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Background Slides from Lecture 1

Background Slides from Lecture 1. Multi-Wavelength SFR Diagnostics. `calorimetric’ IR.  (  m) 1 10 100 1000. 24  m. 70  m. 160  m. 8  m. [OII]. P . H . UV.

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Background Slides from Lecture 1

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  1. Background Slides from Lecture 1

  2. Multi-Wavelength SFR Diagnostics `calorimetric’ IR  (m) 1 10 100 1000 24 m 70 m 160 m 8 m [OII] P H UV Dale et al. 2007, ApJ, 655, 863

  3. 0.1 1 10 100 mag (AV)

  4. GALEX FUV + NUV (1500/2500 A) Ha + R IRAC 8.0 mm MIPS 24 mm

  5. Spitzer Infrared Nearby Galaxies Survey (SINGS) • complete IRAC, MIPS imaging of 75 nearby galaxies (3.5 – 160 mm) • IRS, MIPS radial strip maps (10 – 100 mm) • IRS maps of centers, 75 extranuclear sources (5–37 mm) • ancillary imaging campaign covering UV to radio Kennicutt et al. 2003, PASP, 115, 928

  6. UV Continuum Emission

  7. Ultraviolet stellar continuum: key advantages • direct photospheric measure of young massive stars • primary groundbased SFR tracer for galaxies at z>2 • However: • heavily attenuated by dust. Dust `correction’ methods have limits (age-dust degeneracy). • dependent on the stellar population mix, usually measures timescales of ~100 Myr. Dale et al. 2007, ApJ, 655, 863

  8. GALEX Mission - all-sky survey - 5 arcsec resolution - 1500 A, 2500 A to AB = 20-21 - 10,000 galaxies to z=0.02 - deep surveys to AB = 25.5, 26.5 - launched April 2003

  9. Steidel et al. 1996, ApJ, 462, L17

  10. Building an Evolutionary Synthesis Model + Kurucz 1979, ApJS, 40, 1 single star SED evolution model Maeder, Meynet 1988, A&AS, 76, 411

  11. “single burst models” “continuous star formation” models (single age star clusters) Leitherer et al. 1999, ApJS, 123, 3 “Starburst99”

  12. apply evolutionary synthesis maodels to constrain IMF Kennicutt, Tamblyn, Congdon 1994, ApJ, 435, 22

  13. UV, Dust, and Age 26 Starbursts A dusty stellar population may have similar UV characteristics of an old population (Calzetti et al. 1994,1995,1996,1997,2000, Meurer et al. 1999, Goldader et al. 2002)

  14. Blue= starbursts Red= normal SF 26

  15. M51Calzetti et al. 2005, ApJ, 633, 871 FUV,Ha, 24mm 3.6,4.5,5.8, 8.0mm

  16. Photoionization Methods: Emission Lines • for ionization-bounded region observed recombination line flux scales with ionization rate • ionization dominated by massive stars (M > 10 Mo), so nebular emission traces SFR in last 3-5 Myr • ionizing UV reprocessed through few nebular lines, detectable to large distances • only traces massive SFR, total rates sensitive to IMF extrapolation • SFRs subject to systematic errors from extinction, escape of ionizing radiation from galaxy SINGG survey, G. Meurer et al. (NOAO)

  17. Kennicutt 1992, ApJS, 79, 255

  18. Local Ha Surveys Survey Ngal Selection PI GOLDMine 277 magnitude Coma/VirgoG. Gavazzi MOSAIC ~1000 HaAbell clustersR. Kennicutt HaGS 450 mag/volume field (<40 Mpc)P. James SINGG/SUNGG*468 HIPASS field (<40 Mpc)G. Meurer STARFORM 150 volume field (<25 Mpc)S. Hameed 11HUGS ***470 volume field (<11 Mpc)R. Kennicutt AMIGA ~270 magnitude isolatedfieldL. Montenegro SINGS ***75 multi-param<30 Mpc R. Kennicutt SMUDGES ~1000 mag field dwarfs L. van Zee UCM 376 objprism field J. Gallego KISS ~2200obj prismfield J. Salzer ** paired GALEX survey

  19. Photoionization Methods: Emission Lines • for ionization-bounded region observed recombination line flux scales with ionization rate • ionization dominated by massive stars (M > 10 Mo), so nebular emission traces SFR in last 3-5 Myr • ionizing UV reprocessed through few nebular lines, detectable to large distances • only traces massive SFR, total rates sensitive to IMF extrapolation • SFRs subject to systematic errors from extinction, escape of ionizing radiation from galaxy SINGG survey, G. Meurer et al. (NOAO)

  20. Leakage of Ionizing Flux at z ~ 3 Shapley et al. 2006, ApJ, 651, 688

  21. composite spectrum Shapley et al. 2006, ApJ, 651, 688

  22. galaxies (integrated fluxes) HII regions Calzetti et al., ApJ, submitted Kennicutt & Moustakas, in prep

  23. Other Emission Lines • - Hb (0.48 mm) • - Paschen-a (1.9 mm) • - Brackett-g (2.2 mm) • - [OII] (0.37 mm) • - Lyman-a (0.12 mm) Scoville et al. 2000, AJ, 122, 3017

  24. Wavelength

  25. Moustakas, Kennicutt, Tremonti 2006, ApJ, 642, 775

  26. Moustakas et al. 2006, ApJ, 642, 775

  27. 11 Mpc Ha/Ultraviolet Survey (11HUGS) SINGG: Survey for Ionization in Neutral-Gas Galaxies SINGG: Survey for Ionization in Neutral-Gas Galaxies M83 = NGC 5236 (Sc)

  28. Lecture 2 Begins Here

  29. Dust Emission • Interstellar dust absorbs ~50% of starlight in galaxies, re-radiates in thermal infrared (3–1000 mm) • Provides near-bolometric measure of SFR in dusty starbursts, where absorbed fraction ~100% • Largest systematic errors from non-absorbed star formation and dust heated by older stars • Different components of IR trace distinct dust species and stellar sub-populations

  30. FIR to SFR? Dale et al. 2007 `calorimetric’ IR  (m) 1 10 100 1000 24 m 70 m 160 m 8 m FIR - sensitive to heating from old stellar populations 8 m - mostly single photon heating (PAH emission) 24 m - both thermal and single photon heating 70 m and 160 m - mostly thermal, also from old stars

  31. NGC 628 (M74) C. Tremonti

  32. Moustakas et al. 2006, ApJ, 642, 775

  33. galaxies (integrated fluxes) HII regions Calzetti et al. 2007 Kennicutt & Moustakas 2007

  34. GALEX FUV + NUV (1500/2500 A) Ha + R IRAC 8.0 mm MIPS 24 mm

  35. M81 Ha + R

  36. M 81 24µm 70µm 160µm

  37. Radio Continuum Emission • exploits tight observed relation between 1.4 GHz radio continuum (synchrotron) and FIR luminosity • correlation may reflect CR particle injection/acceleration by supernova remnants, and thus scale with SFR • no ab initio SFR calibration, bootstrapped from FIR calibration • valuable method when no other tracer is available Bell 2003, ApJ, 586, 794

  38. Cookbook Extinction-Free Limit(Salpeter IMF, Z=ZSun) SFR (Mo yr-1) = 1.4 x 10-28 Ln (1500) ergs/s/Hz SFR (Mo yr-1) = 7.9 x 10-42 L (Ha) (ergs/s) Extinction-Dominated Limit; SF Dominated SFR (Mo yr-1) = 4.5 x 10-44 L (FIR) (ergs/s) SFR (Mo yr-1) = 5.5 x 10-29 L (1.4 GHz) (ergs/Hz) Composite: SF Dominated Limit SFR (Mo yr-1) = 7.9 x 10-42 [L H, obs + a L24m ] (erg s-1) [a = 0.15 – 0.31] SFR (Mo yr-1) = 4.5 x 10-44 [L(UV) + L (FIR)] (ergs/s)

  39. General Points and Cautions • Different emission components trace distinct stellar populations and ages • nebular emission lines and resolved 24 mm dust sources trace ionizing stellar population, with ages <5-10 Myr • UV starlight mainly traces “intermediate” age population, ages 10-200 Myr • diffuse dust emission and PAH emission trace same “intermediate” age and older stars– 10 Myr to 10 Gyr(!) • Consequence: it is important to match the SFR tracer to the application of interest • emission lines – Schmidt law, early SF phases • UV – time-averaged SFR and SFR in low surface brightness systems • dust emission – high optical depth regions • Multiple tracers can constrain SF history, properties of starbursts, IMF, etc.

  40. Demographics of Local Star-Forming Galaxies and Starbursts M82: Spitzer/CXO/HST

  41. Primary Datasets • Spitzer Infrared Nearby Galaxies Survey (SINGS) • resolved UV  radio mapping of 75 galaxies • selection: maximize diversity in type, mass, IR/optical • 11 Mpc Ha/Ultraviolet Survey (11HUGS) • resolved Ha, UV imaging, integrated/resolved IR of 400 galaxies • selection: volume-complete within 11 Mpc (S-Irr) • Survey for Ionization in Neutral-Gas Galaxies (SINGG) • resolved Ha, UV imaging, integrated/resolved IR of 500 galaxies • selection: HI-complete in 3 redshift slices • Integrated Measurements • Ha flux catalogue (+IR, UV) for >3000 galaxies within 150 Mpc - integrated spectra (+IR, UV) for ~600 galaxies in same volume(Moustakas & Kennicutt 2006, 2007)

  42. Thanks to: S. Akiyama, J. Lee, C. Tremonti, J. Moustakas, C. Tremonti (Arizona), J. Funes (Vatican), S. Sakai (UCLA), L. van Zee (Indiana) + The SINGS Team: RCK, D. Calzetti, L. Armus, G. Bendo, C. Bot, J. Cannon, D. Dale, B. Draine, C. Engelbracht, K. Gordon, G. Helou, D. Hollenbach, T. Jarrett, S. Kendall, L. Kewley, C. Leitherer, A. Li, S. Malhotra, M. Meyer, E. Murphy, M. Regan, G. Rieke, M. Rieke, H. Roussel, K. Sheth, JD Smith, M. Thornley, F. Walter

  43. Spitzer Local Volume Legacy • UV/Ha/IR census of local volume • HST ANGST sample to 3.5 Mpc • GALEX 11HUGS sampel to 11 Mpc

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