Simulations of a z=1.3 Galaxy Using the Adaptive Refinenment Tree (ART) method in an N-body + hydrodynamic code allows very high resolution of particle mass and gas physics in regions where the dynamic and collapse timescales are short, while also allowing us to follow the formed galaxies in the cosmological setting. The gas cells are resolved at roughly 20pc (comoving). We simulate the formation and evolution of galaxies in the greater cosmic web and incorporate star formation and feedback physics, including real-time metal enrichment of the gas and radiative heating and colling in this metal enriched gas. Kinetics from the supernovae chemically enrich and deposit heat into the gas in the galaxies; the gas then outflows via kinetic impulse and natural advection. These simulations naturally yield metal enriched extended gaseous halos around the galaxies (as is observed in the universe using the technique of quasar absorption lines). The physical state (gas density, temperature, velocity, and metallicity) associated with a galaxy at z=1.3 is illustrated in N-body + hydrodynamic simulations. Each image is 1 Mpc across (co-moving). The galaxy stars, which are confined to the inner central 20 kpc region, are not shown in these images, only the gas. - (upper left) Hydrogen density distribution (red is 0.1, yellow is 0.001). - (upper right) Temperature distribution (white should emit soft X-rays, green is photoionized). - (lower left) velocity field (red upward and blue downward is 300 km/s OUTFLOW!). - (lower right) metallicity distribution (red is 0.5 solar, yellow is 0.05 solar). What you are seeing: In the density slice (upper left panel), the false color yellow gas has a density of n ~ 0.001 atoms per cubic centimeter. The long extended structures to the upper right and lower left are infalling filaments from the cosmic web. Red colored gas has n ~ 0.1 atoms per cubic centimeter. In the temperature slice (upper right panel), this gas corresponds to T ~ 30,000 Kelvin. Note the halo out to 500 kpc that is T ~ few x 10^5 K. In the center of these images is the galaxy, which is surrounded by turbulent, shock heated and adiabatically cooling gas. The lower right panel shows the metallicity of this halo gas (the filaments are chemically poor). These metals are distributed along a direction perpendicular to the infalling filaments. The lower left panel shows the gas kinematics in the plane of the sky. The X direction is positive upward, so the red colored gas is outflowing upward from the galaxy at ~300 km/s, whereas the blue colored gas is outflowing downward from the galaxy at ~300 km/s. The key to these simulations is that stellar feedback is required to heat the gas, which then outflows (> 300 km/s) in a perpendicular direction to the inflowing cool filaments. Natural advection propels the metals to distances of 500 kpc. We run "mock" quasar lines of sight through these halos, generate synthetic quasar spectra, study the absorption lines from the MgII 2796,2803, CIV 1548,1550, and OVI 1031,1037 transitions, and compare them to observed spectra of these transitions. We use the observations and mock spectra to place constraints on the physics of stellar feedback. There are no ad-hoc processes- everything seen here is the results of natural phsyical processes in the simulations. (Right click on images and drag on "View Image" to see enlarged views.)

Galaxy and Halo Kinematics In view of the above simulations, one of the observational constraints that can be placed on the physics implemented in the simulations is the relative kinematics of the galaxy and the chemically enriched halo gas. To do this, we locate quasars that have foreground galaxies with small angular projections in which the line of sight to the quasar pierces the extended gaseous halos of the galaxies. We then obtain high resolution spectra of the background quasar (to obtain absorption line diagnostics of the halo gas) and moderate resolution spectra of the foreground galaxies (to obtain their rotation curves). Below is an example of two galaxies associated with the same metal-line absorption system detected in high resolution spectrum of the quasar (obtained with the UVES spectrograph on the VLT). The rotation curves were obtained with the ESI spectrograph on the Keck II Telescope. - (center panel) HST/WFPC2 F702W image of the quasar field, including the two foreground galaxies, G1 and G2. The quasar (unmarked) is the brightest object in the right-center location of the image (note the dffraction spikes). Though you cannot "see" the chemically enriched gas extended around these galaxies, these galaxies do have extended halos similar to those shown in the simulations above (the gas is observed in absorption in the quasar spectrum). The ESI slit positions are superimposed over the galaxies; the relative spatial position (in arcseconds) along the slit are indicated with "+" and "-," with "+" referring to positive spatial positions. Note that these directions are marked on the y-axes of the upper left and right panels illustrating the galaxy rotation curves. - (left panels) The top panel is the projected rotation curve (kinematics) of galaxy G1 given in rest-frame velocity relative to the galaxy systemtic redshift; the center panel is the absorption from the MgII 2796 transition (observed in the quasar spectum) and the lower panel is that of the MgII 2803 transition. The velocity scale of the absorbing gas is also relative to the galaxy systemtic redshift. - (right panels) Same as left panels but for galaxy G2. Note that the both of the galaxies' rotational velocities overlap completely with the observed MgII absorption kinematics. Halo models show that absorbing gas kinematics are consistent with extended an gaseous halo exhibiting disk-like rotation. Tidal tails of both G1 and G2 seen in the HST image suggest possible galaxy-galaxy harassment/interaction. Thus, it is likely that both of these galaxies are host to the absorption. Look out for two upcoming papers; one on the analysis two double galaxy systems (Kacprzak et al. 2007d, in prep) and the other is a comparison study of gaseous halo and galaxy kinematics (Kacprzak et al. 2007e, in prep). The second paper will show that the halo gas does NOT exhibit extend disk-like rotation as previously shown.