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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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Multi wavelength sfr diagnostics
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



GALEX FUV + NUV (1500/2500 A)

Ha + R

IRAC 8.0 mm

MIPS 24 mm


Spitzer infrared nearby galaxies survey sings
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



  • 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


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


Steidel et al. 1996,

ApJ, 462, L17


Building an Evolutionary Synthesis Model

+

Kurucz 1979, ApJS, 40, 1

single star SED evolution model

Maeder, Meynet 1988, A&AS, 76, 411


“single burst models” “continuous star formation” models

(single age star clusters)

Leitherer et al. 1999, ApJS, 123, 3 “Starburst99”


apply evolutionary synthesis maodels to constrain IMF star formation” models

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


Uv dust and age
UV, Dust, and Age star formation” models

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)


Blue= starbursts star formation” models

Red= normal SF

26


M51 star formation” modelsCalzetti et al. 2005, ApJ, 633, 871

FUV,Ha, 24mm

3.6,4.5,5.8, 8.0mm


Photoionization Methods: Emission Lines star formation” models

  • 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)


Kennicutt 1992, ApJS, 79, 255 star formation” models


Local h a surveys
Local H star formation” modelsa 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


Photoionization Methods: Emission Lines star formation” models

  • 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)


Leakage of Ionizing Flux at z ~ 3 star formation” models

Shapley et al. 2006, ApJ, 651, 688


composite spectrum star formation” models

Shapley et al. 2006, ApJ, 651, 688


galaxies (integrated fluxes) star formation” models

HII regions

Calzetti et al., ApJ, submitted

Kennicutt & Moustakas, in prep


  • Other Emission Lines star formation” models

    • - 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


Wavelength star formation” models



Moustakas et al. 2006, ApJ, 642, 775 star formation” models


11 Mpc Ha/Ultraviolet Survey star formation” models (11HUGS)

SINGG: Survey for Ionization in Neutral-Gas Galaxies

SINGG: Survey for Ionization in Neutral-Gas Galaxies

M83 = NGC 5236 (Sc)


Lecture 2 Begins Here star formation” models


Dust emission
Dust Emission star formation” models

  • 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


Fir to sfr
FIR to SFR? star formation” models

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


NGC 628 star formation” models

(M74)

C. Tremonti


Moustakas et al. 2006, ApJ, 642, 775 star formation” models


galaxies (integrated fluxes) star formation” models

HII regions

Calzetti et al. 2007

Kennicutt & Moustakas 2007


GALEX star formation” modelsFUV + NUV (1500/2500 A)

Ha + R

IRAC 8.0 mm

MIPS 24 mm


M81 star formation” models

Ha + R


M 81 star formation” models

24µm

70µm

160µm


Radio Continuum Emission star formation” models

  • 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


Cookbook star formation” models

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)


General points and cautions
General Points and Cautions star formation” models

  • 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.


Demographics of local star forming galaxies and starbursts
Demographics of Local Star-Forming Galaxies and Starbursts star formation” models

M82: Spitzer/CXO/HST


Primary Datasets star formation” models

  • 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)


Thanks to: star formation” models

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


Spitzer Local Volume Legacy star formation” models

  • UV/Ha/IR census of local volume

    • HST ANGST sample to 3.5 Mpc

    • GALEX 11HUGS sampel to 11 Mpc


The starburst bestiary
The Starburst Bestiary star formation” models

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


Demographics of star forming galaxies
Demographics of Star-Forming Galaxies star formation” models

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


11HUGS/LVL Sample star formation” models

R = 100 pc

1 kpc

10 kpc


11HUGS Sample + H star formation” modelsaGS + Goldmine Virgo Sample

(James et al. 2003; Gavazzi et al. 2003)


SFR star formation” models* ~5 Mo/yr

Gronwall 1998


LIGs, ULIGs star formation” models(Dopita et al., Soifer et al, Scoville et al)

merger-driven

inflows, starbursts


Martin 2005, ApJ, 619, L59 star formation” models


M star formation” modelsgas/tHubble

Mgas/tdyn

1 O5V/3_Myr

Meurer limit

0.5” @ 4 Mpc

Sgas/tHubble

Scrit


Lecture 2 Ended Here star formation” models

Extra Slides Follow

(from Lecture 4)


10 star formation” models8

109

1010

1011 Mo


11MPC + BCGs (Gil de Paz et al. 2003) star formation” models


11HUGS Sample + H star formation” modelsaGS + Goldmine Virgo Sample

(James et al. 2003; Gavazzi et al. 2003)


Disk sfrs main results
Disk SFRs: Main Results star formation” models

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


Disk star formation rates and histories
Disk Star Formation Rates and Histories star formation” models

  • 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


Bruzual, Charlot 1993, ApJ, 405, 538 star formation” models


Kennicutt 1992, ApJS, 79, 255 star formation” models


Disk SF – Global Trends star formation” models

Kennicutt 1998, ARAA, 36, 189

Bendo et al. 2002, AJ, 124, 1380



Sandage 1986, A&A, 161, 89 star formation” models


Kennicutt 1998, ARAA, 36, 189 star formation” models


Bell, de Jong 2000, star formation” models

MNRAS, 312, 497


  • Gas consumption star formation” models

    • typical timescales for depletion ~few Gyr

    • stellar recycling of gas is significant factor!


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



blue sequence red sequence



Lee & Kennicutt,

in preparation





Application to starburst duty cycles
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)


Disk sfrs main results1
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



NGC 1512

(GALEX FUV/NUV)


Sakamoto et al. 1999, ApJ, 525, 691

Kormendy & Kennicutt 2004, ARAA, 42, 603


M82

NGC 3034



IR-luminous galaxies

ELS limit

normal galaxies

Kennicutt 1998, ARAA, 36, 189


Circumnuclear Star Formation - Trends with Type

ellipticals too?!

Yi et al. 2005,

ApJ, 619, L111

Ho et al. 1997, ApJ, 487, 595



Contributions to the global star formation budget

IR-luminous: ~5-8%

circumnuclear: ~3-4%

BCGs, ELGs: ~5-8%

Total fraction ~10-20%


total

IR-luminous

starbursts

L’Floch et al. 2005, ApJ, 632, 169


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