J. J. McMahon
A5040775718- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Dark Matter and Cosmic Phenomena
- Superconducting and THz Device Technology
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Microwave Engineering and Waveguides
- Neutrino Physics Research
- Computational Physics and Python Applications
- Photonic and Optical Devices
- Astronomical Observations and Instrumentation
- Calcium Carbonate Crystallization and Inhibition
- Optical Coatings and Gratings
- Particle Detector Development and Performance
- Radio Frequency Integrated Circuit Design
- Solar and Space Plasma Dynamics
- Antenna Design and Optimization
- Advanced Differential Geometry Research
University of Chicago
2011-2025
University of Michigan–Ann Arbor
2013-2024
Fermi National Accelerator Laboratory
2009-2024
Kavli Institute for Particle Astrophysics and Cosmology
2023
Michigan United
2012-2018
Lawrence Berkeley National Laboratory
2015
University of Pennsylvania
2014
Clariant (United States)
2010-2011
California University of Pennsylvania
2010
Argonne National Laboratory
2009
We present new arcminute-resolution maps of the Cosmic Microwave Background temperature and polarization anisotropy from Atacama Cosmology Telescope, using data taken 2013-2016 at 98 150 GHz. The cover more than 17,000 deg$^2$, deepest 600 deg$^2$ with noise levels below 10 $\mu$K-arcmin. use power spectrum derived almost 6,000 these to constrain cosmology. ACT enable a measurement angular scale features in both divergence-like anisotropy, tracing velocity density last-scattering. From one...
We present a catalog of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect signature from 2500 deg$^2$ South Pole Telescope (SPT) data. This work represents the complete sample detected at high significance in 2500-square-degree SPT-SZ survey, which was completed 2011. A total 677 (409) cluster candidates are identified above signal-to-noise threshold $\xi$ =4.5 (5.0). Ground- and space-based optical near-infrared (NIR) imaging confirms overdensities similarly colored galaxies...
We present a measurement of the cosmic microwave background (CMB) temperature power spectrum using data from recently completed South Pole Telescope Sunyaev–Zel'dovich (SPT-SZ) survey. This is made observations 2540 deg2 sky with arcminute resolution at 150 GHz, and improves upon previous measurements SPT by tripling area. report CMB anisotropy over multipole range 650 < ℓ 3000. fit bandpowers, combined 7 yr Wilkinson Microwave Anisotropy Probe (WMAP7) data, six-parameter ΛCDM cosmological...
Gravitational lensing of the cosmic microwave background generates a curl pattern in observed polarization. This "B-mode" signal provides measure projected mass distribution over entire observable Universe and also acts as contaminant for measurement primordial gravity-wave signals. In this Letter we present first detection gravitational B modes, using first-season data from polarization-sensitive receiver on South Pole Telescope (SPTpol). We construct template B-mode by combining E-mode...
We report the results of an 87 square-degree point-source survey centered at R.A. 5h30m, decl. -55 deg. taken with South Pole Telescope (SPT) 1.4 and 2.0 mm wavelengths arc-minute resolution milli-Jansky depth. Based on ratio flux in two bands, we separate detected sources into populations, one consistent synchrotron emission from active galactic nuclei (AGN) thermal dust. present source counts for each population 11 to 640 mJy 4.4 800 mm. The are dominated by synchrotron-dominated across...
We present the temperature and polarization angular power spectra of CMB measured by Atacama Cosmology Telescope (ACT) from 5400 deg$^2$ 2013-2016 survey, which covers $>$15000 at 98 150 GHz. For this analysis we adopt a blinding strategy to help avoid confirmation bias and, related this, show numerous checks for systematic error done before unblinding. Using likelihood cosmological constrain secondary sources anisotropy foreground emission, derive "CMB-only" spectrum that extends...
We present a detection-significance-limited catalog of 21 Sunyaev-Zel'dovich selected galaxy clusters. These clusters, along with 1 unconfirmed candidate, were identified in 178 deg^2 sky surveyed 2008 by the South Pole Telescope to depth 18 uK-arcmin at 150 GHz. Optical imaging from Blanco Cosmology Survey (BCS) and Magellan telescopes provided photometric (and some cases spectroscopic) redshift estimates, redshifts ranging z=0.15 z>1, median z = 0.74. Of confirmed three previously as...
We use South Pole Telescope data from 2008 and 2009 to detect the non-Gaussian signature in cosmic microwave background (CMB) produced by gravitational lensing measure power spectrum of projected potential. constrain ratio measured amplitude signal that expected a fiducial ΛCDM cosmological model be 0.86 ± 0.16, with no disfavored at 6.3σ. Marginalizing over models allowed Wilkinson Microwave Anisotropy Probe (WMAP7) results measurement Alens = 0.90 0.19, indicating matter fluctuations...
(abridged) We present cosmological constraints obtained from galaxy clusters identified by their Sunyaev-Zel'dovich effect signature in the 2500 square degree South Pole Telescope Sunyaev Zel'dovich survey. consider 377 cluster candidates at z>0.25 with a detection significance greater than five, corresponding to 95% purity threshold for compute on models using measured abundance as function of mass and redshift. include additional multi-wavelength observations, including Chandra X-ray data...
We present a catalog of galaxy cluster candidates, selected through their Sunyaev–Zel'dovich (SZ) effect signature in the first 720 deg2 South Pole Telescope (SPT) survey. This area was mapped with SPT 2008 and 2009 austral winters to depth ∼18 μKCMB-arcmin at 150 GHz; 550 it also ∼44 95 GHz. Based on optical imaging all 224 candidates near-infrared majority we have found and/or infrared counterparts for 158, which then classify as confirmed clusters. Of these 158 clusters, 135 were...
ABSTRACT We present the first three-frequency South Pole Telescope (SPT) cosmic microwave background (CMB) power spectra. The band powers presented here cover angular scales 2000 < ℓ 9400 in frequency bands centered at 95, 150, and 220 GHz. At these frequencies scales, a combination of primary CMB anisotropy, thermal kinetic Sunyaev–Zel'dovich (SZ) effects, radio galaxies, infrared (CIB) contributes to signal. combine Planck /HFI SPT data GHz constrain amplitude shape CIB spectrum find...
We explore extensions to the $\Lambda$CDM cosmology using measurements of cosmic microwave background (CMB) from recent SPT-SZ survey, along with data WMAP7 and $H_0$ BAO. check for consistency within between these datasets, find some tension. The CMB alone gives weak support physics beyond $\Lambda$CDM, due a slight trend relative decreasing power towards smaller angular scales. While it may be statistical fluctuation, this could also explained by several extensions. consider running index...
We present the temperature and polarization angular power spectra measured by Atacama Cosmology Telescope Polarimeter (ACTPol). analyze night-time data collected during 2013-14 using two detector arrays at 149 GHz, from 548 deg$^2$ of sky on celestial equator. use these spectra, with MBAC camera ACT 2008-10, in combination Planck WMAP to estimate cosmological parameters temperature, polarization, temperature-polarization cross-correlations. find new ACTPol be consistent LCDM model. The...
We use measurements from the South Pole Telescope (SPT) Sunyaev Zel'dovich (SZ) cluster survey in combination with X-ray to constrain cosmological parameters. present a statistical method that fits for scaling relations of SZ and observables mass while jointly fitting cosmology. The is generalizable multiple observables, self-consistently accounts effects selection uncertainties calibration on derived constraints. apply this data set consisting an SZ-selected catalog 18 galaxy clusters at z...
We present measurements of the $E$-mode polarization angular auto-power spectrum ($EE$) and temperature-$E$-mode cross-power ($TE$) cosmic microwave background (CMB) using 150 GHz data from three seasons SPTpol observations. report power spectra over spherical harmonic multipole range $50 < \ell \leq 8000$, detect nine acoustic peaks in $EE$ with high signal-to-noise ratio. These are most sensitive to date $TE$ at $\ell > 1050$ 1475$, respectively. The observations cover 500 deg$^2$, a...
The imprint left on the cosmic microwave background (CMB) from CMB photons scattering off high-energy electrons in galaxies and clusters is known as Sunyaev-Zel'dovich (SZ) effect subject of these two papers Atacama Cosmology Telescope (ACT). ACT measurements combined with those Planck BOSS are shown to provide a rich picture electron gas thermodynamics galactic cluster medium. This can be used test improve cosmological simulations relevant for upcoming experiments.
The early dark energy (EDE) scenario aims to increase the value of Hubble constant (${H}_{0}$) inferred from cosmic microwave background (CMB) data over that found in standard cosmological model ($\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$), via introduction a new form density Universe. EDE component briefly accelerates expansion just prior recombination, which reduces physical size sound horizon imprinted CMB. Previous work has nonzero is not preferred by Planck CMB power spectrum alone,...
Abstract We present tomographic measurements of structure growth using cross-correlations Atacama Cosmology Telescope (ACT) DR6 and Planck cosmic microwave background (CMB) lensing maps with the unWISE Blue Green galaxy samples, which span redshift ranges 0.2 ≲ z 1.1 0.3 1.8, respectively. improve on prior not just by making use new, high-precision ACT maps, but also including additional spectroscopic data for calibration analyzing our a more flexible theoretical model. determine amplitude...
Observations of the millimeter sky contain valuable information on a number signals, including blackbody cosmic microwave background (CMB), Galactic emissions, and Compton-y distortion due to thermal Sunyaev-Zel'dovich (tSZ) effect. Extracting new insight into cosmological astrophysical questions often requires combining multiwavelength observations spectrally isolate one component. In this work, we present arc-minute-resolution map, which traces out line-of-sight-integrated electron...
Abstract We investigate the impact and mitigation of extragalactic foregrounds for cosmic microwave background (CMB) lensing power spectrum analysis Atacama Cosmology Telescope (ACT) data release 6 (DR6) data. Two independent sky simulations are used to test a range strategies. demonstrate that finding then subtracting point sources, models clusters, using profile bias-hardened estimator together reduce fractional biases well below statistical uncertainties, with inferred amplitude, A lens ,...
The South Pole Telescope (SPT) is conducting a Sunyaev–Zel'dovich (SZ) effect survey over large areas of the southern sky, searching for massive galaxy clusters to high redshift. In this preliminary study, we focus on 40 deg2 area targeted by Blanco Cosmology Survey (BCS), which centered roughly at right ascension 5h30m, declination −53° (J2000). Over two seasons observations, entire region has been mapped SPT 95 GHz, 150 and 225 GHz. We report four most significant detections SZ in field,...
The six-meter Atacama Cosmology Telescope (ACT) in Chile was built to measure the cosmic microwave background (CMB) at arcminute angular scales. We are building a new polarization sensitive receiver for ACT (ACTPol). ACTPol will characterize gravitational lensing of CMB and aims constrain sum neutrino masses with ~ 0.05 eV precision, running spectral index inflation-induced fluctuations, primordial helium abundance better than 1 %. Our observing fields overlap SDSS BOSS survey optical...