1. Shock-induced Molecular Astrochemistry in Dense Clouds Jeonghee Rho Jeonghee Rho SOFIA Science Center SOFIA Science Center Universities Space Research Association Universities Space Research Association NASA Ames Research Center, CA NASA Ames Research Center, CA Collaborators Collaborators RS, Toulouse) J. Hewitt (NASA/GSFC), M. Anderson (ESA, ESTEC, Netherland), A. Tappe (CfA, Harvard Smithsonian), W. T. Reach (SOFIA SMO/NASA Ames), and J. P. Bernard (CNRS, Toulouse)

2. Interaction with CSM/ISM radiative shock in dense gas heating, chemistry, dust processing Massive Stars form in GMC Young adiabatic SNR >8 Msol dies within cloud lifetime (~40% SNe in the field) expanding in wind cavity ejecta mixing, dust creation, cosmic ray accel SNR merges into ISM Superbubble / Chimney release of cosmic rays

3. W44, enveloped by a molecular cloud Radiative signatures: IR-bright => shock cooling in relatively dense gas (>10 3 cm -3 ) Broad molecular lines (eg. CO 2-1) Supernova Remnants Interacting with Clouds Spitzer IRAC color image (Reach, Rho et al. 2006): Shocked H 2 (4.5 μm, green), PAH and dust (8 μm, red) Reach, Rho, Jarrett (2005) 12CO(2-1), ΔV=40 km/s)

4. IC 443 : prototype of interacting SNR Optical, radio are shell-like X-rays: shell + bright inside Interaction with clouds: Near-IR H 2 image (Burton et al. 1988) CO broad lines (van Dishoeck et al.) 2MASS images: bright K emission (H 2 ) in the southern ridge and J,H emission ([Fe II]) in the northern rim H 2 lines; 1-0 S(1) in K, 1-0 S(7) in H, 2-1 S(1) in J (Rho et al. 2001) [Fe II] H2H2

5. Spitzer GLIMPSE survey detected 18 IR-bright SNRs Colors hint at dominant cooling lines and shock type. However... Color-typing shows large scatter, even within the same SNR IR spectroscopy is clearly needed Supernova Remnants Interacting with Clouds from Reach et al. 2006 Molecular Ionic PAH

6. Must explain mix of IR lines: H 2 S(0)-S(7) [Fe II], [Ne II], [Si II], [S III] PAHs, Dust continuum brightest IR clumps in 14 SNRs long-slit: remove Galactic emission Hewitt et al. 2009, Andersen et al. (submitted) Spitzer 5 to 95 μm Spectroscopy G349.7 Kes 17 IRAC 3-color images Spitzer IRS SL/LL 5-35μm R~100 Complements IRS mapping 4 SNRs (Neufeld et al.)

7. Two H 2 components (warm, hot) T(H 2 )= 320 1150 K OPR = 1.0 3.0 ● H 2 fitting with shock models (Le Bourlot 2002) V S = 10, 40 km/s n H = 10 5, 10 4 cm -3 P S = 1x10 -6, 3x10 -7 dyne cm -2 over-pressure in warm, dense clumps Multi-shock fitting: BEST FIT H 2 Excitation in Kes 69

8. Rho, Hewitt, Jarrett et al.(in prep.) H 2 Excitation in G348.5-0.0 ● Spitzer IRS + near-IR with AAT ● H 2 2-1 S(1)/1-0 S(1) Ratio [=X] ~ 7 Shock: X=12-15 (IC 443), UV pumping: X=2-4 => shock + UV pumping (Chang & Martin 1991) NIR H 2 lines

9. Para-to-ortho H 2 conversion via reactions with atomic-H: τ conv ≈ 3000 yrs [100 cm -3 /n(H)] E A /k ~ 4000 K Ortho-to-Para Ratio in Equilibrium H 2 Excitation: Ortho-to-Para warm H 2 : OPR ~ 0.4-3 equilibrium: OPR LTE ~ 3

10. Para-to-ortho H 2 conversion via reactions with atomic-H: τ conv ≈ 3000 yrs [100 cm -3 /n(H)] E A /k ~ 4000 K Ortho-to-Para Ratio in Equilibrium H 2 Excitation: Ortho-to-Para warm H 2 : OPR ~ 0.4-3 equilibrium: OPR LTE ~ 3 OPR < 3 in T H2 = 250-600 K requires τ shock < τ conv => slow C-shocks into cold, quiescent clouds; no significant pre-heating of MC Kes 69 3C396 G346.6 G348.5 G349.7 Kes 17

11. Excitation of ionic species: Fe+, Ne+, Ne++, Si+, S++ requires V S >100 km/s, n e ~10 2-3 cm -3 Ionic emission spatially segregated from H 2 along the IRS slit. => multiple shocks Fast, Dissociative Shocks Neon Line Ratio

12. Good fits obtained for Dust. T BB = 35-50 K Relative grain abundances: SNRs MW Y VSG/BG 0.23-1.0 0.13 Y PAH/BG 0.01-0.2 0.004 => Processing of grain size distribution by SNR shock Dust Emission from SNRs IRS SL/LL MIPS SED Dust continuum modeling (DUSTEM, Campiegne et al. 2008, Poster #35) Parameters: Big Grains, Very Small Grains, PAHs, and Radiation Field 0.01-0.2 μm0.001-0.01μm line-subtracted spectrum

13. Milky Way Value V S > 60 km/sV S < 60 km/s Sputtering efficient for fast shocks, affecting all grain sizes Shattering in dense/slow shocks, destroys BGs, but not VSG/PAHs Observe VSG/BG consistent with shattering, increasing with V S from Borkowski et al. 1995 Dust Processing by SNR shocks

14. Dust Heating by SNR shocks fitted ISRF ~ 20-100 Dust continuum is a significant coolant! Fit Radiation Field, case B H-recomb. (normalized to ISRF) Milky Way Value SNRs have even higher UV radiation from H-recomb (fast shocks, [Fe II])

15. 100 L Θ 1 L Θ 10 4 L Θ Dust Heating: Collisional heating unlikely. Two anomalous fits: G11.2, G344.7 require very high ISRF and silicates! Radiative Cooling: SNR/MCs G349.7 Kes20A Kes17 L H2 is ~0.6-6% of L Dust in SNR/MCs [O I] 63μm line detected in 10/14 SNRs, L [OI] /L Dust ~ 1-7% What are other coolings?

16. Fermi γ-ray detections of SNR/MCs Maser SNR subset: interaction, distance, cloud mass, n=10 5 cm -3 For π 0 -decay origin (Drury et al. 1994) F γ ~ M cloud d kpc -2 ω CR Given M cloud, d kpc : determines CR ionization rate ζ CR ≈ ω CR ζ local Maser SNRs have ω CR ~ 10-50 enhanced over local density Significant ionization, >10 -16 s -1 Kes69 G16.7 12/24 SNRs detected by Fermi (Hewitt et al. 2011) enhances n(H,e)/n(H 2 ) in C-shocks Fermi image of W44

17. Far-infrared Spectroscopy Abundances of Fe: 99% locked in grains => dust vaporized by shocks Febry-Perot spectrum of [OI] shows resolved broad line  V~100 km/s. H 2 O, OH, CO lines are detected <= from warm, dense (10 5 cm -3 ) gas O + H 2 => OH (T>400K) OH + H 2 => H 2 O Fe II ISO Reach & Rho 1996 [O I] 63μm [Fe II] 26μm Water abundance was smaller than expected relative to OH or CO

18. Herschel/SOFIA Observations of MSNRs 18 hours of Herschel time is granted 3 brightest molecular interacting SNRs What is the post-shock abundance and excitation of water, hydroxyl, CO and atomic oxygen?? What mechanism produces the observed non-equilibrium oxygen chemistry? Hershel: PACS, SPIRE, HIFI Complement with SOFIA: GREAT (1hr)

19. The violent lives of Supernova Remnants SNR shocks are a spectacular probe of molecular clouds Future directions Non-equilibrium chemistry, driven by enhanced ionization and radiation field? Both collisional and radiative cooling Chemistry. Water chemistry. Shock-induced molecule cooling and astrochemical processes Challenges of molecular astrochemistry modeling Multiple shocks, through a multi-phase cloud trace thermal history of the cloud (OPR) Radiative cooling: dust continuum, IR lines Enhanced radiation field ~20-100 x ISRF evidenced by Dust heating, H 2 UV excitation Grain processing: shattering decreases large grain size Accelerate cosmic rays yielding up to few % E SN

22. 3 km/s 300km/s SOFIA Observations of Shocks/PDRs Molecular lines: CO, OH, H 2 O Shock cooling, Ionic lines Dust Sputtering: Fe, Si [OI] [CII] velocity and mapping Shock processed PAHs Maps of dust processing

23. GREAT GREAT First Light April 6, 2011 German REceiver for Astronomy at Teraherz Frequencies (GREAT) PI: Rolf Güsten, MPIfR in Bonn M17 (Omega Nebula) CO (J=13-12, green) and [C II] (white) spectra Velocity (x-axis): from -10 to 50 km/s GREAT Spectral resolution is between 10 6 and 10 8. Efficient Scan mapping capability.

24. GREAT  OB (yellow) stars, [CII] (green) contours on VLA image (ionizing flux). Inserted CO (J=13-12) image with [CII] contours.  [CII] is ionized gas at the boundary of dense warm CO. (Perez-Beaupuits, Güsten, and GREAT team, in preparation) Lee et al. 1996 VLA image [CII] image CO (13-12) contours

25. GREAT  OB (yellow) stars, [CII] (green) contours on VLA image (ionizing flux). Inserted CO (J=13-12) image with [CII] contours.  [CII] is ionized gas at the boundary of dense warm CO. (Perez-Beaupuits, Güsten, and GREAT team, in preparation) Lee et al. 1996 VLA image [CII] image CO (13-12) contours

27. Comparison between Herschel and SOFIA far-IR instruments PACS spec FIFI-LSHIFIGREATPACS imager HAWC Wavelength range (μm) 55-21042-110, 110-220 157-213, 240-625 60, 110-125, 156-165, 200-240 55-21053, 89, 115, 216 Field of View 47’’x47’’30’’x30’’ 60’’x60’’ Single pixel Single pixel (7 pixels in future) 47’’x47’’ 27’’x72’’, 42’’x112’’, 72’’x192’’,9 6’’x256’’ Pixel size9’’6’’, 12’’13’’, 39’’20’’9’’2.3’’,3.5’’, 6’’, 8’’ Sensitivity2-5x10 -18 Wm -2 100-250mJy Similar to PACSspec within a factor of 3-5, but efficient mapping A few to 100 mK Similar to HIFI with a factor of 2-8, but efficient mapping 2-5x10 -18 Wm -2 100-250 mJy 60-120 mJy Spectral Resolution 2600-5400 (55- 72μm)900- 3000 1000- 5000 1000-10 7 10 6 -10 8 2600-5400 (55- 72μm)900- 3000 None

28. Current Schedule GREAT Short Science Flights: April 2011 FORCAST Basic Science Flights: May to June 2011 GREAT Basic Science Flights: July and September 2011 FLITECAM Verification flights: Aug 2011 Draft AO for 2nd Generation Instruments Draft AO: http://soma.larc.nasa.gov/SOFIA/sofiapbtelecon_agenda.html Anticipated proposal announcement: Mid- 2011 (it is coming soon) Asilomar meeting proceedings http://www.sofia.usra.edu/Science/workshops/asilomar.html Next Science Proposal Call Fall to Winter 2011, 300 hours observing time: open internationally FORCAST(w/grism), GREAT, FLITECAM and HIPO are scheduled to be included. Data Analysis funding is available for US Investigators

29. W44, enveloped by a molecular cloud Radiative signatures: IR-bright => shock cooling in relatively dense gas (>10 3 cm -3 ) Broad molecular lines (eg. CO 2-1) OH(1720 MHz) Masers (Hewitt et al. 2008, 2010) Catalog of SNR/MCs (Jiang et al. 2009) 34 confirmed (24 w/Masers) 11 probable 19 possible 64 of 274 Galactic SNRs (~23%) expect ~40% of SNe in field Supernova Remnants Interacting with Clouds 20cm Radio Recent Spitzer IR surveys have made the largest contribution (Reach et al. 2006; Hewitt, Rho et al. 2009; Anderson, Rho et al. 2011)

30. Spitzer GLIMPSE survey detected 18 IR-bright SNRs Colors hint at dominant cooling lines and shock type. Supernova Remnants Interacting with Clouds from Reach et al. 2006

31. Shocks into multi-phase Molecular Clouds (Chevalier 1999, Cox et al. 1999, Reach et al. 2005) How to reconcile different IR lines? multiple shocks in a multi-phase medium What about dust emission? Dense Clump Atomic Gas

32. Dust Heating by SNR shocks Collisional Heating dominates through collisions with electrons H coll ≈ 5.4 E -18 a 2 n e T 3/2 [erg/s] Radiative Heating dominates through H recomb. emission [Fe II] emitting gas: n e ~100-1000 cm -3, T=5-10 x 10 3 K Above assumes radiative field is = ISRF SNRs have even higher UV radiation from H-recomb (fast shocks, [Fe II])

33. Maser-emitting SNRsYoung SNR