70 research outputs found
Cosmological Tensions and the Transitional Planck Mass Model
In this followup analysis, we update previous constraints on the Transitional
Planck Mass (TPM) modified gravity model using the latest version of EFTCAMB
and provide new constraints using SPT and Planck anisotropy data along with
Planck CMB lensing, BAO, SNe Ia, and an prior from local measurements. We
find that large shifts in the Planck mass lead to large suppression of power on
small scales that is disfavored by both SPT and Planck. Using only SPT TE-EE
data, this suppression of power can be compensated for by an upward shift of
the scalar index to resulting in kmsMpc and a shift in the Planck
mass. Including Planck TT and Planck TE-EE data restricts the
shift to be at with
kmsMpc. Excluding the prior, SPT and Planck data constrain
the shift in the Planck mass to be at with a best-fit value of
, consistent with the CDM limit. In this case kmsMpc, which is partially elevated by the
dynamics of the scalar-field in the late universe. This differs from EDE models
that prefer higher values of when high Planck TT data are
excluded. We additionally constrain TPM using RSD data from BOSS DR 12 and
cosmic shear, galaxy-galaxy lensing, and galaxy clustering data from DES Y1
finding both disfavor transitions close to recombination, but earlier Planck
mass transitions are allowed.Comment: 25 pages, 8 figures, 8 table
The Atacama Cosmology Telescope: Lensing of CMB Temperature and Polarization Derived from Cosmic Infrared Background Cross-Correlation
We present a measurement of the gravitational lensing of the Cosmic Microwave Background (CMB) temperature and polarization fields obtained by cross-correlating the reconstructed convergence signal from the first season of Atacama Cosmology Telescope Polarimeter data at 146 GHz with Cosmic Infrared Background (CIB) fluctuations measured using the Planck satellite. Using an effective overlap area of 92.7 square degrees, we detect gravitational lensing of the CMB polarization by large-scale structure at a statistical significance of 4.5 sigma. Combining both CMB temperature and polarization data gives a lensing detection at 9.1 sigma significance. A B-mode polarization lensing signal is present with a significance of 3.2 sigma. We also present the first measurement of CMB lensing-CIB correlation at small scales corresponding to l \u3e 2000. Null tests and systematic checks show that our results are not significantly biased by astrophysical or instrumental systematic effects, including Galactic dust. Fitting our measurements to the best-fit lensing-CIB cross-power spectrum measured in Planck data, scaled by an amplitude A, gives A = 1.02(-0.08)(+0.12)(stat.) +/- 0.06(syst.), consistent with the Planck results
Power-law Template for Infrared Point-source Clustering
We perform a combined fit to angular power spectra of unresolved infrared (IR) point sources from the Planck
satellite (at 217, 353, 545, and 857 GHz, over angular scales 100 ≾ ℓ ≾ 2200), the Balloon-borne Large-Aperture
Submillimeter Telescope (BLAST; 250, 350, and 500μm; 1000 ≾ ℓ ≾ 9000), and from correlating BLAST and Atacama Cosmology Telescope (ACT; 148 and 218 GHz) maps. We find that the clustered power over the range of angular scales and frequencies considered is well fitted by a simple power law of the form C^(clust)_ℓ ∝ ℓ^(-n) with n = 1.25 ± 0.06. While the IR sources are understood to lie at a range of redshifts, with a variety of dust properties, we find that the frequency dependence of the clustering power can be described by the square of a modified blackbody, ν^(β)B(ν, T_(eff)), with a single emissivity index β = 2.20 ± 0.07 and effective temperature T_(eff) = 9.7 K. Our predictions for the clustering amplitude are consistent with existing ACT and South Pole Telescope results at around 150 and 220 GHz, as is our prediction for the effective dust spectral index, which we find to be α_(150–220) = 3.68±0.07 between 150 and 220 GHz. Our constraints on the clustering shape and frequency dependence can be used to model the IR clustering as a contaminant in cosmic microwave background anisotropy measurements. The combined Planck and BLAST data also rule out a linear bias clustering model
Calibrating CHIME, A New Radio Interferometer to Probe Dark Energy
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a transit
interferometer currently being built at the Dominion Radio Astrophysical
Observatory (DRAO) in Penticton, BC, Canada. We will use CHIME to map neutral
hydrogen in the frequency range 400 -- 800\,MHz over half of the sky, producing
a measurement of baryon acoustic oscillations (BAO) at redshifts between 0.8 --
2.5 to probe dark energy. We have deployed a pathfinder version of CHIME that
will yield constraints on the BAO power spectrum and provide a test-bed for our
calibration scheme. I will discuss the CHIME calibration requirements and
describe instrumentation we are developing to meet these requirements
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