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SPIDER is a balloon-borne instrument designed to map the cosmic microwave background at degree-angular scales in the presence of Galactic foregrounds. SPIDER has mapped a large sky area in the Southern Hemisphere using more than 2000 transition-edge sensors (TESs) during two NASA Long Duration Balloon flights above the Antarctic continent. During its first flight in January 2015, SPIDER observed in the 95 GHz and 150 GHz frequency bands, setting constraints on the B-mode signature of primordial gravitational waves. Its second flight in the 2022-23 season added new receivers at 280 GHz, each using an array of TESs coupled to the sky through feedhorns formed from stacks of silicon wafers. These receivers are optimized to produce deep maps of polarized Galactic dust emission over a large sky area, providing a unique data set with lasting value to the field. In this work, we describe the instrument's performance during SPIDER's second flight., Comment: Submitted to SPIE Astronomical Telescopes + Instrumentation 2024, JATIS

Using data from the first flight of SPIDER and from Planck HFI, we probe the properties of polarized emission from interstellar dust in the SPIDER observing region. Component separation algorithms operating in both the spatial and harmonic domains are applied to probe their consistency and to quantify modeling errors associated with their assumptions. Analyses spanning the full SPIDER region demonstrate that i) the spectral energy distribution of diffuse Galactic dust emission is broadly consistent with a modified-blackbody (MBB) model with a spectral index of $\beta_\mathrm{d}=1.45\pm0.05$ $(1.47\pm0.06)$ for $E$ ($B$)-mode polarization, slightly lower than that reported by Planck for the full sky; ii) its angular power spectrum is broadly consistent with a power law; and iii) there is no significant detection of line-of-sight decorrelation of the astrophysical polarization. The size of the SPIDER region further allows for a statistically meaningful analysis of the variation in foreground properties within it. Assuming a fixed dust temperature $T_\mathrm{d}=19.6$ K, an analysis of two independent sub-regions of that field results in inferred values of $\beta_\mathrm{d}=1.52\pm0.06$ and $\beta_\mathrm{d}=1.09\pm0.09$, which are inconsistent at the $3.9\,\sigma$ level. Furthermore, a joint analysis of SPIDER and Planck 217 and 353 GHz data within a subset of the SPIDER region is inconsistent with a simple MBB at more than $3\,\sigma$, assuming a common morphology of polarized dust emission over the full range of frequencies. These modeling uncertainties have a small--but non-negligible--impact on limits on the cosmological tensor-to-scalar ratio derived from the \spider dataset. The fidelity of the component separation approaches of future CMB polarization experiments may thus have a significant impact on their constraining power., Comment: 21 pages, 15 figures

Experiments deploying large arrays of transition-edge sensors (TESs) often require a robust method to monitor gain variations with minimal loss of observing time. We propose a sensitive and non-intrusive method for monitoring variations in TES responsivity using small square waves applied to the TES bias. We construct an estimator for a TES's small-signal power response from its electrical response that is exact in the limit of strong electrothermal feedback. We discuss the application and validation of this method using flight data from SPIDER, a balloon-borne telescope that observes the polarization of the cosmic microwave background with more than 2000 TESs. This method may prove useful for future balloon- and space-based instruments, where observing time and ground control bandwidth are limited., Comment: 7 pages, 3 figures; Proceedings of the 19th International Workshop on Low Temperature Detectors (LTD19); Minor updates to match published version

Modern CMB analysis pipelines regularly employ complex time-domain filters, beam models, masking, and other techniques during the production of sky maps and their corresponding angular power spectra. However, these processes can generate couplings between multipoles from the same spectrum and from different spectra, in addition to the typical power attenuation. Within the context of pseudo-$C_\ell$ based, MASTER-style analyses, the net effect of the time-domain filtering is commonly approximated by a multiplicative transfer function, $F_{\ell}$, that can fail to capture mode mixing and is dependent on the spectrum of the signal. To address these shortcomings, we have developed a simulation-based spectral correction approach that constructs a two-dimensional transfer matrix, $J_{\ell\ell'}$, which contains information about mode mixing in addition to mode attenuation. We demonstrate the application of this approach on data from the first flight of the SPIDER balloon-borne CMB experiment., Comment: 14 pages, 7 figures; updated to match published version

We present the XFaster analysis package. XFaster is a fast, iterative angular power spectrum estimator based on a diagonal approximation to the quadratic Fisher matrix estimator. XFaster uses Monte Carlo simulations to compute noise biases and filter transfer functions and is thus a hybrid of both Monte Carlo and quadratic estimator methods. In contrast to conventional pseudo-$C_\ell$ based methods, the algorithm described here requires a minimal number of simulations, and does not require them to be precisely representative of the data to estimate accurate covariance matrices for the bandpowers. The formalism works with polarization-sensitive observations and also data sets with identical, partially overlapping, or independent survey regions. The method was first implemented for the analysis of BOOMERanG data, and also used as part of the Planck analysis. Here, we describe the full, publicly available analysis package, written in Python, as developed for the analysis of data from the 2015 flight of the SPIDER instrument. The package includes extensions for self-consistently estimating null spectra and for estimating fits for Galactic foreground contributions. We show results from the extensive validation of XFaster using simulations, and its application to the SPIDER data set., Comment: 18 pages, 11 figures

We present the first linear polarization measurements from the 2015 long-duration balloon flight of SPIDER, an experiment designed to map the polarization of the cosmic microwave background (CMB) on degree angular scales. Results from these measurements include maps and angular power spectra from observations of 4.8% of the sky at 95 and 150 GHz, along with the results of internal consistency tests on these data. While the polarized CMB anisotropy from primordial density perturbations is the dominant signal in this region of sky, Galactic dust emission is also detected with high significance; Galactic synchrotron emission is found to be negligible in the SPIDER bands. We employ two independent foreground-removal techniques in order to explore the sensitivity of the cosmological result to the assumptions made by each. The primary method uses a dust template derived from Planck data to subtract the Galactic dust signal. A second approach, employing a joint analysis of SPIDER and Planck data in the harmonic domain, assumes a modified-blackbody model for the spectral energy distribution of the dust with no constraint on its spatial morphology. Using a likelihood that jointly samples the template amplitude and $r$ parameter space, we derive 95% upper limits on the primordial tensor-to-scalar ratio from Feldman-Cousins and Bayesian constructions, finding $r<0.11$ and $r<0.19$, respectively. Roughly half the uncertainty in $r$ derives from noise associated with the template subtraction. New data at 280 GHz from SPIDER's second flight will complement the Planck polarization maps, providing powerful measurements of the polarized Galactic dust emission., Comment: 29 pages, 13 figures

In this work we describe upgrades to the Spider balloon-borne telescope in preparation for its second flight, currently planned for December 2021. The Spider instrument is optimized to search for a primordial B-mode polarization signature in the cosmic microwave background at degree angular scales. During its first flight in 2015, Spider mapped ~10% of the sky at 95 and 150 GHz. The payload for the second Antarctic flight will incorporate three new 280 GHz receivers alongside three refurbished 95- and 150 GHz receivers from Spider's first flight. In this work we discuss the design and characterization of these new receivers, which employ over 1500 feedhorn-coupled transition-edge sensors. We describe pre-flight laboratory measurements of detector properties, and the optical performance of completed receivers. These receivers will map a wide area of the sky at 280 GHz, providing new information on polarized Galactic dust emission that will help to separate it from the cosmological signal., Comment: 13 pages, 8 figures; as published in the conference proceedings for SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X (2020)

Future mm-wave and sub-mm space missions will employ large arrays of multiplexed Transition Edge Sensor (TES) bolometers. Such instruments must contend with the high flux of cosmic rays beyond our atmosphere that induce "glitches" in bolometer data, which posed a challenge to data analysis from the Planck bolometers. Future instruments will face the additional challenges of shared substrate wafers and multiplexed readout wiring. In this work we explore the susceptibility of modern TES arrays to the cosmic ray environment of space using two data sets: the 2015 long-duration balloon flight of the SPIDER cosmic microwave background polarimeter, and a laboratory exposure of SPIDER flight hardware to radioactive sources. We find manageable glitch rates and short glitch durations, leading to minimal effect on SPIDER analysis. We constrain energy propagation within the substrate through a study of multi-detector coincidences, and give a preliminary look at pulse shapes in laboratory data., Comment: 9 pages, 6 figures, Proceedings of the 18th International Workshop on Low Temperature Detectors

Given the recent detection of gravitational waves from individual sources it is almost a certainty that some form of background of gravitational waves will be detected in future. The most promising candidate for such a detection are backgrounds made up of incoherent superposition of the signal of unresolved astrophysical or, backgrounds sourced by earlier cosmological events. Such backgrounds will also contain anisotropies about an average value. The information contained in the background level and any anisotropies will be extremely valuable as an astrophysical and cosmological probe. As such, the ability to reconstruct sky maps of the signal will become important as the sensitivity increases. We build and test a pixel--based, maximum--likelihood Gravitational Wave Background (GWB) map-maker that uses the cross-correlation of sets of generalised baselines as input. The resulting maps are a representation of the GWB power, or strain "intensity" on the sky. We test the algorithm by reconstructing known input maps with different baseline configurations. We also apply the map-maker to a subset of the Advance LIGO data., Comment: 13 pages

SPIDER is a balloon-borne instrument designed to map the polarization of the millimeter-wave sky at large angular scales. SPIDER targets the B-mode signature of primordial gravitational waves in the cosmic microwave background (CMB), with a focus on mapping a large sky area with high fidelity at multiple frequencies. SPIDER's first longduration balloon (LDB) flight in January 2015 deployed a total of 2400 antenna-coupled Transition Edge Sensors (TESs) at 90 GHz and 150 GHz. In this work we review the design and in-flight performance of the SPIDER instrument, with a particular focus on the measured performance of the detectors and instrument in a space-like loading and radiation environment. SPIDER's second flight in December 2018 will incorporate payload upgrades and new receivers to map the sky at 285 GHz, providing valuable information for cleaning polarized dust emission from CMB maps., Comment: 10 pages, 7 figures, LTD17 Conference

We describe the construction and characterization of the 280 GHz bolometric focal plane units (FPUs) to be deployed on the second flight of the balloon-borne SPIDER instrument. These FPUs are vital to SPIDER's primary science goal of detecting or placing an upper limit on the amplitude of the primordial gravitational wave signature in the cosmic microwave background (CMB) by constraining the B-mode contamination in the CMB from Galactic dust emission. Each 280 GHz focal plane contains a 16 x 16 grid of corrugated silicon feedhorns coupled to an array of aluminum-manganese transition-edge sensor (TES) bolometers fabricated on 150 mm diameter substrates. In total, the three 280 GHz FPUs contain 1,530 polarization sensitive bolometers (765 spatial pixels) optimized for the low loading environment in flight and read out by time-division SQUID multiplexing. In this paper we describe the mechanical, thermal, and magnetic shielding architecture of the focal planes and present cryogenic measurements which characterize yield and the uniformity of several bolometer parameters. The assembled FPUs have high yields, with one array as high as 95% including defects from wiring and readout. We demonstrate high uniformity in device parameters, finding the median saturation power for each TES array to be ~3 pW at 300 mK with a less than 6% variation across each array at one standard deviation. These focal planes will be deployed alongside the 95 and 150 GHz telescopes in the SPIDER-2 instrument, slated to fly from McMurdo Station in Antarctica in December 2018.

We present a new upper limit on CMB circular polarization from the 2015 flight of SPIDER, a balloon-borne telescope designed to search for $B$-mode linear polarization from cosmic inflation. Although the level of circular polarization in the CMB is predicted to be very small, experimental limits provide a valuable test of the underlying models. By exploiting the non-zero circular-to-linear polarization coupling of the HWP polarization modulators, data from SPIDER's 2015 Antarctic flight provide a constraint on Stokes $V$ at 95 and 150 GHz from $33<\ell<307$. No other limits exist over this full range of angular scales, and SPIDER improves upon the previous limit by several orders of magnitude, providing 95% C.L. constraints on $\ell (\ell+1)C_{\ell}^{VV}/(2\pi)$ ranging from 141 $\mu K ^2$ to 255 $\mu K ^2$ at 150 GHz for a thermal CMB spectrum. As linear CMB polarization experiments become increasingly sensitive, the techniques described in this paper can be applied to obtain even stronger constraints on circular polarization., Comment: 9 pages, 4 figures, 5 tables - Updated to version accepted for publication in ApJ, modified acknowledgements

We describe the SPIDER flight cryostat, which is designed to cool six millimeter-wavelength telescopes during an Antarctic long-duration balloon flight. The cryostat, one of the largest to have flown on a stratospheric payload, uses liquid helium-4 to deliver cooling power to stages at 4.2 and 1.6 K. Stainless steel capillaries facilitate a high flow impedance connection between the main liquid helium tank and a smaller superfluid tank, allowing the latter to operate at 1.6 K as long as there is liquid in the 4.2 K main tank. Each telescope houses a closed cycle helium-3 adsorption refrigerator that further cools the focal planes down to 300 mK. Liquid helium vapor from the main tank is routed through heat exchangers that cool radiation shields, providing negative thermal feedback. The system performed successfully during a 17 day flight in the 2014-2015 Antarctic summer. The cryostat had a total hold time of 16.8 days, with 15.9 days occurring during flight., Comment: 15 pgs, 17 figs

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 $\mu$K$\cdot$arcmin at each frequency, which is a factor of $\sim$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 well prepared 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., Comment: 25 pages, 14 figures. Presented at SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII, June 26, 2014. To be published in Proceedings of SPIE Volume 9153

We present the second generation BLASTbus electronics. The primary purposes of this system are detector readout, attitude control, and cryogenic housekeeping, for balloon-borne telescopes. Readout of neutron transmutation doped germanium (NTD-Ge) bolometers requires low noise and parallel acquisition of hundreds of analog signals. Controlling a telescope's attitude requires the capability to interface to a wide variety of sensors and motors, and to use them together in a fast, closed loop. To achieve these different goals, the BLASTbus system employs a flexible motherboard-daughterboard architecture. The programmable motherboard features a digital signal processor (DSP) and field-programmable gate array (FPGA), as well as slots for three daughterboards. The daughterboards provide the interface to the outside world, with versions for analog to digital conversion, and optoisolated digital input/output. With the versatility afforded by this design, the BLASTbus also finds uses in cryogenic, thermometry, and power systems. For accurate timing control to tie everything together, the system operates in a fully synchronous manner. BLASTbus electronics have been successfully deployed to the South Pole, and flown on stratospheric balloons., Comment: Presented at SPIE Ground-based and Airborne Telescopes V, June 23, 2014. To be published in Proceedings of SPIE Volume 9145

We introduce the light-weight carbon fiber and aluminum gondola designed for the SPIDER balloon-borne telescope. SPIDER is designed to measure the polarization of the Cosmic Microwave Background radiation with unprecedented sensitivity and control of systematics in search of the imprint of inflation: a period of exponential expansion in the early Universe. The requirements of this balloon-borne instrument put tight constrains on the mass budget of the payload. The SPIDER gondola is designed to house the experiment and guarantee its operational and structural integrity during its balloon-borne flight, while using less than 10% of the total mass of the payload. We present a construction method for the gondola based on carbon fiber reinforced polymer tubes with aluminum inserts and aluminum multi-tube joints. We describe the validation of the model through Finite Element Analysis and mechanical tests., Comment: 16 pages, 11 figures. Presented at SPIE Ground-based and Airborne Telescopes V, June 23, 2014. To be published in Proceedings of SPIE Volume 9145

An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of SPIDER, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. In the 2010 and 2012 BLASTPol flights from McMurdo Station, Antarctica, the system demonstrated an accuracy of <5' rms in-flight, and <5" rms post-flight., Comment: 16 pages, 10 figures, Presented at SPIE Ground-based and Airborne Telescopes V, June 23, 2014. To be published in Proceedings of SPIE Volume 9145

Templates for polarised emission from Galactic foregrounds at frequencies relevant to Cosmic Microwave Background (CMB) polarisation experiments are obtained by modelling the Galactic Magnetic Field (GMF) on large scales. This work extends the results of O'Dea et al. by including polarised synchrotron radiation as a source of foreground emission. The polarisation direction and fraction in this calculation are based solely on the underlying choice of GMF model and therefore provide an independent prediction for the polarisation signal on large scales. Templates of polarised foregrounds may be of use when forecasting effective experimental sensitivity. In turn, as measurements of the CMB polarisation over large fractions of the sky become routine, this model will allow for the data to constrain parameters in the, as yet, not well understood form of the GMF., Comment: 9 pages, 7 figures

The upcoming generation of cosmic microwave background (CMB) experiments face a major challenge in detecting the weak cosmic B-mode signature predicted as a product of primordial gravitational waves. To achieve the required sensitivity these experiments must have impressive control of systematic effects and detailed understanding of the foreground emission that will influence the signal. In this paper, we present templates of the intensity and polarisation of emission from one of the main Galactic foregrounds, interstellar dust. These are produced using a model which includes a 3D description of the Galactic magnetic field, examining both large and small scales. We also include in the model the details of the dust density, grain alignment and the intrinsic polarisation of the emission from an individual grain. We present here Stokes parameter template maps at 150GHz and provide an on-line repository (http://www.imperial.ac.uk/people/c.contaldi/fgpol) for these and additional maps at frequencies that will be targeted by upcoming experiments such as EBEX, Spider and SPTpol., Comment: 7 pages, 4 figures

We evaluate the ability of SPIDER, a balloon-borne polarimeter, to detect a divergence-free polarization pattern ("B-modes") in the Cosmic Microwave Background (CMB). In the inflationary scenario, the amplitude of this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. We show that the expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological signal with r=0.03. We present a scanning strategy that enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while accessing a relatively wide range of angular scales. Evaluating the amplitude of the polarized Galactic emission in the SPIDER field, we conclude that the polarized emission from interstellar dust is as bright or brighter than the cosmological signal at all SPIDER frequencies (90 GHz, 150 GHz, and 280 GHz), a situation similar to that found in the "Southern Hole." We show that two ~20-day flights of the SPIDER instrument can constrain the amplitude of the B-mode signal to r<0.03 (99% CL) even when foreground contamination is taken into account. In the absence of foregrounds, the same limit can be reached after one 20-day flight., Comment: 29 pages, 8 figures, 4 tables; v2: matches published version, flight schedule updated, two typos fixed in Table 2, references and minor clarifications added, results unchanged

We describe the cryogenic system for SPIDER, a balloon-borne microwave polarimeter that will map 8% of the sky with degree-scale angular resolution. The system consists of a 1284 L liquid helium cryostat and a 16 L capillary-filled superfluid helium tank, which provide base operating temperatures of 4 K and 1.5 K, respectively. Closed-cycle helium-3 adsorption refrigerators supply sub-Kelvin cooling power to multiple focal planes, which are housed in monochromatic telescope inserts. The main helium tank is suspended inside the vacuum vessel with thermally insulating fiberglass flexures, and shielded from thermal radiation by a combination of two vapor cooled shields and multi-layer insulation. This system allows for an extremely low instrumental background and a hold time in excess of 25 days. The total mass of the cryogenic system, including cryogens, is approximately 1000 kg. This enables conventional long duration balloon flights. We will discuss the design, thermal analysis, and qualification of the cryogenic system., Comment: 11 pages, 4 figures; as published in the conference proceedings for SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010)

Here we describe the design and performance of the Spider instrument. Spider is a balloon-borne cosmic microwave background polarization imager that will map part of the sky at 90, 145, and 280 GHz with sub-degree resolution and high sensitivity. This paper discusses the general design principles of the instrument inserts, mechanical structures, optics, focal plane architecture, thermal architecture, and magnetic shielding of the TES sensors and SQUID multiplexer. We also describe the optical, noise, and magnetic shielding performance of the 145 GHz prototype instrument insert., Comment: 12 pages, 5 figures, Proceedings of SPIE, Astronomical Telescopes and Instrumentation 2010, San Diego, CA

We describe SPIDER, a balloon-borne instrument to map the polarization of the millimeter-wave sky with degree angular resolution. Spider consists of six monochromatic refracting telescopes, each illuminating a focal plane of large-format antenna-coupled bolometer arrays. A total of 2,624 superconducting transition-edge sensors are distributed among three observing bands centered at 90, 150, and 280 GHz. A cold half-wave plate at the aperture of each telescope modulates the polarization of incoming light to control systematics. Spider's first flight will be a 20-30-day Antarctic balloon campaign in December 2011. This flight will map \sim8% of the sky to achieve unprecedented sensitivity to the polarization signature of the gravitational wave background predicted by inflationary cosmology. The Spider mission will also serve as a proving ground for these detector technologies in preparation for a future satellite mission., Comment: 12 pages, 6 figures; as published in the conference proceedings for SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010)

Spider is a balloon-borne instrument designed to map the polarization of the cosmic microwave background (CMB) with degree-scale resolution over a large fraction of the sky. Spider's main goal is to measure the amplitude of primordial gravitational waves through their imprint on the polarization of the CMB if the tensor-to-scalar ratio, r, is greater than 0.03. To achieve this goal, instrumental systematic errors must be controlled with unprecedented accuracy. Here, we build on previous work to use simulations of Spider observations to examine the impact of several systematic effects that have been characterized through testing and modeling of various instrument components. In particular, we investigate the impact of the non-ideal spectral response of the half-wave plates, coupling between focal plane components and the Earth's magnetic field, and beam mismatches and asymmetries. We also present a model of diffuse polarized foreground emission based on a three-dimensional model of the Galactic magnetic field and dust, and study the interaction of this foreground emission with our observation strategy and instrumental effects. We find that the expected level of foreground and systematic contamination is sufficiently low for Spider to achieve its science goals., Comment: submitted to APJ, 15 pages, 12 figures

We assess the strengths and weaknesses of several likelihood formalisms, including the XFaster likelihood. We compare the performance of the XFaster likelihood to that of the Offset Lognormal Bandpower likelihood on simulated data for the Planck satellite. Parameters estimated with these two likelihoods are in good agreement. The advantages of the XFaster likelihood can therefore be realized without compromising performance., Comment: 16 pages, 8 figures, 1 table, submitted to MNRAS

We develop the XFaster Cosmic Microwave Background (CMB) temperature and polarization anisotropy power spectrum and likelihood technique for the Planck CMB satellite mission. We give an overview of this estimator and its current implementation and present the results of applying this algorithm to simulated Planck data. We show that it can accurately extract the power spectrum of Planck data for the high-l multipoles range. We compare the XFaster approximation for the likelihood to other high-l likelihood approximations such as Gaussian and Offset Lognormal and a low-l pixel-based likelihood. We show that the XFaster likelihood is not only accurate at high-l, but also performs well at moderately low multipoles. We also present results for cosmological parameter Markov Chain Monte Carlo estimation with the XFaster likelihood. As long as the low-l polarization and temperature power are properly accounted for, e.g., by adding an adequate low-l likelihood ingredient, the input parameters are recovered to a high level of accuracy., Comment: 25 pages, 20 figures, updated to reflect published version: slightly extended account of XFaster technique, added improved plots and minor corrections. Accepted for publication in MNRAS

We use Minkowski Functionals (MF) to constrain a primordial non-Gaussian contribution to the CMB intensity field as observed in the 150 GHz and 145 GHz BOOMERanG maps from the 1998 and 2003 flights, respectively, performing for the first time a joint analysis of the two datasets. A perturbative expansion of the MF formulae in the limit of a weakly non-Gaussian field yields analytical formulae, derived by Hikage et al. (2006), which can be used to constrain the coupling parameter f_NL without the need for non-Gaussian simulations. We find -1020

The Sunyaev-Zel'dovich (SZ) effect is the inverse Compton-scattering of cosmic microwave background (CMB) photons by hot electrons in the intervening gas throughout the universe. The effect has a distinct spectral signature that allows its separation from other signals in multifrequency CMB datasets. Using CMB anisotropies measured at three frequencies by the BOOMERanG 2003 flight we constrain SZ fluctuations in the 10 arcmin to 1 deg angular range. Propagating errors and potential systematic effects through simulations, we obtain an overall upper limit of 15.3 uK (2 sigma) for rms SZ fluctuations in a broad bin between multipoles of of 250 and 1200 at the Rayleigh-Jeans (RJ) end of the spectrum. When combined with other CMB anisotropy and SZ measurements, we find that the local universe normalization of the density perturbations is sigma-8(SZ) < 0.96 at the 95% confidence level, consistent with sigma-8 determined from primordial perturbations., Comment: accepted for publication in ApJ. Letters

Modern cosmology has sharpened questions posed for millennia about the origin of our cosmic habitat. The age-old questions have been transformed into two pressing issues primed for attack in the coming decade: How did the Universe begin? and What physical laws govern the Universe at the highest energies? The clearest window onto these questions is the pattern of polarization in the Cosmic Microwave Background (CMB), which is uniquely sensitive to primordial gravity waves. A detection of the special pattern produced by gravity waves would be not only an unprecedented discovery, but also a direct probe of physics at the earliest observable instants of our Universe. Experiments which map CMB polarization over the coming decade will lead us on our first steps towards answering these age-old questions., Comment: Science White Paper submitted to the US Astro2010 Decadal Survey. Full list of 212 author available at http://cmbpol.uchicago.edu

We present final results on the angular power spectrum of total intensity anisotropies in the CMB from the CBI. Our analysis includes all primordial anisotropy data collected between January 2000 and April 2005, and benefits significantly from an improved maximum likelihood analysis pipeline. It also includes results from a 30 GHz foreground survey conducted with the Green Bank Telescope (GBT) which places significant constraints on the possible contamination due to foreground point sources. We improve on previous CBI results by about a factor of two in the damping tail. These data confirm, at ~3-sigma, the existence of an excess of power over intrinsic CMB anisotropy on small angular scales (l > 1800). Using the GBT survey, we find currently known radio source populations are not capable of generating the power; a new population of faint sources with steeply rising spectral indices would be required to explain the excess with sources... We also present a full cosmological parameter analysis of the new CBI power spectrum... With CBI alone, the full parameter analysis finds the excess is 1.6-sigma above the level expected for a sigma_8=0.8 universe. We find the addition of high-l CMB data substantially improves constraints on cosmic string contributions to the TT power spectrum as well as the running of the scalar spectral index... We also present forecasts for what other experiments should see at different frequencies and angular resolutions given the excess power observed by CBI. We find that the reported high-l bandpowers from current high resolution CMB bolometer experiments are consistent with each other and CBI if the excess power is due to the SZE at the CBI-level of 2.5 +/- 1 times the sigma_8=0.8 standard SZ template. , Comment: 38 Pages, 9 Figures, 5 Tables v2 - fixed typos

Spider is a balloon-borne experiment that will measure the polarization of the Cosmic Microwave Background over a large fraction of a sky at 1 degree resolution. Six monochromatic refracting millimeter-wave telescopes with large arrays of antenna-coupled transition-edge superconducting bolometers will provide system sensitivities of 4.2 and 3.1 micro K_cmb rt s at 100 and 150 GHz, respectively. A rotating half-wave plate will modulate the polarization sensitivity of each telescope, controlling systematics. Bolometer arrays operating at 225 GHz and 275 GHz will allow removal of polarized galactic foregrounds. In a 2-6 day first flight from Alice Springs, Australia in 2010, Spider will map 50% of the sky to a depth necessary to improve our knowledge of the reionization optical depth by a large factor., Comment: To appear in Proceedings of SPIE Volume 7010, Editors: Jacobus M. Oschmann, Jr.; Mattheus W. M. de Graauw; Howard A. MacEwen, "Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter"

In this paper, we present results from the complete set of cosmic microwave background (CMB) radiation temperature anisotropy observations made with the Arcminute Cosmology Bolometer Array Receiver (ACBAR) operating at 150 GHz. We include new data from the final 2005 observing season, expanding the number of detector-hours by 210% and the sky coverage by 490% over that used for the previous ACBAR release. As a result, the band-power uncertainties have been reduced by more than a factor of two on angular scales encompassing the third to fifth acoustic peaks as well as the damping tail of the CMB power spectrum. The calibration uncertainty has been reduced from 6% to 2.1% in temperature through a direct comparison of the CMB anisotropy measured by ACBAR with that of the dipole-calibrated WMAP5 experiment. The measured power spectrum is consistent with a spatially flat, LambdaCDM cosmological model. We include the effects of weak lensing in the power spectrum model computations and find that this significantly improves the fits of the models to the combined ACBAR+WMAP5 power spectrum. The preferred strength of the lensing is consistent with theoretical expectations. On fine angular scales, there is weak evidence (1.1 sigma) for excess power above the level expected from primary anisotropies. We expect any excess power to be dominated by the combination of emission from dusty protogalaxies and the Sunyaev-Zel'dovich effect (SZE). However, the excess observed by ACBAR is significantly smaller than the excess power at ell > 2000 reported by the CBI experiment operating at 30 GHz. Therefore, while it is unlikely that the CBI excess has a primordial origin; the combined ACBAR and CBI results are consistent with the source of the CBI excess being either the SZE or radio source contamination., Comment: Submitted to ApJ; Changed to apply a WMAP5-based calibration. The cosmological parameter estimation has been updated to include WMAP5

Spider is a long-duration, balloon-borne polarimeter designed to measure large scale Cosmic Microwave Background (CMB) polarization with very high sensitivity and control of systematics. The instrument will map over half the sky with degree angular resolution in I, Q and U Stokes parameters, in four frequency bands from 96 to 275 GHz. Spider's ultimate goal is to detect the primordial gravity wave signal imprinted on the CMB B-mode polarization. One of the challenges in achieving this goal is the minimization of the contamination of B-modes by systematic effects. This paper explores a number of instrument systematics and observing strategies in order to optimize B-mode sensitivity. This is done by injecting realistic-amplitude, time-varying systematics in a set of simulated time-streams. Tests of the impact of detector noise characteristics, pointing jitter, payload pendulations, polarization angle offsets, beam systematics and receiver gain drifts are shown. Spider's default observing strategy is to spin continuously in azimuth, with polarization modulation achieved by either a rapidly spinning half-wave plate or a rapidly spinning gondola and a slowly stepped half-wave plate. Although the latter is more susceptible to systematics, results shown here indicate that either mode of operation can be used by Spider., Comment: 15 pages, 12 figs, version with full resolution figs available here http://www.astro.caltech.edu/~lgg/spider_front.htm

We analyze the BOOMERanG 2003 (B03) 145 GHz temperature map to constrain the amplitude of a non Gaussian, primordial contribution to CMB fluctuations. We perform a pixel space analysis restricted to a portion of the map chosen in view of high sensitivity, very low foreground contamination and tight control of systematic effects. We set up an estimator based on the three Minkowski functionals which relies on high quality simulated data, including non Gaussian CMB maps. We find good agreement with the Gaussian hypothesis and derive the first limits based on BOOMERanG data for the non linear coupling parameter f_NL as -300

We report improved measurements of temperature anisotropies in the cosmic microwave background (CMB) radiation made with the Arcminute Cosmology Bolometer Array Receiver (ACBAR). In this paper, we use a new analysis technique and include 30% more data from the 2001 and 2002 observing seasons than the first release to derive a new set of band-power measurements with significantly smaller uncertainties. The planet-based calibration used previously has been replaced by comparing the flux of RCW38 as measured by ACBAR and BOOMERANG to transfer the WMAP-based BOOMERANG calibration to ACBAR. The resulting power spectrum is consistent with the theoretical predictions for a spatially flat, dark energy dominated LCDM cosmology including the effects of gravitational lensing. Despite the exponential damping on small angular scales, the primary CMB fluctuations are detected with a signal-to-noise ratio of greater than 4 up to multipoles of l=2000. This increase in the precision of the fine-scale CMB power spectrum leads to only a modest decrease in the uncertainties on the parameters of the standard cosmological model. At high angular resolution, secondary anisotropies are predicted to be a significant contribution to the measured anisotropy. A joint analysis of the ACBAR results at 150 GHz and the CBI results at 30 GHz in the multipole range 2000 < l < 3000 shows that the power, reported by CBI in excess of the predicted primary anisotropy, has a frequency spectrum consistent with the thermal Sunyaev-Zel'dovich effect and inconsistent with primary CMB. The results reported here are derived from a subset of the total ACBAR data set; the final ACBAR power spectrum at 150 GHz will include 3.7 times more effective integration time and 6.5 times more sky coverage than is used here., Comment: 19 pages, 9 figures, ApJ

We discuss instrumental and analytic methods that have been developed for the first generation of bolometric cosmic microwave background (CMB) polarimeters. The design, characterization, and analysis of data obtained using Polarization Sensitive Bolometers (PSBs) are described in detail. This is followed by a brief study of the effect of various polarization modulation techniques on the recovery of sky polarization from scanning polarimeter data. Having been successfully implemented on the sub-orbital Boomerang experiment, PSBs are currently operational in two terrestrial CMB polarization experiments (QUaD and the Robinson Telescope). We investigate two approaches to the analysis of data from these experiments, using realistic simulations of time ordered data to illustrate the impact of instrumental effects on the fidelity of the recovered polarization signal. We find that the analysis of difference time streams takes full advantage of the high degree of common mode rejection afforded by the PSB design. In addition to the observational efforts currently underway, this discussion is directly applicable to the PSBs that constitute the polarized capability of the Planck HFI instrument., Comment: 23 pages, 11 figures. for submission to A&A

We investigate the effect of foreground residuals in the WMAP data (Bennet et al. 2004) by adding foreground contamination to Gaussian ensembles of CMB signal and noise maps. We evaluate a set of non-Gaussian estimators on the contaminated ensembles to determine with what accuracy any residual in the data can be constrained using higher order statistics. We apply the estimators to the raw and cleaned Q, V, and W band first year maps. The foreground subtraction method applied to clean the data in Bennet et al. (2004a) appears to have induced a correlation between the power spectra and normalized bispectra of the maps which is absent in Gaussian simulations. It also appears to increase the correlation between the dl=1 inter-l bispectrum of the cleaned maps and the foreground templates. In a number of cases the significance of the effect is above the 98% confidence level., Comment: 9 pages, 4 figures

We present new measurements of the power spectra of the E-mode of CMB polarization, the temperature T, the cross-correlation of E and T, and upper limits on the B-mode from 2.5 years of dedicated Cosmic Background Imager (CBI) observations. Both raw maps and optimal signal images in the uv-plane and real space show strong detections of the E-mode (11.7 sigma for the EE power spectrum overall) and no detection of the B-mode. The power spectra are used to constrain parameters of the flat tilted adiabatic Lambda-CDM models: those determined from EE and TE bandpowers agree with those from TT, a powerful consistency check. There is little tolerance for shifting polarization peaks from the TT-forecast locations, as measured by the angular sound crossing scale theta = 100 ell_s = 1.03 +/- 0.02 from EE and TE cf. 1.044 +/- 0.005 with the TT data included. The scope for extra out-of-phase peaks from subdominant isocurvature modes is also curtailed. The EE and TE measurements of CBI, DASI and BOOMERANG are mutually consistent, and, taken together rather than singly, give enhanced leverage for these tests., Comment: 15 pages, 9 figures, submitted to ApJ -- Accepted version. The fine-bin spectrum, covariance matrix, and window functions are now available on the web (suitable for use in COSMOMC) at: http://www.astro.caltech.edu/~tjp/CBI/data2006/index.html The pipeline in the previous version inadvertently omitted one antenna, so the new spectrum contains ~15% more data. We emphasize that previous results were in no way biased, and that the (small) changes to the spectrum solely reflect the inclusion of the additional data. Numbers and figures in the paper have been updated correspondingly. All maps now have color bars

We present a measurement of the temperature-polarization angular cross power spectrum, , of the Cosmic Microwave Background. The result is based on $\sim 200$ hours of data from 8 polarization sensitive bolometers operating at 145 GHz during the 2003 flight of BOOMERANG. We detect a significant correlation in the $\ell$-range between 50 and 950 with a statistical significance > 3.5 sigma. Contamination by polarized foreground emission and systematic effects are negligible in comparison with statistical uncertainty. The spectrum is consistent with previous detections and with the "concordance model" that assumes adiabatic initial conditions. This is the first measurement of using bolometric detectors., Comment: Submitted to Ap.J.; Version with high resolution figures will be available at: http://oberon.roma1.infn.it/boomerang/b2k and http://cmb.phys.cwru.edu/boomerang/

We report on observations of the Cosmic Microwave Background (CMB) obtained during the January 2003 flight of Boomerang . These results are derived from 195 hours of observation with four 145 GHz Polarization Sensitive Bolometer (PSB) pairs, identical in design to the four 143 GHz Planck HFI polarized pixels. The data include 75 hours of observations distributed over 1.84% of the sky with an additional 120 hours concentrated on the central portion of the field, itself representing 0.22% of the full sky. From these data we derive an estimate of the angular power spectrum of temperature fluctuations of the CMB in 24 bands over the multipole range (50 < l < 1500). A series of features, consistent with those expected from acoustic oscillations in the primordial photon-baryon fluid, are clearly evident in the power spectrum, as is the exponential damping of power on scales smaller than the photon mean free path at the epoch of last scattering (l > 900). As a consistency check, the collaboration has performed two fully independent analyses of the time ordered data, which are found to be in excellent agreement., Comment: 11 pages, 7 figures, 3 tables. High resolution figures and data are available at http://cmb.phys.cwru.edu/boomerang/ and http://oberon.roma1.infn.it/boomerang/b2k

We present the cosmological parameters from the CMB intensity and polarization power spectra of the 2003 Antarctic flight of the BOOMERANG telescope. The BOOMERANG data alone constrains the parameters of the $\Lambda$CDM model remarkably well and is consistent with constraints from a multi-experiment combined CMB data set. We add LSS data from the 2dF and SDSS redshift surveys to the combined CMB data set and test several extensions to the standard model including: running of the spectral index, curvature, tensor modes, the effect of massive neutrinos, and an effective equation of state for dark energy. We also include an analysis of constraints to a model which allows a CDM isocurvature admixture., Comment: 18 pages, 10 figures, submitted to ApJ

We report measurements of the CMB polarization power spectra from the January 2003 Antarctic flight of BOOMERANG. The primary results come from six days of observation of a patch covering 0.22% of the sky centered near R.A. = 82.5 deg., Dec= -45 deg. The observations were made using four pairs of polarization sensitive bolometers operating in bands centered at 145 GHz. Using two independent analysis pipelines, we measure a non-zero signal in the range 100< l <1000 with a significance 4.8-sigma, a 2-sigma upper limit of 8.6 uK^2 for any contribution, and a 2-sigma upper limit of 7.0 uK^2 for the spectrum. Estimates of foreground intensity fluctuations and the non-detection of and signals rule out any significant contribution from galactic foregrounds. The results are consistent with a Lambda-CDM cosmology seeded by adiabatic perturbations. We note that this is the first detection of CMB polarization with bolometric detectors., Comment: Submitted to Astrophysical Journal

We present the BOOMERanG-03 experiment and maps of the Stokes parameters I, Q, U of the microwave sky obtained during a 14 day balloon flight in 2003. Three regions of the southern sky were surveyed: a deep survey (~ 90 square degrees) and a shallow survey (~ 750 square degrees) at high Galactic latitudes (both centered at RA ~ 5.5 h, dec ~ -45 deg) and a survey of ~ 300 square degrees across the Galactic plane at RA ~ 9.1 h, dec ~ -47 deg. All three surveys were carried out in three wide frequency bands centered at 145, 245 and 345 GHz, with an angular resolution of ~ 10'. The 145 GHz maps of Stokes I are dominated by Cosmic Microwave Background (CMB) temperature anisotropy, which is mapped with high signal to noise ratio. The measured anisotropy pattern is consistent with the pattern measured in the same region by BOOMERanG-98 and by WMAP. The 145 GHz maps of Stokes Q and U provide a robust statistical detection of polarization of the CMB when subjected to a power spectrum analysis. This amplitude of the polarization is consistent with that of the CMB in the $\Lambda$CDM cosmological scenario. At 145 GHz, in the CMB surveys, the intensity and polarization of the astrophysical foregrounds are found to be negligible with respect to the cosmological signal. At 245 and 345 GHz we detect ISD emission correlated to the 3000 GHz IRAS/DIRBE maps, and give upper limits for any other non-CMB component. We also present intensity maps of the surveyed section of the Galactic plane. These are compared to monitors of different interstellar components, showing that a variety of emission mechanisms is present in that region., Comment: see http://oberon.roma1.infn.it/boomerang/b2k and http://cmb.phys.cwru.edu/boomerang/ for a high resolution version

We present coincident observations of the Cosmic Microwave Background (CMB) from the Very Small Array (VSA) and Cosmic Background Imager (CBI) telescopes. The consistency of the full datasets is tested in the map plane and the Fourier plane, prior to the usual compression of CMB data into flat bandpowers. Of the three mosaics observed by each group, two are found to be in excellent agreement. In the third mosaic, there is a 2 sigma discrepancy between the correlation of the data and the level expected from Monte Carlo simulations. This is shown to be consistent with increased phase calibration errors on VSA data during summer observations. We also consider the parameter estimation method of each group. The key difference is the use of the variance window function in place of the bandpower window function, an approximation used by the VSA group. A re-evaluation of the VSA parameter estimates, using bandpower windows, shows that the two methods yield consistent results., Comment: 10 pages, 6 figures. Final version. Accepted for publication in MNRAS

Polarization observations of the cosmic microwave background with the Cosmic Background Imager from September 2002 to May 2004 provide a significant detection of the E-mode polarization and reveal an angular power spectrum of polarized emission showing peaks and valleys that are shifted in phase by half a cycle relative to those of the total intensity spectrum. This key agreement between the phase of the observed polarization spectrum and that predicted based on the total intensity spectrum provides support for the standard model of cosmology, in which dark matter and dark energy are the dominant constituents, the geometry is close to flat, and primordial density fluctuations are predominantly adiabatic with a matter power spectrum commensurate with inflationary cosmological models., Comment: 28 pages including 11 color figures (reduced in quality for astro-ph). Version 2 includes supplementary material (window functions etc.) and matches the published paper

We review the currrent cosmic parameter determinations of relevance to inflation using the WMAP-1year, Boomerang, CBI, Acbar and other CMB data. The basic steps in the pipelines which determine the bandpowers from the raw data from which these estimations are made are summarized. We forecast how the precision is likely to improve with more years of WMAP in combination with future ground-based experiments and with Planck. We address whether the current data indicates strong breaking from uniform acceleration through the relatively small region of the inflaton potential that the CMB probes, manifest in the much-discussed running spectral index or in even more radical braking/breaking scenarios. Although some weak ``anomalies'' appear in the current data, the statistical case is not there. However increased precision, at the high multipole end and with polarization measurements, will significantly curtail current freedom., Comment: 24 pages, 10 figures, 2 tables, Int. J. Theor. Phys. 2004, ed. E. Verdaguer, "Peyresq Physics 8", "The Early Universe: Confronting theory with observations" (June 21-27, 2003)

Two years of microwave background observations with the Cosmic Background Imager (CBI) have been combined to give a sensitive, high resolution angular power spectrum over the range 400 < l < 3500. This power spectrum has been referenced to a more accurate overall calibration derived from WMAP. The data cover 90 deg^2 including three pointings targeted for deep observations. The uncertainty on the l > 2000 power previously seen with the CBI is reduced. Under the assumption that any signal in excess of the primary anisotropy is due to a secondary Sunyaev-Zeldovich anisotropy in distant galaxy clusters we use CBI, ACBAR, and BIMA data to place a constraint on the present-day rms mass fluctuation sigma_8. We present the results of a cosmological parameter analysis on the l < 2000 primary anisotropy data which show significant improvements in the parameters as compared to WMAP alone, and we explore the role of the small-scale cosmic microwave background data in breaking parameter degeneracies., Comment: 16 pages including 14 color figures; accepted by ApJ. v2: new parameter analysis including latest VSA

In the 1998-99 flight, BOOMERanG has produced maps of $\sim 4 %$ of the sky at high Galactic latitudes, at frequencies of 90, 150, 240 and 410 GHz, with resolution $\simgt 10'$. The faint structure of the Cosmic Microwave Background at horizon and sub-horizon scales is evident in these maps. These maps compare well to the maps recently obtained at lower frequencies by the WMAP experiment. Here we compare the amplitude and morphology of the structures observed in the two sets of maps. We also outline the polarization sensitive version of BOOMERanG, which was flown early this year to measure the linear polarization of the microwave sky at 150, 240 and 350 GHz., Comment: IAU Symposium 216: Maps of the Cosmos. Sydney 14-17 July 2003 - ASP Conference Series

Abbreviated: We highlight the remarkable evolution in the CMB power spectrum over the past few years, and in the cosmological parameters for minimal inflation models derived from it. Grand unified spectra (GUS) show pre-WMAP optimal bandpowers are in good agreement with each other and with the one-year WMAP results, which now dominate the L < 600 bands. GUS are used to determine calibrations, peak/dip locations and heights, and damping parameters. These CMB experiments significantly increased the case for accelerated expansion in the early universe (the inflationary paradigm) and at the current epoch (dark energy dominance) when they were combined with `prior' probabilities on the parameters. A minimal inflation parameter set is applied in the same way to the evolving data. Grid-based and and Monte Carlo Markov Chain methods are shown to give similar values, highly stable over time and for different prior choices, with the increasing precision best characterized by decreasing errors on uncorrelated parameter eigenmodes. After marginalizing over the other cosmic and experimental variables for a weak+LSS prior, the pre-WMAP data of Jan03 cf. the post-WMAP data of Mar03 give Omega_{tot} =1.03^{+0.05}_{-0.04} cf. 1.02^{+0.04}_{-0.03}. Adding the flat prior, n_s =0.95^{+0.07}_{-0.04} cf. 0.97^{+0.02}_{-0.02}, with < 2\sigma evidence for a log variation of n_s. The densities have concordance values. The dark energy pressure-to-density ratio is not well constrained by our weak+LSS prior, but adding SN1 gives w_Q < -0.7. We find \sigma_8 = 0.89^{+0.06}_{-0.07} cf. 0.86^{+0.04}_{-0.04}, implying a sizable SZ effect; the high L power suggest \sigma_8 \sim 0.94^{+0.08}_{-0.16} is needed to be SZ-compatible., Comment: 36 pages, 5 figures, 5 tables, Jan 2003 Roy Soc Discussion Meeting on `The search for dark matter and dark energy in the Universe', published PDF (Oct 15 2003) is http://www.cita.utoronto.ca/~bond/roysoc03/03TA2435.pdf