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Quasar Absorption Lines

Quasar Absorption Lines. Tracing Cosmic Structure Growth & Galaxy Evolution Over Cosmic Time. Motivations and Astrophysical Context. Mg II arises in environments ranging over five decades of N(HI). Statistical Cross-Sections, n s. DLAs: N(HI)>2 x 10 20 cm -2.

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Quasar Absorption Lines

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  1. Quasar Absorption Lines Tracing Cosmic Structure Growth & Galaxy Evolution Over Cosmic Time

  2. Motivations and Astrophysical Context Mg II arises in environments ranging over five decades of N(HI) Statistical Cross-Sections, ns • DLAs: N(HI)>2x1020 cm-2 Giant molecular clouds?; 0.1 L* and LSB galaxies with wide range of morphologies; intergalactic clumps; ns~15 kpc; black-bottom absorption with Dv~200 km s-1; average C IV absorption (eg. Le Brun et al 1997; Rao & Turnshek 2000; Bouche’ etal 2000; cwc etal (II) 2000) • LLSs: N(HI)>2x1017 cm-2 “Normal” HSB galaxies with >0.1 L*; ns~40 kpc; complex kinematics with “high velocity” components with Dv~100-400 km s-1; range of C IV absorption (eg. Steidel et al 1994; cwc etal 1996; cwc 1997; cwc & Vogt 2000) Sub-LLS assuming F*=0.03 h3 Mpc-3 • sub-LLSs: N(HI)<6x1016 cm-2 “forest clouds”? LSB galaxies?; dwarf galaxies?; few associated with HSB galaxies; mostly single unresolved clouds; ns~70 kpc; sizes ~10 pc to 1 kpc; Z>0.1 solar; [a/Fe]~0 to +0.5; Cf~0.15; range of C IV absorption (eg. cwc & Le Brun 1998; cwc etal ApJS 1999 ; Rigby etal 2001) Mg II selects a wide range of astrophysical sites, which can be traced from redshift 0 to 5

  3. What the sensitivity and resolution buy… Steidel & Sargent (1992) cwc (1997); cwc & Charlton (1999)

  4. cwc & Charlton 1999

  5. cwc 2001

  6. Statistically, Profiles are Consistent with … Monte-Carlo Models of Absorbing Galaxies (Charlton & cwc 1998) What is probability distribution for such models? Assume r~r-2 probability distribution of clouds in disk and in halo Assume Vrot=Vinfall kinematics of clouds in disk and in halo

  7. Voigt Profiles cwc (1997); cwc, Vogt, & Charlton, ApJ, (2001) Assume minimum number of components that are statistically significant (MINFIT). Parameterization does not account for asymmetric line-of-sight streaming motion.

  8. “Weak Systems” • Single Clouds, Wr(MgII)<0.3 A, isolated • in redshift • Unresolved line widths at 6 km s-1 • Power law equivalent width distribution • down to Wr(MgII)=0.02 A cwc etal, ApJS (1999) Steidel & Sargent (1992)

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