1. Galactic Gas Kinematics and High Velocity Clouds at z~1 Chris Churchill (Penn State) Mg II 2796,2803 absorption from galaxies and ??? in quasar spectra observed with HIRES/Keck

2. Chris Churchill (PSU)2 Motivations and Astrophysical Context Mg II arises in environments ranging over five decades of N(HI) DLAs: N(HI)>2 x 10 20 cm -2 LLSs: N(HI)>2 x 10 17 cm -2 sub-LLSs: N(HI)<6 x 10 16 cm -2 Statistical Cross-Sections, n  Giant molecular clouds?; 0.1 L * and LSB galaxies with wide range of morphologies; intergalactic clumps; n  ~15 kpc; black-bottom absorption with  v~200 km s -1 ; average C IV absorption (eg. Le Brun et al 1997; Rao & Turnshek 2000; Bouche’ etal 2000; cwc etal (II) 2000) “Normal” HSB galaxies with >0.1 L * ; n  ~40 kpc; complex kinematics with “high velocity” components with  v~100-400 km s -1 ; range of C IV absorption (eg. Steidel et al 1994; cwc etal 1996; cwc 1997; cwc & Vogt 2000) assuming  * =0.03 h 3 Mpc -3 “forest clouds”? LSB galaxies?; dwarf galaxies?; few associated with HSB galaxies; mostly single unresolved clouds; n  ~70 kpc; sizes ~10 pc to 1 kpc; Z>0.1 solar; [  /Fe]~0 to +0.5; C f ~0.15; range of C IV absorption (eg. cwc & Le Brun 1998; cwc etal ApJS 1999 ; Rigby etal 2001) Sub-LLS Mg II selects a wide range of astrophysical sites, which can be traced from redshift 0 to 5

3. Chris Churchill (PSU)3 Redshift and Sensitivity Coverage W min = 0.3  ; 0.3<z<2.2 (Steidel & Sargent 1992) W min = 0.02  ; 0.4<z<1.4 (cwc etal, ApJS 1999)

4. Chris Churchill (PSU)4 What the sensitivity and resolution buy… Steidel & Sargent (1992) cwc (1997); cwc & Charlton (1999)

5. Chris Churchill (PSU)5 How to objectively quantify rich, complex kinematics? Multiple subsystems Complex subcomponents Overall kinematics Subsystem kinematics Comparative subsystem kinematics Define “kinematic subsystems” and then measure their relative velocities, equivalent widths, velocity widths, and asymmetries Conventional Voigt profile fitting- which yields subcomponent column densities, Doppler widths, and velocities; however…

6. Chris Churchill (PSU)6 Voigt Profiles: Do you believe them? Assume minimum number of components that are statistically significant (MINFIT). Parameterization does not account for asymmetric line-of-sight streaming motion. cwc (1997); cwc, Vogt, & Charlton, ApJ, (2001)

7. Chris Churchill (PSU)7 cwc & Vogt, 2000, AJ, submitted B: 0.30-0.59 A C: 0.60-0.99 A E: >1.0 A

8. Chris Churchill (PSU)8

9. 9 cwc 2001

10. Chris Churchill (PSU)10 Statistically, Profiles are Consistent with … (Charlton & cwc 1998) Monte-Carlo Models of Absorbing Galaxies What is probability distribution for such models? Assume  ~r -2 probability distribution of clouds in disk and in halo Assume V rot =V infall kinematics of clouds in disk and in halo

11. Chris Churchill (PSU)11 Column Density per Unit Velocity Interval Probability Distribution For Disk+Halo Model Observed Distribution For Selected Sample C Systems cwc & Vogt 2000

12. Chris Churchill (PSU)12 “Moderate-” to “High-Velocity” Clouds Equivalent Width vs. VelocityVelocity Width vs. Velocity Dominant, or “main” kinematic subsystem Moderate-velocity 40<v<160 km s -1 High-velocity v>160 km s -1 What you do not see is multiple >0.3  subsystems; only single >0.3  subsystems with weak clouds having velocities from 40-400 km s -1 cwc & Vogt (2000)

13. Chris Churchill (PSU)13 There is a paucity of “small” intermediate- and high-velocity kinematic subsystems (clouds) … Equivalent WidthsColumn Densities Turnover below W r =0.08  for v>40 km s -1 kinematic subsystems cwc & Vogt (2000)

14. Chris Churchill (PSU)14 cwc & Charlton 1999

15. Chris Churchill (PSU)15 cwc etal II (2000) The Kinematics of C IV Absorption

16. Chris Churchill (PSU)16 cwc etal, ApJL (1999)

17. Chris Churchill (PSU)17 Weak Galactic HVCs: Clouds with N(HI)<10 17 cm -2 ?

18. Chris Churchill (PSU)18 1.HST/STIS Cycle 9 Program: 22, 0.4<z<1.4 Systems with R=30,000 2.HST/STIS Cycle 10 Proposed: 30 Galactic Systems with R=30,000 NEEDED: High Resolution C IV, C II, Si IV, Si II, Lyman-series, etc. Study weak systems and hvc components, ionization conditions, metalicities, And kinematics Proposed Program Rosetta Stone for high z Chart low N(HI) HVCs Kinematic substructure in known large N(HI) HVCs Trends with sky location Aitoff Projection showing sky locations of proposed extragalactic lines of sight through the Galaxy

19. Chris Churchill (PSU)19 Q. Where Can We Get Further Clues? A. The population of “weak systems” Summary: Moderate- to High-Velocity Subsytems 1. They are weak compared to the dominant subsystem 2. There is a cut off below N(MgII)=10 11.8 cm -2 3. The C IV absorption strength is proportional to their kinematic spread Are these high redshift analogues of Galactic HVCs? 4. Overall profile asymmetries are consistent with a model in which their kinematics is symmetric about an offset, dominant subsystem

20. Chris Churchill (PSU)20 “Weak Systems” Single Clouds, W r (MgII)<0.3 , isolated in redshift Unresolved line widths at 6 km s -1 Power law equivalent width distribution down to W r (MgII)=0.02  cwc etal, ApJS (1999) Steidel & Sargent (1992)

21. Chris Churchill (PSU)21

22. Chris Churchill (PSU)22 Weak Systems are Optically Thin, i.e. N(HI)<10 17 cm -2 StatisticalDirect Measurements of Lyman Limit W r (MgII)=0.3  cwc etal I (2000)

23. Chris Churchill (PSU)23 Statistically, Weak Systems Z>0.1 Solar cwc etal, ApJS (1999) Photo-ionization models (Cloudy) for Z=0.1 solar metalicity Grid moves down 1:1 with decreasing Z; Lower Z implies higher N(HI). log N(HI), cm -2 log U, = n  /n H Line core F/F c =0.5 for unresolved line is log N(MgII) = 12.5 cm -2

24. Chris Churchill (PSU)24 Variations in Fe II and in C IV indicate wide range of ionization parameters/densities When both Fe II and C IV are strong, multiphase conditions are suggested, inferred to be due to different densities. Ionization Conditions Constrained by Fe II and C IV 0.5 dex uncertainty in [  /C] is ~0.2 dex uncertainty in ionization parameter, U Rigby, Charlton, & cwc (2001) 0.5 dex uncertainty in [  /Fe] is ~2.5 dex uncertainty in U for log U < -2.5

25. Chris Churchill (PSU)25 +.5 Isolated weak Moderate- High-Velocity Fe II Variations: Ionization or Abundance? Single, unresolved only When upper limits on C IV are stringent, then we have an upper limit on ionization parameter, and thus an upper limit on [  /Fe] Typically, we have Si II, Si III, Si IV, C II, C III and/or Ly  Abundance [  /Fe]~.5 [Fe/H]<-1 [  /Fe]~0 [Fe/H]>-1 Star formation chronometer

26. 26 alignedaligned + blended + offset Strong: blended +offset offset

27. Chris Churchill (PSU)27 Weak System Clouds Optically thin to neutral hydrogen (direct evidence) Variations in N(FeII)/N(MgII) and N(CIV)/N(MgII) Multiphase Ionization Conditions; sometimes kinematically aligned Metalicities commonly solar, almost always greater than 0.1 solar [  /Fe]=0 abundance pattern, rare for  -group enhancement Cloud “sizes” follow power-law distribution- no lower cut off to 0.02  Typically not within 40 kpc (projected) of normal, bright galaxies Covering Factor, C f <0.1 Sizes, D~10-100 pc n(weak)/n(galaxies) ~ 10 6 (!) What they are depends upon how they cluster wrt Galaxies Dwarf Galaxies? Super Star Clusters? IGM condensations?

28. Chris Churchill (PSU)28 Intermediate- High-Velocity “Clouds” Optically thin to neutral hydrogen (indirect evidence) Variations in N(FeII)/N(MgII) {need high resolution C IV} Arise in regions coincident with broad C IV absorption (multiphase) Metalicities commonly solar, almost always greater than 0.1 solar [  /Fe]=0 abundance pattern common, some can be  -group enhanced Cloud “sizes” follow power law, but with lower cut off at 0.08  Typically within 40 kpc (projected) of normal, bright galaxies Clues to be sought with z=0 Galactic HST Program

29. Chris Churchill (PSU)29 Redshift and Sensitivity Coverage W min = 0.3  ; 0.3<z<2.2 (Steidel & Sargent 1992) W min = 0.02  ; 0.4<z<1.4 (cwc etal, ApJS 1999) (revisited)

30. Chris Churchill (PSU)30 Evolution of Strongest Systems As W min increased – evolution is stronger Steidel & Sargent (1992) dN/dz = N 0 (1+z)  What is the nature of the evolution??? Is it related to high velocity clouds???

31. Chris Churchill (PSU)31 Charting the Evolution of Galaxy-IGM Evolution Sophisticated simulations reveal direct, dynamic connections between the IGM and galaxy evolution- Mg II is the best tracer for star forming objects For z>2.2, Infrared high-resolution spectrograph required: JCAM/HET Uniform survey with R=11,000-60,000 and W r (2796)=0.05  limit (5  ) 0.3 A 0.02 A 0.05 A

32. Chris Churchill (PSU)32 Future Projects… Cycle 9 STIS/HST R=30,000 for z=0.5-1.5 Cycle 10 STIS/HST R=30,000 of low N(HI) Galactic HVCs in Mg II Narrow-Band Imaging for O II] emission of weak systems for z=0.5-1.0 HRS/HET R=60,000-120,000 for Mg II for z=0.6-2.8 JCAM/HET R=11,000 of Mg II for z=2.8-4.0 Thanks for listening!