Probing the Dynamics of Galaxy-Gas Interactions in Groups and Clusters with Chandra and XMM-Newton Marie Machacek Smithsonian Astrophysical Observatory IGM Workshop 3/8/2005

Thanks to my collaborators Christine Jones William R. Forman Paul Nulsen Ralph Kraft Alexey Vikhlinin Maxim Markevitch Liviu Stirbat

Galaxy-IGM Interactions in Three Systems Elliptical NGC 1404 Fornax Cluster kT = 1.5 keV Transonic ram-pressure stripping Elliptical NGC 4552 Virgo Cluster kT = 2.2 keV Supersonic ram-pressure stripping Spiral NGC 6872 Pavo Group kT = 0.5 keV High velocity encounter

NGC 1404 in Fornax Dosaj et al ; Scharf et al. 2004; Machacek et al NGC Mpc Chandra keV ks NGC1404 R p = 54 kpc

Surface Brightness Map Temperature Map T g = keV A = Z s

Model Assumptions N1404 & N1399 in same plane - r ~ r p : stripped tail  ICM dense - sharp edge  inclination angle  not large N isothermal sphere - density n g  r -  Surface brightness jump  (  g n g 2 /  c n c 2 ) Vikhlinin et al. 2001; Mazzotta et al. 2001

Surface Brightness Profile  1.54  =0.5 r e =7.64 kpc  0.3, r c =395”

NGC 1404’s Transverse Velocity T g /T c = 0.36 n g /n c = 6.0 p g /p c = 2.1 M 1 ~ 1.0 v = 657 km/s v r = 450 km/s * v t = 478 km/s  ~ 43˚ *Drinkwater et al Pressure ratio vs Mach Number

NGC 4552 in Virgo Chandra 54.4 ks keV Machacek et al. 2005

Surface Brightness Profile r 1 = 1.29 kpc r 2 = 3.12 kpc  =1.29

Surface Brightness Profile r 1 = 1.29 kpc r 2 = 3.12 kpc T 1 = 0.61 keV T 2 = 0.44 keV A g = 0.6±0.2 Z s T c = 2.2 keV

NGC 4552’s Transverse Velocity T g /T c = 0.2 n g /n c = 37 ± 5 p g /p c = 7.3 ± 1.1 M 1 = 2.1 ± 0.2 v = 1646 km/s v r = -968 km/s * v t = 1331 km/s  ~ 36˚ ± 3˚ Pressure ratio vs Mach Number

Tail Properties T = keV n ~ cm -3 >> n c p ~ a few  p ICM length ~ 10 kpc bowed

Shock Model for Inner Rings  Mach = 1.7 t = 1.32 Myr E mech = 2.4  f v ergs L mech = 5.8  f v ers/s L mech - L radio  6.4  ergs/s Birzan et al. 2004

Tidal Interactions NGC 6872/ IC 4970 VLT-ANTU+FORS1 ESO Top 20 images

NGC 6872 in Pavo D = 53.5 Mpc  v r = 849 km/s * *Martimbeau & Huchra CfA Redshift Survey 2004

Strong Interaction with Pavo XMM pn+mos keV 32.2 ks Machacek et al astro-ph v2

Trail Properties Hot T ~1 kev ~2T IGM Dense n ~ 1.7n IGM Low abundance A ~ 0.2 ± 0.1 Z s Large extent ~ 67  90 kpc

Trail Formation Models Tidal Stripping - distortions of other tracers ? Ram Pressure Stripping - T high? A low? n < 2 n ICM - not like NGC 4552! Bondi-Hoyle Gravitional Focusing Turbulent Viscous Stripping

Bondi Gravitational Focusing Mach ~ 3  /  flat  long trail no large central peak large gravitating halo ? v circ ~ ? a = 20 kpc ? sufficient heating ? T ad ~ 1.4 T IGM For NFW profile

Turbulent Viscous Stripping v ~ 1300 km/s  ~ 40    Stripping Rate Energy Extent + Adiabatic expansion v = v r / sin 

Signatures in the Trail Filaments, streamers gas? stars? dust? Abundance galaxy, IGM or mix? T & n profile thermalization region? cools, broadens & dims?

Conclusions Constrain 3-D motion of galaxy Show stripping processes in action Reveal interactions previously overlooked Differentiate between different stripping processes X-ray Observations of Edges, Tails and Trails