The Prevalence and Properties of Outflowing Galactic Winds at z = 1 Katherine A. Kornei (UCLA) UC Riverside Astronomy Talk January 27, 2012

Crystal Martin (UCSB) Alice Shapley (UCLA) Alison Coil (UCSD) Several important people. 1

Galaxies are not closed boxes. enrich the IGM in metals/dust …quench star formation …regulate black hole growth Outflows IGM 2

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

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. 4

Galaxies near and far show blueshifted absorption lines. ULIRG z = 0.2 LBGs z = 3 Interstellar Absorption 5

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. 7

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 8

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 9

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 10

Many analyses are possible. LRIS spectroscopy fit FeII absorption lines to determine z out measure fine structure FeII* emission lines define z sys ([OII], Balmer series) characterize MgII emission 11

72 LRIS objects are in the Extended Groth Strip. EGS (72) Other fields (140) star-formation rates dust attenuations HST imaging 12

More analyses are possible for EGS objects. 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 13

Blue, star-forming galaxies at z = 1. 14

Defining systemic and outflow velocities. z sys z out Define a systemic reference frame, ideally from the LRIS spectra. Fit multiple emission lines ([OII], OIII, Balmer) using template spectra. tilted [OII] lines (small fraction of sample) resonance abs. fine structure emission 2250, , Å FeII 15

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. 16

Blueshifted FeII absorption features are not ubiquitous in the sample z = 1.20 Inflow? Other outflow diagnostics: MgII, FeII* Velocities from FeII Outflows Inflows 17

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 18

No trend between outflow velocity and star- formation rate. Martin M sun yr M sun yr -1 19

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. 20

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 21

Higher star-formation rate surface density objects show larger blueshifts. No trend seen: Rubin et al (used half-light radius) Steidel et al (ground-based imaging) Kornei et al., in prep. 22

Composite spectra show same trends as individual objects. Kornei et al., in prep. High Low Star-formation rate surface density composites:: High: dV = -31 ± 7 km s -1 Low: dV = 44 ± 15 km s -1 High: dV = -300 km s -1 Mg II shows more kinematic variation than Fe II MgII SN II FeII MgII in supernova ejecta; FeII merely entrained? 23

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 24

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 25

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 26

Fine structure FeII* emission. z sys v = 0 v = +100 v = -100    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/” 27

FeII* emission is prevalent. Kornei et al., in prep. Stacks of FeII* emitters/non-emitters FeII* emitters FeII* non-emitters Kornei et al., in prep. The strongest FeII* emitters are bright and blue. FeII* emission appears to be ubiquitous FeII, FeII* MgII stronger FeII* = stronger MgII emission 28

Complexities of the MgII feature at ≈ 2800 Å. Composite spectrum Individual spectra show MgII emission AGN? (Weiner et al. 2009) Scattered wind? (Rubin et al. 2010) MgII MgII and FeII absorption are kinematically distinct. 29

Measuring an outflow velocity from MgII 2796 Å (resonance) A resonantly trapped transition. MgII V max where 90% of the continuum is met. No correlation: SFR and V max Significant correlation: SFRSD and V max 30

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. 31

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