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

Galaxies are not closed boxes. enrich the intergalactic medium in metals …quench star formation …regulate black hole growth Outflows IGM 1

Outflows are seen in local starbursts. HST/ACS BVIHα (M. Westmoquette) M82 (z=0.0008)  6” 2

Outflows can be inferred through line offsets. MgI MgII Given outflowing material between the observer and the galaxy: [OII] 3727 Å Nebular line – at z sys z sys Velocity (km/sec) MgII 2796/2803 MgI 2852 Outflowing gas will be blueshifted with respect to nebular lines tracing star forming regions. 3

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

The necessary data set. Spectroscopy of lines tracing outflowing gas lines tracing the systemic redshift + Photometry for calculating stellar masses, etc. + Ancillary data for obtaining dust-corrected SFRs, morphologies, galaxy inclinations, etc. The ideal data set. 5

50,000 galaxies at z ≈ 1 in 3.5 deg 2 DEIMOS on Keck II (90 nights: ‘02-’05) DEEP2 survey (the origin of our sample). Slitmasks with 120 targets R = 5000 (70 km s -1 ) Resolved [OII] doublets ≈ 1 hour integration Color cuts in 3/4 fields for z > 0.75 z < 0.75 z > 0.75 R-I 6

Extended Groth Strip – no color cuts and lots of ancillary data. F606W HST imaging (F606W, F814W) 6” Spitzer imaging (IRAC, MIPS) GALEX imaging (FUV, NUV) The ideal data set. Photometry, imaging ✓ The necessary data set. Lines tracing outflows & systemic z 7

LRIS observations to cover lines tracing winds. LRIS: Å LRIS: Å DEIMOS: Å [OII] (z sys ) CIV, FeII, MgII, MgI (z out ) 212 objects; B < < z < 1.35 = CIV 1549, MgI 2852 coverage Rest Wavelength (angstroms) Si II, C IV Fe II Mg II Al II Mg I 8

Many analyses are possible. LRIS spectroscopy fit FeII absorption lines measure fine structure FeII* emission lines define z sys ([OII], Balmer series) characterize MgII emission HST imaging morphologies colors galaxy areas inclinations SFRs, dust attenuations from GALEX 9

Blue, star-forming galaxies at z = 1. 10

Defining systemic and outflow velocities. z sys z out Define a systemic reference frame. Fit multiple emission lines ([OII], OIII, Balmer) using template spectra. 2250, , Å FeII 11 Measure an outflow velocity. Fit multiple FeII absorption lines.

A physical model for fitting absorption lines. A single component fit with 4 free parameters. covering fraction op. depth at line center line center Doppler parameter Primary quantity of interest is λ 0, from which we estimate an outflow velocity. 12

Blueshifted FeII absorption features are not ubiquitous in the sample z = 1.20 Inflow? Other outflow diagnostics: MgII, FeII* Velocities from FeII Outflows Inflows 13

The strength of outflows is correlated with various galaxy properties. SFR (M * /yr) dwarf starbursts ULIRGs Outflow velocity increases with increasing star formation rate. Chen et al Na D edge-on face-on Outflows not seen in edge-on systems. edge-on 14

No trend between outflow velocity and star- formation rate. Martin M sun yr M sun yr -1 15

Are outflows correlated with star-formation rate surface densities? Σ UV, 24 μm, emission lines, etc. Half-light radius? Petrosian radius? A = πR 2 F606W 6” Clumpy objects at high z – need a better area estimate that traces luminous regions. 16

A new technique for estimating galaxy areas. Given “clumpy” galaxies: Include only those pixels brighter than a certain surface brightness threshold, thereby flagging clumps. F606W Petrosian area Clump area 17

Higher star-formation rate surface density objects show larger Fe II blueshifts. Kornei et al., in prep. 18

Composite spectra show same trends as individual objects. Kornei et al., in prep. High density Low density Star-formation rate surface density composites:: V fe2 = -31 ± 7 km s -1 V fe2 = 44 ± 15 km s Mg II shows more kinematic variation than Fe II Hα Bright clumps Interclump regions

Theory supports a correlation between outflows and the density of star formation. 20 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

The geometry of outflowing winds at z = 1. Chen et al Na D edge-on face-on edge-on Estimate inclination from axis ratios from HST imaging: i = cos -1 (b/a) b a 21

Face-on galaxies show stronger blueshifts than edge-on systems. More edge-on: dV = 28 ± 11 km s -1 More face-on: dV = -19 ± 9 km s -1 Inclination composites:: Low High edge-on 22 Azimuthal angle relative to galaxy disk axis

Mergers are not required to drive outflows. Gini (G) – measure of how light is distributed in a galaxy high Glow G M20 – second order moment of a galaxy’s 20% brightest pixels high M20 low M20 23

Fine structure FeII* emission. z sys v = 0 v = +100 v = -100    Fe II 2600 Å (resonance) 2626 Å (fine structure) Leitherer et al Kornei et al., in prep. probing very different scales at z = 1 and z = 0 Does this emission come from star forming regions or from outflows? F606W 8400 pc/”16 pc/” 24

Complexities of the MgII feature at ≈ 2800 Å. Some individual spectra show MgII in emission MgII 25 The composite spectrum shows MgII in absorption. MgII and FeII absorption are kinematically distinct.

Mapping winds. 26 What are the kinematics and extent of galactic winds? IFU observations with MUSE.

Summary. Reddy et al Petrosian area Clump area Kornei et al., in prep. LRIS: Å LRIS: Å DEIMOS: Å CIV, FeII, MgII, MgI (z out ) [OII] (z sys ) Outflow velocity most strongly correlated with the concentration of star formation. 27

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