Core Collapse of Self-Interacting Dark Matter Halos Kimberly Boddy - PowerPoint PPT Presentation

Core Collapse of Self-Interacting Dark Matter Halos Kimberly Boddy 
 Johns Hopkins University Searching for New Physics, University of Utah Leaving No Stone Unturned 5-10 August 2019

N-body Simulations CDM-only! • Dark matter density halo profiles are cuspy and dense • There are many more small halos than large ones • Substructure is abundant and almost self-similar Bullock & Boylan-Kolchin, Annu. Rev. Astron. Astrophys. (2017)

Small-Scale Structure Dwarf spheroidals LSBs Galaxy Clusters small-scale structure puzzles arise in various systems: core-cusp, missing satellites, too-big-to-fail, diversity

Missing satellites Core-cusp Oh+, ApJ (2010) Buckley & Peter, Phys. Rept. (2018) Diversity TBTF Creasey+ (2017) Boylan-Kolchin+, MNRAS (2012)

SIDM Solution Alleviate tensions? Spergel and Steinhardt, PRL (2000) Rocha+, MNRAS (2013) Zavala+, MNRAS (2013) 10 4 g H cm 2 ê g â km ê s L 2 ê m c 0 0 1 Dwarfs 10 3 g 2 ê m c 0 1 10 2 Clusters g 2 ê m X s v \ê m c 1 LSBs 10 g 2 ê m c 1 0 g . 2 0 ê m = c 1 m . ê 0 s 1 10 50 100 500 1000 5000 H km ê s L X v \ Further investigations with SIDM+baryons are ongoing Kaplinghat, Tulin, Yu, PRL (2016)

Millennium-II, Boylan-Kolchin+ (2009) Can we understand SIDM halo evolution without needing to run N-body simulations? Yes! Use semi-analytic methods. Gravothermal evolution. In globular clusters: ✦ Lynden-Bell and Eggleton (1980) In SIDM halos: ✦ Balberg, S. Shapiro, Inagaki (2002); Ahn, P . Shapiro (2004); Koda, P . Shapiro (2011)

Gravothermal Evolution Two time scales: • Mass conservation 
 = σ /m t r = λ mfp ∂ M ∂ r = 4 π r 2 ρ a ν a ρν t d = H • Hydrostatic equilibrium 
 ν = (4 πρ G ) − 1 / 2 ∂ ( ρν 2 ) = − GM ρ r 2 ∂ r • Laws of thermodynamics 
 ✓ ∂ ✓ ν 3 ◆ ◆ ∂ L ∂ r = − 4 π r 2 ρν 2 ln ∂ t ρ • Heat conduction M 4 π r 2 = − κ∂ T L ∂ r

Gravothermal Evolution M i , ν i • Mass conservation 
 ∂ M ∂ r = 4 π r 2 ρ • Hydrostatic equilibrium 
 ∂ ( ρν 2 ) = − GM ρ r 2 ∂ r • Laws of thermodynamics 
 ✓ ∂ ∆ r i ✓ ν 3 L i ◆ ◆ ∂ L ∂ r = − 4 π r 2 ρν 2 ln ∂ t ρ • Heat conduction 
 M � − 1 ∂ν 2 ⇣ σ ⇣ σ ⌘  4 π r 2 = − κ∂ T 4 π G L ⌘ 2 + b ∂ r = − 3 2 ab ν a ρν 2 ∂ r m m C

Calibration 10 0 σ m = 0 . 1 cm 2 / g σ m = 0 . 5 cm 2 / g σ m = 1 cm 2 / g 10 � 1 ρ [M � / pc 3 ] σ m = 5 cm 2 / g σ m = 10 cm 2 / g Matching densities works well across a range 10 � 2 of cross sections Pippin CDM 10 � 3 10 2 10 3 10 4 r [pc] 47 . 5 45 . 0 v 3D [km / s] 42 . 5 Matching velocity dispersions σ m = 0 . 1 cm 2 / g is more problematic 40 . 0 σ m = 0 . 5 cm 2 / g σ m = 1 cm 2 / g 37 . 5 σ m = 5 cm 2 / g σ m = 10 cm 2 / g Pippin CDM 35 . 0 500 1000 1500 2000 2500 3000 Simulation reference: Elbert+, MNRAS (2015) r [pc] Nishikawa, KB, Kaplinghat (arXiv: 1901.00499)

Central Density initial NFW profile σ m = 0 . 1 cm 2 / g 10 3 σ m = 0 . 5 cm 2 / g σ m = 1 cm 2 / g ρ c (= ρ c / ρ s ) σ m = 5 cm 2 / g 10 2 σ m = 10 cm 2 / g σ m = 50 cm 2 / g σ m = 100 cm 2 / g ˜ 10 1 10 0 10 1 10 2 250 300 350 400 ˜ t (= t/t 0 ) ∼ ( σ /m ) r s ρ 3 / 2 t − 1 s 0 Nishikawa, KB, Kaplinghat (arXiv: 1901.00499)

˜ t = 0 ( t = 0 Gyr) 10 6 1 . 0 Density L (= L/L 0 ) 3D Velocity Dispersion 10 3 3 v/v 0 ) 0 . 8 Positive Luminosity Negative Luminosity 10 0 0 . 6 √ ρ (= ρ / ρ s ), ˜ v (= 10 − 3 0 . 4 3 ˜ √ 10 − 6 0 . 2 ˜ 10 − 9 10 − 2 10 − 1 10 0 10 1 10 2 r (= r/r s ) ˜ Nishikawa, KB, Kaplinghat (arXiv: 1901.00499)

˜ ˜ t = 1 ( t = 0.3 Gyr) t = 0 ( t = 0 Gyr) 10 6 10 6 1 . 0 1 . 0 Density Density L (= L/L 0 ) L (= L/L 0 ) 3D Velocity Dispersion 3D Velocity Dispersion 10 3 10 3 3 v/v 0 ) 3 v/v 0 ) 0 . 8 0 . 8 Positive Luminosity Positive Luminosity Negative Luminosity Negative Luminosity 10 0 10 0 0 . 6 0 . 6 √ √ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ v (= v (= 10 − 3 10 − 3 0 . 4 0 . 4 3 ˜ 3 ˜ √ √ 10 − 6 10 − 6 0 . 2 0 . 2 ˜ ˜ 10 − 9 10 − 9 10 − 2 10 − 2 10 − 1 10 − 1 10 0 10 0 10 1 10 1 10 2 10 2 r (= r/r s ) r (= r/r s ) ˜ ˜ Nishikawa, KB, Kaplinghat (arXiv: 1901.00499)

˜ ˜ ˜ t = 53 ( t = 13.5 Gyr) t = 1 ( t = 0.3 Gyr) t = 0 ( t = 0 Gyr) 10 6 10 6 10 6 1 . 0 1 . 0 1 . 0 Density Density Density L (= L/L 0 ) L (= L/L 0 ) L (= L/L 0 ) 3D Velocity Dispersion 3D Velocity Dispersion 3D Velocity Dispersion 10 3 10 3 10 3 3 v/v 0 ) 3 v/v 0 ) 3 v/v 0 ) 0 . 8 0 . 8 0 . 8 Positive Luminosity Positive Luminosity Positive Luminosity Negative Luminosity Negative Luminosity Negative Luminosity 10 0 10 0 10 0 0 . 6 0 . 6 0 . 6 √ √ √ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ v (= v (= v (= 10 − 3 10 − 3 10 − 3 0 . 4 0 . 4 0 . 4 3 ˜ 3 ˜ 3 ˜ √ √ √ 10 − 6 10 − 6 10 − 6 0 . 2 0 . 2 0 . 2 ˜ ˜ ˜ 10 − 9 10 − 9 10 − 9 10 − 2 10 − 2 10 − 2 10 − 1 10 − 1 10 − 1 10 0 10 0 10 0 10 1 10 1 10 1 10 2 10 2 10 2 r (= r/r s ) r (= r/r s ) r (= r/r s ) ˜ ˜ ˜ Nishikawa, KB, Kaplinghat (arXiv: 1901.00499)

˜ ˜ ˜ ˜ t = 53 ( t = 13.5 Gyr) t = 351 ( t = 90 Gyr) t = 1 ( t = 0.3 Gyr) t = 0 ( t = 0 Gyr) 10 6 10 6 10 6 10 6 1 . 0 1 . 0 1 . 0 1 . 0 Density Density Density Density L (= L/L 0 ) L (= L/L 0 ) L (= L/L 0 ) L (= L/L 0 ) 3D Velocity Dispersion 3D Velocity Dispersion 3D Velocity Dispersion 3D Velocity Dispersion 10 3 10 3 10 3 10 3 3 v/v 0 ) 3 v/v 0 ) 3 v/v 0 ) 3 v/v 0 ) 0 . 8 0 . 8 0 . 8 0 . 8 Positive Luminosity Positive Luminosity Positive Luminosity Positive Luminosity Negative Luminosity Negative Luminosity Negative Luminosity Negative Luminosity 10 0 10 0 10 0 10 0 0 . 6 0 . 6 0 . 6 0 . 6 √ √ √ √ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ v (= v (= v (= v (= 10 − 3 10 − 3 10 − 3 10 − 3 0 . 4 0 . 4 0 . 4 0 . 4 3 ˜ 3 ˜ 3 ˜ 3 ˜ √ √ √ √ 10 − 6 10 − 6 10 − 6 10 − 6 0 . 2 0 . 2 0 . 2 0 . 2 ˜ ˜ ˜ ˜ 10 − 9 10 − 9 10 − 9 10 − 9 10 − 2 10 − 2 10 − 2 10 − 2 10 − 1 10 − 1 10 − 1 10 − 1 10 0 10 0 10 0 10 0 10 1 10 1 10 1 10 1 10 2 10 2 10 2 10 2 r (= r/r s ) r (= r/r s ) r (= r/r s ) r (= r/r s ) ˜ ˜ ˜ ˜ Nishikawa, KB, Kaplinghat (arXiv: 1901.00499)

˜ ˜ ˜ ˜ ˜ t = 374.56 ( t = 95.7 Gyr) t = 53 ( t = 13.5 Gyr) t = 351 ( t = 90 Gyr) t = 1 ( t = 0.3 Gyr) t = 0 ( t = 0 Gyr) 10 6 10 6 10 6 10 6 10 6 1 . 0 1 . 0 1 . 0 1 . 0 1 . 0 Density Density Density Density L (= L/L 0 ) L (= L/L 0 ) L (= L/L 0 ) L (= L/L 0 ) L (= L/L 0 ) 3D Velocity Dispersion 3D Velocity Dispersion 3D Velocity Dispersion 3D Velocity Dispersion 10 3 10 3 10 3 10 3 10 3 3 v/v 0 ) 3 v/v 0 ) 3 v/v 0 ) 3 v/v 0 ) 3 v/v 0 ) 0 . 8 0 . 8 0 . 8 0 . 8 0 . 8 Positive Luminosity Positive Luminosity Positive Luminosity Positive Luminosity Negative Luminosity Negative Luminosity Negative Luminosity Negative Luminosity 10 0 10 0 10 0 10 0 10 0 0 . 6 0 . 6 0 . 6 0 . 6 0 . 6 √ √ √ √ √ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ ρ (= ρ / ρ s ), ˜ v (= v (= v (= v (= v (= 10 − 3 10 − 3 10 − 3 10 − 3 10 − 3 0 . 4 0 . 4 0 . 4 0 . 4 0 . 4 3 ˜ 3 ˜ 3 ˜ 3 ˜ 3 ˜ √ √ √ √ √ 10 − 6 10 − 6 10 − 6 10 − 6 10 − 6 0 . 2 0 . 2 0 . 2 0 . 2 0 . 2 ˜ ˜ ˜ ˜ ˜ 10 − 9 10 − 9 10 − 9 10 − 9 10 − 9 10 − 2 10 − 2 10 − 2 10 − 2 10 − 3 10 − 1 10 − 1 10 − 1 10 − 1 10 − 2 10 − 1 10 0 10 0 10 0 10 0 10 0 10 1 10 1 10 1 10 1 10 1 10 2 10 2 10 2 10 2 10 2 r (= r/r s ) r (= r/r s ) r (= r/r s ) r (= r/r s ) r (= r/r s ) ˜ ˜ ˜ ˜ ˜ Nishikawa, KB, Kaplinghat (arXiv: 1901.00499)

Tidal Truncation ρ s ρ NFW = ( r/r s )[1 + ( r/r s ) 2 ] ( 1 r < r t ρ trunc = ρ NFW × 1 r > r t ( r/r t ) 5 σ m [cm 2 / g] corresponding to t = 13 Gyr 0.1 1 10 TNFW r t = r s σ m = 5 cm 2 / g 10 1 TNFW r t = r s TNFW r t = r s after 3Gyr 10 3 TNFW r t = 3 r s NFW NFW ρ c [M � / pc 3 ] ρ c (= ρ c / ρ s ) 10 2 10 0 ˜ 10 1 10 � 1 10 0 10 1 10 2 0 5 10 ˜ t (= t/t 0 ) t [Gyr] In progress: BH formation Nishikawa, KB, Kaplinghat (arXiv: 1901.00499)

Halo Survivability Phat ELVIS Simulation Prediction for SIDM: ✦ Core collapse phase may help subhalos survive infall ✦ High central densities Accelerated collapse from: ✦ Dissipative DM 
 Essig+ (1809.01144) ✦ Baryonic potential 
 (ongoing with Kaplinghat and Necib) Kelley+, MNRAS (2019)

Simulations with Infall Sameie, Yu, Sales, Vogelsberger, Zavala (1904.07872) Zavala, Lovell, Vogelsberger, Burger (1904.09998) Can obtain wide diversity of halo profiles

Simulations with Infall Field halos ∝ ( σ /m ) r s ρ 3 / 2 Recall: t − 1 s 0 c 3 200 ρ s ∝ ln(1 + c 200 ) − c 200 / (1 + c 200 ) c 200 = r 200 /r s high concentration Satellites (short period orbit) low concentration Satellites (long period orbit) Kahlhoefer, Kaplinghat, Slatyer, Wu (1904.10539)

TBTF Revisited Kaplinghat, Valli, Yu (1904.04939)

Outlook Drlica-Wagner+ (incl. KB) (1902.01055)