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Theoretical Cosmology and Particle Astrophysics at Caltech

Theoretical Cosmology and Particle Astrophysics at Caltech. Marc Kamionkowski August 7, 2006. Cosmology/ Û Particle/Nuclear Astrophysics Physics. Dark matter Dark energy Inflation Neutrino astrophysics Ultrahigh-energy cosmic rays Baryogenesis. Postdocs:

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Theoretical Cosmology and Particle Astrophysics at Caltech

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  1. Theoretical Cosmology and Particle Astrophysics at Caltech Marc Kamionkowski August 7, 2006

  2. Cosmology/ Û Particle/Nuclear Astrophysics Physics • Dark matter • Dark energy • Inflation • Neutrino astrophysics • Ultrahigh-energy cosmic rays • Baryogenesis

  3. Postdocs: Dan Babich (Moore prize scholar) Shin’ichiro Ando (Fairchild Fellow) Daisuke Nagai (Fairchild Fellow) Nicole Bell (Fairchild Fellow; just until January ‘07) Stefano Profumo (~60% Task B) Faculty: Marc Kamionkowski (Professor) Sean Carroll (Senior Research Associate [i.e., research professor]; Moore; are requesting DoE research funds for Sean) Andrew Benson (Senior Research Fellow [i.e., research asst prof]; Moore) Chris Hirata (assistant professor, arriving Fall 2007) People to be affiliated with Caltech theoretical cosmology and particle astrophysics 2006-2007

  4. Graduate Students: Jonathon Pritchard (5th year; DoE/NASA) Tristan Smith (4th year; TA) Anthony Pullen (3rd year; NSF Fellow) Adrienne Erickcek (3rd year; NSF Fellow) Dan Grin (3rd year; Moore Fellow) Martin Springer (3rd year; Oxford student with Benson) People to be affiliated with Caltech theoretical cosmology and particle astrophysics 2006-2007 • Visiting Associates: • Asantha Cooray (UC, Irvine) • Kris Gorski (JPL) • Elena Pierpaoli (USC) • Visitors: • Robert Caldwell (Dartmouth; 2 months; fall 2006) • Orfeu Bertolami (Lisbon; 6 months)

  5. Students: None graduating this year Postdocs/SRFs: Steven Furlanetto (assistant professor, Yale) Elena Pierpaoli (assistant professor, USC) Milos Milosavljevic (assistant professor, UT Austin) Nicole Bell (assistant professor, Adelaide) This past year’s graduates:

  6. Theory: Added Sean Carroll and Andrew Benson to research faculty (Moore). Chris Hirata will start as assistant professor fall 2007 Caltech is building in theoretical particle astrophysics: Recently funded (10-year grant) Moore Center for Theoretical Cosmology and Physics pays salaries for Benson, Carroll, two prize postdoctoral scholars, and some visitors

  7. Our recent (~year) research topics • Substructure in SUSY dark-matter halos • Tests of equivalence principle for dark matter • Probes of inflationary gravitational waves • New upper limit to gravitational-wave background • Galactic-halo merger rates • Search for dark-matter-annihilation radiation • Search for axion decay lines • Intergalactic medium • Supersymmetric dark matter • Neutrino astrophysics • The first stars and reionization ~100 refereed publications over past 5 years

  8. Our work is relevant for • SNAP/JDEM • CMB experiments (WMAP, Planck, CMBPOL… • GLAST/VERITAS/STACEE/…. • Collider experiments (to some extent) • Neutrino experiments • CDMS, etc. • Super-K, IceCube…. • LSST • SDSS/2dF…. • AMS….

  9. Benefits of this program to DoE • DoE funding heavily leveraged by Caltech • Maintains theoretical activity at major center for experimental particle astrophysics and early-Universe cosmology • Supports training of some of the best postdocs and students in the field • Grad student support goes only to advanced students, when they are most productive

  10. Funding profile • 1999-2003: ~$100K/year (PI summer salary plus student) • 2003-2004: ~$150K/year (PI summer salary, student, plus 2nd student or 50% postdoc) • 2004-2005; ~$140K/year • 2005-2006; ~$150K/year • Current request: continued funding at current level plus $50K/year supplement to provide research expenses for new faculty member (Sean Carroll) in theoretical particle astrophysics

  11. Journal articles completed over past 12 months under Task B ``Galilean Equivalence for Galactic Dark Matter,'' M. Kesden and M. Kamionkowski, astro-ph/0606566. ``Cosmological Bounds on Dark-Matter--Neutrino Interactions,'' G. Mangano, A. Melchiorri, P. Serra, A. Cooray, and M. Kamionkowski, astro-ph/0606190. ``21-cm fluctations from inhomogeneous x-ray heating before reionization,'' J. R. Pritchard and S. R. Furlanetto, astro-ph/0607234. ``The scattering of Lyman-Series Photons in the Intergalactic Medium,'' J. R. Pritchard and S. R. Furlanetto, astro-ph/0605680.

  12. ``Supermassive Black Hole Merger Rates: Uncertainties from Halo Merger Theory,'' A. L. Erickcek, M. Kamionkowski and A. J. Benson, astro-ph/0604281. To appear in MNRAS. ``Galaxy surveys, inhomogeneous reionization, and dark energy,'' J. R. Pritchard, S. R. Furlanetto and M.~Kamionkowski, ``A new cosmic microwave background constraint to primordial gravitational waves,'' T. L. Smith, E. Pierpaoli and M. Kamionkowski, Phys. Rev. Lett. 97, 021301 (2006). ``What mass are the smallest protohalos?'' S. Profumo, K. Sigurdson, and M. Kamionkowski, Phys. Rev. Lett. 97, 031301 (2006). ``Detecting dark matter WIMPs in the Draco dwarf: A multi-wavelength perspective,'' S. Colafrancesco, S. Profumo, P. Ullio, astro-ph/0607073.

  13. ``Mixed higgsino dark matter from a reduced SU(3) gaugino mass: Consequences for dark matter and collider searches,'' H. Baer, A. Mustafayev, E. K. Park, S. Profumo and X. Tata, JHEP 0604, 041 (2006). ``Baryogenesis, electric dipole moments and dark matter in the MSSM,'' V. Cirigliano, S. Profumo and M. J. Ramsey-Musolf, JHEP 0607, 002 (2006). ``Dark matter and the CACTUS gamma-ray excess from Draco,'' S. Profumo and M. Kamionkowski, JCAP 0603, 003 (2006). ``Cluster magnetic fields from large-scale-structure and galaxy-cluster shocks,'' M. V. Medvedev, L. O. Silva and M. Kamionkowski, Astrophys. J. 642, L1 (2006). ``Cosmological Parameter Estimation Using 21 cm Radiation from the Epoch of Reionization,'' M. McQuinn, O. Zahn, M. Zaldarriaga, L. Hernquist and S. R. Furlanetto, astro-ph/0512263. ``Have We Detected Patchy Reionization in Quasar Spectra?,'' A. Lidz, S. P. Oh and S. R. Furlanetto, Astrophys. J. 639, L47 (2006).

  14. ``Exploring the BWCA (Bino-Wino co-annihilation) scenario for neutralino dark matter,'' H. Baer, T. Krupovnickas, A. Mustafayev, E. K. Park, S. Profumo and X. Tata, arXiv:hep-ph/0511034. ``Low energy antideuterons: Shedding light on dark matter,'' H.~Baer and S.~Profumo, JCAP 0512, 008 (2005). ``The Evidence of Absence: Galaxy Voids in the Excursion Set Formalism,'' S. Furlanetto and T. Piran, MNRAS 366, 467 (2006). ``Cluster Merger Variance and the Luminosity Gap Statistic,'' M. Milosavljevic, C. J. Miller, S. R. Furlanetto and A. Cooray, Astrophys. J. 637, L9 (2006). ``Descending from on high: Lyman series cascades and spin-kinetic temperature coupling in the 21 cm line,'' J. R. Pritchard and S. R. Furlanetto, MNRAS 367, 1057 (2006).

  15. Big News: Sean Carroll joins Caltech faculty • Senior theorist with interests/expertise spanning string theory, particle theory, QFT, tests of Lorentz symmetry, general relativity, dark energy, and physical cosmology. • Has been DoE supported investigator at U Chicago (as asst prof). • Doubles Caltech faculty associated with Task B • Strengthens Caltech’s effort in exploring theoretical ideas for cosmic acceleration and dark energy • Enhances connection between cosmological phenomenology, particle theory, and string theory

  16. Some Recent Research

  17. New probe of primordial GWsSmith, Pierpaoli, MK, PRL 2006 “Conventional” way to probe them: 1) low-l plateau versus peaks 2) curl mode polarization New approach: Small-wavelength GWs behave as massless particles. They contribute to the energy density of the Universe and affect CMB fluctuationsand large-scale structure.

  18. New limits on gravitational-wave energy density at frequencies 10-16-10-11 Hz. At higher frequencies, constraints now comparable, and in future, stronger, than BBN , constraints Smith, Pierpaoli, MK (PRL 2006)

  19. Galilean equivalence for Galactic dark matterKesden and MK, 2006 • Does dark matter fall the same way in a gravitational field as ordinary matter? • Models that couple dark matter and dark energy may lead to additional 1/r2 force law that mimics a Newton’s constant G that is different for dark matter. • We thus consider force law for dark matter that is bigger by factor (1+2).

  20. Tidal Disruptions • Galaxies form hierarchically; smaller satellites are tidally disrupted in the haloes of larger hosts • Several stellar streams have been found in the MW, e.g. the Sgr dwarf at 24 kpc • disrupted stars retain similar orbits to satellite; trail/lead with gain/loss in energy

  21. Stellar Streams of Sgr Dwarf

  22. Tidal Streams Probe “Fifth” Force

  23. Conclusions • A coupling between dark matter and dark energy naturally leads to a “fifth” force that acts effectively as a violation of the equivalence principle for dark matter • Tidally disrupting galaxies provide perfect test; core is DM-dominated but not streams • Attractive DM-force sweeps core ahead; leading-to-trailing ratio suppressed. • Current data show roughly equally populated tidal streams; already suggests Newton constant for dark matter differs by no more than 10% from ordinary matter. • More detailed analysis of current data should be sensitive at the ~ 1% level

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