On Dust in the Early Universe
Takaya Nozawa(IPMU, University of Tokyo)
Contents:
1. Observations of dust at high-z
2. Formation of dust in supernovae
3. Critical metallicity
4. EMP-stars and dust
2010/07/29

1. Observations of dust at high-z1-1. Discovery of large amounts of dust at z > 5・ The submm observations have confirmed the presenceof dust in excess of 10^8 Msun in 30% of z > 5 quasars➔ We see warm dust grains heated by absorbing
stellar lights in the host galaxies of the quasars
SDSS J1148+5251 at z=6.4
LIR>10^13 Lsun

180 K, β=040 K, β=2
Wang+08, ApJ, 687, 848

Robson+04, MNRAS, 351, L29

1-2. What are sources of dust in z =6.4 quasar?
・ Type II SNe arising from short-lived massive stars－ ~0.1 Msun per SN (Maiolino+06, MmSAI, 77, 643)
－ > 1 Msun per SN (Dwek+07, ApJ, 662, 927)
－ sufficient only with SN-dust (Li+08, ApJ, 678, 41)
・ AGB stars are more dominant than SNe (50-80 %)(Valiante+09, MNRAS, 397, 1661)➔ ~0.01 Msun per AGB, ~0.05 Msun per SN・ grain growth in the ISM(Draine 2009, arXiv:0903.1658)

・ quasar outflow(Elvis+02, ApJ, 567, L107)

1-3. Herschel Observations of z=6.4 quasar
Leipski+10(arXiv:1005.5016)
z=6.4

z=4.7
*Herschel (3.5m)
・ PACS :70, 100, 160 μm
・ SPIRE
250, 350, 500 μm

・ a broad range of dust
temperature (LIR > 10^14 Lsun)
・ Another source northwestof the QSO J1148+5251 at
z=6.4 is clearly visible

1-4. Sources of dust in 5 < z < 6.4
Michalowski+10(arXiv:1006.5466)

Grain growth in the ISM is required
for at least 3 out of 9 QSOs at z > 5

1-5. Dust production in submm galaxies at z > 4
Michalowski+10, ApJ, 712, 942
Population synthesis (GRASIL)
・ average SFR : ~2500 Msun/yr
・ stellar mass : ~3.6x10^11 Msun・ dust mass : ~6.7x10^8 Msun・ gas-to dust ratio : ~60
Dominant dust sources
・ AGB stars for three・ SNe (0.15-0.65 Msun) for three

Yoshida (2010)

1-6. Dust mass in submm galaxies at 2 < z < 4Santini+10 (arXiv:1005.5678)
using Herschel/PACS and GRASIL

・ overdense region of LBGs
(9 objects) at z=5.16
Non-detection at 870 μm➔ Mdust < 1.2 x 10^8 Msun
Stanway+10 (arXiv:1007.0440)

1-7. Extinction curves at high-z quasars
Maiolino+04, Nature, 431, 533
SDSS J1048+4637 at z=6.2
Broad absorption line (BAL) quasars

different dust properties
from those at low redshifts

1-8. Extinction curves from high-z GRBs
GRB 050904 at z=6.3

GRB 071025 at z~5Stratta+07, ApJ, 661, L9
additional evidence for different
dust properties at high-z (z > 5)but see Zafar+10, A&A, 514, 94

Perley+09 (arXiv:0912.2999)

1-9. Extinction curves at 3.9 < z < 6.4
Gallerani+10(arXiv:1006.4463)
7 of 33 requires
substantial dust
extinction,
which deviatesfrom the SMC

The mean
Extinction
curves for
BAL quasars
deviates fromthe SMC withlevel > 95 %

1-10. Concluding remarks
・ what are the main sources of a huge amountdust grains at z > 4➔ SNe? AGB stars? grain growth in the ISM?
quasar outflow? mass-loss winds of massive stars?
how about PISNe? any other sources?

・ Properties of dust at high-z are likely to bedifferent from those at low-z➔ Is there really no extinction in many high-z quasarsystems?

・ Are there massive dust in primeval galaxies suchas LBGs?

2. Formation of dust in SNe2-1. Theory vs. Observation
SNe are important sources of interstellar dust?
・ Theoretical studies－ before destruction : 0.08-2 Msun in Type II-P SNe(Todini & Ferrara 2001; Nozawa et al. 2003)－ after destruction :0.01-0.1 Msun (Bianchi & Schneider 2007)
0.08-0.8 Msun (Nozawa et al. 2007)
・ Observational works－ IR observations of dust-forming SNe : < 10-2 Msun(e.g., Meikle et al. 2007, Kotak et al. 2009)－ submm observations of SNRs : ~1 Msun
(Dunne et al. 2003; Morgan et al. 2003)－ FIR obdervation of Cas A : 0.03-0.075 Msun
(Sibthorpe et al. 2009; Barlow et al. 2010)

2-2. Dust formation in primordial SNe
Nozawa+03, ApJ, 598, 785
・ nucleation and grain growth theory (Kozasa & Hasegawa 1988)

・ no mixing of elements within the He-core
・ complete formation of CO and SiO, sticking probability=1〇 Population III SNe model (Umeda & Nomoto 2002)
・ SNe II-P ： MZAMS = 13, 20, 25, 30 Msun (E51=1)
・ PISNe ： MZAMS = 170 Msun (E51=20), 200 Msun (E51=28)

Menv ~ 12 Msun

Menv ~ 90 Msun

2-3. Size distribution spectrum of dust

・ grain radii range from a few A up to 1 μm
・ average dust radius is smaller for PISNe than SNe II-P
amount of newly formed dust grains
SNe II-P： Mdust = 0.1-1 Msun, fdep = Mdust / Mmetal = 0.2-0.3
PISNe ： Mdust =20-40 Msun, fdep = Mdust / Mmetal = 0.3-0.4

2-4. Total mass and size of surviving dust
Nozawa+07, ApJ, 666, 955

Total dust mass surviving thedestruction in Type II-P SNRs;
0.08-0.8 Msun (nH,0 = 0.1-1 cm-3)

Size distribution of surviving
dust is domimated by large
grains (> 0.01 μm)

2-5. Flattened extinction curves at high-z
Hirashita+08, MNRAS, 384, 1725

z=5.8, BAL

z=5.1, BAL

Maiolino+04, A&A, 420, 889
z=0.69z=4z=0.54
z=1.16

Shatteringenhances
small grains
at Z=Zsun

Hirashita+10,
MNRAS, 404,1437

2-6. Dust formation in Type IIb SN
Nozawa+10, ApJ, 713, 356○ SN IIb model (SN1993J-like model)－ MH-env = 0.08 Msun
MZAMS = 18 Msun
Meje = 2.94 Msun

－ E51 = 1, M(56Ni) = 0.07 Msun

average radius

0.01 μm

・ SN IIb without massive
H-env ➔ adust < 0.01 μm
・ SN II-P with massive
H-env ➔ adust > 0.01 μm

2-7. Destruction of dust in Type IIb SNR
constant-density CSM

stellar-wind CSM
330 yrtotal mass of dust
formed : 0.167 M sunnH,1 = 30, 120, 200 /cc➔ dM/dt = 2.0, 8.0, 13x10-5 Msun/yr for vw=10 km/s

Almost all newly formed grains are destroyed in shockedgas within the SNR for CSM gas density of nH > 0.1 /cc➔ small radius of newly formed dust
➔ early arrival of the reverse shock at the He core

2-8. Comparison with observations of Cas A

Sibthorpe+09 (arXiv:0910.1094)

observed IR SED canbe well reproduced！
↑・ Md,warm ~ 0.008 Msun
・ Md,cool ~ 0.072 Msun
with Tdust ~ 40 K

AKARI reduced 90μm image➔ centrally peaked cool
dust component↓
Md,cool = 0.03-0.06 Msun
with Tdust = 33-41 K

2-9. Herschel observations of Cas A
Barlow+10, A&A, 518, L138

・ Md,warm ~ 0.008 Msun
・ Md,cool ~ 0.072 Msun
with Tdust ~ 40 K

confirmation of a cool dust
component emitting at 70160 μm inside reverse shock↓
Md,cool = 0.075 Msun
Td ~ 35 K

2-10. Conclusion remarks
・ Type II SNe and PISNe
Average grain radii are larger than 0.01 μm➔ primordial SNe may be important sources of dust

・ Type IIb, Type Ib/Ic, and Type Ia SNe
Average grain radii are smaller than 0.01 μm➔ envelope-stripped SNe may not be major sourcesof dust

・ Extinction curves in the early universe are
expected to be flat
・ Model of dust destruction in Type IIb SNR canwell reproduce the observed SED of Cas A

3. Critical metallicity

3-1. Critical metallicity
First (Pop III) star : very massive > 10-100 Msun
➔ when low-mass population II stars can form?
・ Atomic cooling－ Z ~ 10^-3.5 Zsun(Bromm+01, MNRAS, 328, 969)
－ [C/H] = -3.5, [O/H] = -3.05(Bromm & Loeb 2003, Nature, 425, 812)

－ extending to [C, O, Si, Fe/H](Santoro & Shull 2006, ApJ, 643, 26)－ Z > 10^-3 Zsun (numerical simulation)(Smith+07, 661, L5)－ Z ~ 10^-3.5 Zsun (cooling by molecules)(Jappsen+09, ApJ, 696, 1065)

3-2. Minimum stellar metallicity
Frebel+09,MNRAS, 392, L50

3-3. Thermal evolution of gas clouds
Effective ratio of specific heatg=0.2

g:= dlog p/dlog rg=1(isothermal)

g=1.3

Li et al. 2003••

γ<１ vigorous fragmentation,
γ＞１fragmentation suppressed
The Jeans mass at γ~1 (Tminimum) gives thefragmentation scale.

Mfrag=MJeans@g=1

3-4. Thermal evolution of gas clouds
Omukai+05,
ApJ, 626, 627
・ one-zone model・ dust model :Pollack+94
・ dust/metal ratio :same as local ISM

・ Dust cooling causes a sudden temperature drop at
high density where MJeans~0.1 Msun, which induces
low-mass fragmentation
・ low-mass fragments are formed only in the dustinduced mode

3-5. Dust from the first stars
Schneider+06, MNRAS, 369, 1437
progenitor: PISNe (195 M sun)progenitor: SN II (22 M sun)Zcr ~ 10-6 Zsun
Dust from SNe➔ larger area per unit dust mass (smaller radius)➔ more refractory composition(silicates, amorphous carbon)

3-6. Fragmentation of SN shell
Nagakura+09, MNRAS,399, 2183

3-7. CMB can affect fragmentation mass
Schneider+10, MNRAS, 369, 1437

3-8. 3D-simulation of cloud fragmentation (1)Tsuribe & Omukai 2005, 642, L61
Tsuribe & Omukai 2008, 676, L45[M/H]=-5.5 (Z=3x10-6 Zsun)
・ ρ-T evolution
given by onezone modelfor PISN-dust

Z >~10-6 Zsun
➔ long filament forms during dust-cooling phase➔ fragmentation into low-mass (0.1-1 Msun) objects

Zcr ~ 10-6-10-5 Zsun

3-9. 3D-simulation of cloud fragmentation (2)Yoshida (2010)
・ Z = 10^-5 Zsun
No fragmentation
・ Z = 10^-4 Zsun
fragmentation
fragment mass ~ 0.1 Msun

3-10. Concluding remarks
・ Critical metallicity (induced by dust) is likely tobe Z = 10^-6 to 10^-4 Zsun

4. EMP-stars and dust

4-1. Peculiar abundances of EMP stars
Vankatesan+06, ApJ, 640, 31

4-2. Chemically peculiar stars
Venn+08, ApJ, 677, 572

・ preferential removal ofmetals by dust formation
・ dilution by the accretion of
metal-poor interstellar gas

4-3. Radiative transport of dust
Vankatesan+06, ApJ, 640, 31

Dust formed in the first SN is transported to SN shells,
and some results of segregated grain transport canreproduce elemental composition of EMP stars

4-4. Evolution of dust within SNRs
Nozawa+07, ApJ, 666, 955
Model : Mpr=20 Msun (E51=1),
nH,0 = 1 cm-3
The evolution of dust
heavily depends on theinitial radius and chemicalcompositionaini = 0.01 μm (dotted)➔ completely destroyedaini = 0.1 μm (solid)➔ trapped in the shellaini = 1 μm (dashed)➔ injected into the ISM

4-5. Elemental abundance in the SNR shell (1)metallicity of shell
Z > Zcr = 10-6 Z☉[Fe/H] = -5.62 (HE0107-5240; Collet et al. 2006)[Fe/H] = -5.96 (HE1327-2326; Frebel et al. 2008)[Fe/H] = -4.75 (HE0557-4840; Noris et al. 2007)
3-D corrected4-6. Elemental abundance in the SNR shell (2)Nozawa+09 (arXiv:0812.1448)－6 ＜ [Fe/H] ＜－5
0 ＜ [Mg, Si/Fe] ＜ 2↓elemental composition of dust piled up
in the shell can reproduce abundance
pattern in HMP stars

The transport of dust segregated from metal-rich gas
can be responsible for the elemental composition ofPopulation II.5 stars formed in the dense SN shell4-7. Elemental abundance of dwarf galaxies (1)Tolstoy+10,ARAA, 47, 371

4-8. Elemental abundance of dwarf galaxies (2)Tolstoy+10

4-9. Confirmation of IGM dust in galaxy halo
Menard (2010)

How dust grains are transported to the IGM?

4-10. Concluding remarks