Michael D. Niemack
A5033083354- Radio Astronomy Observations and Technology
- Superconducting and THz Device Technology
- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Physics of Superconductivity and Magnetism
- Dark Matter and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Microwave Engineering and Waveguides
- Scientific Research and Discoveries
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Radio Frequency Integrated Circuit Design
- Geophysics and Gravity Measurements
- Optical Coatings and Gratings
- Thermal Radiation and Cooling Technologies
- Photonic and Optical Devices
- Astrophysical Phenomena and Observations
- Antenna Design and Optimization
- Computational Physics and Python Applications
- Precipitation Measurement and Analysis
- Spacecraft and Cryogenic Technologies
Cornell University
2016-2025
Lawrence Berkeley National Laboratory
2024
Columbia University
2023
University of Michigan–Ann Arbor
2023
University of California, Berkeley
2023
University of Southern California
2022
Arizona State University
2018
Max Planck Institute for Radio Astronomy
2015
Max Planck Society
2015
Quantum Devices (United States)
2009-2014
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...
SCUBA-2 is an innovative 10000 pixel bolometer camera operating at submillimetre wavelengths on the James Clerk Maxwell Telescope (JCMT). The has capability to carry out wide-field surveys unprecedented depths, addressing key questions relating origins of galaxies, stars and planets. With two imaging arrays working simultaneously in atmospheric windows 450 850 microns, vast increase count means that maps sky 100-150 times faster than previous SCUBA instrument. In this paper we present...
This book lays out the scientific goals to be addressed by next-generation ground-based cosmic microwave background experiment, CMB-S4, envisioned consist of dedicated telescopes at South Pole, high Chilean Atacama plateau and possibly a northern hemisphere site, all equipped with new superconducting cameras. CMB-S4 will dramatically advance cosmological studies crossing critical thresholds in search for B-mode polarization signature primordial gravitational waves, determination number...
We present constraints on cosmological and astrophysical parameters from high-resolution microwave background maps at 148 GHz 218 made by the Atacama Cosmology Telescope (ACT) in three seasons of observations 2008 to 2010. A model primary secondary foreground is fit map power spectra lensing deflection spectrum, including contributions both thermal Sunyaev-Zeldovich (tSZ) effect kinematic (kSZ) effect, Poisson correlated anisotropy unresolved infrared sources, radio correlation between tSZ...
[Abridged] We present a catalog of 68 galaxy clusters, which 19 are new discoveries, detected via the Sunyaev-Zel'dovich effect (SZ) at 148 GHz in Atacama Cosmology Telescope (ACT) survey 504 square degrees on celestial equator. A subsample 48 clusters within 270 degree region overlapping SDSS Stripe 82 is estimated to be 90% complete for M_500c > 4.5e14 Msun and 0.15 < z 0.8. While matched filters used detect sample studied further through "Profile Based Amplitude Analysis" using...
We present cosmological parameters derived from the angular power spectrum of cosmic microwave background (CMB) radiation observed at 148 GHz and 218 over 296 deg2 with Atacama Cosmology Telescope (ACT) during its 2008 season. ACT measures fluctuations scales 500 < ℓ 10, 000. fit a model for lensed CMB, Sunyaev–Zel'dovich (SZ), foreground contribution to spectra, including thermal kinetic SZ, Poisson radio infrared point sources, clustered sources. At = 3000, about half comes primary CMB...
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 the temperature power spectra of cosmic microwave background (CMB) derived from three seasons data Atacama Cosmology Telescope (ACT) at 148 GHz and 218 GHz, as well cross-frequency spectrum between two channels. detect correct for contamination due to Galactic cirrus in our equatorial maps. results a number tests possible systematic error conclude that any effects are not significant compared statistical errors we quote. Where they overlap, cross-correlate ACT South Pole (SPT)...
We report the first detection of gravitational lensing cosmic microwave background through a measurement four-point correlation function in temperature maps made by Atacama Cosmology Telescope. verify our calculating levels potential contaminants and performing number null tests. The resulting convergence power spectrum at 2° angular scales measures amplitude matter density fluctuations on comoving length around 100 Mpc redshifts 0.5 to 3. measured signal agrees with Lambda cold dark...
Using high-resolution microwave sky maps made by the Atacama Cosmology Telescope, we for first time present strong evidence motions of galaxy clusters and groups via background temperature distortions due to kinematic Sunyaev-Zel'dovich effect. Galaxy are identified their constituent luminous galaxies observed Baryon Oscillation Spectroscopic Survey, part Sloan Digital Sky Survey III. We measure mean pairwise momentum clusters, with a probability signal being random errors 0.002, is...
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...
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 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 (sub)millimeter sky contains a vast wealth of information that is both complementary and inaccessible to other wavelengths. Over half the light we receive observable at millimeter submillimeter wavelengths, yet have mapped only small portion sufficient spatial resolution sensitivity detect resolve distant galaxies or star-forming cores within their large- scale environments. For decades, astronomical community has highlighted need for large, high-throughput ( λ ~ 0.35–10 mm) single dish....
We report on 23 clusters detected blindly as Sunyaev–ZEL'DOVICH (SZ) decrements in a 148 GHz, 455 deg2 map of the southern sky made with data from Atacama Cosmology Telescope 2008 observing season. All SZ detections announced this work have confirmed optical counterparts. Ten are new discoveries. One newly discovered cluster, ACT-CL J0102−4915, redshift 0.75 (photometric), has an decrement comparable to most massive systems at lower redshifts. Simulations cluster recovery method reproduce...
The Atacama Cosmology Telescope was designed to measure small-scale anisotropies in the Cosmic Microwave Background and detect galaxy clusters through Sunyaev-Zel'dovich effect. instrument is located on Cerro Toco Desert, at an altitude of 5190 meters. A six-meter off-axis Gregorian telescope feeds a new type cryogenic receiver, Millimeter Bolometer Array Camera. receiver features three 1000-element arrays transition-edge sensor bolometers for observations 148 GHz, 218 277 GHz. Each detector...
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...
We present a detailed analysis from new multi-wavelength observations of the exceptional galaxy cluster ACT-CL J0102-4915 "El Gordo," likely most massive, hottest, X-ray luminous and brightest Sunyaev-Zeldovich (SZ) effect known at z>0.6. The Atacama Cosmology Telescope collaboration discovered El Gordo as significant SZ decrement in sky survey area 755 deg^2. Our VLT/FORS2 spectra 89 member galaxies yield redshift, z=0.870, velocity dispersion, s=1321+/-106 km/s. Chandra reveal hot system...
We report on measurements of the cosmic microwave background (CMB) and celestial polarization at 146 GHz made with Atacama Cosmology Telescope Polarimeter (ACTPol) in its first three months observing. Four regions sky covering a total 270 square degrees were mapped an angular resolution $1.3'$. The map noise levels four are between 11 17 $\mu$K-arcmin. present TT, TE, EE, TB, EB, BB power spectra from these regions. observed E-mode spectrum, displaying six acoustic peaks range...
The Atacama Cosmology Telescope has measured the angular power spectra of microwave fluctuations to arcminute scales at frequencies 148 and 218 GHz, from three seasons data. At small in primordial Cosmic Microwave Background (CMB) become increasingly obscured by extragalactic foregounds secondary CMB signals. We present results a nine-parameter model describing these effects, including thermal kinematic Sunyaev-Zel'dovich (tSZ kSZ) power; clustered Poisson-like Infrared (CIB) sources, their...