1. The Cosmic Star Formation
and Metallicity History
Lisa Kewley
Hubble Fellow
U. Hawaii
with C. Kobulnicky (U.Wyoming), S. Ellison (U. Vic),
M. Geller (CfA), R. Jansen (ASU)

2. Summary Motivation Star Formation Rates Cosmic Star Formation History
Metallicity diagnostics
Cosmic Metallicity History
Conclusions & Future Directions

3. Motivation Galaxy Evolution Image credit: R. Thompson, NASA
Image credit: NASA

4. Star Formation History
Madau et al. (1996)
Lilly et al. (1996)
Madau - Hubble Deep Field
Lilly - Canada France Redshift Survey

5. Optical Spectrum SFR measured in infrared, optical, radio, UV, X-rays
[OII]

6. Optical Spectrum disagreement
SFR measured in infrared, optical, radio, UV, X-rays
disagreement

7. Star Formation Rate Discrepancies
Teplitz et al. (2003)
filled = [OII]
unfilled = Ha

8. Star Formation Rate Discrepancies
Teplitz et al. (2003)
Norman et al. (2003) UV
[OII] Ha IR
radio
comb * + x
-0.5
-1.5 -1 -2
-2.5
0.2
0.4
0.6
0.8
SFR
Density
log (MO / yr / Mpc3) .
Redshift

9. Towards SFR agreement Nearby Field Galaxy Survey (NFGS)
Jansen et al. (2000,2001)
198 galaxies objectively selected from the CfA galaxy survey
(Davis & Peebles 1983, Huchra et al. 1983)
full range in Hubble type
full range of absolute magnitudes in CfA survey
integrated optical spectra

10. Measuring Star Formation Rates
Infrared
SFRIR = 4.5 x x LIR
e.g., Kennicutt (1998)
NASA/JPL-Caltech/S. Willner (CfA)
Assumptions:
young stars dominate emission
large optical depth
continuous burst model
Salpeter IMF

11. Measuring Star Formation Rates
Optical : Ha
SFRHa = 7.9 x x LHa
e.g., Kennicutt (1998)
Image credit: Fabio Bresolin (U. Hawaii)
Assumptions:
no dust
total re-emission of ionizing photons
Salpeter IMF

12. Ha vs. Infrared SFRs SFR(IR) SFR (Ha) Kewley et al.
(2002, AJ, 124, 3135)
SFR(IR)
SFR (Ha)

13. Star Formation Rate Discrepancies
Teplitz et al. (2003)
filled = [OII]
unfilled = Ha

14. [OII] SFR SFR([OII]) = (1.4 +/- 0.4) x 10-41 x L([OII])
(Kennicutt 1998, 1992)
Key Assumptions:
Observed [OII]/Ha = 0.6
Observed [NII]/Ha = 0.5 (blended)
No effect from ionization state of gas
Independent of metallicity
Salpeter IMF

15. [OII] & Ha SFRs rms = 0.11 SFR [OII] SFR (Ha) Kewley, Geller, & Jansen
(2004, AJ, 127, 2002)
0.01
100
1.0
SFR (Ha)
0.4
ratio
-0.4
SFR
[OII]

16. [OII] SFR SFR([OII]) = (1.4 +/- 0.4) x 10-41 x L([OII])
(Kennicutt 1998, 1992)
Key Assumptions:
Observed [OII]/Ha = 0.6
Observed [NII]/Ha = 0.5 (blended)
No effect from ionization state of gas
Independent of metallicity
Salpeter IMF

17. Ionizing Radiation Field
Starburst99
(Leitherer et al. 1999, Crowther et al. 2006)
Instantaneous & Continuous
Burst Models
Extended Wolf-Rayet
Atmospheres

18. Photoionization Models
Kewley et al. (2001)
Mappings III - radiative transfer including dust
Sutherland & Dopita 1993, Groves et al. 2003, 2006
Metallicity: 0.05, 0.2, 0.4, 1.0, 2.0 x solar
Ionization Parameter: 1e7, 2e7, 4e7, 8e7, 1.5e8, 3e8 cm/s
alternative: CLOUDY (Ferland et al. 1998)
Self-consistent photoionization models to calculate radiative transfer through gas
in the presence of dust.

19. ( ) Definitions Metallicity = Gas-phase Oxygen Abundance = log +12
Solar ~ 8.7 (Allende Prieto et al. 2001)
log
( ) O H
Ionization parameter:
q = SH nH
(cm/s)
H ionizing photons/Area/s
hydrogen density

20. New [OII] calibration: Theoretical

21. New [OII] calibration: Theoretical
kHa L([OII])
SFR([OII],Z) =
a+ bZ - cZ2 + dZ3
where Z = metallicity = log(O/H)+12
Includes Metallicity & Ionization Parameter Correction
Kewley, Geller, & Jansen (2004, AJ, 127, 2002)

22. New [OII] calibration: Theoretical
rms=
(c.f. 0.11)

23. Metallicity at High-z
Lilly, Carollo & Stockton 2003: M91
0.5 < z < 1.0 : log(O/H)+12~8.9 (c.f. 8.6 locally)
Hippelein et al. (2003):
0.25 < z < 1.2 : [OII]/Ha = 0.9 (intrinsic)
our [OII]/Ha - metallicity calibration
log(O/H)+12~8.77
Teplitz et al. (2003):
0.4 < z < 1.4 : [OII]/Ha = 0.45 (observed)
= 0.83 (intrinsic)
log(O/H)+12~8.81
Luminosity
Selection
Effect

24. High-z Galaxies 0.8 < z < 1.6 Hicks et al. (2002)
0.5 < z < 1.1 Tresse et al. (2002)

25. Star Formation History
K98 [OII] SFR
inconsistent reddening correction
filled = [OII]
unfilled = Ha
data from Teplitz et al. (2003)
Our [OII] SFR
log(O/H)+12~8.6,
consistent reddening correction
also: Rosa-Gonzalez, Terlevich, &
Terlevich (2002)
Our [OII] SFR
log(O/H)+12~8.8
consistent reddening and metallicity
correction
Kewley, Geller, & Jansen (2004)

26. Metallicity History Metallicity history of star-forming galaxies
still largely theoretical.
Nagamine et al. (2001)

27. Metallicity History Galactic Winds
An idea of the extent and orientation of the galactic wind of M82 is seen in this image, which traces the ionised hydrogen (red) contained within it. The wind extends ~10,000 light years from the centre of the galaxy where the starbust is taking place. The burst of star formation powering the wind was probably caused by an interaction with the neighbouring galaxy M81 (not shown).
Image credit: FOCAS, Subaru 8.2-m Telescope, NAOJ.

28. Theoretical Metallicity History
Predicted for:
Star-forming gas
Stars
Neutral gas
Figure from Dave & Oppenheimer?
Once done, copy to end of presentation for questions about stellar metallicities and DLAs
Add a slide about stellar metallicities (Savaglio work) and DLA metallicity evolution (Ellison, Prochaska, Fall)
- also include a plot from Wild, Hewitt, Pettini work on contribution of DLAs to SF history.
e.g., Dave & Oppenheimer (2007)

29. Theoretical Metallicity History
Predicted for:
Star-forming gas
Stars
Neutral gas
Figure from Dave & Oppenheimer?
Once done, copy to end of presentation for questions about stellar metallicities and DLAs
Add a slide about stellar metallicities (Savaglio work) and DLA metallicity evolution (Ellison, Prochaska, Fall)
- also include a plot from Wild, Hewitt, Pettini work on contribution of DLAs to SF history.
e.g., Dave & Oppenheimer (2007)

30. Metallicity Diagnostics
“R23”
Kewley & Dopita (2002, ApJS, 142, 35)
Also: Pagel (1979), McCall et al. (1985), ...,
Skillman et al. (1989), McGaugh (1991),...,
Zaritsky et al. (1994), Charlot (2001), ...

31. Metallicity Diagnostics - [NII]/Ha
Kewley & Dopita (2002)
also:
Denicolo, Terlevich &
Terlevich (2002)
Pettini & Pagel (2004)
R23 and [NII]/Ha
re-parameterized
Kobulnicky & Kewley
(2004)

32. Ionization Parameter - O32
q = SH nH
(cm/s)
H ionizing photons/Area/s
hydrogen
density
Kewley & Dopita
(2002)

33. Local Samples: NFGS + SDSS
Kewley, Jansen & Geller (2005)
45,086 SDSS
star-forming galaxies
g-band covering
fraction > 20%

34. GOODS+ : 0.3 < z< 1 ~450 galaxies from: GOODS +
Lilly et al. (2003)
Kobulnicky et al. (2003)
Maier et al. (2004,05,06)
Liang et al. (2004)
Lamareille et al. (2005)
Savaglio et al. (2005)

35. GOODS+ : 0.3 < z< 1 ~450 galaxies from: GOODS +
Lilly et al. (2003)
Kobulnicky et al. (2003)
Maier et al. (2004,05,06)
Liang et al. (2004)
Lamareille et al. (2005)
Savaglio et al. (2005)

36. High-z sample 5 galaxies: 1<z<1.5 (Shapley et al. 2005)
[OII], [OIII], Hb, [NII]
7 galaxies: 2 < z < 2.5 (Shapley et al. 2004)
[NII], Ha
2 galaxies: z=2.3, 2.9 (Kobulnicky & Koo 2000)
[OII], [OIII], Hb
5 galaxies: 2.7<z<3.4 (Pettini et al. 2001)
Check what the ensemble galaxy paper is by Shapley - is it the 2004 paper?

37. Metallicity Diagnostic Discrepancies
Kewley & Ellison (2007)
SDSS mass-metallicity
relation
Tremonti et al. (2004)

38. Metallicity Diagnostic Discrepancies
Kewley & Ellison (2007)

39. Metallicity Diagnostic Discrepancies
Before:
After:
Kewley & Ellison (2007)

40. Metallicity History 0<z<3
NFGS
Lyman
Break
Galaxies
SDSS
0.15 dex/z
GOODS+
assumes
upper
branch
Kewley & Kobulnicky
(2006, in prep)

41. Metallicity History 0<z<3
Models:
Dave &
Oppenheimer (2006)
Kewley & Kobulnicky
(2006, in prep)

42. Metallicity History Bias: 0.4 < z < 1
Assumptions:
R23 upper branch
AV = 1
Kewley & Kobulnicky
(2006, in prep)

43. Solution: 0.4 < z < 1 NIR multi-object spectroscopy
Subaru - MOIRCS
observations ongoing
Soon to come:
VLT - NIRMOS (2008/2009)
Gemini-S - Flamingos-II (2008)
Magellan - MMIRS (2008)

44. Metallicity History Bias: z > 1
Color selection
BzK
Lyman Break

45. High-z Metallicity Bias?
Try alternative selection:
Lensed galaxies
GRB Hosts
[OII], [OIII] emitters
Luminous red star-forming galaxies

46. Alternative selection: Lensed Galaxies
Lemoine-Busserolle et al. (2003)
z=1.9
log(O/H)+12 ~ 7.6 +/- 0.2
log(O/H)+12 ~ 9.0 +/- 0.1

47. Metallicity History 0<z<3
Models:
Dave &
Oppenheimer (2006)
Kewley & Kobulnicky
(2006, in prep)

48. Alternative selection: GRB Hosts
Local GRB hosts may favor
low metallicity galaxies
GRB Hosts
Kewley et al. (2006)

49. SFR Conclusions Agreement between SFRIR and SFRHa
Discrepancy between SFR[OII] and SFRHa:
reddening and metallicity
New theoretical SFR[OII] calibration removes
this discrepancy
... but what if metallicity changes with redshift?

50. Metallicity Conclusions
Metallicity History for star-forming galaxies
Metallicity evolution observed
First comparison with appropriate metallicities
from cosmological hydrodynamic simulations
Steeper Metallicity evolution predicted
More work needed for robust metallicity history...

51. Future Directions GOODS Near-IR Spectra Near future:
Subaru - MOIRCS - observations ongoing
: VLT, Magellan, Gemini-S
COS: UV spectra => Si, N, C, abundances
Modelling of emission-line + other selection effects
Investigate alternative selection methods
Near future:

52. Future Directions NIRSpec: faint More distant future: JWST
galaxies z > 1
NIRSpec + MIRI:
metallicity for z > 3
More distant future:
JWST
Microshutter Assembly - thousands of microshutters of NIRspec will allow many galaxies to be obtained spectroscopically at once. For example, in the same J-band spectrum, NIRspec will be able to simultaneously observe [NII]/Ha for galaxies at 0.4<z<1, [OIII]/Hb for galaxies at z= In H-band, [NII]/Ha could be obtained for those galaxies, as well as [OII] for galaxies at z~3. In K, [OIII], Hb would be obtained for the z~3 galaxies. MIRI would be required for galaxies at redshifts > 3.

53. Future Directions NIRSpec: faint galaxies More distant future: JWST
z > 1
NIRSpec + MIRI:
metallicity for z > 3
More distant future:
JWST
NIRSpec
NIRSpec + MIRI

54. Future Directions NIRSpec, MIRI More distant future: JWST
metallicity for z > 1
FGS-TFI metallicity
gradient evolution
More distant future:
JWST
JWST simulation: Windhorst, Conselice & Petro

55. Future Directions NIRSpec, MIRI
metallicity for z > 1
FGS-TFI metallicity
gradient evolution
More distant future:
JWST
Link SF & metallicity history through chemical
evolution & galactic wind models
JWST simulation: Windhorst, Conselice & Petro

56. Starburst99-Mappings On-Line L. Kewley & C. Leitherer
Available Now!
Starburst99-Mappings On-Line L. Kewley & C. Leitherer
Starburst99-Mappings Interface:
Mappings Interface:
Pre-run model grids
Interactive web form to run models

57. AGN Removal
Kewley et al. 2001, 2006

58. AGN Removal
Kewley, Heckman, & Kauffmann (in prep)

59. Aperture Effects Large scatter => SFR errors unless integrated
spectra are used
Kewley, Geller, & Jansen 2004
PASP, submitted
covering fraction

60. Alternative selection: Lensed Galaxies
Lemoine-Busserolle et al. (2003)
z=1.9
log(O/H)+12 ~ 7.6 +/- 0.2
log(O/H)+12 ~ 9.0 +/- 0.1

61. Alternative selection: GRB Hosts
Kewley, Brown & Geller (2006)
Stanek et al. (2006)

62. IR SFRs SFR(IR) = 4.5 x 10-44 L(IR) 7.9 x 10-44 L(FIR) ~
(Kennicutt 1998, Calzetti et al. 2000)
Assumptions:
young stars dominate emission
large optical depth
continuous burst model
Saltpeter IMF

63. [OII]/Ha & Reddening

64. [OII] and metallicity

65. Measuring Star Formation Rates
Infrared
SFRIR = kIR x LIR
e.g., Kennicutt (1998)
Figure credit: Dale et al. (2001)
See also Sanders & Mirabel (1996)

66. Metallicity at Higher redshift
Lilly, Carollo & Stockton (2003)
Luminosity
Selection
Effect
0.5 < z < 1.0 CFRS
log(O/H)+12~8.9
local NFGS:
log(O/H)+12~8.6

67. High-z Galaxies 0.8 < z < 1.6 Hicks et al. (2002)
0.5 < z < 1.1 Tresse et al. (2002)

68. [OII] and luminosity
Jansen et al. (2001)

69. Why are SFRs important?
Galaxy evolution models
Age, metallicity, SED
Star formation history
of galaxies
Measured in infrared, optical, radio, UV, X-rays