Galaxies and CGM gas at z~2-3: Results from the Keck Baryonic - - PowerPoint PPT Presentation

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Galaxies and CGM gas at z~2-3: Results from the Keck Baryonic - - PowerPoint PPT Presentation

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Galaxies and CGM gas at z~2-3: Results from the Keck Baryonic Structure Survey (KBSS) C. Steidel (Caltech) G. Rudie What Matters? Durham 2017 June 18 What Matters Checklist 1. What is the origin and fate of the CGM? 2. What are the

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Galaxies and CGM gas at z~2-3: Results from the Keck Baryonic Structure Survey (KBSS)

  • C. Steidel (Caltech)
  • G. Rudie

What Matters? Durham 2017 June 18

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SLIDE 2

“What Matters” Checklist

  • 1. What is the origin and fate of the CGM? ✓
  • 2. What are the morphological and physical properties of

the CGM? ✓

  • 3. What are the relevant physical processes on large (kpc)

and small (pc) scales? ✓

  • 4. What is the relationship between CGM and galaxy

properties? ✓

  • 5. How does the CGM evolve and what can we learn by

comparing different epochs and tracers? ♪

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SLIDE 3

Useful things to remember…

When comparing CGM properties at low and high redshift:

  • 1. Virial radius:
  • for DM halos with log(Mh/M)=12.0

– Rvir ≈ 90 pkpc (z=2.5) – Rvir ≈ 250 pkpc (z=0)

2.Correlation scales:

  • Beware co-moving vs. physical units (one and the same at

z=0)

– 1h-1 cMpc ≈ 1.4 cMpc = 1.40 pMpc (z=0) – 1h-1 cMpc ≈ 1.4 cMpc ≈ 0.35 pMpc (z=3)

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SLIDE 4

Alternative Questions

(with focus on high redshifts)

  • A. How do galaxy-scale outflows affect/interact with accreting material (and

when and where does it matter?)

  • B. What is the expected metal content of wind material? Accreted material?
  • C. How well-mixed are metals in CGM gas (vs. time)?
  • D. What is the causal relationship (if any) between superwinds and CGM on 10-

500 kpc scales? How should we recognize the “smoking gun” when we see it?

  • E. Outflows from galaxies are obviously multi-phase; to what extent are the

low-ish ions most commonly observed good tracers of what is happening?

  • F. What is the expected “fossil record” of past super-winds, as a function of

time?

  • G. Feedback from AGN vs. Stars/SNe :which, how, when, where?
  • H. What is the impact of superwind-induced gas flows on stellar and gas-phase

metallicity, on both short and long timescales?

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SLIDE 5

Why z=2-3 is Optimal for Establishing Statistical Baselines for High Redshift Galaxies and their CGM

  • Peak of the “epoch of galaxy formation”, black hole accretion,

blah, blah

  • The “magic” redshift range for diagnostic rest-optical nebular

spectroscopy from terrestrial sites : z=2.1-2.6 ne, ionization, excitation, extinction, SFR, kinematics, chemistry; long heritage from nearby galaxy studies

  • Rest-frame far-UV can be observed without going to space, Lyα

forest opacity is manageable

  • 3200-3730 Å : OVI @z=2.1-2.6 , higher Ly series
  • 3200-6000 Å Lya, Lyb, CII,CIII,CIV,SiII,SiIII,SiIV,NII,NV,etc.
  • Luv*  g’=24.0 at z=2.3: lots of galaxies to make the “grid”
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SLIDE 6

Madau & Dickinson 2014, ARAA

M* “Bright Ages”? “End of the Beginning”? T SFR “Mad Owl” Plot

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SLIDE 7

Keck Baryonic Structure Survey ([insert logo here])

(2007-2017)

  • 15 independent fields, total solid angle of 0.25 deg2,
  • Not GOODS, COSMOS, EGS, HUDF, CANDELS, etc.

– each field centered on one of brightest QSOs in the entire sky with 2.55 < z < 2.85

  • High density sampling of structure focused on 1.8 < z < 3.5 and (especially) z=2-2.6
  • Intensive spectroscopy from UV to near-IR

– 0.31-0.80 μ Keck/HIRES (QSO spectroscopy, S/N~100)

  • 19 central QSOs in 15 fields

– 0.32-0.70 μ Keck/LRIS (KBSS-UV)

  • ~2400 with R~800-1500, covering ~1000-2000 Å in rest-frame

– 1.15-2.40 μ Keck/MOSFIRE (KBSS-MOSFIRE)

  • ~1200 galaxies, ~400 with J,H,K

– 0.34-0.70 μ NB-selected Lyα Emitters (KBSS-Lyα) –

  • 10 of 15 fields, ~600 spectra (R=1500)

– 0.35-0.70 μ (LRIS-B+R)+ 1.1-2.4 μ (J,H,K) MOSFIRE (KBSS-LM)

  • R~1500 (rest UV), R~3600 (rest optical)
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SLIDE 8

KBSS-

15 fields, 0.25 sq. degrees, ~4000 spectra <z>=2.4 ~2700 rest-UV spectra ~1300 rest-optical (MOSFIRE) spectra

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Typical Field, 5.5’ x 7’, 184 spectroscopic redshifts , z~1.5-3.5

KBSS 0100+13 zQ=2.721 MOSFIRE

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SLIDE 10

Why did KBSS take ~10 years to get this to this point?

2 main reasons: 22

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SLIDE 11

Reason 1. It is a lot of data; and, we had to take essentially all of it ourselves

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SLIDE 12

MOSFIRE in the Caltech “Synchrotron” lab, just prior to shipping (Feb. 2012)

Photos: C. Johnson, UCLA

12

Reason 2: MOSFIRE project timeline: Oct 2004 (start) - Sep 2012 (commissioning)

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SLIDE 13

z=2.0-2.6 CS,Rudie,Strom+14

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SLIDE 14

astronomer

v

Resonance Lyman α photons scattered from “back” side of flow- acquire redshift with respect to stars Photons absorbed by gas moving toward

  • bserver, acquire

blueshift Nebular emission lines from gas around forming stars- at rest with respect to galaxy redshift

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SLIDE 15
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  • <SFR> ≈ 30 M/yr
  • <M*> ≈ 1010 M; MDM ≈ 1012 M
  • <Vc> ≈ 150 km/s
  • Mgas > M* (gas-dominated)
  • Gas-phase O/H ≈ 0.5 solar
  • Stellar Fe/H ≈ 0.1 solar
  • Outflows:
  • extends to vmax ≈ -1000 km/s
  • <vout> = -190 km/s
  • <vlya> = +290 km/s

The View “Down the Barrel” (30 KBSS galaxies @ z~2.4)

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SLIDE 17

Q2343-BX418 z=2.3054 Q2343-BX587 z=2.2427

Outflow kinematics of individual galaxies

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Lyα and Hα in Faint Galaxies

(z=2.57, R~27 in continuum (~0.1L*)

Lyα (LRIS-B) Hα (MOSFIRE)

Trainor, CS + 2015

V (km/s relative to systemic)

Stack of 32 Ly α– selected galaxies, Hα+Lyα

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SLIDE 19

z

QSO

Background Foreground

Densely Sampling the Universe @z~1.8-3.5: “Hi-Fi” Version

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SLIDE 20

NHI > 1014.5 cm-2 absorbers

  • > 4 times more likely to

hit a log(N)>14.5 absorber near a galaxy than in the general IGM

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SLIDE 21

HI Gas Around z=2.3 KBSS galaxies

Rudie+2012

Galaxy Galaxy

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SLIDE 22

The Physical State of the CGM Gas

  • Line width traces kinetic energy

in the gas

  • Increasing line width

(turbulence?) with decreasing impact parameter

Rudie+ 2012a

bd

2 = bturb 2 + 2kT

m

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SLIDE 23

1.2 1.0 0.8 0.6 0.4 0.2 0.0 0.2 0.4 0.6 0.8 1.0 Median (log10 HI) 0.1 1.0 Transverse distance [pMpc] 0.1 1.0 LOS Hubble distance [pMpc]

H I

100 1000 LOS velocity [km/s]

2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0 1.9 1.8 Median (log10 CIV) 0.1 1.0 Transverse distance [pMpc] 0.1 1.0 LOS Hubble distance [pMpc]

CI V

100 1000 LOS velocity [km/s] 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 Median (log10 OVI) 0.1 1.0 Transverse distance [pMpc] 0.1 1.0 LOS Hubble distance [pMpc]

OVI

100 1000 LOS velocity [km/s]

KBSS Galaxy-centric 2-D maps of HI, metals

Lyα

OVI CIV Turner+2014, KBSS-MOSFIRE sample

Galaxy redshifts to σ≈15 km/s

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SLIDE 24

KBSS Galaxies and Dark Matter Halos in the EAGLE Simulations

Turner+17 KBSS and EAGLE

KBSS

logMh>10.5 logMh>11.5 logMh>12.5 Lyα C IV Si IV

Typical halo masses of KBSS galaxies independently estimated to be Mh ~ 1012

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SLIDE 25

Subtleties of OVI in the CGM of KBSS Galaxies

Turner, Schaye, CS, Rudie, Strom 2015

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SLIDE 26

The Smoking Gun of Galaxy Feedback?:

  • hot (>300,000 K) Gas within 200 kpc of forming galaxies…
  • near-solar metal content, and still moving at high velocity
  • <z>=2.4, <d>=140 kpc (physical).

Turner, Schaye, CS, Rudie, Strom 2015

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SLIDE 27

Corollaries

  • This hot phase is hard to identify, and easily

masked by “normal” photoionized CGM material

  • Beware making assumptions about the

mapping between HI and “over-density”- hot

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SLIDE 28

Last Slide

  • The connection between the

physical properties of forming galaxies during the peak of the galaxy formation era with the circumgalactic gas is eminently accessible to observation.

  • The “smoking gun” identified?–

evidence for the direct influence

  • f feedback , originating in the

central, intensely star-forming regions -- on the larger-scale (200 kpc) properties of the CGM

  • “Recently disturbed” CGM is

kinematically and chemically distinct from the more easily-

  • bserved, cooler CGM gas
  • Poor mixing between

newly-formed metals and the larger CGM is indicated

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SLIDE 29

KBSS-LM1: same 30 galaxies @z~2.4:

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The Smoking Gun of Galaxy Feedback?:

  • hot (>300,000 K) Gas within 200 kpc of forming galaxies…
  • near-solar metal content, and still moving at high velocity
  • <z>=2.4, <d>=120 kpc (physical).

Turner, Schaye, CS, Rudie, Strom 2015

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SLIDE 31

z=1.6265 DLA/LLS: Path Sep= ~1kpc z=2.3555 Dgal=75 kpc, path separation ~ 0.4 kpc

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Q0100-BX210

  • SFR~ 40 M/yr
  • Log(M*/M) ~ 10.2
  • O/H ~ 0.6 solar
  • 89 physical kpc from

background QSO sightline

HST-F140W

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SLIDE 33
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SLIDE 34
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SLIDE 35

Low-Metallicity near the Systemic Velocity

Rudie + in prep

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SLIDE 36

Even Lower Metallicity at the Systemic Velocity

Note the non-detection

  • f CIV and SiIV
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SLIDE 37

Near Solar Metallicity at Δv~+200 km/s

Rudie + in prep

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SLIDE 38

Solar Metallicity at Δv~-550 to -300 km/s

Rudie + in prep

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SLIDE 39

Orange: BPASSv2-300bin, Z=0.001, t=108 Cyan: same, reddened using Reddy,CS,+2016 extinction

(Eldridge & Stanway 2016)

CS+2017

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SLIDE 40

Z=3.05 SMC, E(B-V)=0.057 A1500=0.74 (x 2.0) z=3.05 Reddy, E(B-V)=0.137 A1500=1.22 (x 3.1)

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Z=2.4 SMC, E(B-V)=0.09 A1500=1.17 (x 2.9) Z=2.4 Calzetti, E(B-V)=0.225 A1500=2.32 (x 8.5)

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SLIDE 42
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SLIDE 43

016 0.0058 0.027 0.049 0.07 0.092 0.11 0.13 0.16 0.18 0.

32.4114"

MD27 2.8189 M11 3.1328 C12 2.9237 C10 3.3913 2.4034 BX212 2.3782 BX196 2.4918 BX196 2.4918 BX195 2.3807 BX188 2.0602 BX186 2.357 BX18

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SLIDE 44

Which absorbers trace the CGM?

Rudie, CS, Trainor+12

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SLIDE 45

KBSS-MOSFIRE: Nebular Excitation

CS, Strom+2016; Strom, CS+2017

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Where are the Metals at z=2-3?

(~1000 galaxies, ~500 CIV systems) Adelberger+2005

See also Simcoe+2006

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SLIDE 47

Where are the Metals (CIV) at z=3?

Adelberger, CS, Shapley, Pettini 2003

Scale of correlation “~600h-1 co-moving kpc”= 250 pkpc

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SLIDE 48

The Smoking Gun of Galaxy Feedback?:

  • hot (>300,000 K) Gas within 200 kpc of forming galaxies…
  • near-solar metal content, and still moving at high velocity
  • <z>=2.4, <d>=120 kpc (physical).

Turner, Schaye, CS, Rudie, Strom 2015

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SLIDE 49
  • For typical galaxy (z=2.5) with a dark matter

halo mass of ~1012 Msun :

(dM/dt)in ~ 120 M /yr (baryonic accretion rate) <SFR> ~ 30 M /yr

What are the expected gas flow rates?

(dM/dt)out ~ 90 M/yr (for “equilibrium”)

 “mass loading” η = (dM/dt)out/ SFR ~ 3

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SLIDE 50

Red ≈ L*, continuum-selected LBGs Black ≈L*/10, Lyα-selected galaxies Trainor, CS + 2015

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SLIDE 51

z

QSO

Densely Sampling the Universe @z~1.8-3.2

Learning to love the “Lo-fi grid”

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SLIDE 52

Galaxies vs. Point Sources as Probes of CGM galaxy: d~2-3 kpc

QSO: d< 0.001 kpc

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SLIDE 53

Galaxy Pair Composite Spectra • 50 pairs 1-5”

(<d>=30 kpc)

  • 190 pairs 5-10”

(<d>=70 kpc)

  • 305 pairs 10-15” (<d>=100 kpc)

zfg

zbg

CS+2010

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SLIDE 54

W0 vs. Galaxy Impact Parameter, z~2-3 LBGs

Models: CS +2010

fc(r) ~ r –γ

rvir

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SLIDE 55

Covering fraction:

fc(r) ~ r-γ

(inferred from transverse sightlines)

Cloud acceleration:

a(r) ~ r-α

constrained by shape of line profile

“Typical” Absorption Line Profiles, matched with a simple flow model CS et al 2010

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SLIDE 56

CS et al 2011; see also Hayashino et al 2004

Average Lyα Emission from ~100 UV-continuum selected galaxies (0.3-3L*UV), <z> ~

2.65

Line-free UV continuum Lyα - continuum 20” ~ 160 kpc (physical)

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SLIDE 57

CS et al 2010,2011

Lyα Scattering Halos and CGM Absorption Strength

CGM Absorption Lyα Emission fc ~ r -0.6 model: fc ~ r -0.6 Reff=90 kpc