Core-collapse supernovae as dust producers: what Spitzer is telling us Rubina Kotak (Queen’s University Belfast)

Outline: Why core-collapse supernovae as dust producers? Model predictions Observational evidence Recent examples Dust mass estimates from SNe SNe as dust destroyers Open issues

Core-collapse SNe: major source of cosmic dust? Cernushi et al. (1967), Hoyle & Wickramasinghe (1970), Clayton (1979), Gehrz (1989), Tielens (1990), Dwek (1998), Todini & Ferrara (2001), Nozawa et al. (2003), … Growing interest as a source of dust at high-z Reddening of background quasars by damped Ly systems FIR emission from DLAs Gas-phase Zn/Cr ratios Detection of far-IR and mm emission from quasars and galaxies at 6.5 > z > 1 --> 107~108 M of dust

Dust at high redshifts The case of SDSS J1148+5251 z ~ 6.4: Smail et al. (1997), Hughes et al. (1998), Omonti et al. (2001,2003), Bertoldi et al. (2003), Maiolino et al. (2004), Robson et al. (2004), Beelen et al. (2006) + … The case of SDSS J1148+5251 z ~ 6.4: Age : 400 Myr (age of Universe ~ 890 Myr) Gas mass : 3x1010 M Dust mass: 2x108 M SFR : 100-3500 Myr-1 Rapid metal and dust enrichment of the ISM. enrichment due to AGB stars too slow CCSNe good candidates Fan et al. (2003) Dwek et al. (2007)

Carbon stars as dust producers at low metallicity? Carbon star (possibly) in Sculptor Galaxy: Z = 0.04 Z(Milky Way) At high redshifts, intermediate mass stars could form as soon as trace quantities of metals appear in the ISM => precursors of carbon stars could form relatively early. Require only ~400 Myr to reach AGB. BUT: -- How much carbon dust? (C dredge-up certain) -- SFR + IMF - dependent Sloan et al. (2009)

dust producers dust destroyers CCSNE dust producers dust destroyers Suitable materials: C, O, Mg, Al, Si, Fe Cooling: expansion + molecules hostile environment (UV, ) thermal sputtering grain-grain collisions …

Models predict 0.1 < M dust < 1 M per SN a few years after explosion e.g. Todini & Ferrara (2001), Nozawa et al. (2003), Nomoto et al. (2006) E.g. if all the refractory elements in a 25 Msun SN condensed into dust, then get 1 Msun of dust. Todini & Ferrara (2001)

What is the observational evidence?

Detecting dust in supernovae: Attenuation of spectral line profiles

[OI] line profiles in Type IIpec SN 1987A at 529 and 738 days post-explosion Danziger et al. (1991)

[OI] line profile in the type II-P SN 2004dj at ~900 days SN spherically symmetric distribution of optically-thin gas. Dust is represented by an opaque disk centred on the los with the flat surfaces parallel to this direction. [OI] line profile in the type II-P SN 2004dj at ~900 days

SN 1998S (type IIn): ejecta/CSM interaction, Dust formation in a cool dense shell behind the shock front. Pozzo et al. (2004)

Detecting dust in supernovae: Attenuation of spectral line profiles Thermal emission of dust grains Until 2003, ~13 cases of core-collapse SNe showing near-IR excesses BUT, -- new dust condensing in SN ejecta, or -- IR-echo due to pre-existing circumstellar dust?

INFRARED ECHO LIGHTCURVES

IR ECHO OR NEW DUST? Monitoring (Echo earlier + brighter) Bouchet et al. 1989, 93 Meikle et al 2006

Do all core-collapse SNe form dust? How much dust? When does dust form? Under what conditions? Molecules a necessary intermediate step? Will it survive? What is the composition, grain size? How does dust production vary with SN subtype? What is the influence (if any) of the environment? …

To assess the ubiquity of dust formation in core-collapse supernovae need: Sample of well-observed “normal” SNe (photometry + spectroscopy) Mid-IR monitoring extremely challenging from the ground. --> No mid-IR studies of SNe since SN 1987A

Detection of SiO SiO ~ 2x10-4 M Liu & Dalgarno model. SN 2005af (type IIP) SiO ~ 2x10-4 M Liu & Dalgarno model. Kotak et al. (2006)

Isothermal dust model Simple analytical model comprising a uniform sphere of isothermal dust grains (Lucy 1989; Osterbrock 1989) Free parameters: (for a given grain composition) grain temperature, sphere radius, grain number density scaling factor Guided by dust condensation calculations based on SN explosion models e.g. Kozasa et al. 1989, Todini & Ferrara (2001), Bianchi & Schneider (2007) Assume that dust of uniform no. density forms throughout the zone containing abundant refractory elements. Extent of this zone from nebular spectra ~ 2500 km/s

SN 2005af (II-P) Spitzer IRAC 3.6-8 μm 576d Age Temp. Md f (d) (K) (10-4 M) 214 800 0.015 0.07 571 420 4.0 0.32

Case study: SN 2004et (type II-Plateau) Extensive set of optical + mid-IR data for the most common type of core-collapse SN ---> evolution of SED

SED evolution: evidence for increasing emission due to dust 3-component black-body fits for days 300-1222: Hot: 5000 - 10000 K --> ejecta Warm: 450 - 700 K --> newly formed dust Cold: 100 - 130 K --> pre-existing dust NB: no attempt was made to match the broad emission feature / lines Optical data from Sahu et al. (2006)

Hot component: ~5000-7000 until 800d. Rise in temp. at last 2 epochs Warm component: 300-800d cooled and faded monotonically; BB surface never exceeded 1600 km/s => consistent with warm emission arising from newly-formed dust. Disfavour echo because a) would require a contrived cavity size b) line-shifts seen in the optical c) decline in optical light curve accelerated Cold component: roughly constant temperature throughout. High velocities rule out newly-formed dust

Example IDM fit: day 464 evidence for newly formed silicate dust SiO + silicate grains Amorphous carbon grains

Silicate dust model fits Temp (K) 900 650 400  (10µm) 2.8 3.6 11.5 M(SiO) 10-4 Msun 5.7 3.7 ~0.5 M(dust) 10-4 Msun 0.39 0.66 1.5 Fading of silicates 690+ d due to Increasing optical depth as more dust forms Increasing contribution from non-silicate dust (e.g. CDS) Silicate feature yields an additional constraint at each epoch => in spite of high , dust mass estimates are not just lower limits

The disappearance and reappearance of 04et 3.6µm Pre-explosion 1222 d 795 d 300 d

Cause of mid-IR rebrightening: ejecta/CSM collision Dust formation in a cool dense shell behind the reverse shock. 10 km/s RSG wind at ~6000 AU Wide boxy profiles + decrease from blue to red => dust

Origin of cold infrared source Echo from pre-existing dust? Applying an IR echo model => dust had to lie 10 pc from SN, => dust mass of 350 Msun (to reproduce luminosity) => cannot be due to the progenitor of SN 2004et More natural explanation: IR interstellar echo -- predicted by Wright (1980); Bode & Evans (1980), but never observed. For 04et, the cold component is well-fit by a single set of parameters from 300-795 d. Prediction: for a cavity of 10pc, expect constant IR luminosity for ~65 yrs.

The multi-faceted nature of SN 2004et Evidence for freshly condensing silicate dust Very-late time ejecta - circumstellar medium interaction => dust in cool dense shell Cold infrared component => IR echo from interstellar dust Disentanglement difficult!

Recent claim of a large dust mass in SN 2003gd (IIP) 0.02 M of dust -- Sugerman et al. (Science, 2006) Sugerman et al. (2006) Meikle et al. (2007) 3.6-8m/~700d upper lts. only 8.0m: 737 Jy 24m /~700d 10616 38090 Jy (same data) 8m difference 24m 670d

Recent claim of a large dust mass in SN 2003gd (IIP) Sugerman et al. (2006) 0.02 M of dust -- Sugerman et al. (Science, 2006) Sugerman et al. (2006) Meikle et al. (2007) 24m /~700d 10616 38090 Jy Error in 24m /~700d flux of Sugerman et al. Outer limit of dust-forming zone > metal line velocities from late-time spectra (~2000km/s)  unphysical Total luminosity > 4 x total radioactive luminosity deposited in ejecta  severe energy deficit Similar decline rates c.f. 87A, but invoke vastly different efficiencies Directly detected dust: SN 2003gd produced no more than few 10-5 M For details see Meikle et al. (2007)

Summary of SN dust mass estimates Type Dust mass (Msun) Technique Ref. 1987A II-Pec 7.5x10-4 mid-IR + opt. line attenuation Ercolano et al. (2007) 1998S IIn >2x10-3 optical + near-IR line attenuation Pozzo et al. (2004) 2006jc Ibn 3x10-4 near-IR + line attenuation Mattila et al.; Sakon et al., Smith et al. 1999em II-P ~10-4 optical line attenuation Elmhamdi et al. 2003gd 4x10-5 mid-IR Meikle et al. (2007) 2004et Few x 10-4 mid-IR + line attenuation Kotak et al. (2009)

Dust mass estimates from supernova remnants CasA: 3x10-3 Msun (Hines et al. 2004) at 80K 0.054-0.02 Msun (Rho et al. 2008) 2Msun Dunne et al. (2003); Krause et al. (2004) 0.2< Msun: sub-mm ~10-4 Msun (Dwek et al.): Fe needles; but Dunne et al. (2009): sub-mm polarization: 0.5-1 Msun if 100% efficiency of dust condensation SNR 1E 0102.2-7219: 8x10-4 Msun (Stanimirovic et al. 2005) -- 10-2 Msun (Rho et al. 2009) Crab, Kepler 10-3 -- 10-2 (Tenim et al. 2006, Blair et al. 2007); 1 Msun (Morgan et al. 2003); 0.1-1.2 Msun (Gomez et al. 2009): sub-mm

Dust Composition Cas A (Rho et al. 2008) 1st type Dust: 21mm-peak dust; Mg proto-silicate, amorphous (am) MgSiO3, am SiO2, FeO, and aluminum oxide (Al2O3). The compositions suggest the dust forms around inner-oxygen and S-Si layers. Total dust mass of 0.02 to 0.054 Msun (depending on dust composition) Featureless Dust Fe, C, Al2O3 (FeO)

Dust mass estimates from supernova remnants CasA: 3x10-3 Msun (Hines et al. 2004) at 80K 0.054-0.02 Msun (Rho et al. 2008) 2Msun Dunne et al. (2003); Krause et al. (2004) 0.2< Msun: sub-mm ~10-4 Msun (Dwek et al.): Fe needles; but Dunne et al. (2009): sub-mm polarization: 0.5-1 Msun if 100% efficiency of dust condensation SNR 1E 0102.2-7219: 8x10-4 Msun (Stanimirovic et al. 2005) -- 10-2 Msun (Rho et al. 2009) Crab, Kepler 10-3 -- 10-2 (Tenim et al. 2006, Blair et al. 2007); 1 Msun (Morgan et al. 2003); 0.1-1.2 Msun (Gomez et al. 2009): sub-mm

Molecules in SN ejecta 2004dj (IIP) 2004et (IIP)

Dust formation in all CCSNe? (Probably) yes for IIPs When does dust form? in IIPs, > few 100d Under what conditions? Molecules always necessary? all IIPs in our sample (6) show CO; some show SiO before few 100d (previously only seen in 1 SN: ‘87A) How much dust? Currently 10-3 - 10-5 M of dust i.e. 10-100x lower than needed. -- much more may exist in optically-thick clumps -- more modelling effort required How does dust production vary with SN subtype? -- currently, only few examples of other types: SN 1987A (II-pec), SN 1990I, 06jc (Ib), SN 1998S (IIn), …