THURSDAY

• 9:00 am — Lyman Page, Princeton
  ACTPol
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• 9:50 am — Kyle Story, University of Chicago
  SPTpol
  SPTpol is a polarization-sensitive receiver installed in early 2012 on the South Pole Telescope (SPT). SPTpol is being used in an on-going survey to map the cosmic microwave background (CMB) in temperature and polarization. These observations have been used to detect B-mode polarization power in the CMB, measure the EE and TE CMB power spectra, and measure the CMB gravitational lensing potential. Measurements of gravitational lensing of the CMB directly probe the projected mass in the universe out to high redshifts. Gravitational lensing encodes a wealth of information in the CMB about the growth and geometry of large-scale structure which is sensitive to cosmic acceleration (dark energy), the expansion history of the universe, and the properties of neutrinos. Additionally, measurements of gravitational lensing can be used to improve inflationary gravitational wave searches in the CMB and constrain the relationship between dark and luminous matter at high redshifts. I will present the current status of SPTpol, including the recently published EE and TE power spectra and the measurement of the CMB gravitational lensing potential.
  
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• 10:40 am — break
• 11:00 am — Marc-Antoine Miville-Deschenes, IAS
  Dust with Planck
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• 11:50 am — Christopher Sheehy, University of Chicago
  BICEP2
  In this talk I will present results from the BICEP2 experiment, a microwave polarimeter that observed at the South Pole from 2010-2012 and that in March 2014 reported a high-significance detection of degree scale B-mode polarization . I will discuss the instrument, analysis and results, and review recent progress made toward understanding the origin of the signal.
  
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• 12:15 pm — Alexandra Rahlin, Princeton University
  SPIDER
  We present the results of integration and characterization of the SPIDER instrument after the 2013 pre-flight campaign. SPIDER is a balloon-borne polarimeter designed to probe the primordial gravitational wave signal in the degree-scale B-mode polarization of the cosmic microwave background. With six independent telescopes housing over 2000 detectors in the 94 GHz and 150 GHz frequency bands, SPIDER will map 7.5% of the sky with a depth of 11 to 14 uK-arcmin at each frequency, which is a factor of about 5 improvement over Planck. We discuss the integration of the pointing, cryogenic, electronics, and power sub-systems, as well as pre-flight characterization of the detectors and optical systems. SPIDER is currently in the field for a December 2014 flight from Antarctica, and is expected to be limited by astrophysical foreground emission, and not instrumental sensitivity, over the survey region.
  
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• 12:40 pm — lunch
• 2:00 pm — Dmitri Pogosyan, University of Alberta
  Topology of the Universe from Planck CMB data
  Cosmic Microwave Background provides us data on the structure of our Universe from the largest
  observable distances. In this talk I will discuss what limits are placed by the recent Planck data on the possibility that our Universe has complex multi-connected space, and how this analysis is performed.
  
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• 2:25 pm — Alexander van Engelen, CITA
  Lensing of the CMB with ACTPol
  The gravitational lensing of the CMB has recently emerged as an important cosmological probe. The lensing signal is sensitive to matter fluctuations on larger scales and at higher redshifts than are accessible through other means. It can also be used in cross-correlation with other surveys to highlight properties of tracer populations. I will show the first results of the measurement of the lensing of the CMB polarization from the ACTPol survey, based on cross-correlation with maps of the cosmic infrared background from the Planck satellite. I will also discuss the constraints on cosmology that will be possible using data from future surveys.
  
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• 2:50 pm — Heather Prince, UKZN
  Real Space Lensing Reconstruction using CMB Temperature and Polarisation
  Gravitational lensing of the cosmic microwave background (CMB) probes the distribution of matter in our universe, of which dark matter forms a dominant part. It also allows us to delens the CMB and obtain an accurate picture of its primordial fluctuations. We explore methods of reconstructing the lensing field from the lensed CMB temperature and polarisation in real space, as an alternative to the harmonic space estimators currently in use. Real space estimators have the advantage of being local in nature and they are thus equipped to deal with the nonuniform sky coverage, galactic cuts and point source excisions found in experimental data. These estimators can be applied to CMB temperature and polarisation maps to reconstruct the lensing convergence and shear, which are directly related to the matter distribution.
  
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• 3:15 pm — Heiko Heilgendorff, UKZN
  C-BASS
  The C-Band All-Sky Survey (C-BASS) is a radio telescope experiment that will measure polarised Galactic synchrotron emission over the entire sky. Maps from C-BASS will be used to remove Galactic foreground contamination in CMB polarisation experiments. The C-BASS experiment consists of two receivers, both operating at 5 GHz with a 1 GHz bandwidth and ~0.7 deg angular resolution. The northern telescope, operating at the Owens Valley Radio Observatory in California, will end its observations early in 2015 while the southern telescope, operating at the SKA Support Site in Klerefontein, is in the final stages of commissioning. In this talk, I will give an overview of the C-BASS experiment and present some preliminary results from the Northern Survey.
  
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• 3:40 pm — break

Thursday evening – hippo cruise and conference banquet

FRIDAY

• 9:00 am — Veeresh Singh, UKZN
  High-redshift radio galaxies and associated overdensities
  Ultra steep spectrum (USS) radio sources are one of the efficient tracers of powerful High-z radio galaxies (HzRGs). Fainter USS samples derived from deeper radio surveys can be useful in finding HzRGs at even higher redshifts and in unveiling a population of obscured weaker radio−loud AGN at moderate redshifts. We study properties of a USS sample derived from deep 325 MHz and 1.4 GHz observations. Our study shows that the criterion of ultra steep spectral index remains a reasonably efficient method to select high-z sources even at sub-mJy flux densities. We find that the powerful HzRGs in our sample tend to reside in (proto)cluster environments.
  
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• 9:30 am — Lee Whittaker, University of Manchester
  Separating weak lensing and intrinsic alignments using polarization information
  Using the polarization position angle of an observed galaxy as a tracer of it’s intrinsic orientation, we develop techniques for cleanly separating weak gravitational lensing signals from intrinsic alignment contamination in forthcoming radio surveys. Errors on the intrinsic orientation estimates introduce biases into the shear estimates, however, we demonstrate that these biases can be corrected for if the error distribution is accurately known. We demonstrate our methods using simulations, where we reconstruct the shear and intrinsic alignment auto and cross spectra in three distinct redshift bins. We find that the polarization position angle information can be used to successfully reconstruct both the lensing and intrinsic alignment spectra with negligible residual biasing.
  
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• 9:50 am — Yin-Zhe Ma, University of Manchester
  Detection of the missing baryons with thermal and kinetic Sunyaev-Zeldovich effect
  Previous studies of galaxy formation have shown that only 10 per cent of the baryons are in compact objects, while 90 per cent of them are missing. Numerical simulation shows that the missing baryons are in a state of diffuse plasma with temperature 10^5 to 10^7 Kevlin, which is hard to be detected by X-ray observations. We will present two studies that coherently detect the missing baryons. The first is the cross-correlation between the kinetic Sunyaev-Zeldovich maps from Planck with the linear reconstructed velocity field. We find significance (4.6 sigma) detection of the peculiar motion of gas on Mpc scales. Further studies show that this bulk motion indicates that the concentration of gas constitutes a fraction of f_b=0.8, which indicates that all baryons are detected with the Planck kSZ maps. Second, we cross-correlate the thermal Sunyaev- Zeldovich from Planck maps with gravitational lensing from the Canada France Hawaii Lensing Survey (CFHTLenS) and constrain the diffuse baryon component with the various pressure profile. We find that the 1 and 2 halo terms detected at 3.96$\sigma$ and 3.67$\sigma$ confidence level (CL) respectively. The effective virial temperature of the isothermal gas is found to be in the range 7 *10^{5}–3*10^{8} K. In addition, by stacking the pairs of luminous red galaxies, we can place a constraint on the temperature of the filament in between the dark matter halos.
  
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• 10:40 am — break
• 11:00 am — Michele Maggiore, University of Geneva
  Nonlocal gravity and comparison with cosmological datasets
  We discuss a recently proposed modification of GR, in which a mass scale is introduced as a coefficient of a suitable non-local term. Such non-localities are expected to emerge at an effective level from a fundamental local theory, as a consequence of infrared effects in curved space. The model has the same number of parameters as LCDM, with a mass parameter replacing the cosmological constant, and is very predictive. We show that at the phenomenological level it works very well: at the background level it generates a dynamical dark energy, and provides a neat prediction for the dark energy EOS, which turns out to be phantom. The cosmological perturbations are well-behaved. We have implemented the perturbations in a Boltzmann code and we find that the model fits well CMB, BAO and SNa data, with a chi2 comparable or slightly better then LCDM. From these datasets we predict a value of h0=72, which would resolve the potential discrepancy with local measurements of H0.
  
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• 11:50 am — Nelson Padilla, P. Universidad Católica de Chile
  Void properties in f(R) gravity
  We investigate void properties in f(R) models using N-body simulations, focusing on their differences from General Relativity (GR) and their detectability. In the Hu-Sawicki f(R) modified gravity (MG) models, the halo number density profiles of voids are not distinguishable from GR. In contrast, the same f(R) voids are more empty of dark matter, and their profiles are steeper. This can in principle be observed by weak gravitational lensing of voids, for which the combination of a spectroscopic redshift and a lensing photometric redshift survey over the same sky is required. Neglecting the lensing shape noise, the f(R) model parameter amplitudes |fR_0|=10^−5 and 10^−4 may be distinguished from GR using the lensing tangential shear signal around voids by 4 and 8σ for a volume of ~1(Gpc/h)^3. The line-of-sight projection of large-scale structure is the main systematics that limits the significance of this signal for the near future wide angle and deep lensing surveys. For this reason, it is challenging to distinguish |fR_0|=10^−6 from GR. We expect that this can be overcome with larger volume. The halo void abundance being smaller and the steepening of dark matter void profiles in f(R) models are unique features that can be combined to break the degeneracy between |fR_0| and σ8.
  
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• 12:40 pm — lunch
• 2:00 pm — J. Richard Bond, CITA
  Inflation from the 2014 Planck Era and Beyond
  I am giving an invited talk at COS, but the organizers have not yet given me the requested topic. I am sure it will involve our Planck 2014 results, which will be released at the beginning of December, probably on inflation.

Local organising committee:

• H. Cynthia Chiang (University of KwaZulu-Natal)
• Matt Hilton (University of KwaZulu-Natal)
• Kavilan Moodley (University of KwaZulu-Natal)
• Jonathan Sievers (University of KwaZulu-Natal)
• Amanda Weltman (University of Cape Town)
• Sahal Yacoob (University of KwaZulu-Natal)