the limits of cosmology

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Dorcas Robbins
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1 the limits of cosmology 10 may 2017 Joseph Silk IAP/JHU

2 We have made remarkable progress in cosmology in past 100 yrs. Now a precision science but the big quesjons are unanswered What is the ma>er? Where do we come from? SUMMARY Dark ma>er Primordial black holes & dwarf galaxies Primordial non-gaussianity & the dark ages

3 What is the ma>er? annihilajon + creajon annihilajon freeze-out m x /T SUSY WIMP thermal freeze-out at T~0.1m x when n<σ ann v> ~ t exp -1 relic abundance <σ ann v>~3x10-26 cm 3 /s ~0.23/Ω x

4 DARK MATTER: future of direct detecjon solar atmospheric Baudis 2014

5 DARK MATTER: status of indirect detecjon AnnihilaJons of majorana WIMPS produce high energy γ, ν, e + Lacroix Lee, S Bartels, R Ajello Daylan,T

DARK MATTER Einstein-Dilaton- Gauss-Bonnet What if we don t find dark ma>er in the next decade(s)? 1.Classification. So far, modifying gravity is ugly and doesn t work!

Lovelock s theorem (1971): degravitation 2T gravity Higher-order scenarios The only second-order, local gravitational field equations Higher dimensions Non-local derivable from an action containing

6 DARK MATTER Einstein-Dilaton- Gauss-Bonnet What if we don t find dark ma>er in the next decade(s)? 1.Classification. So far, modifying gravity is ugly and doesn t work! Look elsewhere leads to exojc opjons such as self- CLASSIFICATION Strings & Branes R f R µ 1 R µ f (G) DGP Some! Lovelock s theorem (1971): degravitation 2T gravity Higher-order scenarios The only second-order, local gravitational field equations Higher dimensions Non-local derivable from an action containing solely the 4D f (R) metric tensor R,etc. Kaluza-Klein (plus related tensors) are the Einstein field equations with a cosmological constant. Lovelock's theorem Vector Randall-Sundrum Ⅰ & Ⅱ Generalisations > 2nd-order time derivatives. of SEH TeVeS Non-local action Add things new field like content. Gauss-Bonnet Introduce new fields. Lovelock gravity Cascading gravity Scalar-tensor & Brans-Dicke Ghost condensates interacjng DM, fuzzy DM and primordial black holes 2 Posit extra Galileons dimensions. the Fab Four Chaplygin gases Non-action Emergent Don t derive field equations Scalarfrom an action. KGB Approaches CDT Padmanabhan Entanglement entropy thermo. cross-secjon Coupled Quintessence Horndeski theories Chern-Simons Cuscuton Lorentz violation Hořava-Lifschitz Tensor f(t) Einstein-Cartan-Sciama-Kibble Einstein-Aether Massive gravity Bigravity EBI Conformal gravity General R μνr μν, Lorentz violation Bimetric MOND Torsion UK theories Dark Energy Strategy 2020 mass

Trujillo-Gomez + 2016 Warm dark ma>er fails

7 mojvated by dwarf problems number density dark ma>er cores Schneider Trujillo-Gomez Warm dark ma>er fails Self-interacJng dark ma>er OK: with σ ~ 10 g/cm 2 and σ v -4

fuzzy dark ma>er ultra-light bosons with large de Broglie wavelength soliton core oscillates at Compton frequency ~ yr for our galaxy Dwarf galaxy core λ/2π=h/mv ~ 1.

8 fuzzy dark ma>er ultra-light bosons with large de Broglie wavelength soliton core oscillates at Compton frequency ~ yr for our galaxy Dwarf galaxy core λ/2π=h/mv ~ 1.9kpc x (10kms -1 /v)(10-22 ev/m) Predict millisecond pulsar Jming signal for PTA and SKA MarJno NB: ULAs constrained by strong simulajon-dependent limits from Lyα forest Schive , 2016 Schrodinger-Poisson equajon: Bose-Einstein condensate surrounded by CDM-like axions

9 Massive black holes and baryonic feedback stellar Primordial or not? supermassive

10 Primordial black holes as dark ma>er Ali-Haimoud & Kamionkoski 2017 Garcia-Bellido 2017 Schutz & Liu 2017 What SKA can fo Tada

11 Young & Byrnes 2015 Young & Byrnes 2015 PBH producjon by isocurvature modes: exponenjally sensijve to theshold & biased CMB PBH

IMBH at the Ω DM ~ 10-4 level RG118 Inoue + 2013 X-ray surveys: occupajon

12 IMBH at the Ω DM ~ 10-4 level RG118 Inoue X-ray surveys: occupajon of AGN in dwarfs ~ 1% SimulaJons M BH -σ Baldassare 2015 Rashkov+ Madau 2013

13 What IMBH can do for dwarf galaxies something new seems to be needed 1. number, cores vs cusps 2. Seeds for SMBH at high z 3. the too big to fail problem 4. ultrafaint dwarfs & ultradiffuse galaxies 5. Reduce baryon fracjon in MWG-like galaxies 6. ReionizaJon: unique 21cm dark ages signature 7. ULXs in outskirts of galaxies: relics of dwarfs 8. AGN triggering of star formajon in dwarfs

14 Black hole seeds are needed Habouzit 2016

15 the too big to fail problem Boylan-Kolchin

16 Ultrafaint dwarfs & ultradiffuse galaxies UDGs in groups SN feedback fails in realisjc ISM Roman&Trujillo 2016 M * =10 6 M sun Bland-Hawthorne

Provides new degree of freedom similar physics whereby SMBH account for massive galaxies φ(l)

17 The dwarf saga conjnues SNe are problemajc. But why invent exojc dark ma>er? which can t even solve all the dwarf problems MBH feedback can do it all! Provides new degree of freedom similar physics whereby SMBH account for massive galaxies φ(l) ConvenJonal scenario theory (CDM-motivated) observations L*= L sun hy primordial BH? strophysical MBH are probably ejected! Galaxy luminosity/mass

18 Another direcjon Dark energy? no predicjon for w -1 To B or not to B: no lower bound primordial bispectrum is unique probe of inflajon. non-gaussian: δt/t (1+ f NL δt/t)

19 THE DARK AGES OF THE UNIVERSE a prisjne environment Spin temperature

20 ULTIMATE PROBE OF INFLATION Only robust predicjon of inflajon is non-gaussianity. The signal is a small fracjon f nl δt/t of temperature fluctuajons f nl < 10 (current limit) vs ~1 (muljfield predicjon) but we d like to get to ~0.04 (vanilla inflajon, guaranteed) Maldacena 2003 f nl ~ n s -1 with Planck n s =0.96 quadrajc correcjon to potenjal simple inflajon already is strongly constrained by failure to detect gravitajonal waves in the cosmic microwave background Planck & PBH-preferred strong field inflajon: f NL ~ 1 Can we improve on Planck precision by 10 or more?

21 Microwave background probes N~10 6 independent samples to l~1000 limijng 2d accuracy N -1/2 ~ 0.1% How do we increase N? predicted! galaxy surveys? 3D probe allow N~ 10 9 but galaxies are biased probes Need to go back to the dark ages and use gas clouds, the building blocks of galaxies. This allows N > > in 3D NOW Long ago dwarf galaxies large-scale structure

22 Power spectrum: CMB vs 21cm CMB has only l ~ 10 3 or ~ 10 6 modes f nl δφ > 1/ N ~ 10-3 N first clouds 21cm Many more modes at 21cm clusters CMB galaxies LSS Kleban+ 2007

23 21cm absorpjon at z~ 50 or frequency ~ 30 MHz f nl δφ ~ (n s -1) δφ 10-6 requires N~10 12 modes (or a few arc-sec resolujon) can slice sky in 3D: eg Δν~0.1 MHz at l ~ 10 5 for N ~ x 10 2 Precision increases as 1/ N ~ 1/l can gain ~ 1000 over cosmic microwave background 10 1 Loeb & Zaldarriaga 2003

24 30-40 MHz is a very difficult frequency range to map from the Earth Need to go to far side of MOON for low radio interference Most radio-quiet environment in inner solar system

25 21 cm astronomy in dark ages OpJmal bandwidth L=1 Mpc (Δν/0.1MHz) slices of the universe Need to resolve ( l ~ 10 5 ) a few arc-seconds at wavelength of 10m seek ~10mK signal for bright sky foreground: T B ~1000K OpJmal telescope array size is l λ/2π or D ~100 km at λ~ 10 m SensiJvity: need millions of dipoles for weak signal: (πd 2 /4)/πλ 2 ~10 7 Allows N ~ patches on sky x 10 2 via tomography to a>ain modes versus 10 6 in CMB Not easy: need to remove non-gaussian foregrounds at level of x10 5 gain up to ~10 3 in N 1/2

CHIME: the world s most powerful radio telescope in BriJsh Columbia 10

antennae SKA-low 10 5 antennae in 2025 LUNAR RADIO ARRAY: 10 20

26 CHIME: the world s most powerful radio telescope in BriJsh Columbia muljplies/sec for 1024 antennae at 400 MHz in 2017 CHIME 1024 antennae SKA-low 10 5 antennae in 2025 LUNAR RADIO ARRAY: muljplies/sec for 10 6 antennae at 30 MHz compujng power achievable in 15 years from now?

27 Lunar Radio Array of ~ 10 6 dipoles Far side of the Moon ~ 2040 sensijvity and high angular resolujon at 40 MHz The uljmate dark ages explorer: a lunar dipole array with > 10 6 dipoles J. Lazio

28 Close-up of south pole Shackleton crater Thermal image

29 ESA concept: Moon Village Aims: business and tourism in 2035+

A non-gaussianity program f nl ~1 is a generic predicjon in muljfield inflajon aim: detect pa>erns of nongaussianity on the sky CMB: suborbital +space N~10 6 f nl ~10 (>3σ)

30 A non-gaussianity program f nl ~1 is a generic predicjon in muljfield inflajon aim: detect pa>erns of nongaussianity on the sky CMB: suborbital +space N~10 6 f nl ~10 (>3σ) OpJcal/IR galaxy surveys N~10 8 f nl ~1 Radio: SKA-Low-2: ~10 6 antennae in 2025 far side of Moon N~10 10 f nl ~0.1 by 2035 and eventually N~10 12 f nl ~0.01 Meerburg

31 conclusions Dark ma>er may be primordial black holes (PBH) over broad mass range PBH of ~ M sun can solve all dwarf galaxy problems Forming PBH requires primordial nongaussianity Nongaussianity is the uljmate probe of inflajon Observable via 21cm in dark ages: need many modes. Lunar radio array will provide Ø 100 improvement in precision cosmology by 2040

Elisabeth Krause, University of Arizona. COSMOLOGY, post-2025

Elisabeth Krause, University of Arizona COSMOLOGY, post-2025 Massively multiplexed spectroscopy with MSE: Science, Project, and Vision - Tucson, 02/26/2019 COSMOLOGY IN THE 2020s - SAME OLD STORY? this