XRay Studies of Nucleosynthesis and Abundances in Supernova

X-Ray Studies of Nucleosynthesis and Abundances in Supernova Remnants John P. Hughes Rutgers University February 20, 2003 Carnegie Symposum 1

Why X-rays? Lya lines of all species from C (0. 368 ke. V) to Zn (9. 3 ke. V) n k. T ~ 106 K to 108 K from shocks in ejecta and CSM/ISM n ASCA Si W 49 B S Ar Ca Fe February 20, 2003 Carnegie Symposum 2

X-ray Emission/Atomic Processes Continuum emission – thermal bremsstrahlung: Line emission: Abundance of element Z February 20, 2003 Ionization fraction of ion i Carnegie Symposum 3

Abundance Determination Issues n Thermodynamic State – – – Nonequilibrium Ionization (NEI) (net~105 cm-3 yr) T, n evolution with time/radius (e. g. , Sedov) Other effects: § § § n Heating/cooling in pure element ejecta T e /T p Nonthermal particles (rates and excitation) Absolute abundances (e. g. , Si/H, O/H, Fe/H) – Rely on assumption of H/He-dominated continuum n Relative abundances (e. g. , Mg/Si, O/Fe) – OK, if species have the same spatial distribution February 20, 2003 Carnegie Symposum 4

Ejecta Mass Determination Issues Volume estimation n Clumping (reduces actual mass) n Distance (M~D 5/2) n Source of electrons n – – Measure EM = nen. IV Solar abundance: ne ~ n. H ~ n. Fe/107. 6 -12 ~ 25000 n. Fe Pure Fe: ne ~ 20 n. Fe Inferred Mpure Fe /Msolar ~ 35 February 20, 2003 Carnegie Symposum 5

Where do we find ejecta? Optical: SNRs with high velocity oxygen-rich features Galactic: Cas A, G 292. 0+1. 8, Puppis A LMC/SMC: N 132 D, E 0540 -69. 3, E 0102. 2 -72. 2 Other: an unresolved SNR in NGC 4449 n Remnants of historical SNe e. g. , SN 1006, SN 1572 (Tycho), SN 1604 (Kepler) Based on [Fe II] in absorption; X-ray spectra n Ejecta-dominated SNRs e. g. , W 49 B, G 352. 7 -0. 1, G 337. 2 -0. 7, G 309. 2 -0. 6 Based on X-ray spectra (mostly ASCA) n Nearly all remnants up to ages of at least ~10, 000 yrs!!! N 49, N 63 A, DEM 71, N 49 B, and E 0103 -72. 6 Based on Chandra spectro-imaging n February 20, 2003 Carnegie Symposum 6

Core Collapse Supernovae n SN II, SN Ib/c (Zwicky & Baade 1934) – Massive stars that explode with (SN II) or w/out (SN Ib/c) their H envelopes – Photodisintegration of Fe, plus electron capture on nuclei, remove central P support – Core collapses, leading to NS or BH – Core stiffens, rebounds and drives an outward moving shock – Neutrinos or jets needed to produce explosion – Mean Rate ~ 1. 3 SNU February 20, 2003 Carnegie Symposum 7

Nucleosynthesis in CC SNe n Hydrostatic nucleosynthesis – During hydrostatic evolution of star – Builds up shells rich in H, He, C, O, and Si – Amount of C, O, Ne, Mg ejected varies strongly with progenitor mass n Explosive nucleosynthesis – Some mechanism drives a shock wave with 1051+ erg through the Fe-core – Burning front T’s of ~109 K cause explosive O- and Siburning – Only affects the central parts of the star – outer layers retain their pre-SN composition February 20, 2003 Carnegie Symposum 8

Explosive Nucleosynthesis Process T (109 K) Main Products Explosive complete Si-burning 5. 0 “Fe”, He Explosive incomplete Si-burning 4. 0 Si, S, Fe, Ar, Ca Explosive O-burning 3. 3 Explosive Ne/C-burning February 20, 2003 1. 2 Carnegie Symposum O, Si, S, Ar, Ca O, Mg, Si, Ne 9

Overturning Our View of Cas A Hughes, Rakowski, Burrows, and Slane 2000, Ap. JL, 528, L 109. February 20, 2003 Carnegie Symposum 10

Cas A - Doppler Imaging by XMM n Similar velocity structures in different lines – – – n SE knots blueshifted N knots redshifted Tight correlation between Si and S velocities Fe – Note velocity distribution in N – Extends to more positive velocities than Si or S Willingale et al 2002, A&A, 381, 1039 February 20, 2003 Carnegie Symposum 11

Cas A – 3 D Ejecta Model “Plane of the sky” “Rotated” Red: Si Ka Green: S Ka Blue: Fe Ka Circle: Main shock Fe-rich ejecta lies outside Si/S-rich ejecta February 20, 2003 Carnegie Symposum 12

Oxygen-Rich SNR G 292. 0+1. 8 Park et al 2001, Ap. JL, 564, L 39 February 20, 2003 Carnegie Symposum 13

Oxygen-Rich SNR G 292. 0+1. 8 Ejecta Rich in O, Ne, and Mg, some Si [O]/[Ne] < 1 No Si-rich or Fe-rich ejecta February 20, 2003 Carnegie Symposum 14

Oxygen-Rich SNR G 292. 0+1. 8 Normal Composition, CSM Central bright bar – an axisymmetric stellar wind (Blondin et al 1996) Thin, circumferential filaments enclose ejecta-dominated material – red/blue supergiant wind boundary February 20, 2003 Carnegie Symposum 15

Thermonuclear Supernovae n SN Ia (Hoyle & Fowler 1960) – No hydrogen, a solar mass of 56 Ni, some intermediate mass elements (O, Mg, Si, S, …) – Subsonic burning (deflagration) of approx. one Chandrasekhar mass of degenerate C/O – C-O white dwarf accreting H/He-rich gas from a companion – No compact remnant – Mean rate ~ 0. 3 SNU February 20, 2003 Carnegie Symposum 16

Identifying Remnants of SN Ia Balmer-dominated SNRs (partially neutral ISM) n Ejecta abundances (Si and Fe rich, poor in O and Ne) n Remnant structure (uniform ISM, “smoother” ejecta, little spectral variation) n Tycho E 0509 -67. 5 February 20, 2003 Carnegie Symposum 17

SN Ia Spectra and Abundances § Comparison to models § O, Ne, Mg: relatively low § Si, S, Ar, Ca: consistent § Fe: very low (<0. 1) § Other spectral results § Fe: co-spatial with Si, but hotter and lower net W 7: Nomoto et al 1984, Thielemann et al 1993 WDD 1: Iwamoto et al 1999 NEI fit: Warren et al 2003 February 20, 2003 Carnegie Symposum 18

ISM Abundances of the LMC n Using SNRs as a probe of the ISM n 7 SNRs, ages from 2, 000 yr to 20, 000 yr n Data from ASCA n Spectra calculated for evolutionary models (Sedov solution) – spatial variation – temporal variation February 20, 2003 Carnegie Symposum 19

LMC SNRs: Integrated Abundances From fits to ASCA global X-ray spectra of 7 evolved LMC remnants N 49 B DEM L 71 Hughes, Hayashi, & Koyama 1998, Ap. J, 505, 732 February 20, 2003 Carnegie Symposum 20

LMC Metal Abundances Species HHK 98 Duf 84 RD 92 O 8. 21(7) 8. 43(8) 8. 35(6) Ne 7. 55(8) 7. 64(10) 7. 61(5) Mg 7. 08(7) . . . 7. 47(13) Si 7. 04(8) . . . ~7. 8 S 6. 77(13) 6. 85(11) 6. 70(9) Fe 7. 01(11) . . . 7. 23(14) HHK 95: ASCA X-ray SNRs Duf 84: UV/Optical spectra H II regions (Dufour 1984) RD 92: F supergiants (Mg, Si, Fe) (Russell & Bessel 1989) H II regions, SNRs (O, Ne, S) (Russell & Dopita 1990) February 20, 2003 Carnegie Symposum 21

DEM L 71 n Middle-aged SNR – 36” (8. 7 pc) in radius – 4, 000 yrs old Rims: LMC composition n Core: [Fe]/[O] > 5 times solar n Ejecta mass: 1. 5 Msun n SN Ia ejecta Hughes, Ghavamian, Rakowski, & Slane 2003, Ap. J, 582, L 95 February 20, 2003 Carnegie Symposum 22

N 49 B n Middle-aged SNR – 80” (19 pc) in radius – 5000 -10, 000 yrs old n Bright and faint rims – LMC composition – ISM density varies by x 10 n Ejecta – Revealed by equivalent-width maps – Mg & Si rich, no strong O or Ne Park, Hughes, Slane, Burrows, Garmire, & Nousek 2003, Ap. J, submitted. February 20, 2003 Carnegie Symposum 23

SNR 0103 -72. 6 n Middle-aged SNR – 87” (25 pc) in radius – >10, 000 yrs old (? ) n Circular rim – SMC composition n Central bright region – O, Ne, Mg, Si-rich ejecta – No Fe enhancement Park, et al 2003, Ap. J, in prep. February 20, 2003 Carnegie Symposum 24

Summary n Core Collapse SNe – Cas A § X-ray ejecta dominated by Si, S, and Fe – explosive nucleosynthesis § Extensive mixing and overturning of ejecta layers – G 292. 0+1. 8 § X-ray ejecta dominated by O, Ne, and Mg (no Fe) § Ambient medium strongly modified by progenitor § Contains “normal” young pulsar and its wind nebula Highly Structured Ejecta/Environment February 20, 2003 Carnegie Symposum 25

Summary n Thermonuclear SNe (Tycho, E 0509 -67. 5) – X-ray ejecta dominated by Si, S, and Fe – Stratification (most of the Fe core unshocked) – Fe: higher k. T, lower net – due to: § evolution (ejecta density profile) § radioactivity – Ejecta relatively smooth and symmetric § only factor of 2 intensity variations § little spectral variation § few (one or two) clumps of Fe-rich ejecta February 20, 2003 Carnegie Symposum 26

Summary n Evolved LMC SNRs – Global X-ray abundances consistent with optical/UV values – Individual SNRs show obvious signs of ejecta § DEM L 71: 4, 000 yrs, Si and Fe-rich SN Ia ejecta § N 49 B: 5, 000 -10, 000 yrs, Mg and Si-rich ejecta § E 0103 -72. 6: 10, 000+ yrs, O, Ne, and Mg-rich ejecta n Issues for nucleosynthesis models – O/Ne ratio < 1 (G 292. 0+1. 8) – O, Ne/Mg << 1 (N 49 B) February 20, 2003 Carnegie Symposum 27

THE END February 20, 2003 Carnegie Symposum 28

SN Ia Spectra and Abundances February 20, 2003 Carnegie Symposum 29

Properties of DEM L 71 Ejecta n n Outer rim: lowered abundances, ~0. 2 solar (LMC ISM) Core: enhanced Fe abundance, [Fe]/[O] > 5 times solar (ejecta) Thick elliptical shell, 32” by 40” across (3. 9 pc by 4. 8 pc) Dynamical mass estimate Wang & Chevalier 2001 r’ ~ 3. 0 Mej = 1. 1 Mch (n/0. 5 cm-3) n EM mass estimate EM ~ ne n. Fe V MFe < 2 Msun n Main error: source of electrons Fe-rich, low mass February 20, 2003 SN Ia Carnegie Symposum 30

N 63 A n Middle-aged SNR – – – n 34” (8. 2 pc) in radius 2000 -5000 yrs old 2 nd brightest LMC SNR “Crescent”-shaped features – Similar to features in Vela – Clumps of high speed ejecta – Not ejecta dominated n Triangular hole – X-ray absorption – Approx. 450 solar mass cloud – On near side n No PSR or PWN – LX < 4 x 1034 erg s-1 Warren, Hughes, & Slane, Ap. J, in press (20 Jan 2003) February 20, 2003 Carnegie Symposum 31