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Galaxy Wind IGM Enrichment from Star Forming Galaxies: 1<z<3 Insights from CDM Simulations Chris Churchill New Mexico State University Daniel Ceverino (HUJ) Jessica Evans (NMSU) Glenn Kacprzak (Swinburne) Anatoly Klypin (NMSU) Liz Klimek (NMSU)
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1.Gas phase baryonic structures are observable in absorption (bright star forming galaxies + QSO absorption lines) with equal visibility at all redshifts, including z=1 to z=3 2.Gas flows into and/or out of galaxies and baryonic halos are sensitively probed in UV absorption lines; cold IGM gas in, heated gas out 3.Observations indicate that z~2-3 galaxies with moderately high star formation rates are blowing out significant amounts of metal enriched gas (courtesy C. Steidel)
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3 lensed galaxies (z=2.7-3.0; R=6000) Composite spectra of z=2.0-2.6 UV selected galaxies (R=1300) (courtesy C. Steidel) Campaign by Steidel et al of UV (rest-frame) selected z=2-3 galaxies find winds in virtually all bright galaxies “down the barrel method” M halo ~ 10 12 - 10 13 M sun L bol ~ 10 11 - 10 12 L sun (r~1-2 kpc) SFR ~ 10 - 100 M sun /yr (LIRG-ULIRG) V c ~ 150 km/s (V esc ~ 450 km/s)
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OUTFLOWS expected to be most common in the redshift desert, where star formation is most active We directly observe the IGM enrichment process when it is peaking We directly observe the interplay (fueling by infall and outflow mass loss) between galaxy evolution and the baryonic environment in the cosmological context Gas expelled at z=1-3 could be the “refueling” material for galaxies at the present epoch WINDS may (and probably do) play crucial role - in shaping mass-metallicity relation in galaxies - explaining difference between galaxy luminosity and mass functions (low end and/or high end mismatch) - heating and chemically enriching of the IGM - termination of star formation (quenching) in low mass galaxies and old stellar populations in said galaxies (the red and the dead)
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C IV absorption and z=3 galaxies For N(CIV) > 10 13 cm -2, the galaxy / CIV absorber cross correlation function is equal to the LBG galaxy auto-correlation function, and it increases by a factor of 1.5-2.0 as the column density is increased to N(CIV) > 10 15 cm -2 Clear causal connection of “strong” CIV absorbers seen in QSO spectra with galaxies; I.e., C IV traces metal enriched gas in vicinity (80 kpc proper) of galaxies O VI absorption and z=3 galaxies For N(OVI) > 10 13.5 cm -2, the OVI absorber temperatures, kinematics, and rate of incidence are well explained as winds extending to 50 kpc (proper) associated with LBGs Adelberger etal (2003, 2005) Simcoe etal (2002) “quasar absorption line (QAL) method” QSO sightline To observer Neutral hydrogen (rest-frame velocity) Mg II, C IV, OVI (rest-frame velocity) Lyman series (obs wavelength)
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1.Galaxies form in the cosmic web 2.They accrete gas, form stars, and deposit energy/metals into IGM 3.Extended metal enriched “halos” are observed from z=0 to z=4 Arguably, some of the most physical and visual insights are derived from simulations; - but need detailed galaxy physics AND cosmological setting - very difficult but crucial 4.5 Mpc Zooming technique! Adaptive Refinement Tree (ART) - increase spatial resolution in proportion to where all the action is and track processes with low resolution where its not
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z = 2.3 z = 1.3 starsdensity cm -3 temp KZ solar 1000 kpc Example of stellar particles, and hydro gas density, temperature, and metals (20-50 pc) - Miller-Scalo IMF Miller-Scalo (1979), Type II and Ia SNe yields f z M * Woosely & Weaver (1995) CDM Hydrodynamic + N-body Adaptive Refinement Tree (ART) in 10 Mpc box - Radiative (UVB) + collisional heating and cooling (atomic+molecular w/ dust as function of metallicity) using Cloudy grids Haardt & Madau (1996); Ferland etal (1998) - Star formation physics based upon 1 pc high resolution simulations Kravstov (2003); Ceverino & Klypin (2008) Kravstov etal (1997); Kravstov (1999); Kravstov, Gnede, & Klypin (2004) - Natural gas hydro only, thermal heating drives winds; no velocity kicks, no rolling dice
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1. Use “mock” background quasar absorption line methods 2. Use “mock” starburst galaxy spectra methods Place “quasar beam” sightlines through simulation box, generate absorption profiles Shoot through target galaxies, can examine different orientations Create grid of sightlines to probe line of sight absorption properties spatially Study kinematic, equivalent width, column density, and Doppler b distributions “down the barrel method” Synthesize spectrum of central star forming region of star forming galaxy Must account for physical extent of nuclear region Can examine different viewing angles Study kinematics of profiles, etc. Generate “observed” spectra, analyze as an observer, quantitatively compare Simulations are complex, involving a tonne of physics, some of which needs extensive testing; Presently, observational data of “halos” and “outflows” are underutilized for constraining galaxy formation physics in cosmological simulations… - how to do it (right)? “QAL method”
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QSO 4.5 Mpc 400 kpc MOCK QUASAR ABSORPTION “PROBING” Z=1.0 (M = 0.8M MW ) resolution ~ 20-50 pc Milky way mass at z=0 - select a galaxy in the box, select orientation for “sky view”, pass line of sight through box - line of sight (LOS) is given impact parameter and passed through the entire 10 Mpc box - record the properties of all gas cells probed by the LOS
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Examining Properties of Gas in Absorption R gas cell QSO To observer R = distance of cell center from galaxy center b = impact parameter (projected R) 1.Apply the Cloudy models to obtain photoionization + collisional equilibrium ionization fractions 2.Determine density of metal ion in cell, obtain optical depth at line of sight velocity 3.Synthesize “realistic” spectrum; analyze absorption; tie detected absorption to detected cells 4.Examine detected cell properties b D, V, n H, T, Z/Z sun, f H V V los
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density temperature metallicity Halo constructed from stellar feedback winds… = 10 -2 - 10 -6 cm -3 T = 10 5 - 10 6.3 K Z = 0.1 - 1 solar QSO LOS GRID 400 x 400 kpc = 20 kpc @ z=3.55 a low SFR “Lyman Break Galaxy”
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Entrained material Schematic of Velocity Flows Filaments inflowing parallel to angular momentum vector (face on). Inner 10 kpc, hot gas outflows perpendicular to the plane, but is overwhelmed by infalling filaments and is redirected sideways into metal enriched supershells that entrain cool gas Metals mix into filaments in inner few hundred kpc, but filaments vigorously fuel the galaxy
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Spatial location of CIV inflow Spatial location of CIV outflow Spatial location of OVI inflow Spatial location of OVI outflow Animated Movies (rotation of structure about angular momentum vector of galaxy)
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“DOWN THE BARREL” CIV & OVI ABSORPTION 3 lensed galaxies z=2.7-3.0 Red is cB58 viewed from “Side B” viewed from “Side A” Observed Blended doublet R = 6000 partial covering is ~ 80% (at any given velocity) slow rising blue wing (wind signature) not always apparent asymmetric for face-on view (along angular momentum vector) Analogous to: Weiner et al (2009) Steidel, Pettini, & Shapley (courtesy C. Steidel) face on edge on
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Absorption line centroids (not maximum velocity extent) Observations with respect to nebular emission (stars) Observed absorption profile mean centroid is -160 km/s - 115 RADIAL VELOCITY DISTRIBUTION (Steidel 1997) outflow (nearside) SFR ~ 10 M sun /yr
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down the barrel D = 8-40 kpc D = 40-80 kpc STACKING: IMPACT PARAMETER BINNING In the real world there are a multitude of background sources- they are just not bright! To increase signal to noise, select impact parameter bins and co-add spectra in the reference frame of the intervening absorber how to get spatial information? D sky viewside view - when you have 100+ fields you can get some really good numbers per bin!
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down the barrel W=1.61A D = 8-40 kpc W=1.62A D = 40-80 kpc W=0.91A Stack 1460 galaxies Keck LRIS-B spectra Perform similar experiment with simulation grids… LRIS-B mock spectra stacked by observed impact parameter range STACKING: IMPACT PARAMETER BINNING courtesy C. Steidel (singlet) Blended doublet @ v(sys) = -390 km/s CIV 1548 0 V=0 @ 1549.5 -500+500 SFR ~ 10 M sun /yr SFR ~ 50 - 100 M sun /yr
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OUTFLOW VELOCITY - STAR FORMATION RATE SCALING V 90 = velocity is defined as the 90% percentile of the gas with outward radial velocity greater than the escape velocity of the galaxy Each data point is a single galaxy The redshift range is z=1-1.5. Directly compared to outflows found in DEEP2 galaxies 10 500 1000 100 0.1100 Weiner et al (2009) Ceverino et al (in preo) In general, the wind velocity scales with SFR in a manner consistent with Mg II winds V 90 ~ SFR 0.5
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z=3.5 FWHM OVI 115 223 CIV 86 357 Ly -27 129 z=1.0 FWHM OVI -142 225 CIV -132 200 Ly -78 176 z=3.5 z=1.0 OUTFLOW TO INFLOW EVOLUTION Dominated by filamentary inflow Distribution of Radial Velocity of Absorbing Cells Giving Rise to Detected Absorption
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CONCLUDING REMARKS Work is still at a very preliminary level…. It is very expensive to run many galaxies to get statistics on the absorption quantities, which aren’t really published yet! We are only making qualitative comparisons at this time, though the absorption line work has constrained the SFR efficiencies from earlier work It is clear that cold flows are prominent and required to fuel the continuation of star formation The scaling of the outflow velocity with SFR qualitatively is promising in its comparison with observations The absorption gas method is probably the most promising in that it incorporates the sensitivity functions of detecting the gas in observed spectra
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(post talk material/fodder for Q/A etc)
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plane of sky +18 kpc 2-comp sub-DLA MgII: Plane of sky, - 150<v<80 km s -1 MgII 18 kpc behind pos, 0<v<+100 km s -1 Two main sights for HI Two sights for CIV absorption- photoionized, not a single cloud! Extended sights for OVI absorption- photo and collisionally ionization, not a single cloud!
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EVOLUTION FROM Z=3.5 TO Z=1 density baryons continue to fall into galaxy local web thins out entrained gas from earlier wind extends to 200 kpc, evolution not symmetric about galaxy
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EVOLUTION FROM Z=3.5 TO Z=1 temperature Xray “coronal” conditions within 80 kpc, non uniform (due to filaments) too much gas cooled to T=10 4 K? OVI collisional ionization condition present in post shock filaments
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EVOLUTION FROM Z=3.5 TO Z=1 metallicity Even though gas is cooling, metals ejected to 200-300 kpc At high z, NB filaments enriched by mixing, but haven fallen into galaxy, at low z, Z~10 -2 metals spread out in more diffuse lower density gas
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400 kpc x 400 kpc QSO Grid: Metallicity vs Galactocentric Distance Inflow Lower metallicity Lower column density Out to 300 kpc Outflow Higher metallicity Higher column density Out to 200 kpc Observed QSO absorption line profiles are result of complicated patterns of gas kinematics, metallicities, and galactocentric distances (metals correlated to kinematics) - Gas cells contributing to objectively detected absorption lines
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