THE WARM AND HOT ISM IN AND NEAR THE MILKY WAY

Blair Savage, Mike Shull, Ken Sembach, BarryWelsh, Charles Danforth, and the COS Science team___________________________________

COS G130M and 160M observations of 10 AGNs situated beyond Milky Way high velocity clouds containing O VI

S/N =30 to 40 observations of ISM C IV, Si IV and NV.

28 Orbits

The High Velocity H I + O VI Sky(Sembach et al. 2003, ApJ, 146. 165)

60% OF THE 100 EXTRAGALACTIC LINES OF SIGHT HAVE HIGH VELOCITY O VI WHICH OFTEN IS ASSOCIATED WITH H I HVCs

THE H I HVCs ARE INTERACTING WITH THE GAS IN THE GALACTIC THICK DISK AND WITH AN EXTENDED (R >50 kpc) HOT GALACTIC CORONA

High Ionization ISM / IGM Species

CIE: Sutherland & Dopita (1993, ApJS, 88, 253)Abundances: Anders & Grevesse (1989,Geochim. Cosmochim Acta, 53, 197)

XMM/Chandra O VII,O VIII

FUSE O VI, S VI

HST N V, C IV, Si IV

ISM COOLNG CURVE PEAKS NEAR

T ~105 to 3x105 K

A MAJOR COOLANT IS EMISSION FROM O VI

1. PRIMARY FOCUS: THE ORIGINS OF THE HIGHLY IONIZED GAS.

2. DIFFERENT IONIZATION ORIGIN MODELS MAKE DIFFERENT PREDICITONS FOR IONIC RATIOS AND RELATIONSHIPS BETWEEN LOW AND HIGH IONS.

3. THE HIGH ION PROFILES OF O VI, N V, C IV AND Si IV WILL BE INTERCOMPARED AND RELATED TO LOW ION PROFILES (O I, S II, Si II, Fe II, etc.) IN ORDER TO EVALUATE THE PHYSICAL CONDITIONS IN AND ORIGINS OF THE HIGHLY IONIZED GAS IN AND NEAR THE MILKY WAY AT LOW AND AT HIGH VELOCITY.

4. OTHER STUDIES WILL BE POSSIBLE WITH THIS DATA SET INCLUDING: STUDIES OF THE ABUNDANCES IN HVCS AND STUDIES OF THE PHYSICAL CONDITIONS AND ABUNDANCES IN LOW REDSHIFT IGM SYSTEMS

ION TO ION RATIOS CAN BE USED TO DISCRIMINATE AMONG DIFFERENT

IONIZATION MECHANISMS

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IONIC RATIOS

over 20 Km s-1 VELOCITY INTERVALS

for 8 EXTRAGALACTIC LINES OF SIGHTFOR THICK DISK GAS

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CONDUCTIVE HEATING &

TURBULENT MIXINGARE CONSISTENT WITH

MANY DATA POINTS

COS TARGET LIST

AGN z ORBITS HVC

MRK 817 0.031 1 C1A @ -109 km/sMRK 290 0.03 2 C1A/C @-138, -105 km/sMRK 876 0.129 2 CD/C1B @ -173, -133 km/sPG1626+554 0.132 3 C @ -121 km/sMRK 106 0.123 3 A @ -176 km/sPG 1011-040 0.058 3 WB @ 123 km/sESO 256-G23 0.056 5 WD @ 117 km/sMRK 335 0.026 2 -v HVCMRC 2251-178 0.066 4 -v HVC MRK 1513 0.063 3 -v HVC

Total = 28

RELATED PROGRAMS

WELSH et al. AN ABSORPTION STUDY OF IVCs USING HOT STARS

IN GLOBULAR CLUSTERS15 ORBITS 10 STARS S/N =30 G130M & G160M

WELSH et al. SAMPLING THE LISM WITH HOT WHITE DWARFS

5 ORBITS 5 WHITE DWARFS S/N = 30 G130M& G160M

WELSH et al. HIGH RESOLUTION OBSERVATIONS OF THE LISM WITH STIS

4 ORBITS 4 HOT STARS S/N = 50

NOTE THAT ALL EXTRAGALACTIC IGM PROGRAMS WITH S/N > 20 WITH THE G130M &G160M MODES WILL PROVIDE IMPORTANT INFORMATION

ABOUT THE HIGH IONS IN AND NEAR THE MILKY WAY