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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

slide5

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

slide9

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

slide10
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

slide12

Building an Evolutionary Synthesis Model

+

Kurucz 1979, ApJS, 40, 1

single star SED evolution model

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

slide13

“single burst models” “continuous star formation” models

(single age star clusters)

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

slide14

apply evolutionary synthesis maodels to constrain IMF

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

uv dust and age
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)

slide16

Blue= starbursts

Red= normal SF

26

slide17

M51Calzetti et al. 2005, ApJ, 633, 871

FUV,Ha, 24mm

3.6,4.5,5.8, 8.0mm

slide19

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)

local h a surveys
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

slide23

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)

slide24

Leakage of Ionizing Flux at z ~ 3

Shapley et al. 2006, ApJ, 651, 688

slide25

composite spectrum

Shapley et al. 2006, ApJ, 651, 688

slide26

galaxies (integrated fluxes)

HII regions

Calzetti et al., ApJ, submitted

Kennicutt & Moustakas, in prep

slide27

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

slide31

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)

dust emission
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
fir to sfr
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

slide37

NGC 628

(M74)

C. Tremonti

slide39

galaxies (integrated fluxes)

HII regions

Calzetti et al. 2007

Kennicutt & Moustakas 2007

slide40

GALEX FUV + NUV (1500/2500 A)

Ha + R

IRAC 8.0 mm

MIPS 24 mm

slide41

M81

Ha + R

slide42

M 81

24µm

70µm

160µm

slide43

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

slide44

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)

general points and cautions
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.
slide48

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)

slide49

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

slide50

Spitzer Local Volume Legacy

  • 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

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

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
slide53

11HUGS/LVL Sample

R = 100 pc

1 kpc

10 kpc

slide54

11HUGS Sample + HaGS + Goldmine Virgo Sample

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

slide55

SFR* ~5 Mo/yr

Gronwall 1998

slide61

Mgas/tHubble

Mgas/tdyn

1 O5V/3_Myr

Meurer limit

0.5” @ 4 Mpc

Sgas/tHubble

Scrit

slide62

Lecture 2 Ended Here

Extra Slides Follow

(from Lecture 4)

slide63

108

109

1010

1011 Mo

slide65

11HUGS Sample + HaGS + Goldmine Virgo Sample

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

disk sfrs main results
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
disk star formation rates and histories
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

slide70

Disk SF – Global Trends

Kennicutt 1998, ARAA, 36, 189

Bendo et al. 2002, AJ, 124, 1380

slide74

Bell, de Jong 2000,

MNRAS, 312, 497

slide75
Gas consumption
    • typical timescales for depletion ~few Gyr
    • stellar recycling of gas is significant factor!
slide77

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

slide81

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
slide89

NGC 1512

(GALEX FUV/NUV)

slide90

Sakamoto et al. 1999, ApJ, 525, 691

Kormendy & Kennicutt 2004, ARAA, 42, 603

slide91

M82

NGC 3034

slide95

IR-luminous galaxies

ELS limit

normal galaxies

Kennicutt 1998, ARAA, 36, 189

slide96

Circumnuclear Star Formation - Trends with Type

ellipticals too?!

Yi et al. 2005,

ApJ, 619, L111

Ho et al. 1997, ApJ, 487, 595

slide100

Contributions to the global star formation budget

IR-luminous: ~5-8%

circumnuclear: ~3-4%

BCGs, ELGs: ~5-8%

Total fraction ~10-20%

slide101

total

IR-luminous

starbursts

L’Floch et al. 2005, ApJ, 632, 169

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