Dark matter heats up in dwarf galaxies Justin I. Read Matthew - PowerPoint PPT Presentation

Dark matter heats up in dwarf galaxies Justin I. Read Matthew Walker, Pascal Steger, Oscar Agertz, Michelle Collins, Denis Erkal, Giuliano Iorio, Filippo Fraternali, Alexandra Gregory, Matthew Orkney, Andrew Pontzen, Martin Rey

The Cusp-Core Problem

The Cusp-Core Problem WLM; Leroy, Nature 2015

The Cusp-Core Problem 45 40 35 30 v c (km s − 1 ) 25 20 15 10 5 0 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 R (kpc) e.g. Flores & Primack 1994; Moore 1994; Read et al. 2017

The Cusp-Core Problem 45 40 35 30 v c (km s − 1 ) 25 20 15 gas 10 stars 5 0 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 R (kpc) e.g. Flores & Primack 1994; Moore 1994; Read et al. 2017

The Cusp-Core Problem CUSP 10 9 45 ρ dm (M � kpc � 3 ) 40 10 8 CORE 35 30 10 7 v c (km s − 1 ) 25 20 10 6 15 10 � 2 10 � 1 10 0 r (kpc) gas 10 stars 5 0 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 R (kpc) e.g. Flores & Primack 1994; Moore 1994; Read et al. 2017

Dark Matter Heating

Dark matter heating Δ x = 4 pc View from top M res = 300 M ⊙ ρ th = 300 atoms/cc R 1/2 T gas,min = 10 K 2 kpc e.g. Navarro et al. 1996; Read & Gilmore 2005; Pontzen & Governato 2012; Read et al. 2016

Dark matter heating 10 9 10 8 ρ DM [M � kpc � 3 ] 10 7 10 6 1 Gyr 4 Gyr 8 Gyr 10 5 14 Gyr R 1 / 2 r 1 / 2 ICs 10 4 10 � 2 10 � 1 10 0 r [kpc] Read et al. 2016

Dark matter heating P NFW u r e d 10 9 a coreNFW r k m a t t e r ρ dm (M � kpc � 3 ) 10 8 DM+baryons 10 7 10 6 R 1 / 2 10 5 10 � 2 10 � 1 10 0 r (kpc) Read et al. 2016

The Cusp-Core Problem Revisited

Measurement | Rotation cuves 45 WLM 40 35 30 v c (km s − 1 ) 25 20 15 gas 10 s t a r s 5 0 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 R (kpc) Read et al. 2016b,2017

Measurement | Rotation cuves 45 WLM 40 35 30 v c (km s − 1 ) 25 20 15 gas 10 s t a r s 5 0 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 R (kpc) Read et al. 2016b,2017

45 70 R min 60 60 40 60 35 50 50 50 30 v c (km s − 1 ) v c (km s − 1 ) v c (km s − 1 ) v c (km s − 1 ) 40 40 40 25 30 30 20 30 15 20 20 Stars Stars Stars 20 10 Gas Gas Gas 10 10 Fit coreNFW 10 Fit coreNFW Fit coreNFW 5 NGC 6822 DDO168 DDO52 0 0 0 0 0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 R (kpc) R (kpc) R (kpc) R (kpc) 30 60 60 60 R min 25 50 50 50 20 40 40 40 v c (km s − 1 ) v c (km s − 1 ) v c (km s − 1 ) v c (km s − 1 ) 15 30 30 30 10 20 20 20 Stars Stars Stars Stars Gas Gas Gas Gas 5 10 10 10 Fit coreNFW Fit coreNFW Fit coreNFW Fit coreNFW CVnIdwA UGC8508 DDO126 DDO154 0 0 0 0 0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 R (kpc) R (kpc) R (kpc) R (kpc) 60 30 R min 70 70 50 25 60 60 40 20 50 50 v c (km s − 1 ) v c (km s − 1 ) v c (km s − 1 ) v c (km s − 1 ) 40 40 30 15 30 30 20 10 Stars Stars Stars Stars 20 20 Gas Gas Gas Gas 10 5 Fit coreNFW Fit coreNFW Fit coreNFW Fit coreNFW 10 10 DDO87 Aquarius DDO133 NGC2366 0 0 0 0 0 1 2 3 4 5 0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0 1 . 2 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 R (kpc) R (kpc) R (kpc) R (kpc)

“Smoking gun” evidence for DM heating

Less star formation ⇒ more cusp WLM Fornax Draco Leroy, Nature 2015 ESO/Digitized Sky Survey 2 Robert Lupton & SDSS D e c r e a s i n g s t a r f o r m a t i o n M o ⇒ r e D M c u s p !

Less star formation ⇒ more cusp WLM Fornax Draco Leroy, Nature 2015 ESO/Digitized Sky Survey 2 Robert Lupton & SDSS Rotation curves Stellar kinematics

Less star formation ⇒ more cusp Today Big Bang 10 9 WLM 10 � 2 Density (M � kpc � 3 ) SFR (M � / yr) 10 8 10 � 3 10 7 10 � 4 WLM 10 � 5 10 6 10 � 1 10 0 0 2 4 6 8 10 12 14 Age (Gyr) Radius (kpc) Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634

Less star formation ⇒ more cusp Today Big Bang 10 9 Fornax 10 � 2 Density (M � kpc � 3 ) SFR (M � / yr) 10 8 10 � 3 10 7 10 � 4 Fornax 10 � 5 10 6 10 � 1 10 0 0 2 4 6 8 10 12 14 Age (Gyr) Radius (kpc) Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634

Less star formation ⇒ more cusp Today Big Bang 10 9 Sculptor 10 � 3 Density (M � kpc � 3 ) SFR (M � / yr) 10 8 10 � 4 10 7 10 � 5 Sculptor 10 � 6 10 6 10 � 1 10 0 0 2 4 6 8 10 12 14 Age (Gyr) Radius (kpc) Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634

Less star formation ⇒ more cusp Today Big Bang 10 9 Draco 10 � 3 Density (M � kpc � 3 ) cusp SFR (M � / yr) 10 8 core 10 � 4 10 7 10 � 5 150pc Draco 10 � 6 10 6 10 � 1 10 0 0 2 4 6 8 10 12 14 Age (Gyr) Radius (kpc) Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634

10 9 ρ DM (150 pc) [M � kpc � 3 ] Tuc Dra LII LI UMi Scl Sex 10 8 Car CVnI For WLM D154 D52 Aq CVn D87 D168 N2366 10 7 10 5 10 6 10 7 10 8 M ⇤ [M � ] Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634; Gregory et al. 2019

10 9 t trunc / Gyrs > 6 ρ DM (150 pc) [M � kpc � 3 ] 3 < t trunc / Gyrs < 6 Tuc t trunc / Gyrs < 3 Dra LII LI UMi Scl Sex 10 8 Car CVnI For WLM D154 D52 Aq CVn D87 D168 N2366 10 7 10 5 10 6 10 7 10 8 M ⇤ [M � ] Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634; Gregory et al. 2019

10 9 ρ DM (150 pc) [M � kpc � 3 ] Tuc Dra LII LI UMi Scl Sex 10 8 Car CVnI For WLM D154 D52 Aq CVn D87 D168 N2366 10 7 10 9 10 10 M 200 [M � ] Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634; Gregory et al. 2019

10 9 Gregory et al. 2019 ρ DM (150 pc) [M � kpc � 3 ] Tuc cusp Dra LII LI UMi Scl Sex 10 8 Car core CVnI For WLM D154 D52 Aq CVn D87 D168 N2366 10 7 10 9 10 10 M 200 [M � ] Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634; Gregory et al. 2019

10 9 Di Cintio et al. (2014) ρ DM (150 pc) [M � kpc � 3 ] Tuc Dra LII LI UMi Scl Sex 10 8 Car CVnI For WLM D154 D52 Aq CVn D168 D87 N2366 10 7 10 � 4 10 � 3 10 � 2 M ⇤ /M 200 Read et al. 2018a,b,c: arXiv:1805.06934; arXiv:1807.07093; arXiv:1808.06634; Gregory et al. 2019

Implications

Martin Rey Matt Orkney Agertz et al. 2019 | arXiv:1904.02723

Implications | Tides Cusped Cored Read et al. 2006; Peñarrubia et al. 2010; Errani et al. 2019

Conclusions

Conclusions • We have found evidence for “dark matter heating” in nearby dwarf galaxies. • If correct, this solves the cusp-core problem (at least for the smallest dwarfs). • Implications ⇒ • Dark matter appears to be a cold, collisionless, fluid that can be heated up and moved around. • Densest dwarfs constrain “beyond-CDM” models. • Dark matter heating will impact galaxy formation from the “bottom up”. We are exploring this with EDGE. Justin I. Read