku University, Sendai, Japan)

Summary

• Extreme Objects in Early Universe – GRB, SMBH, and Proto-clusters

• Current results present challenges to theoretical/observational studies

• Exciting era to study the first objects in the universe