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

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 The orign and evolution of dust in galaxies

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 The orign and evolution of dust in galaxies Infrared Wavelength (micron) Log (λ * L λ ) (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 The orign and evolution of dust in galaxies >8(10?) M  1- 8(10?) M  Concept of cycle of matter Past: Theory/models (population synthesis/chemical evolution models of galaxies) Current: measurements of dust

Large Magellanic Cloud (LMC) One of the nearest galaxies 50 kpc Spitzer Space Telescope observations Spectroscopic survey Photometric survey micron Entire census of AGB stars C.f. projection problem of the Milky Way The orign and evolution of dust in galaxies Optical image Spitzer Space Telescope Spitzer image (SAGE) 3.6 micron: blue 8.0 micron: green 24 micron: red

Analysis (1) : selection of dust forming AGB stars The orign and evolution of dust in galaxies 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]

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 Evolution of dust in galaxies 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 The orign and evolution of dust in galaxies Detecting dust-embedded AGB stars using Spitzer Matsuura et al. (2009, MNRAS, 396, 918; in preparation) AGB stars SourcesGas (10 -2 Msun yr -1 ) Dust (10 -5 Msun yr -1 ) Dust species AGB stars2-4 (total) 5-11(total) Carbon-rich 4-8Amorphous carbon, SiC, PAHs Oxygen-rich 1.5-3Silicate Carbon-rich Oxygen-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 Evolution of dust in galaxies

Star formation rate (SFR) > Gas injection rate from SNe and AGBStar formation rate (SFR) > Gas injection rate from SNe and AGB LMC star formation depends on the large reservoir of existing ISM gasLMC 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.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)Chemical evolution of the LMC ISM is very slow process (~1 Gyrs) –ISM gas : 8x10 8 Msun (H I + H 2 ) = Gas injection rate ( Msun yr -1 ) x 1 Grys–ISM gas : 8x10 8 Msun (H I + H 2 ) = Gas injection rate ( Msun yr -1 ) x 1 Grys Gas budget of the LMC Evolution of dust in galaxies SNe +AGB M  yr -1 Star formation rate M  yr -1 Star formation rate (SFR) > Gas injection rate from SNe and AGBStar formation rate (SFR) > Gas injection rate from SNe and AGB LMC star formation depends on the large reservoir of existing ISM gasLMC 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.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)Chemical evolution of the LMC ISM is very slow process (~1 Gyrs) –ISM gas : 8x10 8 Msun (H I + H 2 ) = Gas injection rate ( Msun yr -1 ) x 1 Grys–ISM gas : 8x10 8 Msun (H I + H 2 ) = Gas injection rate ( 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: 2x10 6 M  H I +H 2 gas mass (8x10 8 M  ) x dust-to-gas ratio (0.0025) (>0.9x10 6 M  ; Meixner et al 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 4-8x10 8 yrs (Jones et al. 1994) Dust deficit is short by a factor of 30 The orign and evolution of dust in galaxies AGB dust (2-9)x10 4 M  over (4-8)x10 8 years ISM dust 2x10 6 M  Other dust sources are needed SNe Dust formation? ( ) 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 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 The orign and evolution of dust in galaxies

Origin and quantity Effects of metallicities Dust compositions Dust formation Implication for the distant galaxies

Dust compositions Targets Polycyclic Aromatic Hydrocarbons (PAHs) in post-AGB stars The orign and evolution of dust in galaxies Blocker (1995)

Difference between Galactic and LMC post-AGB stars: unique PAH features The orign and evolution of dust in galaxies 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 The orign and evolution of dust in galaxies 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 Effects of metallicities Dust compositions Dust formation Dust in different environment: low-metallicity galaxies Bridging local group galaxies to high-z galaxies Implication for the distant galaxies

Can dust be formed at low metallicities? Dust needs (astronomical) metals! Oxides Olivines : Mg 2x Fe (2-2x) SiO 4 Pyroxenes : Mg x Fe 1-x SiO 3 Carbonaceous dust Graphite : C Amorphous : C Polycyclic aromatic hydrocarbons (PAHs) The orign and evolution of dust in galaxies Dust mass : as a function of metallicity of galaxies It has been suggested that it is difficult to form dust grains in stars in low metallicity (Z<0.1 Z  ) galaxies Dust mass : as a function of metallicity of galaxies It 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 The orign and evolution of dust in galaxies Sculptor dwarf spheroidal (dSph) galaxy [Z/H]~-1.33 Fornax dwarf spheroidal galaxy [Z/H]~-1.0

Spitzer spectra The orign and evolution of dust in galaxies Sculptor dSph galaxy [Z/H]~-1.33 Sloan, Matsuura et al. (2009, Science 323, 353) Contrary to expectation, we detected dust at low metallicities SiC Amorphous Carbon Fornax dSph galaxy [Z/H]~-1.0 Matsuura et al. (2007, MNRAS 382, 1889)

Dust at low metallicity AGB 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 The orign and evolution of dust in galaxies (Fornax and Sculptor dSph galaxies) (Our Galaxy) Matsuura et al. (2005 A&A 434, 691)

Origin and quantity Effects of metallicities Dust compositions Dust formation Implication for the distant galaxies

Implications for high-z galaxies with dust Dust sources: AGB stars + SNe About solar metallicity 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) The orign and evolution of dust in galaxies

Hi-GAL The Herschel infrared Galactic Plane Survey Heritage HERschel 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. The orign and evolution of dust in galaxies

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 The orign and evolution of dust in galaxies