Exotic Physics in the Dark Ages Katie Mack Institute of Astronomy / Kavli Institute for Cosmology, University of Cambridge

19 February 2010Cosmological ReionizationKatie Mack 2/35 Summary Future high-redshift 21cm observations will be uniquely suitable for constraining exotic physics in the Dark Ages

19 February 2010Cosmological ReionizationKatie Mack 3/35 Summary Future high-redshift 21cm observations will be uniquely suitable for constraining exotic physics in the Dark Ages My work: the evaporation of primordial black holes can produce interesting signatures in the all-sky 21cm brightness temperature and the power spectrum [arXiv: ]

19 February 2010Cosmological ReionizationKatie Mack 4/35 Summary Future high-redshift 21cm observations will be uniquely suitable for constraining exotic physics in the Dark Ages My work: the evaporation of primordial black holes can produce interesting signatures in the all-sky 21cm brightness temperature and the power spectrum [arXiv: ] Other approaches and focused searches in 21cm can improve our understanding of cosmology and fundamental physics

19 February 2010Cosmological ReionizationKatie Mack 5/35

19 February 2010Cosmological ReionizationKatie Mack 6/35

19 February 2010Cosmological ReionizationKatie Mack 7/35 Spin temperature and signal Pritchard & Loeb 2008 CMB temp Gas kinetic temp Spin temp What happens to this picture when energy is injected during the Dark Ages?

19 February 2010Cosmological ReionizationKatie Mack 8/35 Exotic physics in the Dark Ages Dark Ages Astrophysically, the Dark Ages are simple: gas is cooling adiabatically and undergoing gravitational collapse

19 February 2010Cosmological ReionizationKatie Mack 9/35 Exotic physics in the Dark Ages Astrophysically, the Dark Ages are simple: gas is cooling adiabatically and undergoing gravitational collapse If any process injects energy into the IGM before z~30, it interrupts the cooling and alters the 21cm brightness temperature Dark Ages

19 February 2010Cosmological ReionizationKatie Mack 10/35 Primordial black holes Pre-stellar black holes Formed in the early universe No stellar intermediary

19 February 2010Cosmological ReionizationKatie Mack 11/35 Primordial black holes Pre-stellar black holes Formed in the early universe No stellar intermediary Two radiation regimes: evaporation: energy injection into IGM through Hawking radiation accretion: X-ray radiation from accretion disks (see Ricotti, Ostriker & KJM 2008, ApJ 680, 829)

19 February 2010Cosmological ReionizationKatie Mack 12/35 Hawking radiation  Spectrum is roughly (but not exactly) blackbody spectral distribution Temperature ~ M -1 Power ~ M -2 Lifetime ~ M 3

19 February 2010Cosmological ReionizationKatie Mack 13/35 Hawking radiation  Spectrum is roughly (but not exactly) blackbody spectral distribution Temperature ~ M -1 Power ~ M -2 Lifetime ~ M 3 Mass Power z 0300

19 February 2010Cosmological ReionizationKatie Mack 14/35 PBH evaporation and IGM ionization Currently strongest constraints on PBH evaporation come from the gamma-ray background Alteration of ionization/temperature history during Dark Ages may be seen in the 21cm signal

19 February 2010Cosmological ReionizationKatie Mack 15/35 PBH evaporation and IGM ionization Currently strongest constraints on PBH evaporation come from the gamma-ray background Alteration of ionization/temperature history during Dark Ages may be seen in the 21cm signal

19 February 2010Cosmological ReionizationKatie Mack 16/35 Results – ionization history high-mass PBHs

19 February 2010Cosmological ReionizationKatie Mack 17/35 Results – ionization history low-mass PBHs

19 February 2010Cosmological ReionizationKatie Mack 18/35 Results – brightness temperature

19 February 2010Cosmological ReionizationKatie Mack 19/35 Results – 21cm power spectrum M = 5 x kg M = kg M = kg

19 February 2010Cosmological ReionizationKatie Mack 20/ gamma-ray constraint potential 21cm constraint PBH mass (kg)

19 February 2010Cosmological ReionizationKatie Mack 21/35 Implications 21cm observations can detect energy injection from PBHs in the Dark Ages Limits from 21cm can improve upon existing limits

19 February 2010Cosmological ReionizationKatie Mack 22/35 Implications 21cm observations can detect energy injection from PBHs in the Dark Ages Limits from 21cm can improve upon existing limits What about other kinds of exotic physics?

19 February 2010Cosmological ReionizationKatie Mack 23/35 Cosmology with 21cm A few proposed uses of 21cm observations:

19 February 2010Cosmological ReionizationKatie Mack 24/35 Cosmology with 21cm A few proposed uses of 21cm observations: Exotic energy injection:

19 February 2010Cosmological ReionizationKatie Mack 25/35 Cosmology with 21cm A few proposed uses of 21cm observations: Dark matter decay and annihilation (Furlanetto et al. 2006, Valdes et al. 2007, Finkbeiner et al. 2008, Myers & Nusser 2008, Natarajan & Schwarz 2009)

19 February 2010Cosmological ReionizationKatie Mack 26/35 Cosmology with 21cm A few proposed uses of 21cm observations: 21cm structure mapping: Longer reach than galaxy surveys More information than CMB Mao et al. 2008

19 February 2010Cosmological ReionizationKatie Mack 27/35 Cosmology with 21cm A few proposed uses of 21cm observations: Dark matter decay and annihilation (Furlanetto et al. 2006, Valdes et al. 2007, Finkbeiner et al. 2008, Myers & Nusser 2008, Natarajan & Schwarz 2009) Cosmological parameter estimation (McQuinn et al. 2006, Bowman et al. 2007, Mao et al. 2008) Primordial non-gaussianity (Cooray et al. 2008) Varying fundamental “constants” (Katri & Wandelt 2007 & 2009) Primordial gravitational waves (Bharadwaj & Sarkar 2009) Inflationary parameters (Barger et al. 2009) Neutrino masses (Pritchard & Pierpaoli 2008) Cosmic superstrings (Khatri & Wandelt 2008) Primordial isocurvature perturbations (Gordon & Pritchard 2009)

19 February 2010Cosmological ReionizationKatie Mack 28/35 Observations 21cm brightness temperature Exotic physics affects the 21cm all-sky brightness temperature signal 21cm power spectrum 21cm power spectrum depends on matter power spectrum as well as gas physics – can be used to distinguish structure formation models Redshift space distortions If the 3D 21cm power spectrum can be measured accurately enough, the underlying matter power spectrum can be extracted, which can be tested against cosmological models

19 February 2010Cosmological ReionizationKatie Mack 29/35 21cm power spectrum Bowman et al Furlanetto et al Finkbeiner et al decaying dark matter “exciting” dark matter cosmological parameters α, h, n s, Ω b

19 February 2010Cosmological ReionizationKatie Mack 30/35 Brightness temperature Furlanetto et al Finkbeiner et al Valdes et al 2007 decaying dark matter “exciting” dark matter decaying and annihilating DM See next talk by Marcos Valdes

19 February 2010Cosmological ReionizationKatie Mack 31/35 Redshift space information Pritchard & Loeb 2008 isotropic μ 4 : sourced by velocity correlations μ2μ2

19 February 2010Cosmological ReionizationKatie Mack 32/35 Angular power spectrum and higher orders Natarajan & Schwarz 2009 Cooray et al Gordon & Pritchard 2009 annihilating DM primordial isocurvature perturbations primordial non-gaussianity

19 February 2010Cosmological ReionizationKatie Mack 33/35 Probing really small scales Tegmark & Zaldarriaga 2009 Small scale measurements plus large volume equals lots of Fourier modes distant future instrument

19 February 2010Cosmological ReionizationKatie Mack 34/35 Probing really small scales Khatri & Wandelt 2008 Khatri & Wandelt 2009 varying fundamental “constants” cosmic superstrings Planck

19 February 2010Cosmological ReionizationKatie Mack 35/35 Outlook Future 21cm experiments can constrain cosmology and exotic physics Foregrounds and instrumental challenges make it difficult, but worth trying Cosmological parameter Improvement in constraint with second- generation array Dark energy density1.7 Matter density2.5 Baryon density1.5 Neutrino mass3.0 Spectral index n s 1.4 Running in spectral index α 2.7 Barger et al Furlanetto et al. 2009; McQuinn et al. 2006

19 February 2010Cosmological ReionizationKatie Mack 36/35