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Demographics of Local Star-Forming Galaxies and Starbursts

Demographics of Local Star-Forming Galaxies and Starbursts. M82: Spitzer/CXO/HST. Primary Datasets. Spitzer Infrared Nearby Galaxies Survey (SINGS) resolved UV  radio mapping of 75 galaxies selection: maximize diversity in type, mass, IR/optical

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Demographics of Local Star-Forming Galaxies and Starbursts

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

  2. 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)

  3. 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

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

  5. The Starburst Bestiary nuclear starbursts circumnuclear starbursts clumpy irregular galaxies Ly-a galaxies E+A galaxies K+A galaxies LBGs DRGs EROs SCUBA galaxies extreme starbursts GEHRs SSCs HII galaxies ELGs CNELGs W-R galaxies BCGs BCDs LIGs, LIRGs ULIGs, ULIRGs LUVGs, UVLGs

  6. Demographics of Star-Forming Galaxies Baseline: 11 Mpc Ha + Ultraviolet Survey (11HUGS) - all known galaxies w/gas within 11 Mpc + Ursa Major cluster - companion GALEX Legacy survey coming… Quantify SF properties in terms of 3 observables: • absolute SFR (Mo/yr) • from Ha corrected for [NII], dust • SFR density, intensity (Mo/yr/kpc2) • defined as SFR/pR2SF • correlates strongly with gas density, SF timescale • normalized SFR/mass; birthrate parameter b • ratio of present SFR to average past SFR • defined here globally – integrated over galaxy • primary evolutionary variable along Hubble sequence

  7. 11HUGS/LVL Sample R = 100 pc 1 kpc 10 kpc

  8. 11HUGS Sample + HaGS + Goldmine Virgo Sample (James et al. 2003; Gavazzi et al. 2003)

  9. SFR* ~5 Mo/yr Gronwall 1998

  10. LIGs, ULIGs (Dopita et al., Soifer et al, Scoville et al) merger-driven inflows, starbursts

  11. Martin 2005, ApJ, 619, L59

  12. Mgas/tHubble Mgas/tdyn 1 O5V/3_Myr Meurer limit 0.5” @ 4 Mpc Sgas/tHubble Scrit

  13. Lecture 4 Begins Here

  14. Contributions to the global star formation budget IR-luminous: ~5-8% circumnuclear: ~3-4% BCGs, ELGs: ~5-8% Total fraction ~10-20%

  15. 108 109 1010 1011 Mo

  16. 11MPC + BCGs (Gil de Paz et al. 2003)

  17. Disk SF – Global Trends Kennicutt 1998, ARAA, 36, 189 Bendo et al. 2002, AJ, 124, 1380

  18. Kennicutt, Tamblyn, Congdon 1994, ApJ, 435, 22

  19. Sandage 1986, A&A, 161, 89

  20. Kennicutt 1998, ARAA, 36, 189

  21. Bell, de Jong 2000, MNRAS, 312, 497

  22. SFR increase reflects an increase in frequency of SF events, and a shift in the mass spectrum of single events

  23. Gas consumption • typical timescales for depletion ~few Gyr • stellar recycling of gas is significant factor!

  24. Brinchmann et al. 2004, MNRAS, 351, 1151

  25. blue sequencered sequence

  26. Kauffmann et al. 2003, MNRAS, 341, 54

  27. Lee & Kennicutt, in preparation

  28. Disk SFRs: Main Results Kennicutt 1998, ARAA, 36, 189 Brinchmann et al. 2004, MNRAS, 351, 1151 • spectra best fitted with IMF ~ Salpeter for M* > 1 Mo • SF is ubiquitous when cold gas is present - <4% S-Irr non-detects in Ha, nearly all show trace SF in UV • average SFR/mass increases by 5-10x per type bin (S0 - Sa - Sb, etc) • proportional changes in disk SF history with type - changes in frequency and characteristic mass of SF events • large residual variation in SFR within a given type • most variation in disk SFR vs B/D ratio • more strongly correlated with mean gas density • temporal SFR variations (bursts) • strong bimodality seen in SFR/mass vs galaxy mass • extension to dwarfs shows evidence for third mode • radial gradients in disk age and metallicity

  29. Janice Lee, PhD thesis

  30. Disk Star Formation Rates and Histories • evolutionary synthesis of integrated colors Tinsley 1968, ApJ, 151, 547 Searle et al. 1973, ApJ, 179, 427 Larson, Tinsley 1978, ApJ, 219, 46 • results • disk colors consistent with sequence of constant age, IMF, Z, and variable SF history y(t) • best fit for ~Salpeter IMF • spectra fit with similar model sequence Kennicutt 1983, ApJ, 272, 54

  31. Bruzual, Charlot 1993, ApJ, 405, 538

  32. starburst duty cycle in dwarf galaxies (Lee 2006)

  33. see poster by Lee et al.

  34. Application to Starburst Duty Cycles • bursts produce 20-40% of present-day SF in dwarfs • fraction of bursting dwarfs in same sample is 5-10% • the galaxies are bursting 5-10% of the time • average burst amplitude is ~4-8x the background SFR • typical burst durations are 10-100 Myr • (e.g., Gallagher, Harris, Calzetti, Zaritsky, Hunter…) • - a typical burst lasts for 0.1-1% of Hubble time • a typical galaxy bursts ~10-20 times over a Hubble time, each time producing a few percent of its stars (every 500-1000 Myr)

  35. NGC 1512 (HST)

  36. NGC 1512 (GALEX FUV/NUV)

  37. Sakamoto et al. 1999, ApJ, 525, 691 Kormendy & Kennicutt 2004, ARAA, 42, 603

  38. M82 NGC 3034

  39. Lo et al. 1987, ApJ, 312, 574

  40. IR-luminous galaxies ELS limit normal galaxies Kennicutt 1998, ARAA, 36, 189

  41. Circumnuclear Star Formation - Trends with Type ellipticals too?! Yi et al. 2005, ApJ, 619, L111 Ho et al. 1997, ApJ, 487, 595

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