Mg II & C IV Absorption Kinematics vs.

Stellar Kinematics in Galaxies

Chris Churchill(Penn State)

J. CharltonJ. DingJ. MasieroD. Schneider

M. DickinsonM. PettiniA. ShapleyC. Steidel

B. JannuziR. MellonJ. Rigby

Extended Gaseous “Envelopes” and Galaxy Formation

The gas came first; but are the extended metal enriched “halos” near galaxies intergalactic in origin or reprocessed galactic gas?

Clues (areas of study) include:

1. High Velocity Clouds in Milky Way

2. Quasar Absorption LinesIGM accretion? Intragroup material? Fountain material? Satellite accretion?

Same Questions…

Must compare to galaxy’s dynamical behavior and environment…

What is connection between gas properties and galaxy properties…?

Comparing kinematics of stars and kinematics of gas a first step…Comparing kinematics of various ionization conditions a second step…

(CWC & Vogt 2001)

Mg II 2796 Transitions (rest—frame velocity space)

(CWC 2001)

Mg II 2796 Transitions and Host Galaxies

Simple Kinematic Models of Absorbing Gas from Galaxies

Absorption kinematics is symmetric about the galaxy’s systemic velocity

Absorption kinematics is offset in the direction of stellar roatation compared to the galaxy’s systemic velocity

Halo/infall + Rotating/disk produces both signatures in single profile

Q0827+243 Q1038+064 Q1148+387

(Steidel et al. 2002)

Mg II kinematics traces the stellar kinematics in 4 of 5 galaxies observed to date.A symmetric infalling “halo” appears rare- there is no symmetry about the galaxy’s systemic velocity.

(CWC et al. 2000)

Mg II 2796 Kinematics – CIV Strengths

The velocity spread of Mg II gas is predictor of CIV absorption strength and kinematics… In Lyman limits systems (LLSs) the more distributed the low ionization phase is in velocity, the stronger is the total absorption strength of the higher ionization gas.

However, the C IV does not arise in the same physical parcels of gas- the gas is multiphase in its ionization conditions.

(aside): Damped Ly- systems (DLAs) exhibit average kinematics, average C IV absorption strengths, but the largest Mg II absorption strengths.

Kinematics: Mg II 2796 and C IV 1548, 1550

(CWC et al. 2000)

The Q1206+459 Multiple System: Multiphase Ionization

(CWC & Charlton 1999; Ding et al. 2002)

STIS/HST

The C IV, N V, and O VI arise in a separate ionization ionization phase- models of Mg II clouds cannot produce higher ionization absorption…

WIYN image of Q1206 field shows four galaxies… Group environment absorbers, or galaxy hosted absorbers?

Mg II 2796 Kinematics + C IV 1548 Kinematics

Case 1: high velocity Mg II clouds appear to have C IV trace them in discreet fashion; though ionization conditions are multiphase

Case 2: Evidence for ionization gradients, where C IV / Mg II ratio changes across profile

Case 3: Where is the C IV?

Case 4: Where is the Mg II?

Case 5: All cases combined!

What about the galaxy kinematics in these cases? How do they stack up in velocity space?

Q0827+243 Q1038+064 Q1148+387

CIV 1548,1550CIV 1548,1550

FOS/HST spectra: they lack the resolution to discern the C IV kinematics…

Kinematics: Stellar, Mg II 2796, and C IV 1548, 1551

(CWC et al. 2002, in prep)

Mg II traces stellar kinematics yet is difficult to explain as extended disk rotation (at 72 kpc impact parameter!). C IV traces Mg II kinematics but has strongest component at galaxy’s systemic velocity, as highlighted in 1551.

What physical entity is giving rise to this C IV component?

Concluding Remarks

• C IV absorption strengths correlate with Mg II kinematic spreads.

• Mg II kinematics consistent with stellar kinematics extended. “Disk” or co-rotating halo kinematics? No signature of symmetric, infalling halo component.

• C IV kinematics does not correspond to Mg II kinematics in all cases.Many Mg II clouds have multiphase ionization in velocity space; but bulk of C IV absorption may not be aligned in velocity with Mg II. Are we seeing high ionization C IV-only “high velocity clouds” or C IV “coronae” strongly coupled to the galaxy systemic velocity. What are the affects of satellite galaxies and merger histories?

Gas coupled to galaxy/stars, no simple IGM accretion; implications for intragroup HVCs?

Galaxy-like C IV corona with adiabatic cooling, infalling Mg II cloudlets? (1999)

25 galaxies with stellar rotation curves (spirals) and stellar velocity dispersions (ellipticals). Collect C IV kinematics with COS on HST.

Future