Person: Kovac, John
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Kovac
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Kovac, John
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Publication The Keck Array: A Multi Camera CMB Polarimeter at the South Pole(Springer Nature, 2012) Staniszewski, Z.; Aikin, R. W.; Amiri, M.; Benton, S. J.; Bischoff, Colin; Bock, J. J.; Bonetti, J. A.; Brevik, J. A.; Burger, B.; Dowell, C. D.; Duband, L.; Filippini, J. P.; Golwala, S. R.; Halpern, M.; Hasselfield, M.; Hilton, G.; Hristov, V. V.; Irwin, K.; Kovac, John; Kuo, C. L.; Lueker, M.; Montroy, T.; Nguyen, H. T.; Ogburn, R. W.; O’Brient, R.; Orlando, A.; Pryke, C.; Reintsema, C.; Ruhl, J. E.; Schwarz, R.; Sheehy, C.; Stokes, S.; Thompson, K. L.; Teply, G.; Tolan, J. E.; Turner, A. D.; Vieregg, Abigail G.; Wilson, P.; Wiebe, D.; Wong, CThe Keck array is a new multi-camera Cosmic Microwave Background (CMB) polarimeter. Each camera contains 256 polarization pairs of antenna-coupled transition edge sensor (TES) bolometers. We recently deployed three of five cameras at the geographic South Pole, and plan to deploy the final two cameras in early 2012. This new telescope is an ideal instrument to search for the primordial B-mode polarization signal imprinted in the CMB by inflationary gravitational waves. We will discuss the design of the detectors and receivers, the status of current observations, and report on progress toward upgrading the instrument with the full compliment of polarized receivers.Publication Inflation Physics from the Cosmic Microwave Background and Large Scale Structure(The Division of Particles and Fields of the American Physical Society, 2013) Abazajian, K. N.; Arnold, K.; Austermann, J.; Benson, B. A.; Bischoff, Colin; Bock, J.; Bond, J. R.; Borrill, J.; Buder, I; Burke, D. L.; Calabrese, E.; Carlstrom, J. E.; Carvalho, C. S.; Chang, C. L.; Chiang, H. C.; Church, S.; Cooray, A.; Crawford, T. M.; Crill, B. P.; Dawson, K. S.; Das, S.; Devlin, M. J.; Dobbs, M.; Dodelson, S.; Doré, O.; Dunkley, J.; Feng, J. L.; Fraisse, A.; Gallicchio, J.; Giddings, S. B.; Green, D.; Halverson, N. W.; Hanany, S.; Hanson, D.; Hildebrandt, S. R.; Hincks, A.; Hlozek, R.; Holder, G.; Holzapfel, W. L.; Honscheid, K.; Horowitz, G.; Hu, W.; Hubmayr, J.; Irwin, K.; Jackson, M.; Jones, W. C.; Kallosh, R.; Kamionkowski, M.; Keating, B.; Keisler, R.; Kinney, W.; Knox, L.; Komatsu, E.; Kovac, John; Kuo, C.-L.; Kusaka, A.; Lawrence, C.; Lee, A. T.; Leitch, E.; Linde, A.; Linder, E.; Lubin, P.; Maldacena, J.; Martinec, E.; McMahon, J.; Miller, A.; Mukhanov, V.; Newburgh, L.; Niemack, M. D.; Nguyen, H.; Nguyen, H. T.; Page, L.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Sehgal, N.; Seljak, U.; Senatore, L.; Sievers, J.; Silverstein, E.; Slosar, A.; Smith, K. M.; Spergel, D.; Staggs, S. T.; Stark, Antony; Stompor, R.; Vieregg, A. G.; Wang, G.; Watson, S.; Wollack, E. J.; Wu, W. L. K.; Yoon, K. W.; Zahn, O.; Zaldarriaga, M.Fluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of CMB and large-scale structure (LSS) experiments are poised to test the leading paradigm for these earliest moments---the theory of cosmic inflation---and to detect the imprints of the inflationary epoch, thereby dramatically increasing our understanding of fundamental physics and the early universe. A future CMB experiment with sufficient angular resolution and frequency coverage that surveys at least 1% of the sky to a depth of 1 uK-arcmin can deliver a constraint on the tensor-to-scalar ratio that will either result in a 5-sigma measurement of the energy scale of inflation or rule out all large-field inflation models, even in the presence of foregrounds and the gravitational lensing B-mode signal. LSS experiments, particularly spectroscopic surveys such as the Dark Energy Spectroscopic Instrument, will complement the CMB effort by improving current constraints on running of the spectral index by up to a factor of four, improving constraints on curvature by a factor of ten, and providing non-Gaussianity constraints that are competitive with the current CMB bounds.Publication Neutrino Physics from the Cosmic Microwave Background and Large Scale Structure(The Division of Particles and Fields of the American Physical Society, 2013) Abazajian, K. N.; Arnold, K.; Austermann, J.; Benson, B. A.; Bischoff, Colin; Bock, J.; Bond, J. R.; Borrill, J.; Calabrese, E.; Carlstrom, J. E.; Carvalho, C. S.; Chang, C. L.; Chiang, H. C.; Church, S.; Cooray, A.; Crawford, T. M.; Dawson, K. S.; Das, S.; Devlin, M. J.; Dobbs, M.; Dodelson, S.; Doré, O.; Dunkley, J.; Errard, J.; Fraisse, A.; Gallicchio, J.; Halverson, N. W.; Hanany, S.; Hildebrandt, S. R.; Hincks, A.; Hlozek, R.; Holder, G.; Holzapfel, W. L.; Honscheid, K.; Hu, W.; Hubmayr, J.; Irwin, K.; Jones, W. C.; Kamionkowski, M.; Keating, B.; Keisler, R.; Knox, L.; Komatsu, E.; Kovac, John; Kuo, C.-L.; Lawrence, C.; Lee, A. T.; Leitch, E.; Linder, E.; Lubin, P.; McMahon, J.; Miller, A.; Newburgh, L.; Niemack, M. D.; Nguyen, H.; Nguyen, H. T.; Page, L.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Sehgal, N.; Seljak, U.; Sievers, J.; Silverstein, E.; Slosar, A.; Smith, K. M.; Spergel, D.; Staggs, S. T.; Stark, Antony; Stompor, R.; Vieregg, A. G.; Wang, G.; Watson, S.; Wollack, E. J.; Wu, W. L. K.; Yoon, K. W.; Zahn, O.This is a report on the status and prospects of the quantification of neutrino properties through the cosmological neutrino background for the Cosmic Frontier of the Division of Particles and Fields Community Summer Study long-term planning exercise. Experiments planned and underway are prepared to study the cosmological neutrino background in detail via its influence on distance-redshift relations and the growth of structure. The program for the next decade described in this document, including upcoming spectroscopic galaxy surveys eBOSS and DESI and a new Stage-IV CMB polarization experiment CMB-S4, will achieve sigma(sum m_nu) = 16 meV and sigma(N_eff) = 0.020. Such a mass measurement will produce a high significance detection of non-zero sum m_nu, whose lower bound derived from atmospheric and solar neutrino oscillation data is about 58 meV. If neutrinos have a minimal normal mass hierarchy, this measurement will definitively rule out the inverted neutrino mass hierarchy, shedding light on one of the most puzzling aspects of the Standard Model of particle physics --- the origin of mass. This precise a measurement of N_eff will allow for high sensitivity to any light and dark degrees of freedom produced in the big bang and a precision test of the standard cosmological model prediction that N_eff = 3.046.Publication Degree-Scale Cosmic Microwave Background Polarization Measurements From Three Years of BICEP1 Data(American Astronomical Society, 2014) Barkats, D.; Aikin, R.; Bischoff, Colin; Buder, I; Kaufman, J. P.; Keating, B. G.; Kovac, John; Su, Meng; Ade, P. A. R.; Battle, J. O.; Bierman, E. M.; Bock, J. J.; Chiang, H. C.; Dowell, C. D.; Duband, L.; Filippini, J.; Hivon, E. F.; Holzapfel, W. L.; Hristov, V. V.; Jones, W. C.; Kuo, C. L.; Leitch, E. M.; Mason, P. V.; Matsumura, T.; Nguyen, H. T.; Ponthieu, N.; Pryke, C.; Richter, S.; Rocha, G.; Sheehy, C.; Kernasovskiy, S. S.; Takahashi, Y. D.; Tolan, J. E.; Yoon, K. W.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 \(21 \leq l \leq 335\) 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 \(15\sigma\). 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.Publication Scientific Verification Of Faraday Rotation Modulators: Detection Of Diffuse Polarized Galactic Emission(American Astronomical Society, 2013) Moyerman, S.; Bierman, E.; Ade, P. A. R.; Aiken, R.; Barkats, D.; Bischoff, Colin; Bock, J. J.; Chiang, H. C.; Dowell, C. D.; Duband, L.; Hivon, E. F.; Holzapfel, W. L.; Hristov, V. V.; Jones, W. C.; Kaufman, J.; Keating, B. G.; Kovac, John; Kuo, C. L.; Leitch, E. M.; Mason, P. V.; Matsumura, T.; Nguyen, H. T.; Ponthieu, N.; Pryke, C.; Richter, S.; Rocha, G.; Sheehy, C.; Takahashi, Y. D.; Tolan, J. E.; Wollack, E.; Yoon, K. W.The design and performance of a wide bandwidth linear polarization modulator based on the Faraday effect is described. Faraday Rotation Modulators (FRMs) are solid-state polarization switches that are capable of modulation up to 10 kHz. Six FRMs were utilized during the 2006 observing season in the Background Imaging of Cosmic Extragalactic Polarization (BICEP) experiment; three FRMs were used at each of BICEP's 100 and 150 GHz frequency bands. The technology was verified through high signal-to-noise detection of Galactic polarization using two of the six FRMs during four observing runs in 2006. The features exhibit strong agreement with BICEP's measurements of the Galaxy using non-FRM pixels and with the Galactic polarization models. This marks the first detection of high signal-to-noise mm-wave celestial polarization using fast, active optical modulation. The performance of the FRMs during periods when they were not modulated was also analyzed and compared to results from BICEP's 43 pixels without FRMs.Publication Self-calibration of BICEP1 three-year data and constraints on astrophysical polarization rotation(American Physical Society (APS), 2014) Kaufman, J. P.; Miller, N. J.; Shimon, M.; Barkats, D.; Bischoff, C.; Buder, I.; Keating, B. G.; Kovac, John; Ade, P. A. R.; Aikin, R.; Battle, J. O.; Bierman, E. M.; Bock, J. J.; Chiang, H. C.; Dowell, C. D.; Duband, L.; Filippini, J.; Hivon, E. F.; Holzapfel, W. L.; Hristov, V. V.; Jones, W. C.; Kernasovskiy, S. S.; Kuo, C. L.; Leitch, E. M.; Mason, P. V.; Matsumura, T.; Nguyen, H. T.; Ponthieu, N.; Pryke, C.; Richter, S.; Rocha, G.; Sheehy, C.; Su, M.; Takahashi, Y. D.; Tolan, J. E.; Yoon, K. W.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 \(\alpha = −2.77^{\circ}\pm0.86^{\circ}\)(statistical) \(\pm1.3^{\circ}\)(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 100GHz and 150GHz 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.Publication A Millimeter-wave Galactic Plane Survey with the BICEP Polarimeter(IOP Publishing, 2011) Bierman, E. M.; Matsumura, T.; Dowell, C. D.; Keating, B. G.; Ade, P.; Barkats, D.; Barron, D.; Battle, J. O.; Bock, J. J.; Chiang, H. C.; Culverhouse, T. L.; Duband, L.; Hivon, E. F.; Holzapfel, W. L.; Hristov, V. V.; Kaufman, J. P.; Kovac, John; Kuo, C. L.; Lange, A. E.; Leitch, E. M.; Mason, P. V.; Miller, N. J.; Nguyen, H. T.; Pryke, C.; Richter, S.; Rocha, G. M.; Sheehy, C.; Takahashi, Y. D.; Yoon, K. W.In order to study inflationary cosmology and the Milky Way Galaxy's composition and magnetic field structure, Stokes I, Q, and U maps of the Galactic plane covering the Galactic longitude range 260? < ? < 340? in three atmospheric transmission windows centered on 100, 150, and 220?GHz are presented. The maps sample an optical depth 1 lsim AV lsim 30, and are consistent with previous characterizations of the Galactic millimeter-wave frequency spectrum and the large-scale magnetic field structure permeating the interstellar medium. The polarization angles in all three bands are generally perpendicular to those measured by starlight polarimetry as expected and show changes in the structure of the Galactic magnetic field on the scale of 60?. The frequency spectrum of degree-scale Galactic emission is plotted between 23 and 220?GHz (including WMAP data) and is fit to a two-component (synchrotron and dust) model showing that the higher frequency BICEP data are necessary to tightly constrain the amplitude and spectral index of Galactic dust. Polarized emission is detected over the entire region within two degrees of the Galactic plane, indicating the large-scale magnetic field is oriented parallel to the plane of the Galaxy. A trend of decreasing polarization fraction with increasing total intensity is observed, ruling out the simplest model of a constant Galactic magnetic field orientation along the line of sight in the Galactic plane. A generally increasing trend of polarization fraction with electromagnetic frequency is found, varying from 0.5%-1.5% at frequencies below 50?GHz to 2.5%-3.5% above 90?GHz. The effort to extend the capabilities of BICEP by installing 220?GHz band hardware is described along with analysis of the new band.Publication BICEP2 / Keck Array V: Measurements of B-mode Polarization at Degree Angular Scales and 150 GHz by the Keck Array(IOP Publishing, 2015) Ade, P. A. R.; Ahmed, Z.; Aikin, R. W.; Alexander, Kate; Barkats, D.; Benton, S. J.; Bischoff, Colin; Bock, J. J.; Brevik, J. A.; Buder, I; Bullock, E.; Buza, Victor; Connors, Jake Anthony; Crill, B. P.; Dowell, C. D.; Dvorkin, Cora; Duband, L.; Filippini, J. P.; Fliescher, S.; Golwala, S. R.; Halpern, M.; Harrison, S.; Hasselfield, M.; Hildebrandt, S. R.; Hilton, G. C.; Hristov, V. V.; Hui, H.; Irwin, K. D.; Karkare, Kirit Sukrit; Kaufman, J. P.; Keating, B. G.; Kefeli, S.; Kernasovskiy, S. A.; Kovac, John; Kuo, C. L.; Leitch, E. M.; Lueker, M.; Mason, P.; Megerian, K. G.; Netterfield, C. B.; Nguyen, H. T.; O’Brient, R.; Ogburn IV, R. W.; Orlando, A.; Pryke, C.; Reintsema, C. D.; Richter, Sonja Valeska; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z. K.; Sudiwala, R. V.; Teply, G. P.; Thompson, K. L.; Tolan, J. E.; Turner, A. D.; Vieregg, A. G.; Weber, A. C.; Willmert, J.; Wong, C. L.; Yoon, K. W.The Keck Array is a system of cosmic microwave background polarimeters, each similar to the Bicep2 experiment. In this paper we report results from the 2012 to 2013 observing seasons, during which the Keck Array consisted of five receivers all operating in the same (150 GHz) frequency band and observing field as Bicep2. We again find an excess of B-mode power over the lensed-ΛCDM expectation of >5σ in the range 30 < ℓ < 150 and confirm that this is not due to systematics using jackknife tests and simulations based on detailed calibration measurements. In map difference and spectral difference tests these new data are shown to be consistent with Bicep2. Finally, we combine the maps from the two experiments to produce final Q and U maps which have a depth of 57 nK deg (3.4 μK arcmin) over an effective area of 400 deg(2) for an equivalent survey weight of 250,000 μK(−)(2). The final BB band powers have noise uncertainty a factor of 2.3 times better than the previous results, and a significance of detection of excess power of >6σ.Publication The QUaD Galactic Plane Survey. II. A Compact Source Catalog(The American Astronomical Society, 2011) Culverhouse, T.; Ade, P.; Bock, J.; Bowden, M.; Brown, M. L.; Cahill, G.; Castro, P. G.; Church, S.; Friedman, R.; Ganga, K.; Gear, W. K.; Gupta, S.; Hinderks, J.; Kovac, John; Lange, A. E.; Leitch, E.; Melhuish, S. J.; Memari, Y.; Murphy, J. A.; Orlando, A.; Pryke, C.; Schwarz, R.; O, C.; Piccirillo, L.; Rajguru, N.; Rusholme, B.; Taylor, A. N.; Thompson, K. L.; Turner, A. H.; Wu, E. Y. S.; Zemcov, M.We present a catalog of compact sources derived from the QUaD Galactic Plane Survey. The survey covers ~800 deg2 of the inner galaxy (|b| < 4°) in Stokes I, Q, and U parameters at 100 and 150 GHz, with angular resolutions of 5 and 3.5 arcmin, respectively. Five hundred and twenty-six unique sources are identified in I, of which 239 are spatially matched between frequency bands, with 53 (234) detected at 100 (150) GHz alone; 170 sources are identified as ultracompact H ii regions. Approximating the distribution of total intensity source fluxes as a power law, we find a slope of γS, 100 = −1.8 ± 0.4 at 100 GHz and γS, 150 = −2.2 ± 0.4 at 150 GHz. Similarly, the power-law index of the source two-point angular correlation function is γθ, 100 = −1.21 ± 0.04 and γθ, 150 = −1.25 ± 0.04. The total intensity spectral index distribution peaks at αI ~ 0.25, indicating that dust emission is not the only source of radiation produced by these objects between 100 and 150 GHz; free–free radiation is likely significant in the 100 GHz band. Four sources are detected in polarized intensity P, of which three have matching counterparts in I. Three of the polarized sources lie close to the Galactic center, Sagittarius A*, Sagittarius B2, and the Galactic Radio Arc, while the fourth is RCW 49, a bright H ii region. An extended polarized source, undetected by the source extraction algorithm on account of its ~0fdg5 size, is identified visually, and is an isolated example of large-scale polarized emission oriented distinctly from the bulk Galactic dust polarization.Publication Improved Constraints on Cosmology and Foregrounds from BICEP2 and Keck Array Cosmic Microwave Background Data with Inclusion of 95 GHz Band(American Physical Society (APS), 2016) Ade, P. A. R.; Ahmed, Z.; Aikin, R. W.; Alexander, K. D.; Barkats, D.; Benton, S. J.; Bischoff, Colin; Bock, J. J.; Bowens-Rubin, Rachel; Brevik, J. A.; Buder, I; Bullock, E.; Buza, Victor; Connors, Jake Anthony; Crill, B. P.; Duband, L.; Dvorkin, Cora; Filippini, J. P.; Fliescher, S.; Grayson, J.; Halpern, M.; Harrison, Sarah; Hilton, G. C.; Hui, H.; Irwin, K. D.; Karkare, Kirit Sukrit; Karpel, E.; Kaufman, J. P.; Keating, B. G.; Kefeli, S.; Kernasovskiy, S. A.; Kovac, John; Kuo, C. L.; Leitch, E. M.; Lueker, M.; Megerian, K. G.; Netterfield, C. B.; Nguyen, H. T.; O’Brient, R.; Ogburn, R. W.; Orlando, A.; Pryke, C; Richter, Sonja Valeska; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z. K.; Steinbach, B.; Sudiwala, R. V.; Teply, G. P.; Thompson, K. L.; Tolan, J. E.; Tucker, C.; Turner, A. D.; Vieregg, A. G.; Weber, A. C.; Wiebe, D. V.; Willmert, J.; Wong, C; Wu, W. L. K.; Yoon, K. W.We present results from an analysis of all data taken by the BICEP2 and Keck Array cosmic microwave background (CMB) polarization experiments up to and including the 2014 observing season. This includes the first Keck Array observations at 95 GHz. The maps reach a depth of 50 nK deg in Stokes Q and U in the 150 GHz band and 127 nK deg in the 95 GHz band. We take auto- and cross-spectra between these maps and publicly available maps from WMAP and Planck at frequencies from 23 to 353 GHz. An excess over lensed ΛCDM is detected at modest significance in the 95 × 150 BB spectrum, and is consistent with the dust contribution expected from our previous work. No significant evidence for synchrotron emission is found in spectra such as 23 × 95, or for correlation between the dust and synchrotron sky patterns in spectra such as 23 × 353. We take the likelihood of all the spectra for a multicomponent model including lensed ΛCDM, dust, synchrotron, and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r) using priors on the frequency spectral behaviors of dust and synchrotron emission from previous analyses of WMAP and Planck data in other regions of the sky. This analysis yields an upper limit r0.05 < 0.09 at 95% confidence, which is robust to variations explored in analysis and priors. Combining these B-mode results with the (more model-dependent) constraints from Planck analysis of CMB temperature plus baryon acoustic oscillations and other data yields a combined limit r0.05 < 0.07 at 95% confidence. These are the strongest constraints to date on inflationary gravitational waves.