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The Prevalence and Properties of Outflowing Galactic Winds at z = 1

The Prevalence and Properties of Outflowing Galactic Winds at z = 1. ETH Zurich February 2012. Katherine A. Kornei (UCLA) Alice Shapley, Crystal Martin, Alison Coil. Galaxies are not closed boxes. outflows?. outflows?. IGM. Outflows.

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The Prevalence and Properties of Outflowing Galactic Winds at z = 1

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  1. The Prevalence and Properties of Outflowing Galactic Winds at z = 1 ETH Zurich February 2012 Katherine A. Kornei (UCLA) Alice Shapley, Crystal Martin, Alison Coil

  2. Galaxies are not closed boxes. outflows? outflows? IGM Outflows enrich the intergalactic medium in metals …quench star formation …regulate black hole growth cold streams? AGN feedback? AGN feedback?

  3. Outflows are seen in local starbursts. 6” M82 (z=0.0008)  HST/ACS BVIHα (M. Westmoquette)

  4. Outflows can be inferred through line offsets. Given outflowing material between the observer and the galaxy: MgII 2796/2803 [OII] 3727 Å Nebular line – at zsys zsys MgI 2852 MgI Weiner et al. 2009 MgII DN/sec/pixel Outflowing gas will be blueshifted with respect to nebular lines tracing star forming regions. Velocity (km/sec)

  5. A variety of absorption lines are used to probe outflows. z z = 0.5 1.0 3.0 Na I D ≈ 5900 Å Fe II/Mg II ≈ 2600 Å H I + others ≈ 1200 Å Reddy et al. 2008

  6. The necessary data set. Spectroscopy of lines tracing outflowing gas lines tracing the systemic redshift The ideal data set. + Photometry for calculating stellar masses, etc. + Ancillary data for obtaining dust-corrected SFRs, morphologies, galaxy inclinations, etc.

  7. DEEP2 survey (the origin of our sample). Slitmasks with 120 targets 50,000 galaxies at z ≈ 1 in 3.5 deg2 DEIMOS on Keck II (90 nights: ‘02-’05) R = 5000 (70 km s-1) B-R Resolved [OII] doublets z < 0.75 z > 0.75 DEEP2 Team R-I Color cuts in 3/4 fields for z > 0.75 ≈ 1 hour integration

  8. Extended Groth Strip – no color cuts and lots of ancillary data. GALEX imaging (FUV, NUV) F606W http://aegis.ucolick.org/ HST imaging (F606W, F814W) 6” • The ideal data set. • Photometry, imaging ✓ • The necessary data set. • Lines tracing outflows & systemic z Spitzer imaging (IRAC, MIPS)

  9. LRIS observations to cover lines tracing winds. [OII] (zsys) CIV, FeII, MgII, MgI (zout) LRIS: 7200-9000 Å LRIS: 3400-6700 Å DEIMOS: 6500-9100 Å 212 objects; B < 24.5 1.19 < z < 1.35 = CIV 1549, MgI 2852 coverage Normalized Flux Mg I Al II Fe II Fe II Si II, C IV Mg II Rest Wavelength (angstroms)

  10. Many analyses are possible. LRIS spectroscopy measure fine structure FeII* emission lines definezsys([OII], Balmer series) fit FeII absorption lines characterize MgII emission HST imaging morphologies colors galaxy areas inclinations SFRs, dust attenuations from GALEX

  11. Blue, star-forming galaxies at z = 1. Kornei et al., in prep. Kornei et al., in prep.

  12. Defining systemic and outflow velocities. Define a systemic reference frame. Fit multiple emission lines ([OII], OIII, Balmer) using template spectra. 2250, 2260 2344, 2374 2587 Å Measure an outflow velocity. Fit multiple FeII absorption lines. zsys zout FeII

  13. A physical model for fitting absorption lines. covering fraction Primary quantity of interest is λ0, from which we estimate an outflow velocity. op. depth at line center line center Doppler parameter A single component fitwith 4 free parameters.

  14. BlueshiftedFeII absorption features are not ubiquitous in the sample. 12100420 z = 1.20 Velocities from FeII Inflow? Martin et al., in prep. Kornei et al., in prep. Inflows Outflows Other outflow diagnostics: MgII, FeII*

  15. The strength of outflows is correlated with various galaxy properties. Na D ULIRGs face-on outflow velocity (km/s) dwarf starbursts edge-on Chen et al. 2010 Martin 2005 SFR (M*/yr) Outflows not seen in edge-on systems. Outflow velocity increases with increasing star formation rate. face-on edge-on

  16. No trend between outflow velocity and star-formation rate. 1000 Msun yr-1 0.1 Msun yr-1 Martin 2005

  17. Are outflows correlated with star-formation rate surface densities? 6” F606W Σ SFR estimate Clumpy objects at high z – need a better area estimate that traces luminous regions. area estimate UV, 24 μm, emission lines, etc. Half-light radius? Petrosian radius? A = πR2

  18. A new technique for estimating galaxy areas. Petrosian area Clump area F606W Include only those pixels brighter than a certain surface brightness threshold, thereby flagging clumps. Given “clumpy” galaxies:

  19. Higher star-formation rate surface density objects show larger Fe II blueshifts. Kornei et al., in prep.

  20. Composite spectra show same trends as individual objects. Star-formation rate surface density composites:: High density Low density Hα Bright clumps Interclump regions Vfe2 = 44 ± 15 km s-1 Vfe2 = -31 ± 7 km s-1 Kornei et al., in prep. Mg II shows more kinematic variation than Fe II Genzel et al. 2011

  21. Theory supports a correlation between outflows and the density of star formation. Fe II Star clusters eject gas at velocities proportional to the gas surface density squared (Murray et al. 2011). [Kennicutt-Schmidt Law] Chen et al. 2010

  22. The geometry of outflowing winds at z = 1. Na D face-on edge-on Chen et al. 2010 Estimate inclination from axis ratios from HST imaging: a face-on edge-on i = cos-1(b/a) b

  23. Face-on galaxies show stronger blueshifts than edge-on systems. Inclination composites:: Low High More edge-on: dV = 28 ± 11 km s-1 More face-on: dV = -19 ± 9 km s-1 Mg II equivalent width Bordoloi et al. 2011 face-on edge-on Azimuthal angle relative to galaxy disk axis

  24. Mergers are not required to drive outflows. Law et al. 2007 high G low G Gini (G) – measure of how light is distributed in a galaxy Lotz et al. 2008 Kornei et al., in prep. low M20 high M20 M20 – second order moment of a galaxy’s 20% brightest pixels

  25. Fine structure FeII* emission. Does this emission come from star forming regions or from outflows? zsys v = 0 F606W     Leitherer et al. 2010 probing very different scales at z = 1 and z = 0 v = +100 v = -100 8400 pc/” 16 pc/” Kornei et al., in prep. 2626 Å (fine structure) Fe II 2600 Å (resonance)

  26. Complexities of the MgII feature at ≈ 2800 Å. MgII and FeII absorption are kinematically distinct. The composite spectrum shows MgII in absorption. Some individual spectra show MgII in emission MgII Martin et al., in prep.

  27. Mapping winds. What are the kinematics and extent of galactic winds? IFU observations with MUSE. Prochaska et al. 2011

  28. Summary. Reddy et al. 2008 [OII] (zsys) CIV, FeII, MgII, MgI (zout) LRIS: 7200-9000 Å LRIS: 3400-6700 Å DEIMOS: 6500-9100 Å Petrosian area Clump area Outflow velocity most strongly correlated with the concentration of star formation. Kornei et al., in prep.

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