Galaxy Wind IGM Enrichment from Star Forming Galaxies: 1<z<3

Insights from CDM Simulations

Chris ChurchillNew Mexico State University

Daniel Ceverino (HUJ)Jessica Evans (NMSU)Glenn Kacprzak (Swinburne)Anatoly Klypin (NMSU)Liz Klimek (NMSU)

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)

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”

Mhalo ~ 1012 - 1013 M sun

Lbol ~ 1011 - 1012 L sun (r~1-2 kpc)

SFR ~ 10 - 100 Msun/yr (LIRG-ULIRG)

Vc ~ 150 km/s (Vesc ~ 450 km/s)

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)

C IV absorption and z=3 galaxies

For N(CIV) > 1013 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) > 1015 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) > 1013.5 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”

QSOsightline

To observer

Neutral hydrogen(rest-frame velocity)

Mg II, C IV, OVI(rest-frame velocity)

Lyman series(obs wavelength)

1. Galaxies form in the cosmic web2. They accrete gas, form stars, and deposit energy/metals into IGM3. 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

z = 2.3

z = 1.3

stars density cm-3 temp K Z 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 fzM* 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

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”

QSO

4.5 Mpc

400 kpc

MOCK QUASAR ABSORPTION “PROBING”

Z=1.0 (M = 0.8MMW)

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

Examining Properties of Gas in Absorption

R

gas cell

QSO To observer

R = distance of cell center from galaxy centerb = 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, nH , T , Z/Zsun , fH

V

Vlos

density

temperature

metallicity

Halo constructed from stellar feedback winds…

= 10-2 - 10-6 cm-3

T = 105 - 106.3 K Z = 0.1 - 1 solar

QSO LOS GRID400 x 400 kpc = 20 kpc

@ z=3.55 a low SFR “Lyman Break Galaxy”

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

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are needed to see this picture.

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QuickTime™ and aVideo decompressor

are needed to see this picture.

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)

“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 doubletR = 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

Absorption line centroids (not maximum velocity extent) Observations with respect to nebular emission (stars)

Observed absorption profile mean centroid is -160 km/s

<vabs> - 115

RADIAL VELOCITY DISTRIBUTION

(Steidel 1997)

outflow (nearside)

outflow (nearside)

SFR ~ 10 Msun/yr

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 view side view

- when you have 100+ fields you can get some really good numbers per bin!

down the barrel W=1.61AD = 8-40 kpc W=1.62AD = 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 Msun/yr

SFR ~ 50 - 100 Msun/yr

OUTFLOW VELOCITY - STAR FORMATION RATE SCALING

V90 = 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

0.1 100

Weiner et al (2009)

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

V90 ~ SFR0.5

z=3.5 <v> FWHMOVI 115 223CIV 86 357Ly -27 129

z=1.0 <v> FWHMOVI -142 225CIV -132 200Ly -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

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

(post talk material/fodder for Q/A etc)

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!

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

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=104 K?

• OVI collisional ionization condition present in post shock filaments

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

400 kpc x 400 kpc QSO Grid: Metallicity vs Galactocentric Distance

InflowLower metallicityLower column densityOut to 300 kpc

OutflowHigher metallicityHigher column densityOut 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