(H. Hirashita)

Importance of Dust in GalaxiesEvolution of Dust AmountImportance of Size Distribution Toward Complete Dust ModelSummary and Plan

1. Importance of Dust in GalaxiesM33: Hinz et al. (2004)Optical (B-band): starsFIR (70 mm): dust

Radiative Processes(0.1 3 mm)UV, opt, NIR(10 1000 mm)MIR, FIR, sub-mmDust graina < 1 mmT ~ 10 1000 KSiCextinctionreemission

Spectral Energy Distribution of Nearby (z ~ 0) GalaxiesFIR: 50 300 mmSchmidt et al. (1997)

What to Quantify for Grains Amount of grains: Mdust Properties of grainsSpecies (Silicate, Graphite, )Size (a ~ 10 1 mm)t ~ (Sdust/ra3) a2Q

2. Evolution of Dust Amount Dust is supplied by Type II SNe (m* > 8 Msun). Dust per SN = 0.4 Msun (Todini & Ferrara 2001). Dust destruction is considered (not efficient).SFR (t) SN II rate (t) Mdust (t) (Salpeter IMF)Given nextHirashita & Ferrara (2002)We concentrate on young (t < 1 Gyr) galaxies.

Star Formation Law: SFR(t)Star formation is deeply related to the abundanceof molecular gas (the main coolant) SFR = (molecular gas mass)/(dynamical mass) = fH2 Mgas / tdynchemical reaction networkH2 formation on dust includedDetermined for(Mvir, zform | cosmology)Self-consistent treatment of dust, H2, and SF!

Dust-Induced Transition!?Dust-polluted galaxiesH2 formation on dust: H + H + grain H2 + grainPrimeval (dust-clean) galaxiesH2 formation in gas phase: H + e - H - H - + H H2 + e

Star Formation Historyzform = 10Mvir = 109 Msun4tdynH2 formation on dust

FIR/UV luminositiesFIR luminosity becomes comparable to the UV luminosity.UV luminosityFIR luminosityzform = 10Mvir = 109 Msun4tdyn

Test of Our Model for z > 5Sub-mm (ALMA)near infrared (JWST)A high-z galaxy

Number Counts (z > 5) 5 s limit for 8 h3 s limit for 105 sALMAJWST

3. Importance of Size DistributionExtinction Curve

Cross Section of GrainsDifferent size = Different optical propertiesdN(a) / da a 3.5 for Milky Way (Mathis et al. 1977)

Dust Size Distribution of SNeNozawa et al. (2003)

Extinction Curves of SNe IIHirashita et al. (2005)Maiolino et al. (2004)for a QSO at z = 6.2

IR Dust EmissionTakeuchi et al. (2005)

4. Toward Complete Dust Model

Processes of Dust Destruction SputteringThermalNonthermalB(2) Shattering(2)(Jones et al. 1996)

Basic Ingredients for ModelingCrater formation and disruption (u, Pcr)Size distribution of fragments ( a 3.3)Jones et al. (1996)Acceleration by compressiondrags

Effects of ShatteringInitial n(a) a3.5n = 0.25 cm3T = 104 KB = 3 mG1 SN passage

5. Summary and Plan(1) Dust determines how galaxies look like (e.g., SED). Extinction and infrared emission.(2) Based on evolution of dust amount, we have predicted sub-mm and NIR number counts in future survey: ALMA, JWST, Herschel, SPICA, (3) But grain size distribution is also very important! a. Extinction curve (consistent with SN production) b. Infrared SED(4) We are now developing dust destruction scheme. Shattering can be treated at this stage: a. Inclusion into my previous one-zone model b. Inclusion into hydrodynamical simulation