Origin and evolution of dust in galaxies Spitzer Observations of Dust in the Local Group Galaxies Implications for dust in high-z galaxies Mikako Matsuura

Origin and evolution of dust in galaxies

Spitzer Observations of Dust in the Local Group Galaxies

Implications for dust in high-z galaxies

Mikako Matsuura

Origin’s fellow, Institute of Origins, University College London

The orign and evolution of dust in galaxies

Team Eric Lagadec Quentin A Parker Warren Reid Takashi Shimonishi E. van de Are H. van Winkle Peter Wood Albert Zijlstra

Karl Gordon Remy Indebetouw Ciska Kemper Massimo Marengo Margaret Meixner Xander Tielens Jacco van Loon Paul Woods

Mikako Matsuura M. J. Barlow Greg Sloan Kevin Volk Jeronimo Bernard-Salas Tom Llyod-Evans You-Hua Chu Robert Gruendl Bruce J. Hrivnak Yoshifusa Ita Kathleen Kraemer


Introduction: IR emission

Infrared (IR) emission of galaxies Thermal emission from dust grains

Indicator of starformation rate

What is the origin of dust?Origin/quantity

Can we account for dust mass in the interstellar medium (ISM) by stellar sources?

Effects of different metallicities Dust compositions Dust formations

Infrared

0.1

1 10

100 1000Wavelength (micron)

Log

(λ *

Lλ)

(L)

Da cunha et al. (2008)

Origin and quantity

Effects of metallicities Dust compositions Dust formation

Implication for the distant galaxies


Cycle of matter (gas and dust) in galaxies

>8(10?) M

1- 8(10?) M

Concept of cycle of matterPast: Theory/models

(population synthesis/chemical evolution models of galaxies)

Current: measurements of dust

Important for galaxy evolution


Large Magellanic Cloud (LMC)

One of the nearest galaxies 50 kpc

Spitzer Space Telescope observations Spectroscopic survey Photometric survey 3.6-160 micron

Entire census of AGB stars

C.f. projection problem of the Milky Way

Optical image

Spitzer Space TelescopeSpitzer image (SAGE)

3.6 micron: blue8.0 micron: green24 micron: red


Analysis (1) : selection of dust forming AGB stars

Matsuura et al. (2009, MNRAS 396, 918)

AGB stars are the brightest population in mid-infrared

Distant galaxies

Foreground stars

Emission line objects(WR stars)

HII regions / YSOs

AGB stars

Mid-infrared color magnitude diagramme [8.0] vs [3.6]-[8.0]

Evolution of dust in galaxies

Analysis (2) estimate of gas and dust lost from individual

AGB stars

Detailed analysis of 40 AGB stars provides dust/gas mass-loss rate rate (M yr-1)

JHKL photometry Spitzer spectra (5-35 micron)

Spectral energy distributions are fitted, using radiative transfer code

Dust mass-loss rate: 3.1x10-8 M yr-1

Log dM/dt=-6.2/[([3.6]-[8.0])+0.83]-3.39


Analysis (3) : measured their gas and dust mass-loss rate from IR

data

Detecting dust-embedded AGB stars using Spitzer

Matsuura et al. (2009, MNRAS, 396, 918; in preparation)

AGB stars

Sources Gas(10-2 Msun yr-1)

Dust (10-

5 Msun yr-

1)

Dust species

AGB stars 2-4(total)

5-11(total)

Carbon-rich 4-8 Amorphous carbon, SiC, PAHs

Oxygen-rich

1.5-3 Silicate

Carbon-richOxygen-rich


Gas feedback in the LMC

Total AGB mass-loss rate: 2-4x10-2 M yr-1

Oxygen-rich + carbon-rich AGB stars

Type II SNe: 2-4x10-2 M yr-1

In the LMC, Type II SNe and AGB stars are both important gas sources

AGB 2-4x10-2 M yr-1

Type II SNe 2-4x10-2 M yr-1


• Star formation rate (SFR) > Gas injection rate from SNe and AGB • LMC star formation depends on the large reservoir of existing ISM

gas• The LMC is getting gas poorer. The SFR is likely to be declining

with time.• Chemical evolution of the LMC ISM is very slow process (~1 Gyrs)

– ISM gas : 8x108 Msun (HI + H2) = Gas injection rate (0.03-0.08 Msun yr-1) x 1 Grys

Gas budget of the LMC

SNe +AGB0.03-0.08 M yr-1

Star formation rate 0.2-0.3 M yr-

1 ISM gas 8x108 M

• Star formation rate (SFR) > Gas injection rate from SNe and AGB • LMC star formation depends on the large reservoir of existing ISM

gas• The LMC is getting gas poorer. The SFR is likely to be declining

with time.• Chemical evolution of the LMC ISM is very slow process (~1 Gyrs)

– ISM gas : 8x108 Msun (HI + H2) = Gas injection rate (0.03-0.08 Msun yr-1) x 1 Grys


Global dust budget in the Large Magellanic Cloud

Missing dust input problem in the LMC!

Current LMC dust mass: 2x106 M

HI+H2 gas mass (8x108 M) x dust-to-gas ratio (0.0025) (>0.9x106 M; Meixner et al. 2010 from Herschel observations)

Dust injection rate from AGB stars: 5x10-5 M yr-1 (up to 11x10-5 M yr-1) requires>20 Gyrs Lifetime of the LMC (~15 Gyrs) Dust lifetime was estimated to be 4-8x108 yrs (Jones et al. 1994)

Dust deficit is short by a factor of 30

AGB dust (2-9)x104 M over (4-8)x108 years

ISM dust2x106 M

Other dust sources are needed

SNeDust formation? (40-80000) M

Shock destruction?


Solutions for the dust deficit?

Lower SN dust destruction rate

Dust from high mass stars Higher SNII dust production rate

Herschel measured dust mass of 0.075 Msun in Galactic SNR Cas A (Barlow et al. 2010) Consistent with values used in our LMC study

Dust formation in LBV and WR stars

Unaccounted dust mass in AGB stars?

Dust mass increases in ISM

External dust sources

If dust mass increases in starforming regions

Gas-to-dust ratios in ISM < in stars (AGB, SNe)

Herschel/ALMA

Origin and quantity




Dust compositionsTargets

Polycyclic Aromatic Hydrocarbons (PAHs) in post-AGB stars

Blocker (1995)


Difference between Galactic and LMC post-AGB stars: unique PAH

features

PAH templates from Galactic objects (Peeters et al. 2002)

LMC post-AGB stars which do not fit to Galactic PAH templates (type A-C) No Galactic counterparts found so far

B

A

F,G

Spectral types of the central stars

New type, D

LMC metallicity~half of the solar metallicity

Matsuura et al. to be submitted


Origin of new type of PAHs

Origin of different spectral shapes of PAH features in the LMC stars from Galactic counterparts- Different structures of PAHs- Reason?: Lower density to prevent collisions between PAHs?

Mixture of lab data(Hudgins and Sandford 1998a, b)

Origin of type-D PAHs

Compact round-shaped PAHs (no quartet)

Quartet(four –H attached to a ring)

Origin and quantity


Dust in different environment: low-metallicity galaxies Bridging local group galaxies to high-z galaxies



Can dust be formed at low metallicities?Dust needs (astronomical) metals!

Oxides Olivines : Mg2xFe(2-2x)SiO4

Pyroxenes : MgxFe1-xSiO3

Carbonaceous dust Graphite : C Amorphous : C Polycyclic aromatic

hydrocarbons (PAHs)

Dust mass : as a function of metallicity of galaxiesIt has been suggested that it is difficult to form dust grains in stars in low metallicity (Z<0.1 Z) galaxies

But … we found unexpected results


The Galaxies of the Local Group

Some galaxies have low metallicities

Sculptor dwarf spheroidal (dSph) galaxy [Z/H]~-1.33

Fornax dwarf spheroidal galaxy[Z/H]~-1.0


Spitzer spectra

Sculptor dSph galaxy [Z/H]~-1.33Sloan, Matsuura et al. (2009, Science 323, 353)

Contrary to expectation, we detected dust at low metallicities

SiC

Amorphous Carbon

Fornax dSph galaxy [Z/H]~-1.0Matsuura et al. (2007, MNRAS 382, 1889)


Dust at low metallicityAGB stars

We detected amorphous (+SiC) dust

Carbon atoms synthesized in AGB stars

Dust formation process around stars is affected not only by the

metallicities of the parent galaxies

but also by elements formed inside stars, in particular, carbon

Amorphous carbon, PAHs

Dust grains are formed around the first generation of AGB stars

(Fornax and Sculptor dSph galaxies)

(Our Galaxy)

Matsuura et al. (2005 A&A 434, 691)

Origin and quantity




Implications for high-z galaxies with dust

Dust sources:AGB stars + SNe About solar metallicity

10-15 Gyrs

Assumed to be low metallicity initially

z~6.4; ~0.4 Gyrs(e.g. Bertoldi et al. 2003)

Dust sources:SNe (>8 Msun)

Metallicity

AGE

(Before our study)

Galaxies in the Local Group

High-z galaxies

Dust can be formed in AGB stars and SNe even at low metallicity

Age of AGB stars is much younger than previously thought (starting 50 Myrs; Vassiliadis & Wood 1993)

Sloan, Matsuura et al. (2009, Science, 323, 353)

AGB + SNe


Hi-GALThe Herschel infrared Galactic Plane Survey

HeritageHERschel Inventory of The Agents of Galaxy Evolution: the Magellanic Cloud Survey

HerMES


Dust grains

We found dust grains in many galaxies …

But still we don’t know where they are from.


Summary Low- and intermediate-mass stars are important dust

sources But still found deficit in dust budget in the LMC

Solutions will be tested using Spitzer/Herschel observations Dust from AGB stars are more carbon-rich, and contain more

PAHs at lower metallicity <-> ISM: weak PAHs High UV radiation in the ISM at low metallicity destroy PAHs

Better constrains of age of dust forming stars required

High-z galaxies Lower metallicities do not hamper dust formation in AGB stars Origins of dust in high-z galaxies are still open question.

Dust mass in high-z galaxies may be explained, if both SNe and AGB stars contribute dust formation

Documents

Origin and evolution of dust in galaxies Spitzer Observations of Dust in the Local Group Galaxies Implications for dust in high-z galaxies Mikako Matsuura