Three Unresolved Problems in Studies of the Circumgalactic Medium - PowerPoint PPT Presentation

Three Unresolved Problems in Studies of the Circumgalactic Medium Joseph F. Hennawi MPIA Starring: F. Arrigoni- S. Cantalupo N. Crighton M. Fumagalli J. X. Prochaska Battaia MPIA visit us @ www.mpia.de/ENIGMA July 16, 2014

I Don’t Believe in AGN Feedback at least not as a panacea for solving problems with massive galaxy formation

I Do Believe in Climate Change

OWLS sims Freeke van de Voort’s talk no feedback The physical state of diffuse gas falling onto galaxies is assumed to be resolved and predicted ab initio by simulations

OWLS sims Freeke van de Voort’s talk no feedback SN + AGN Feedback might alter the structure of the CGM. If CGM modeled incorrectly/unresolved, sims may not be believable

Probing the Circumgalactic Medium (CGM) background QSO Use absorption θ vir ~ 10” lines to probe foreground diffuse gas galaxy halo r vir ~ 80 kpc r ~ 30 – 200 kpc Virial Radius N HI ~ 10 12-22 cm -2 and T ~ 10 2-6 K R ⊥ Observational Challenge: b/g sightline find distant galaxies at small impact parameter to bright b/g QSO

What Can we Actually Measure? b/g QSO b/g QSO b/g QSO b/g QSO r cloud R ⊥ R ⊥ R ⊥ f/g QSO R ⊥ f/g QSO f/g QSO f/g QSO n M Gas mass, Multiphase? Metal Covering factor cloud density, Cold, Warm, Enrichment? & kinematics size? Hot? Moderate R ~ 2000 Echelle R ~ 5000-50,000, 6-60 km/s 150 km/s

The CGM of a Low-Mass Galaxy Crighton, Hennawi+ 2014b b/g QSO z = 2.76 LBT/VLT survey for z ~ 2 galaxies in f/g of b/g QSOs with archival high-S/N echelle spectra.

The CGM of a Low-Mass Galaxy Crighton, Hennawi+ 2014b b/g QSO z = 2.76 Ly α z = 2.50 LAE f/g LAE z = 2.50 f/g Ly α -emitter @ R ⊥ = 50 kpc L = 0.2L * ; SFR ~ 1.5 M ¤ ¤ /yr M ★ ~ 10 9.1 M ¤ ¤ ; M h ~ 10 11.4 M ¤ ¤ LBT/VLT survey for z ~ 2 galaxies in f/g of b/g QSOs with archival high-S/N echelle spectra.

The CGM of a Low-Mass Galaxy Crighton, Hennawi+ 2014b b/g QSO z = 2.76 Ly α z = 2.50 LAE f/g LAE z = 2.50 f/g Ly α -emitter @ R ⊥ = 50 kpc L = 0.2L * ; SFR ~ 1.5 M ¤ ¤ /yr M ★ ~ 10 9.1 M ¤ ¤ ; M h ~ 10 11.4 M ¤ ¤ Background QSO observed for 50 hours on UVES, S/N ~ 70

The CGM of a Low-Mass Galaxy High-Resln. Spectrum of b/g QSO Crighton, Hennawi+ 2014b b/g QSO z = 2.76 Ly α z = 2.50 f/g LAE z = 2.50 f/g Ly α -emitter @ R ⊥ = 50 kpc L = 0.2L * ; SFR ~ 1.5 M ¤ ¤ /yr M ★ ~ 10 9.1 M ¤ ¤ ; M h ~ 10 11.4 M ¤ LLS logN HI = 10 16.94 ± 0.1 @ R ⊥ = 50 kpc ¤ • Sensitive column densities for 13 ionic metal states • Full Lyman series analysis gives HI for each component

The CGM of a Low-Mass Galaxy High-Resln. Spectrum of b/g QSO Crighton, Hennawi+ 2014b b/g QSO z = 2.76 Ly α z = 2.50 f/g LAE z = 2.50 f/g Ly α -emitter @ R ⊥ = 50 kpc L = 0.2L * ; SFR ~ 1.5 M ¤ ¤ /yr Δ v = 430 km/s; MgII EW = 0.37Å M ★ ~ 10 9.1 M ¤ ¤ ; M h ~ 10 11.4 M ¤ ¤ • Perfect alignment between metal and HI kinematics ➡ gas well mixed. HI smoother because of thermal broadening

Precise Determination of CGM Parameters log n H = -2.85 ± 0.33 (cm -3 ) log Z = -0.70 ± 0.14 (Z ⨀ ) log N H = 18.18 ± 0.16 (cm -2 ) log r cloud = -0.58 ± 0.42 (kpc) x HI = -3.30 ± 0.16 • Photoionization models provide excellent fit to the data • Bayesian MCMC modeling gives robust errors fully accounting for parameter degeneracies

Precise Determination of CGM Parameters • Enriched (0.2-0.6 Z ⊙ ) LLS (log N HI =17) with 430 km/s motions ➡ ︎ outflow?

Precise Determination of CGM Parameters • Enriched (0.2-0.6 Z ⊙ ) LLS (log N HI =17) with 430 km/s motions ➡ ︎ outflow? • Extremely small clouds! r cloud = 100-400 pc and cloud masses M cloud = 200-5 × 10 4 M ⊙ • Uncertain radiation field not an issue. Local sources make clouds denser and smaller • Large cool gas mass implied M cool = π R 2 N H f cov M cool ' 4 ⇥ 10 8 M � ⇠ 0 . 6 M ?

The Small Scale Structure of the CGM Blob Test: Agertz et al. (2007) ◆ 1 / 2 ✓ n cold t cc ' 5 r cloud v bulk n hot

The Small Scale Structure of the CGM Blob Test: Agertz et al. (2007) ◆ 1 / 2 ✓ n cold t cc ' 5 r cloud v bulk n hot • Clouds ablated in 10 7 yr << dynamical time ~ 10 8 yr, assuming: – r cloud = 300 pc – M cloud = 2 × 10 4 M ⊙ – n cold = 5 × 10 -3 cm -3 – n hot = 6 × 10 -4 cm -3 – v bulk = 300 km/s

The Small Scale Structure of the CGM Blob Test: Agertz et al. (2007) ◆ 1 / 2 ✓ n cold t cc ' 5 r cloud v bulk n hot • Clouds ablated in 10 7 yr << dynamical time ~ 10 8 yr, assuming: – r cloud = 300 pc – M cloud = 2 × 10 4 M ⊙ – n cold = 5 × 10 -3 cm -3 – n hot = 6 × 10 -4 cm -3 – v bulk = 300 km/s • Do current simulations resolve this?

The Small Scale Structure of the CGM Blob Test: Agertz et al. (2007) ◆ 1 / 2 ✓ n cold t cc ' 5 r cloud v bulk n hot • Clouds ablated in 10 7 yr << dynamical time ~ 10 8 yr, assuming: – r cloud = 300 pc – M cloud = 2 × 10 4 M ⊙ – n cold = 5 × 10 -3 cm -3 – n hot = 6 × 10 -4 cm -3 – v bulk = 300 km/s Not even close • Do current simulations resolve this? Requiring ~ 3 resolution elements per r cloud implies: - Grid hydro: grid cells ~ 100 pc - SPH: ~ 7000 particles per cloud, or M gas ~ 3 M ⊙ Eris2 zoom-in: M gas = 2 × 10 4 M ⊙ , FIRE: 5 × 10 3 M ⊙

Problem #1: The Small Scale Structure of the CGM is Likely Unresolved by Current Models This has been seen before…. Absorption HVCs Lensed QSOs Line Modeling QSO CGM Sizes r < 50 pc R ⊥ ≈ 30 pc Sizes r < 100 pc n H ~ 1-5 cm -3 clump r ~ 10-100 pc r M HI n HI [pc] [ M � ] [cm − 3 ] [ N HI = 10 16 cm -2 A 45 470 0.14 Prochaska & B 45 280 0.06 C 49 160 0.06 Hennawi 2009 D 36 150 0.06 E 32 160 0.07 Schaye et al. 2007 Ben Bekhti et al. 2009 Rauch et al. 1990 The entire CGM could be in r cloud ~ 300 pc clumps

We Need a Sub-Grid Model for the CGM Stability of Cold Streams Thermal Instabilities in ICM Yuval Birnboim’s talk Brian O’Shea’s talk

Probing the CGM of High Mass Halos background QSO θ vir ~ 20” In rare projected r vir ~ 160 kpc foreground pairs, a b/g QSO QSO halo Virial probes a f/g QSO Radius in absorption R ⊥ M halo = 10 12.5 M ¤ ¤ b/g sightline • QSOs trace massive halos M halo ~ 10 12.5 M ¤ ¤ at z ~ 2, 6 × larger than LBGs. Progenitors of local quenched galaxies • Why QSOs? Because we can find 10 6 in digital sky surveys (SDSS) • Herschel studies indicate QSOs lie on star-forming main sequence (Rosario et al. 2013; Knud Jahnke’s talk) and represent unbiased tracers

Δθ = 16.3” Δθ z bg = 2.17 R ⊥ = 139 kpc 2’ logN HI = 20.3 z fg = 2.11 b/g QSO f/g QSO Hennawi+ 2006, 2007, 2013; Prochaska, Hennawi+ 2013

Δθ = 13.3” Δθ z bg = 2.53 R ⊥ = 108 kpc 2’ logN HI = 19.7 z fg = 2.43 b/g QSO f/g QSO Hennawi+ 2006, 2007, 2013; Prochaska, Hennawi+ 2013

Δθ = 3.7” Δθ z bg = 3.13 R ⊥ = 31 kpc 2’ logN HI = 20.5 z fg = 2.29 b/g QSO f/g QSO Hennawi+ 2006, 2007, 2013; Prochaska, Hennawi+ 2013

A Massive Reservoir of Cool Gas Around QSOs only sizeable sample of QSO pairs z fg (f/g redshift) strong absorber N HI > 10 17.2 cm -2 no strong absorber Hennawi+ 2006, 2007, 2013 Prochaska, Hennawi+ 2013ab Covering Factor 74 sightlines with R ⊥ < 300 kpc R ⊥ (impact parameter)

A Massive Reservoir of Cool Gas Around QSOs only sizeable sample of QSO pairs z fg (f/g redshift) strong absorber N HI > 10 17.2 cm -2 no strong absorber Hennawi+ 2006, 2007, 2013 Prochaska, Hennawi+ 2013ab Covering Factor 74 sightlines with R ⊥ < 300 kpc R ⊥ (impact parameter) • High ~ 60% covering factor for R < r vir = 160 kpc

A Massive Reservoir of Cool Gas Around QSOs only sizeable sample of QSO pairs z fg (f/g redshift) strong absorber N HI > 10 17.2 cm -2 no strong absorber Hennawi+ 2006, 2007, 2013 Prochaska, Hennawi+ 2013ab Covering Factor 74 sightlines with R ⊥ < 300 kpc R ⊥ (impact parameter) • High ~ 60% covering factor for R < r vir = 160 kpc • CGM is dominated by a cool (T ~ 10 4 K) massive (>10 10 M ⊙ ) metal-enriched medium (Z > 0.1Z ⊙ )

Simulating CGM Observations M = 10 11.2 ; r vir = 58 kpc M = 10 11.9 ; r vir = 98 kpc M = 10 12.6 ; r vir = 153 kpc Fumagalli, Hennawi+ 2014 ART AMR zoom-in + ionizing rad. transfer Ceverino et al. 2010

Problem #2: The Perplexing CGM of Massive Halos Fumagalli, Hennawi+ 2014 log N HI LBGs: M = 10 11.9 22.0 Prochaska, Hennawi+ 2013 QSOs Crighton, Hennawi+ 2014a 20.8 19.7 star-forming gals 18.5 sims 17.3 16.2 15.0

Problem #2: The Perplexing CGM of Massive Halos Fumagalli, Hennawi+ 2014 log N HI LBGs: M = 10 11.9 22.0 Prochaska, Hennawi+ 2013 QSOs Crighton, Hennawi+ 2014a 20.8 19.7 star-forming gals QSOs: M = 10 12.6 18.5 sims 17.3 16.2 15.0 • More cold gas observed at high-mass (QSOs) than sims predict

Problem #2: The Perplexing CGM of Massive Halos Fumagalli, Hennawi+ 2014 log N HI LBGs: M = 10 11.9 22.0 Prochaska, Hennawi+ 2013 QSOs Crighton, Hennawi+ 2014a 20.8 19.7 star-forming gals QSOs: M = 10 12.6 18.5 sims 17.3 16.2 15.0 • More cold gas observed at high-mass (QSOs) than sims predict • Solutions: QSO feedback? Is this what we want/expect it to ¤ cold gas? QSOs are special (unlikely)? look like ~ 10 11 M ¤ • Small-scale structure unresolved in sims?