J. J. Bock

California Institute of Technology, Pasadena, California, United States

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Publications (604)1398.2 Total impact

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    ABSTRACT: The inflationary paradigm of the early universe predicts a stochastic background of gravitational waves which would generate a B-mode polarization pattern in the cosmic microwave background (CMB) at degree angular scales. Precise measurement of B-modes is one of the most compelling observational goals in modern cosmology. Since 2011, the Keck Array has deployed over 2500 transition edge sensor (TES) bolometer detectors at 100 and 150 GHz to the South Pole in pursuit of degree-scale B-modes, and Bicep3 will follow in 2015 with 2500 more at 100 GHz. Characterizing the spectral response of these detectors is important for controlling systematic effects that could lead to leakage from the temperature to polarization signal, and for understanding potential coupling to atmospheric and astrophysical emission lines. We present complete spectral characterization of the Keck Array detectors, made with a Martin-Puplett Fourier Transform Spectrometer at the South Pole, and preliminary spectra of Bicep3 detectors taken in lab. We show band centers and effective bandwidths for both Keck Array bands, and use models of the atmosphere at the South Pole to cross check our absolute calibration. Our procedure for obtaining interferograms in the field with automated 4-axis coupling to the focal plane represents an important step towards efficient and complete spectral characterization of next-generation instruments more than 10000 detectors.
    No preview · Conference Paper · Aug 2014
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    ABSTRACT: Searching for evidence of inflation by measuring B-modes in the cosmic microwave background (CMB) polarization at degree angular scales remains one of the most compelling experimental challenges in cosmology. BICEP2 and the Keck Array are part of a program of experiments at the South Pole whose main goal is to achieve the sensitivity and systematic control necessary for measurements of the tensor-to-scalar ratio at σ(r) ~0:01. Beam imperfections that are not sufficiently accounted for are a potential source of spurious polarization that could interfere with that goal. The strategy of BICEP2 and the Keck Array is to completely characterize their telescopes' polarized beam response with a combination of in-lab, pre-deployment, and on-site calibrations. We Sereport the status of these experiments, focusing on continued improved understanding of their beams. Far-field measurements of the BICEP2 beam with a chopped thermal source, combined with analysis improvements, show that the level of residual beam-induced systematic errors is acceptable for the goal of σ(r) ~ 0:01 measurements. Beam measurements of the Keck Array side lobes helped identify a way to reduce optical loading with interior cold baffles, which we installed in late 2013. These baffles reduced total optical loading, leading to a ~ 10% increase in mapping speed for the 2014 observing season. The sensitivity of the Keck Array continues to improve: for the 2013 season it was 9:5 μK _/s noise equivalent temperature (NET). In 2014 we converted two of the 150-GHz cameras to 100 GHz for foreground separation capability. We have shown that the BICEP2 and the Keck Array telescope technology is sufficient for the goal of σ(r) ~ 0:01 measurements. Furthermore, the program is continuing with BICEP3, a 100-GHz telescope with 2560 detectors.
    No preview · Conference Paper · Aug 2014
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    ABSTRACT: BICEP3 is a 550 mm-aperture refracting telescope for polarimetry of radiation in the cosmic microwave background at 95 GHz. It adopts the methodology of BICEP1, BICEP2 and the Keck Array experiments - it possesses sufficient resolution to search for signatures of the inflation-induced cosmic gravitational-wave background while utilizing a compact design for ease of construction and to facilitate the characterization and mitigation of systematics. However, BICEP3 represents a significant breakthrough in per-receiver sensitivity, with a focal plane area 5$\times$ larger than a BICEP2/Keck Array receiver and faster optics ($f/1.6$ vs. $f/2.4$). Large-aperture infrared-reflective metal-mesh filters and infrared-absorptive cold alumina filters and lenses were developed and implemented for its optics. The camera consists of 1280 dual-polarization pixels; each is a pair of orthogonal antenna arrays coupled to transition-edge sensor bolometers and read out by multiplexed SQUIDs. Upon deployment at the South Pole during the 2014-15 season, BICEP3 will have survey speed comparable to Keck Array 150 GHz (2013), and will significantly enhance spectral separation of primordial B-mode power from that of possible galactic dust contamination in the BICEP2 observation patch.
    Full-text · Article · Jul 2014 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: 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.
    Full-text · Article · Jul 2014 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: 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.
    Full-text · Article · Jul 2014 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: 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.
    Full-text · Article · Jul 2014 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: 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.
    Full-text · Article · Jul 2014
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    ABSTRACT: TIME-Pilot is designed to make measurements from the Epoch of Reionization (EoR), when the first stars and galaxies formed and ionized the intergalactic medium. This will be done via measurements of the redshifted 157.7 um line of singly ionized carbon ([CII]). In particular, TIME-Pilot will produce the first detection of [CII] clustering fluctuations, a signal proportional to the integrated [CII] intensity, summed over all EoR galaxies. TIME-Pilot is thus sensitive to the emission from dwarf galaxies, thought to be responsible for the balance of ionizing UV photons, that will be difficult to detect individually with JWST and ALMA. A detection of [CII] clustering fluctuations would validate current theoretical estimates of the [CII] line as a new cosmological observable, opening the door for a new generation of instruments with advanced technology spectroscopic array focal planes that will map [CII] fluctuations to probe the EoR history of star formation, bubble size, and ionization state. Additionally, TIME-Pilot will produce high signal-to-noise measurements of CO clustering fluctuations, which trace the role of molecular gas in star-forming galaxies at redshifts 0 < z < 2. With its unique atmospheric noise mitigation, TIME-Pilot also significantly improves sensitivity for measuring the kinetic Sunyaev-Zel’dovich (kSZ) effect in galaxy clusters. TIME-Pilot will employ a linear array of spectrometers, each consisting of a parallel-plate diffraction grating. The spectrometer bandwidth covers 185-323 GHz to both probe the entire redshift range of interest and to include channels at the edges of the band for atmospheric noise mitigation. We illuminate the telescope with f/3 horns, which balances the desire to both couple to the sky with the best efficiency per beam, and to pack a large number of horns into the fixed field of view. Feedhorns couple radiation to the waveguide spectrometer gratings. Each spectrometer grating has 190 facets and provides resolving power above 100. At this resolution, the longest dimension of the grating is 31 cm, which allows us to stack gratings in two blocks (one for each polarization) of 16 within a single cryostat, providing a 1x16 array of beams in a 14 arcminute field of view. Direct absorber TES sensors sit at the output of the grating on six linear facets over the output arc, allowing us to package and read out the detectors as arrays in a modular manner. The 1840 detectors will be read out with the NIST time-domain-multiplexing (TDM) scheme and cooled to a base temperature of 250 mK with a 3He sorption refrigerator. We present preliminary designs for the TIME-Pilot cryogenics, spectrometers, bolometers, and optics.
    Full-text · Conference Paper · Jul 2014
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    ABSTRACT: 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.
    No preview · Conference Paper · Jun 2014
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    ABSTRACT: We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around ℓ∼80. The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled transition edge sensor 150 GHz bolometers each with temperature sensitivity of ≈300 μK_(CMB)√s. BICEP2 observed from the South Pole for three seasons from 2010 to 2012. A low-foreground region of sky with an effective area of 380 square deg was observed to a depth of 87 nK deg in Stokes Q and U. In this paper we describe the observations, data reduction, maps, simulations, and results. We find an excess of B-mode power over the base lensed-ΛCDM expectation in the range 30<ℓ5σ. Through jackknife tests and simulations based on detailed calibration measurements we show that systematic contamination is much smaller than the observed excess. Cross correlating against WMAP 23 GHz maps we find that Galactic synchrotron makes a negligible contribution to the observed signal. We also examine a number of available models of polarized dust emission and find that at their default parameter values they predict power ∼(5–10)× smaller than the observed excess signal (with no significant cross-correlation with our maps). However, these models are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal. Cross correlating BICEP2 against 100 GHz maps from the BICEP1 experiment, the excess signal is confirmed with 3σ significance and its spectral index is found to be consistent with that of the CMB, disfavoring dust at 1.7σ. The observed B-mode power spectrum is well fit by a lensed-ΛCDM+tensor theoretical model with tensor-to-scalar ratio r=0.20^(+0.07)_(−0.05), with r=0 disfavored at 7.0σ. Accounting for the contribution of foreground, dust will shift this value downward by an amount which will be better constrained with upcoming data sets.
    No preview · Article · Jun 2014 · Physical Review Letters
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    ABSTRACT: We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around l ∼ 80. The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled transition edge sensor 150 GHz bolometers each with temperature sensitivity of ≈300 μK CMB ffiffi s p . BICEP2 observed from the South Pole for three seasons from 2010 to 2012. A low-foreground region of sky with an effective area of 380 square deg was observed to a depth of 87 nK deg in Stokes Q and U. In this paper we describe the observations, data reduction, maps, simulations, and results. We find an excess of B-mode power over the base lensed-ΛCDM expectation in the range 30 < l < 150, inconsistent with the null hypothesis at a significance of > 5σ. Through jackknife tests and simulations based on detailed calibration measurements we show that systematic contamination is much smaller than the observed excess. Cross correlating against WMAP 23 GHz maps we find that Galactic synchrotron makes a negligible contribution to the observed signal. We also examine a number of available models of polarized dust emission and find that at their default parameter values they predict power ∼(5–10)× smaller than the observed excess signal (with no significant cross-correlation with our maps). However, these models are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal. Cross correlating BICEP2 against 100 GHz maps from the BICEP1 experiment, the excess signal is confirmed with 3σ significance and its spectral index is found to be consistent with that of the CMB, disfavoring dust at 1.7σ. The observed B-mode power spectrum is well fit by a lensed-ΛCDM þ tensor theoretical model with Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Published by the American Physical Society tensor-to-scalar ratio r ¼ 0.20 þ0.07 −0.05 , with r ¼ 0 disfavored at 7.0σ. Accounting for the contribution of foreground, dust will shift this value downward by an amount which will be better constrained with upcoming data sets.
    Full-text · Article · Jun 2014 · Physical Review Letters
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    ABSTRACT: This paper presents the large-scale polarized sky as seen by Planck HFI at 353 GHz, which is the most sensitive Planck channel for dust polarization. We construct and analyse large-scale maps of dust polarization fraction and polarization direction, while taking account of noise bias and possible systematic effects. We find that the maximum observed dust polarization fraction is high (pmax > 18%), in particular in some of the intermediate dust column density (AV < 1mag) regions. There is a systematic decrease in the dust polarization fraction with increasing dust column density, and we interpret the features of this correlation in light of both radiative grain alignment predictions and fluctuations in the magnetic field orientation. We also characterize the spatial structure of the polarization angle using the angle dispersion function and find that, in nearby fields at intermediate latitudes, the polarization angle is ordered over extended areas that are separated by filamentary structures, which appear as interfaces where the magnetic field sky projection rotates abruptly without apparent variations in the dust column density. The polarization fraction is found to be anti-correlated with the dispersion of the polarization angle, implying that the variations are likely due to fluctuations in the 3D magnetic field orientation along the line of sight sampling the diffuse interstellar medium.We also compare the dust emission with the polarized synchrotron emission measured with the Planck LFI, with low-frequency radio data, and with Faraday rotation measurements of extragalactic sources. The two polarized components are globally similar in structure along the plane and notably in the Fan and North Polar Spur regions. A detailed comparison of these three tracers shows, however, that dust and cosmic rays generally sample different parts of the line of sight and confirms that much of the variation observed in the Planck data is due to the 3D structure of the magnetic field.
    Full-text · Article · May 2014 · Astronomy and Astrophysics
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    ABSTRACT: Planck has mapped the intensity and polarization of the sky at microwave frequencies with unprecedented sensitivity. We make use of the Planck 353 GHz I, Q, and U Stokes maps as dust templates, and cross-correlate them with the Planck and WMAP data at 12 frequencies from 23 to 353 GHz, over circular patches with 10 degree radius. The cross-correlation analysis is performed for both intensity and polarization data in a consistent manner. We use a mask that focuses our analysis on the diffuse interstellar medium at intermediate Galactic latitudes. We determine the spectral indices of dust emission in intensity and polarization between 100 and 353 GHz, for each sky-patch. The mean values, $1.63\pm0.03$ for polarization and $1.52\pm0.02$ for intensity, for a mean dust temperature of 18.7 K, are close, but significantly different. We determine the mean spectral energy distribution (SED) of the microwave emission, correlated with the 353 GHz dust templates, by averaging the results of the correlation over all sky-patches. We find that the mean SED increases for decreasing frequencies at $\nu < 60$ GHz, for both intensity and polarization. The rise of the polarization SED towards low frequencies may be accounted for by a synchrotron component correlated with dust, with no need for any polarization of the anomalous microwave emission. We use a spectral model to separate the synchrotron and dust polarization and to characterize the spectral dependence of the dust polarization fraction. The polarization fraction ($p$) of the dust emission decreases by $(34\pm10)$ % from 353 to 70 GHz. The decrease of $p$ could indicate differences in polarization efficiency among components of interstellar dust (e.g., carbon versus silicate grains), or, alternatively, it could be a signature of magnetic dipole emission from ferromagnetic inclusions within interstellar grains.
    Full-text · Article · May 2014 · Astronomy and Astrophysics
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    ABSTRACT: The Planck survey provides unprecedented full-sky coverage of the submillimetre polarized emission from Galactic dust, bringing new constraints on the properties of dust. The dust grains that emit the radiation seen by Planck in the submillimetre also extinguish and polarize starlight in the optical. Using ancillary catalogues of interstellar polarization and extinction of starlight, we obtain the degree of polarization, $p_V$, and the optical depth in the $V$ band to the star, $\tau_V$. We extract the submillimetre polarized intensity, $P_S$, and total intensity, $I_S$, measured toward these stars in the Planck 353 GHz channel. We compare the position angle measured in the optical with that measured at 353 GHz, and the column density measure $E(B - V)$ with that inferred from the Planck product map of the submillimetre dust optical depth. For those lines of sight suitable for this comparison, we measure the polarization ratios $R_{S/V} = (P_S/I_S)/(p_V/\tau_V)$ and $R_{P/p} = P_S / p_V$ through a correlation analysis. We find $R_{S/V} = 4.3$ with statistical and systematic uncertainties 0.2 and 0.4, respectively, and $R_{P/p} = 5.6$ MJy sr$^{-1}$, with statistical and systematic uncertainties 0.2 and 0.4 MJy sr$^{-1}$, respectively. Our estimate of $R_{S/V}$ is reasonably compatible with current dust models, not yet very discriminating among them. However, the observed $R_{P/p}$ is a more discriminating diagnostic for the polarizing grain population and is not compatible with predictions of dust models, the observations being higher by a factor of about 2.5. These new diagnostics from Planck, including the spectral dependence in the submillimetre, will be important for constraining and understanding the full complexity of the grain models, and for further interpretation of the Planck thermal dust polarization.
    Full-text · Article · May 2014 · Astronomy and Astrophysics
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    Full-text · Article · May 2014
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    Full-text · Article · May 2014
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    ABSTRACT: The Planck High Frequency Instrument (HFI) surveyed the sky continuously from August 2009 to January 2012. Its noise and sensitivity performance were excellent, but the rate of cosmic ray impacts on the HFI detectors was unexpectedly high. Furthermore, collisions of cosmic rays with the focal plane produced transient signals in the data (glitches) with a wide range of characteristics. A study of cosmic ray impacts on the HFI detector modules has been undertaken to categorize and characterize the glitches, to correct the HFI time-ordered data, and understand the residual effects on Planck maps and data products. This paper presents an evaluation of the physical origins of glitches observed by the HFI detectors. In order to better understand the glitches observed by HFI in flight, several ground-based experiments were conducted with flight-spare HFI bolometer modules. The experiments were conducted between 2010 and 2013 with HFI test bolometers in different configurations using varying particles and impact energies. The bolometer modules were exposed to 23 MeV protons from the Orsay IPN TANDEM accelerator, and to $^{241}$Am and $^{244}$Cm $\alpha$-particle and $^{55}$Fe radioactive X-ray sources. The calibration data from the HFI ground-based preflight tests were used to further characterize the glitches and compare glitch rates with statistical expectations under laboratory conditions. Test results provide strong evidence that the dominant family of glitches observed in flight are due to cosmic ray absorption by the silicon die substrate on which the HFI detectors reside. Glitch energy is propagated to the thermistor by ballistic phonons, while there is also a thermal diffusion contribution. The implications of these results for future satellite missions, especially those in the far-infrared to sub-millimetre and millimetre regions of the electromagnetic spectrum, are discussed.
    Full-text · Article · Mar 2014 · Astronomy and Astrophysics
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    ABSTRACT: The Planck High Frequency Instrument (HFI) has been surveying the sky continuously from the second Lagrangian point (L2) between August 2009 and January 2012. It operates with 52 high impedance bolometers cooled at 100mK in a range of frequency between 100 GHz and 1THz with unprecedented sensivity, but strong coupling with cosmic radiation. At L2, the particle flux is about 5 $cm^{-2} s^{-1}$ and is dominated by protons incident on the spacecraft. Protons with an energy above 40MeV can penetrate the focal plane unit box causing two different effects: glitches in the raw data from direct interaction of cosmic rays with detectors (producing a data loss of about 15% at the end of the mission) and thermal drifts in the bolometer plate at 100mK adding non-gaussian noise at frequencies below 0.1Hz. The HFI consortium has made strong efforts in order to correct for this effect on the time ordered data and final Planck maps. This work intends to give a view of the physical explanation of the glitches observed in the HFI instrument in-flight. To reach this goal, we performed several ground-based experiments using protons and $\alpha$ particles to test the impact of particles on the HFI spare bolometers with a better control of the environmental conditions with respect to the in-flight data. We have shown that the dominant part of glitches observed in the data comes from the impact of cosmic rays in the silicon die frame supporting the micro-machinced bolometric detectors propagating energy mainly by ballistic phonons and by thermal diffusion. The implications of these results for future satellite missions will be discussed.
    Full-text · Article · Mar 2014 · Journal of Low Temperature Physics
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    ABSTRACT: Cosmic microwave background (CMB) polarimeters aspire to measure the faint B-mode signature predicted to arise from inflationary gravitational waves. They also have the potential to constrain cosmic birefringence, rotation of the polarization of the CMB arising from parity-violating physics, which would produce nonzero expectation values for the CMB’s temperature to B-mode correlation (TB) and E-mode to B-mode correlation (EB) spectra. However, instrumental systematic effects can also cause these TB and EB correlations to be nonzero. In particular, an overall miscalibration of the polarization orientation of the detectors produces TB and EB spectra which are degenerate with isotropic cosmological birefringence, while also introducing a small but predictable bias on the BB spectrum. We find that Bicep1 three-year spectra, which use our standard calibration of detector polarization angles from a dielectric sheet, are consistent with a polarization rotation of α=−2.77°±0.86°(statistical)±1.3°(systematic). We have revised the estimate of systematic error on the polarization rotation angle from the two-year analysis by comparing multiple calibration methods. We also account for the (negligible) impact of measured beam systematic effects. We investigate the polarization rotation for the Bicep1 100 GHz and 150 GHz bands separately to investigate theoretical models that produce frequency-dependent cosmic birefringence. We find no evidence in the data supporting either of these models or Faraday rotation of the CMB polarization by the Milky Way galaxy’s magnetic field. If we assume that there is no cosmic birefringence, we can use the TB and EB spectra to calibrate detector polarization orientations, thus reducing bias of the cosmological B-mode spectrum from leaked E-modes due to possible polarization orientation miscalibration. After applying this “self-calibration” process, we find that the upper limit on the tensor-to-scalar ratio decreases slightly, from r<0.70 to r<0.65 at 95% confidence.
    No preview · Article · Mar 2014
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    ABSTRACT: BICEP1 is a millimeter-wavelength telescope designed specifically to measure the inflationary B-mode polarization of the cosmic microwave background at degree angular scales. We present results from an analysis of the data acquired during three seasons of observations at the South Pole (2006-2008). This work extends the two-year result published in Chiang et al., with additional data from the third season and relaxed detector-selection criteria. This analysis also introduces a more comprehensive estimation of band power window functions, improved likelihood estimation methods, and a new technique for deprojecting monopole temperature-to-polarization leakage that reduces this class of systematic uncertainty to a negligible level. We present maps of temperature, E- and B-mode polarization, and their associated angular power spectra. The improvement in the map noise level and polarization spectra error bars are consistent with the 52% increase in integration time relative to Chiang et al. We confirm both self-consistency of the polarization data and consistency with the two-year results. We measure the angular power spectra at 21 ≤ ℓ ≤ 335 and find that the EE spectrum is consistent with Lambda cold dark matter cosmology, with the first acoustic peak of the EE spectrum now detected at 15σ. The BB spectrum remains consistent with zero. From B-modes only, we constrain the tensor-to-scalar ratio to r = 0.03^(+0.27)_(-0.23), or r < 0.70 at 95% confidence level.
    No preview · Article · Mar 2014

Publication Stats

16k Citations
1,398.20 Total Impact Points

Institutions

  • 1997-2015
    • California Institute of Technology
      • • Jet Propulsion Laboratory
      • • Department of Physics
      • • Division of Physics, Mathematics, and Astronomy
      Pasadena, California, United States
  • 2006-2014
    • NASA
      • Jet Propulsion Laboratory
      Вашингтон, West Virginia, United States
    • University of Toronto
      Toronto, Ontario, Canada
  • 2011
    • University of California, Irvine
      • Department of Physics and Astronomy
      Irvine, California, United States
  • 2002-2011
    • University of Colorado at Boulder
      • Center for Astrophysics and Space Astronomy
      Boulder, Colorado, United States
    • Carnegie Mellon University
      • Department of Physics
      Pittsburgh, PA, United States
  • 2008-2010
    • Cardiff University
      • School of Physics and Astronomy
      Cardiff, WLS, United Kingdom
  • 2009
    • Nagoya University
      Nagoya, Aichi, Japan
    • The Ohio State University
      • Department of Astronomy
      Columbus, OH, United States
  • 2004-2008
    • University of Wales
      Cardiff, Wales, United Kingdom
  • 2003
    • University of Chicago
      • Department of Astronomy and Astrophysics
      Chicago, IL, United States
  • 2000
    • Institute for Advanced Study
      Princeton Junction, New Jersey, United States
  • 1995
    • University of California, Berkeley
      • Department of Physics
      Berkeley, California, United States