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Hilton, M., et al., We present a catalog of 4195 optically confirmed Sunyaev–Zel’dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13,211 deg of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150 GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04 < z < 1.91 (median z = 0.52). The catalog contains 222 z > 1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M > 3.8 × 10 M, evaluated at z = 0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2 4. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566 deg), the Hyper Suprime-Cam Subaru Strategic Program (469 deg), and the Kilo Degree Survey (825 deg). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10 Gyr., The DES Data Management System is supported by the NSF under Grant Nos. AST-1138766 and AST-1536171. The DES participants from Spanish institutions are partially supported by MICINN under grants ESP2017-89838, PGC2018-094773, PGC2018-102021, SEV-2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Unionʼs Seventh Framework Program (FP7/2007-2013) including ERC grant agreements 240672, 291329, and 306478. We acknowledge support from the Brazilian Instituto Nacional de Ciência e Tecnologia (INCT) do e-Universo (CNPq grant 465376/2014-2).

Near-field radio holography is a common method for measuring and aligning mirror surfaces for millimeter and sub-millimeter telescopes. In instruments with more than a single mirror, degeneracies arise in the holography measurement, requiring multiple measurements and new fitting methods. We present HoloSim-ML, a Python code for beam simulation and analysis of radio holography data from complex optical systems. This code uses machine learning to efficiently determine the position of hundreds of mirror adjusters on multiple mirrors with few micron accuracy. We apply this approach to the example of the Simons Observatory 6m telescope., Software is publicly available at: https://github.com/McMahonCosmologyGroup/holosim-ml

We are developing arrays of 150 GHz transition edge sensor (TES) polarimeters for the South Pole Telescope polarimeter (SPTpol). Prototype devices use an aluminum manganese (Al-Mn) alloy TES with a normal resistance Rn suited to frequency domain multiplexing (fMUX) used in SPTpol. Using the fMUX readout, the devices exhibit noise performance consistent with expectations when R >; 0.8Rn. Below 0.8Rn, the detectors have high loopgain and become unstable, which is predicted by use of a compound TES model. We address this issue in a recent fabrication with increased TES heat capacity and normal metal structures on the TES to tune the temperature sensitivity.

Advanced ACTPol is a polarization-sensitive upgrade for the 6 m aperture Atacama Cosmology Telescope (ACT), adding new frequencies and increasing sensitivity over the previous ACTPol receiver. In 2016, Advanced ACTPol will begin to map approximately half the sky in five frequency bands (28-230 GHz). Its maps of primary and secondary cosmic microwave background (CMB) anisotropies -- imaged in intensity and polarization at few arcminute-scale resolution -- will enable precision cosmological constraints and also a wide array of cross-correlation science that probes the expansion history of the universe and the growth of structure via gravitational collapse. To accomplish these scientific goals, the Advanced ACTPol receiver will be a significant upgrade to the ACTPol receiver, including four new multichroic arrays of cryogenic, feedhorn-coupled AlMn transition edge sensor (TES) polarimeters (fabricated on 150 mm diameter wafers); a system of continuously rotating meta-material silicon half-wave plates; and a new multiplexing readout architecture which uses superconducting quantum interference devices (SQUIDs) and time division to achieve a 64-row multiplexing factor. Here we present the status and scientific goals of the Advanced ACTPol instrument, emphasizing the design and implementation of the Advanced ACTPol cryogenic detector arrays., 9 pages, 3 figures, conference proceedings submitted to Journal of Low Temperature Physics

We evaluate the modulation of Cosmic Microwave Background (CMB) polarization using a rapidly-rotating, half-wave plate (HWP) on the Atacama B-Mode Search (ABS). After demodulating the time-ordered-data (TOD), we find a significant reduction of atmospheric fluctuations. The demodulated TOD is stable on time scales of 500-1000 seconds, corresponding to frequencies of 1-2 mHz. This facilitates recovery of cosmological information at large angular scales, which are typically available only from balloon-borne or satellite experiments. This technique also achieves a sensitive measurement of celestial polarization without differencing the TOD of paired detectors sensitive to two orthogonal linear polarizations. This is the first demonstration of the ability to remove atmospheric contamination at these levels from a ground-based platform using a rapidly-rotating HWP.

The next generation of Cosmic Microwave Background (CMB) experiments probing for signals of inflation and small angular scale polarization anisotropies require higher sensitivity and better control of systematics. We are developing monolithic arrays of orthomode transducer (OMT) coupled transition edge sensor (TES) polarimeters designed for operation at 150 GHz to address these requirements. OMT coupling allows for simultaneous and independent detection of two orthogonal linear polarization states incident on a single pixel. We present measurements of optical efficiencies η op of single pixels with on-chip band-defining filters, with η op = 57±4 stat±9 sys %. We also provide evidence for an out-of-band blue leak and address possible sources as well as mitigation techniques. Additionally, we discuss methods for increasing efficiency being implemented in the next generation of pixels, currently in fabrication. Still under development, these pixels are produced as monolithic polarimeter arrays and are slated for use in the Atacama Cosmology Telescope Polarization (ACTpol) and South Pole Telescope Polarization (SPTpol) experiments, while single-pixel polarimeters are to be deployed in the Atacama B-mode Search (ABS) experiment.

The next generation of cosmic microwave background (CMB) polarization experiments targeting the signatures of inflation will require unprecedented sensitivities in addition to careful control of systematics. With existing detector technologies approaching the photon noise limit, improvements in system sensitivities must come from ever‐larger focal plane arrays of millimeter‐wave detectors. We report on the design and performance of microfabricated planar orthomode transducer (OMT) coupled TES polarimeters and silicon micromachined platelet feedhorns optimized for scaling to large monolithic arrays. Future versions of these detectors are targeted for deployment in a number of upcoming CMB experiments, including ABS, SPTpol, and ACTpol.

We present data characterizing the optical properties of feedhorn‐coupled TES polarimeters useful for future CMB measurements. In this detector architecture, TES bolometers are coupled to radiation through superconducting microstrip to a planar ortho‐mode transducer inserted into waveguide. Filters in the microstrip define the pass bands for the detectors. We will present measurements of the co‐polar optical efficiency, the cross‐polar isolation and the detector bandpass and compare these results to expectations from simulations.

We present simulations and discuss measurements of a planar orthomode transducer (OMT) being developed for use with bolometric detectors in observations of the polarization of the cosmic microwave background (CMB). This OMT couples radiation from a circular waveguide onto microstrip where it is filtered and then detected. A corrugated feed horn defines the optical beam. Simulations suggest this OMT achieves a coupling efficiency of greater than 96% with cross‐polarization below 1% over 30% bandwidth.

We present results from modeling the electrothermal performance of feedhorn‐coupled transition edge sensor (TES) polarimeters under development for use in cosmic microwave background (CMB) polarization experiments. Each polarimeter couples radiation from a corrugated feedhorn through a planar orthomode transducer, which transmits power from orthogonal polarization modes to two TES bolometers. We model our TES with two‐ and three‐block thermal architectures. We fit the complex impedance data at multiple points in the TES transition. From the fits, we predict the noise spectra. We present comparisons of these predictions to the data for two TESes on a prototype polarimeter.

We are developing feedhorn‐coupled TES polarimeters to measure the polarization anisotropies of the cosmic microwave background (CMB) radiation. These devices will be deployed in arrays of hundreds to thousands and will be measured using multiplexed SQUID readout electronics. Since multiplexed devices share common circuitry, a high degree of uniformity is required in the electrothermal properties of the TES bolometers and readout circuits in order to operate all channels simultaneously with high sensitivity. Our cryogenic test bed can probe dozens of devices simultaneously, thus providing useful detector statistics on relatively short time scales. We describe the TES bolometer design and present dark (no optical loading) measurements of the electrical and thermal properties and uniformity of prototype bolometers across two 3‐inch diameter production wafers, including (standard deviation in parenthesis): TES transition temperature (∼1%), normal resistance (∼10%), thermal conductance (≲10%), time constant (∼20%), shunt resistance (≲5%), and noise properties.

Protein myristoylation was investigated in the yeast secretory pathway. Conditional secretory mutations were used to accumulate inteRmediaries in the pathway between the endoplasmic reticulum and Golgi (sec 18, 20), within the Golgi (sec 7), and between the Golgi and plasma membrane (sec 1, 3, 4, 5, 6, 8, 9). The accumulation of vesicles was paralleled by the enrichment of a defined subset of proteins modified either via ester or amide linkages to myristic acid: Myristoylated proteins of 21, 32, 49, 56, 75, and 136 kDa were enriched between the endoplasmic reticulum and Golgi; proteins of 21, 32, 45, 56, 75, 136 kDa were enriched by blocks within the Golgi; and proteins of 18, 21, 32, 36, 49, 68, and 136 kDa were trapped in a myristoylated form by blocks between the Golgi and plasma membrane. This enrichment of myristoylated proteins was reversed upon returning the cells to the permissive temperature for secretion. The fatty acid was linked to the 21-kDa protein via a hydroxylamine-resistant amide linkage (N-myristoylation) and to the proteins of 24, 32, 49, 56, 68, 136 kDa via hydroxylamine-labile ester linkage (E-myristoylation). In addition, myristoylated proteins of 21, 56, and 136 kDa were glycosylated via amino linkages to asparagine. This suggests they are exposed to the lumen of the secretory pathway. Three proteins (24, 32, and 56) were E-myristoylated in the presence of protein synthesis inhibitors, indicating this modification can occur posttranslationally. After using cycloheximide to clear protein passengers from the secretory pathway the 21-, 32-, and 56-kDa proteins continued to accumulate in a myristoylated form when vesicular transport was blocked between the Golgi and plasma membrane. These data suggest that myristoylation occurs on a component of the secretory machinery rather than on a passenger protein.