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[ C II ] 158 m m Emission from Damped Ly a Systems

[ C II ] 158 m m Emission from Damped Ly a Systems. Art Wolfe and Ken Nagamine UCSD. DLAS are. Definition of Damped Ly a System (DLA): N(HI) > 2*10 20 cm -2 Distinguishing characteristic of DLAs : Gas is Neutral. DLAS are. Definition: N(HI) > 2*10 20 cm -2

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[ C II ] 158 m m Emission from Damped Ly a Systems

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  1. [C II] 158 mm Emission from Damped Lya Systems Art Wolfe and Ken Nagamine UCSD

  2. DLAS are • Definition of Damped Lya System (DLA): N(HI) > 2*1020 cm-2 • Distinguishing characteristic of DLAs : Gas is Neutral

  3. DLAS are • Definition: N(HI) > 2*1020 cm-2 • Distinguishing characteristic of DLAs : Gas is Neutral Stars form out of cold gas

  4. Relevance of DLAs for Star Formation • DLAs Dominate the Neutral Gas Content of the Universe at z=[0,5] • Gas Content of DLAs at z=[3,4] Accounts for current visible Mass • DLAs Serve as Important Neutral Gas Reservoirs for Star Formation

  5. DLAs Dominate the Neutral Gas Content of the Universe at z=[0,5] • Gas Content of DLAs at z=[3,4] Accounts for current visible Mass • DLAs Serve as Important Neutral Gas Reservoirs for Star Formation Mass per unit Comoving Volume versus redshift

  6. DLAs Dominate the Neutral Gas Content of the Universe at z=[0,5] • Gas Content of DLAs at z=[3,4] Accounts for current visible Mass • DLAs Serve as Important Neutral Gas Reservoirs for Star Formation Current Visible Matter Neutral Gas at High z

  7. HIRES Metal-line Velocity Profiles in DLAs • High-resolution spectroscopy on very large telescopes can yield quantitative information about DLAs: • Cooling Rates • Star formation rates. Nucleosynthesis Chemistry Thermal Pressure Nucleosynthesis Dust & Nucleosynthesis Kinematics SFRs Nucleosynthesis

  8. Obtaining Cooling Rates from CII* Absorption • [C II] 158 micron transition dominates cooling of neutral gas in Galaxy ISM • Spontaneous emission rate per atom lc=nL[CII] obtained from strength of 1335.7 absorption and Lyman alpha absorption • Thermal equilibrium condition lc= Gpe gives heating rate per atom

  9. [C II] 158 micron Emission rates vs N(H I) • Median lc=10-26.6 ergs s-1 H-1 for positive Detections • Upper limits tend to have low N(H I) • DLA lc values about 30 times lower than for Galaxy: explained by lower dust content and similar SFRs per unit area

  10. Effect of Adding Local FUV Heating

  11. An LBG Galaxy Associated with a DLA (Moller etal ‘02) [O III] Emission Lya Emission 8.4 kpc CII* Absorption

  12. [C II] contours superposed on 6.75 mm Image

  13. [C II] Flux Densities Predicted for DLAs

  14. Predicted Sn0 for DLA 2206-19A • 3s Alma limit for 20 hr integration time • 90 % Mass range predicted for CDM Models of DLAs • MH I =mDM

  15. Tentative lc versus Dv relation • DLA2206-19A • CDM Models predict Dv = 0.6vc • M=vc3/10GH(z)

  16. DLA2206-19A • Sn0impliedfor Mass predicted by lc versus Dv relation

  17. 608 MHz VLBI Map of PKS 0458-02 17 kpc

  18. Single-Dish versus VLBI 21 cm Absorption profiles for DLA 0458-02 at z=2.0394

  19. Alma Sensitivity for Detection of C II Emission • Lower Limit for DLA0458-02 for MH I=1010 Msun

  20. Predicted Sn0 for full Sample • “Redshift Desert’’ • CNM confirmed by absence of Si II* 1264 absorption

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