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1. Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations

Author

The HERA Collaboration, Abdurashidova, Zara, Adams, Tyrone, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Baartman, Rushelle, Balfour, Yanga, Barkana, Rennan, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Breitman, Daniela, Bull, Philip, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, Choudhuri, Samir, DeBoer, David R., Acedo, Eloy de Lera, Dexter, Matt, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fialkov, Anastasia, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Garsden, Hugh, Glendenning, Brian, Gorce, Adélie, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Heimersheim, Stefan, Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lewis, David, Liu, Adrian, Loots, Anita, Ma, Yin-Zhe, MacMahon, David H. E., Malan, Lourence, Malgas, Keith, Malgas, Cresshim, Maree, Matthys, Marero, Bradley, Martinot, Zachary E., McBride, Lisa, Mesinger, Andrei, Mirocha, Jordan, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Muñoz, Julian B., Murray, Steven G., Nagpal, Vighnesh, Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta D., Nuwegeld, Hans, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Qin, Yuxiang, Razavi-Ghods, Nima, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Smith, Craig, Swarts, Hilton, Tan, Jianrong, Thyagarajan, Nithyanandan, Wilensky, Michael J., Williams, Peter K. G., van Wyngaarden, Pieter, and Zheng, Haoxuan

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We report the most sensitive upper limits to date on the 21 cm epoch of reionization power spectrum using 94 nights of observing with Phase I of the Hydrogen Epoch of Reionization Array (HERA). Using similar analysis techniques as in previously reported limits (HERA Collaboration 2022a), we find at 95% confidence that $\Delta^2(k = 0.34$ $h$ Mpc$^{-1}$) $\leq 457$ mK$^2$ at $z = 7.9$ and that $\Delta^2 (k = 0.36$ $h$ Mpc$^{-1}) \leq 3,496$ mK$^2$ at $z = 10.4$, an improvement by a factor of 2.1 and 2.6 respectively. These limits are mostly consistent with thermal noise over a wide range of $k$ after our data quality cuts, despite performing a relatively conservative analysis designed to minimize signal loss. Our results are validated with both statistical tests on the data and end-to-end pipeline simulations. We also report updated constraints on the astrophysics of reionization and the cosmic dawn. Using multiple independent modeling and inference techniques previously employed by HERA Collaboration (2022b), we find that the intergalactic medium must have been heated above the adiabatic cooling limit at least as early as $z = 10.4$, ruling out a broad set of so-called "cold reionization" scenarios. If this heating is due to high-mass X-ray binaries during the cosmic dawn, as is generally believed, our result's 99% credible interval excludes the local relationship between soft X-ray luminosity and star formation and thus requires heating driven by evolved low-metallicity stars., Comment: 57 pages, 37 figures. Updated to match the accepted ApJ version. Corresponding author: Joshua S. Dillon

Published
2022
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2. First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum

Author

The HERA Collaboration, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Dibblee-Barkman, Taylor, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Lewis, David, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta D., Parsons, Aaron R., Patra, Nipanjana, Pascua, Robert, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Singh, Saurabh, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

We report upper-limits on the Epoch of Reionization (EoR) 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights of data ($\sim36$ hours of integration) from Phase I of the Hydrogen Epoch of Reionization Array (HERA). The Phase I data show evidence for systematics that can be largely suppressed with systematic models down to a dynamic range of $\sim10^9$ with respect to the peak foreground power. This yields a 95% confidence upper limit on the 21 cm power spectrum of $\Delta^2_{21} \le (30.76)^2\ {\rm mK}^2$ at $k=0.192\ h\ {\rm Mpc}^{-1}$ at $z=7.9$, and also $\Delta^2_{21} \le (95.74)^2\ {\rm mK}^2$ at $k=0.256\ h\ {\rm Mpc}^{-1}$ at $z=10.4$. At $z=7.9$, these limits are the most sensitive to-date by over an order of magnitude. While we find evidence for residual systematics at low line-of-sight Fourier $k_\parallel$ modes, at high $k_\parallel$ modes we find our data to be largely consistent with thermal noise, an indicator that the system could benefit from deeper integrations. The observed systematics could be due to radio frequency interference, cable sub-reflections, or residual instrumental cross-coupling, and warrant further study. This analysis emphasizes algorithms that have minimal inherent signal loss, although we do perform a careful accounting in a companion paper of the small forms of loss or bias associated with the pipeline. Overall, these results are a promising first step in the development of a tuned, instrument-specific analysis pipeline for HERA, particularly as Phase II construction is completed en route to reaching the full sensitivity of the experiment., Comment: Accepted to ApJ. https://reionization.org/science/public-data-release-1/

Published
2021
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3. Effects of model incompleteness on the drift-scan calibration of radio telescopes

Author

Gehlot, Bharat K., Jacobs, Daniel C., Bowman, Judd D., Mahesh, Nivedita, Murray, Steven G., Kolopanis, Matthew, Beardsley, Adam P., Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Bernardi, Gianni, Billings, Tashalee S., Bradley, Richard F., Bull, Phil, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Lewis, David, Liu, Adrian, Ma, Yin-Zhe, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Monsalve, Raul A., Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Nikolic, Bojan, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Smith, Craig, Syce, Angelo, Tegmark, Max, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Precision calibration poses challenges to experiments probing the redshifted 21-cm signal of neutral hydrogen from the Cosmic Dawn and Epoch of Reionization (z~30-6). In both interferometric and global signal experiments, systematic calibration is the leading source of error. Though many aspects of calibration have been studied, the overlap between the two types of instruments has received less attention. We investigate the sky based calibration of total power measurements with a HERA dish and an EDGES style antenna to understand the role of auto-correlations in the calibration of an interferometer and the role of sky in calibrating a total power instrument. Using simulations we study various scenarios such as time variable gain, incomplete sky calibration model, and primary beam model. We find that temporal gain drifts, sky model incompleteness, and beam inaccuracies cause biases in the receiver gain amplitude and the receiver temperature estimates. In some cases, these biases mix spectral structure between beam and sky resulting in spectrally variable gain errors. Applying the calibration method to the HERA and EDGES data, we find good agreement with calibration via the more standard methods. Although instrumental gains are consistent with beam and sky errors similar in scale to those simulated, the receiver temperatures show significant deviations from expected values. While we show that it is possible to partially mitigate biases due to model inaccuracies by incorporating a time-dependent gain model in calibration, the resulting errors on calibration products are larger and more correlated. Completely addressing these biases will require more accurate sky and primary beam models., Comment: 16 pages, 13 figures, 1 table; accepted for publication in MNRAS main journal

Published
2021
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4. Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline

Author

Aguirre, James E., Murray, Steven G., Pascua, Robert, Martinot, Zachary E., Burba, Jacob, Dillon, Joshua S., Jacobs, Daniel C., Kern, Nicholas S., Kittiwisit, Piyanat, Kolopanis, Matthew, Lanman, Adam, Liu, Adrian, Whitler, Lily, Abdurashidova, Zara, Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Julius, Austin, Kerrigan, Joshua, Kohn, Saul A., La Plante, Paul, Lekalake, Telalo, Lewis, David, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Nikolic, Bojan, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Singh, Saurabh, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We describe the validation of the HERA Phase I software pipeline by a series of modular tests, building up to an end-to-end simulation. The philosophy of this approach is to validate the software and algorithms used in the Phase I upper limit analysis on wholly synthetic data satisfying the assumptions of that analysis, not addressing whether the actual data meet these assumptions. We discuss the organization of this validation approach, the specific modular tests performed, and the construction of the end-to-end simulations. We explicitly discuss the limitations in scope of the current simulation effort. With mock visibility data generated from a known analytic power spectrum and a wide range of realistic instrumental effects and foregrounds, we demonstrate that the current pipeline produces power spectrum estimates that are consistent with known analytic inputs to within thermal noise levels (at the 2 sigma level) for k > 0.2 h/Mpc for both bands and fields considered. Our input spectrum is intentionally amplified to enable a strong `detection' at k ~0.2 h/Mpc -- at the level of ~25 sigma -- with foregrounds dominating on larger scales, and thermal noise dominating at smaller scales. Our pipeline is able to detect this amplified input signal after suppressing foregrounds with a dynamic range (foreground to noise ratio) of > 10^7. Our validation test suite uncovered several sources of scale-independent signal loss throughout the pipeline, whose amplitude is well-characterized and accounted for in the final estimates. We conclude with a discussion of the steps required for the next round of data analysis., Comment: 32 pages, 20 figures. Submitted to the Astrophysical Journal

Published
2021
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5. A Real Time Processing System for Big Data in Astronomy: Applications to HERA

Author

La Plante, Paul, Williams, Peter K. G., Kolopanis, Matthew, Dillon, Joshua S., Beardsley, Adam P., Kern, Nicholas S., Wilensky, Michael, Ali, Zaki S., Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Balfour, Yanga, Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Phil, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jaspar, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Lanman, Adam, Lekalake, Telalo, Lewis, David, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven, Neben, Abraham R., Nikolic, Bojan, Parsons, Aaron R., Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, and Zheng, Haoxuan

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

As current- and next-generation astronomical instruments come online, they will generate an unprecedented deluge of data. Analyzing these data in real time presents unique conceptual and computational challenges, and their long-term storage and archiving is scientifically essential for generating reliable, reproducible results. We present here the real-time processing (RTP) system for the Hydrogen Epoch of Reionization Array (HERA), a radio interferometer endeavoring to provide the first detection of the highly redshifted 21 cm signal from Cosmic Dawn and the Epoch of Reionization by an interferometer. The RTP system consists of analysis routines run on raw data shortly after they are acquired, such as calibration and detection of radio-frequency interference (RFI) events. RTP works closely with the Librarian, the HERA data storage and transfer manager which automatically ingests data and transfers copies to other clusters for post-processing analysis. Both the RTP system and the Librarian are public and open source software, which allows for them to be modified for use in other scientific collaborations. When fully constructed, HERA is projected to generate over 50 terabytes (TB) of data each night, and the RTP system enables the successful scientific analysis of these data., Comment: 15 pages, 3 figures, published in Astronomy and Computing

Published
2021
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6. Detection of Cosmic Structures using the Bispectrum Phase. II. First Results from Application to Cosmic Reionization Using the Hydrogen Epoch of Reionization Array

Author

Thyagarajan, Nithyanandan, Carilli, Chris L., Nikolic, Bojan, Kent, James, Mesinger, Andrei, Kern, Nicholas S., Bernardi, Gianni, Matika, Siyanda, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carey, Steve, Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Lewis, David, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Syce, Angelo, Williams, Peter K. G., and Zheng, Haoxuan

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Characterizing the epoch of reionization (EoR) at $z\gtrsim 6$ via the redshifted 21 cm line of neutral Hydrogen (HI) is critical to modern astrophysics and cosmology, and thus a key science goal of many current and planned low-frequency radio telescopes. The primary challenge to detecting this signal is the overwhelmingly bright foreground emission at these frequencies, placing stringent requirements on the knowledge of the instruments and inaccuracies in analyses. Results from these experiments have largely been limited not by thermal sensitivity but by systematics, particularly caused by the inability to calibrate the instrument to high accuracy. The interferometric bispectrum phase is immune to antenna-based calibration and errors therein, and presents an independent alternative to detect the EoR HI fluctuations while largely avoiding calibration systematics. Here, we provide a demonstration of this technique on a subset of data from the Hydrogen Epoch of Reionization Array (HERA) to place approximate constraints on the brightness temperature of the intergalactic medium (IGM). From this limited data, at $z=7.7$ we infer "$1\sigma$" upper limits on the IGM brightness temperature to be $\le 316$ "pseudo" mK at $\kappa_\parallel=0.33$ "pseudo" $h$ Mpc$^{-1}$ (data-limited) and $\le 1000$ "pseudo" mK at $\kappa_\parallel=0.875$ "pseudo" $h$ Mpc$^{-1}$ (noise-limited). The "pseudo" units denote only an approximate and not an exact correspondence to the actual distance scales and brightness temperatures. By propagating models in parallel to the data analysis, we confirm that the dynamic range required to separate the cosmic HI signal from the foregrounds is similar to that in standard approaches, and the power spectrum of the bispectrum phase is still data-limited (at $\gtrsim 10^6$ dynamic range) indicating scope for further improvement in sensitivity as the array build-out continues., Comment: 22 pages, 12 figures (including sub-figures). Published in PhRvD. Abstract may be slightly abridged compared to the actual manuscript due to length limitations on arXiv

Published
2020
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7. Redundant-Baseline Calibration of the Hydrogen Epoch of Reionization Array

Author

Dillon, Joshua S., Lee, Max, Ali, Zaki S., Parsons, Aaron R., Orosz, Naomi, Nunhokee, Chuneeta Devi, La Plante, Paul, Beardsley, Adam P., Kern, Nicholas S., Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Balfour, Yanga, Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Phil, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, Lekalake, Telalo, Lewis, David, Liu, Adrian, Ma, Yin-Zhe, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven, Neben, Abraham R., Nikolic, Bojan, Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Santos, Mario G., Sims, Peter, Smith, Craig, Syce, Angelo, Tegmark, Max, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

In 21 cm cosmology, precision calibration is key to the separation of the neutral hydrogen signal from very bright but spectrally-smooth astrophysical foregrounds. The Hydrogen Epoch of Reionization Array (HERA), an interferometer specialized for 21 cm cosmology and now under construction in South Africa, was designed to be largely calibrated using the self-consistency of repeated measurements of the same interferometric modes. This technique, known as "redundant-baseline calibration" resolves most of the internal degrees of freedom in the calibration problem. It assumes, however, on antenna elements with identical primary beams placed precisely on a redundant grid. In this work, we review the detailed implementation of the algorithms enabling redundant-baseline calibration and report results with HERA data. We quantify the effects of real-world non-redundancy and how they compare to the idealized scenario in which redundant measurements differ only in their noise realizations. Finally, we study how non-redundancy can produce spurious temporal structure in our calibration solutions--both in data and in simulations--and present strategies for mitigating that structure., Comment: 24 Pages, 19 Figures. Updated to match the accepted MNRAS version

Published
2020
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8. Redundant-baseline calibration of the hydrogen epoch of reionization array

Author

Dillon, Joshua S, Lee, Max, Ali, Zaki S, Parsons, Aaron R, Orosz, Naomi, Nunhokee, Chuneeta Devi, La Plante, Paul, Beardsley, Adam P, Kern, Nicholas S, Abdurashidova, Zara, Aguirre, James E, Alexander, Paul, Balfour, Yanga, Bernardi, Gianni, Billings, Tashalee S, Bowman, Judd D, Bradley, Richard F, Bull, Phil, Burba, Jacob, Carey, Steve, Carilli, Chris L, Cheng, Carina, DeBoer, David R, Dexter, Matt, de Lera Acedo, Eloy, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R, Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J, Hewitt, Jacqueline N, Hickish, Jack, Jacobs, Daniel C, Julius, Austin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A, Kolopanis, Matthew, Lanman, Adam, Lekalake, Telalo, Lewis, David, Liu, Adrian, Ma, Yin-Zhe, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E, Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F, Mosiane, Tshegofalang, Murray, Steven, Neben, Abraham R, Nikolic, Bojan, Pascua, Robert, Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C, Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Santos, Mario G, Sims, Peter, Smith, Craig, Syce, Angelo, Tegmark, Max, Thyagarajan, Nithyanandan, Williams, Peter KG, and Zheng, Haoxuan

Subjects
instrumentation: interferometers, dark ages, reionization, first stars, dark ages, reionization, first stars, astro-ph.IM, astro-ph.CO, Astronomical and Space Sciences, Astronomy & Astrophysics
Abstract

In 21-cm cosmology, precision calibration is key to the separation of the neutral hydrogen signal from very bright but spectrally smooth astrophysical foregrounds. The Hydrogen Epoch of Reionization Array (HERA), an interferometer specialized for 21-cm cosmology and now under construction in South Africa, was designed to be largely calibrated using the self-consistency of repeated measurements of the same interferometric modes. This technique, known as redundant-baseline calibration resolves most of the internal degrees of freedom in the calibration problem. It assumes, however, on antenna elements with identical primary beams placed precisely on a redundant grid. In this work, we review the detailed implementation of the algorithms enabling redundant-baseline calibration and report results with HERA data.We quantify the effects of real-world non-redundancy and how they compare to the idealized scenario in which redundant measurements differ only in their noise realizations. Finally, we study how non-redundancy can produce spurious temporal structure in our calibration solutions-both in data and in simulations-and present strategies for mitigating that structure.

Published
2020

20. Introduction

Author

Baverstock, Alison, primary, Bowen, Susannah, additional, and Carey, Steve, additional

Published
2023
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29. AMI-CL J0300+2613: a Galactic anomalous-microwave-emission ring masquerading as a galaxy cluster

Author

Perrott, Yvette C., Cantwell, Therese M., Carey, Steve H., Elwood, Patrick J., Feroz, Farhan, Grainge, Keith J. B., Green, David A., Hobson, Michael P., Javid, Kamran, Jin, Terry Z., Pooley, Guy G., Razavi-Ghods, Nima, Rumsey, Clare, Saunders, Richard D. E., Scaife, Anna M. M., Schammel, Michel P., Scott, Paul F., Shimwell, Timothy W., Titterington, David J., and Waldram, Elizabeth M.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

The Arcminute Microkelvin Imager (AMI) carried out a blind survey for galaxy clusters via their Sunyaev-Zel'dovich effect decrements between 2008 and 2011. The first detection, known as AMI-CL J0300+2613, has been reobserved with AMI equipped with a new digital correlator with high dynamic range. The combination of the new AMI data and more recent high-resolution sub-mm and infra-red maps now shows the feature in fact to be a ring of positive dust-correlated Galactic emission, which is likely to be anomalous microwave emission (AME). If so, this is the first completely blind detection of AME at arcminute scales., Comment: 11 pages, 13 figures, 4 tables. Submitted to MNRAS

Published
2017
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30. A Digital Correlator Upgrade for the Arcminute MicroKelvin Imager

Author

Hickish, Jack, Razavi-Ghods, Nima, Perrott, Yvette C., Titterington, David J., Carey, Steve H., Scott, Paul F., Grainge, Keith J. B., Scaife, Anna M. M., Alexander, Paul, Saunders, Richard D. E., Crofts, Mike, Javid, Kamran, Rumsey, Clare, Jin, Terry Z., Ely, John A., Shaw, Clive, Northrop, Ian G., Pooley, Guy, D'Alessandro, Robert, Doherty, Peter, and Willatt, Greg P.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Arcminute Microkelvin Imager (AMI) telescopes located at the Mullard Radio Astronomy Observatory near Cambridge have been significantly enhanced by the implementation of a new digital correlator with 1.2 MHz spectral resolution. This system has replaced a 750-MHz resolution analogue lag-based correlator, and was designed to mitigate the effects of radio frequency interference, particularly from geostationary satellites that contaminate observations at low declinations. The upgraded instrument consists of 18 ROACH2 Field Programmable Gate Array platforms used to implement a pair of real-time FX correlators -- one for each of AMI's two arrays. The new system separates the down-converted RF baseband signal from each AMI receiver into two 2.3 GHz-wide sub-bands which are each digitized at 5-Gsps with 8 bits of precision. These digital data streams are filtered into 2048 frequency channels and cross-correlated using FPGA hardware, with a commercial 10 Gb Ethernet switch providing high-speed data interconnect. Images formed using data from the new digital correlator show over an order of magnitude improvement in dynamic range over the previous system. The ability to observe at low declinations has also been significantly improved., Comment: 11 pages, 10 figures, accepted to MNRAS

Published
2017
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32. The UK 64-element SKA1-LOW development array

Author

Razavi-Ghods, Nima, primary, Magro, Alessio, additional, Chiello, Riccardo, additional, Ely, John, additional, Carey, Steve, additional, Gueuning, Quentin, additional, Shaw, Clive, additional, Scott, Paul, additional, Faulkner, Andrew, additional, Zarb-Adami, Kristian, additional, and de Lera Acedo, Eloy, additional

Published
2023
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33. Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations

Author

Abdurashidova, The HERA Collaboration: Zara, primary, Adams, Tyrone, additional, Aguirre, James E., additional, Alexander, Paul, additional, Ali, Zaki S., additional, Baartman, Rushelle, additional, Balfour, Yanga, additional, Barkana, Rennan, additional, Beardsley, Adam P., additional, Bernardi, Gianni, additional, Billings, Tashalee S., additional, Bowman, Judd D., additional, Bradley, Richard F., additional, Breitman, Daniela, additional, Bull, Philip, additional, Burba, Jacob, additional, Carey, Steve, additional, Carilli, Chris L., additional, Cheng, Carina, additional, Choudhuri, Samir, additional, DeBoer, David R., additional, de Lera Acedo, Eloy, additional, Dexter, Matt, additional, Dillon, Joshua S., additional, Ely, John, additional, Ewall-Wice, Aaron, additional, Fagnoni, Nicolas, additional, Fialkov, Anastasia, additional, Fritz, Randall, additional, Furlanetto, Steven R., additional, Gale-Sides, Kingsley, additional, Garsden, Hugh, additional, Glendenning, Brian, additional, Gorce, Adélie, additional, Gorthi, Deepthi, additional, Greig, Bradley, additional, Grobbelaar, Jasper, additional, Halday, Ziyaad, additional, Hazelton, Bryna J., additional, Heimersheim, Stefan, additional, Hewitt, Jacqueline N., additional, Hickish, Jack, additional, Jacobs, Daniel C., additional, Julius, Austin, additional, Kern, Nicholas S., additional, Kerrigan, Joshua, additional, Kittiwisit, Piyanat, additional, Kohn, Saul A., additional, Kolopanis, Matthew, additional, Lanman, Adam, additional, La Plante, Paul, additional, Lewis, David, additional, Liu, Adrian, additional, Loots, Anita, additional, Ma, Yin-Zhe, additional, MacMahon, David H. E., additional, Malan, Lourence, additional, Malgas, Keith, additional, Malgas, Cresshim, additional, Maree, Matthys, additional, Marero, Bradley, additional, Martinot, Zachary E., additional, McBride, Lisa, additional, Mesinger, Andrei, additional, Mirocha, Jordan, additional, Molewa, Mathakane, additional, Morales, Miguel F., additional, Mosiane, Tshegofalang, additional, Muñoz, Julian B., additional, Murray, Steven G., additional, Nagpal, Vighnesh, additional, Neben, Abraham R., additional, Nikolic, Bojan, additional, Nunhokee, Chuneeta D., additional, Nuwegeld, Hans, additional, Parsons, Aaron R., additional, Pascua, Robert, additional, Patra, Nipanjana, additional, Pieterse, Samantha, additional, Qin, Yuxiang, additional, Razavi-Ghods, Nima, additional, Robnett, James, additional, Rosie, Kathryn, additional, Santos, Mario G., additional, Sims, Peter, additional, Singh, Saurabh, additional, Smith, Craig, additional, Swarts, Hilton, additional, Tan, Jianrong, additional, Thyagarajan, Nithyanandan, additional, Wilensky, Michael J., additional, Williams, Peter K. G., additional, van Wyngaarden, Pieter, additional, and Zheng, Haoxuan, additional

Published
2023
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35. First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum

Author

Massachusetts Institute of Technology. Department of Physics, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, de Lera Acedo, Eloy, Dibblee-Barkman, Taylor, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N, Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Lewis, David, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham Richard, Nikolic, Bojan, Nunhokee, Chuneeta D., Parsons, Aaron R., Patra, Nipanjana, Pascua, Robert, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Singh, Saurabh, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., Zheng, Haoxuan, Massachusetts Institute of Technology. Department of Physics, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, de Lera Acedo, Eloy, Dibblee-Barkman, Taylor, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N, Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Lewis, David, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham Richard, Nikolic, Bojan, Nunhokee, Chuneeta D., Parsons, Aaron R., Patra, Nipanjana, Pascua, Robert, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Singh, Saurabh, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

We report upper limits on the Epoch of Reionization 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights of data (∼36 hr of integration) from Phase I of the Hydrogen Epoch of Reionization Array (HERA). The Phase I data show evidence for systematics that can be largely suppressed with systematic models down to a dynamic range of ∼109 with respect to the peak foreground power. This yields a 95% confidence upper limit on the 21 cm power spectrum of ${{\rm{\Delta }}}_{21}^{2}\leqslant {(30.76)}^{2}\ {\mathrm{mK}}^{2}$ at k = 0.192 h Mpc−1 at z = 7.9, and also ${{\rm{\Delta }}}_{21}^{2}\leqslant {(95.74)}^{2}\ {\mathrm{mK}}^{2}$ at k = 0.256 h Mpc−1 at z = 10.4. At z = 7.9, these limits are the most sensitive to date by over an order of magnitude. While we find evidence for residual systematics at low line-of-sight Fourier k∥ modes, at high k∥ modes we find our data to be largely consistent with thermal noise, an indicator that the system could benefit from deeper integrations. The observed systematics could be due to radio frequency interference, cable subreflections, or residual instrumental cross-coupling, and warrant further study. This analysis emphasizes algorithms that have minimal inherent signal loss, although we do perform a careful accounting in a companion paper of the small forms of loss or bias associated with the pipeline. Overall, these results are a promising first step in the development of a tuned, instrument-specific analysis pipeline for HERA, particularly as Phase II construction is completed en route to reaching the full sensitivity of the experiment.

Published
2022

36. First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum

Author

Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, de Lera Acedo, Eloy, Dibblee-Barkman, Taylor, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Lewis, David, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta D., Parsons, Aaron R., Patra, Nipanjana, Pascua, Robert, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Singh, Saurabh, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., Zheng, Haoxuan, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steve, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, de Lera Acedo, Eloy, Dibblee-Barkman, Taylor, Dillon, Joshua S., Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steven R., Gale-Sides, Kingsley, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Halday, Ziyaad, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kern, Nicholas S., Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Lewis, David, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Mesinger, Andrei, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Murray, Steven G., Neben, Abraham R., Nikolic, Bojan, Nunhokee, Chuneeta D., Parsons, Aaron R., Patra, Nipanjana, Pascua, Robert, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Singh, Saurabh, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

We report upper limits on the Epoch of Reionization 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights of data (∼36 hr of integration) from Phase I of the Hydrogen Epoch of Reionization Array (HERA). The Phase I data show evidence for systematics that can be largely suppressed with systematic models down to a dynamic range of ∼109 with respect to the peak foreground power. This yields a 95% confidence upper limit on the 21 cm power spectrum of ${{\rm{\Delta }}}_{21}^{2}\leqslant {(30.76)}^{2}\ {\mathrm{mK}}^{2}$ at k = 0.192 h Mpc−1 at z = 7.9, and also ${{\rm{\Delta }}}_{21}^{2}\leqslant {(95.74)}^{2}\ {\mathrm{mK}}^{2}$ at k = 0.256 h Mpc−1 at z = 10.4. At z = 7.9, these limits are the most sensitive to date by over an order of magnitude. While we find evidence for residual systematics at low line-of-sight Fourier k∥ modes, at high k∥ modes we find our data to be largely consistent with thermal noise, an indicator that the system could benefit from deeper integrations. The observed systematics could be due to radio frequency interference, cable subreflections, or residual instrumental cross-coupling, and warrant further study. This analysis emphasizes algorithms that have minimal inherent signal loss, although we do perform a careful accounting in a companion paper of the small forms of loss or bias associated with the pipeline. Overall, these results are a promising first step in the development of a tuned, instrument-specific analysis pipeline for HERA, particularly as Phase II construction is completed en route to reaching the full sensitivity of the experiment.

Published
2022

37. First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum

Author

Abdurashidova, Zara, primary, Aguirre, James E., additional, Alexander, Paul, additional, Ali, Zaki S., additional, Balfour, Yanga, additional, Beardsley, Adam P., additional, Bernardi, Gianni, additional, Billings, Tashalee S., additional, Bowman, Judd D., additional, Bradley, Richard F., additional, Bull, Philip, additional, Burba, Jacob, additional, Carey, Steve, additional, Carilli, Chris L., additional, Cheng, Carina, additional, DeBoer, David R., additional, Dexter, Matt, additional, de Lera Acedo, Eloy, additional, Dibblee-Barkman, Taylor, additional, Dillon, Joshua S., additional, Ely, John, additional, Ewall-Wice, Aaron, additional, Fagnoni, Nicolas, additional, Fritz, Randall, additional, Furlanetto, Steven R., additional, Gale-Sides, Kingsley, additional, Glendenning, Brian, additional, Gorthi, Deepthi, additional, Greig, Bradley, additional, Grobbelaar, Jasper, additional, Halday, Ziyaad, additional, Hazelton, Bryna J., additional, Hewitt, Jacqueline N., additional, Hickish, Jack, additional, Jacobs, Daniel C., additional, Julius, Austin, additional, Kern, Nicholas S., additional, Kerrigan, Joshua, additional, Kittiwisit, Piyanat, additional, Kohn, Saul A., additional, Kolopanis, Matthew, additional, Lanman, Adam, additional, La Plante, Paul, additional, Lekalake, Telalo, additional, Lewis, David, additional, Liu, Adrian, additional, MacMahon, David, additional, Malan, Lourence, additional, Malgas, Cresshim, additional, Maree, Matthys, additional, Martinot, Zachary E., additional, Matsetela, Eunice, additional, Mesinger, Andrei, additional, Molewa, Mathakane, additional, Morales, Miguel F., additional, Mosiane, Tshegofalang, additional, Murray, Steven G., additional, Neben, Abraham R., additional, Nikolic, Bojan, additional, Nunhokee, Chuneeta D., additional, Parsons, Aaron R., additional, Patra, Nipanjana, additional, Pascua, Robert, additional, Pieterse, Samantha, additional, Pober, Jonathan C., additional, Razavi-Ghods, Nima, additional, Ringuette, Jon, additional, Robnett, James, additional, Rosie, Kathryn, additional, Sims, Peter, additional, Singh, Saurabh, additional, Smith, Craig, additional, Syce, Angelo, additional, Thyagarajan, Nithyanandan, additional, Williams, Peter K. G., additional, and Zheng, Haoxuan, additional

Published
2022
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38. Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline

Author

Aguirre, James E., primary, Murray, Steven G., additional, Pascua, Robert, additional, Martinot, Zachary E., additional, Burba, Jacob, additional, Dillon, Joshua S., additional, Jacobs, Daniel C., additional, Kern, Nicholas S., additional, Kittiwisit, Piyanat, additional, Kolopanis, Matthew, additional, Lanman, Adam, additional, Liu, Adrian, additional, Whitler, Lily, additional, Abdurashidova, Zara, additional, Alexander, Paul, additional, Ali, Zaki S., additional, Balfour, Yanga, additional, Beardsley, Adam P., additional, Bernardi, Gianni, additional, Billings, Tashalee S., additional, Bowman, Judd D., additional, Bradley, Richard F., additional, Bull, Philip, additional, Carey, Steve, additional, Carilli, Chris L., additional, Cheng, Carina, additional, DeBoer, David R., additional, Dexter, Matt, additional, de Lera Acedo, Eloy, additional, Ely, John, additional, Ewall-Wice, Aaron, additional, Fagnoni, Nicolas, additional, Fritz, Randall, additional, Furlanetto, Steven R., additional, Gale-Sides, Kingsley, additional, Glendenning, Brian, additional, Gorthi, Deepthi, additional, Greig, Bradley, additional, Grobbelaar, Jasper, additional, Halday, Ziyaad, additional, Hazelton, Bryna J., additional, Hewitt, Jacqueline N., additional, Hickish, Jack, additional, Julius, Austin, additional, Kerrigan, Joshua, additional, Kohn, Saul A., additional, La Plante, Paul, additional, Lekalake, Telalo, additional, Lewis, David, additional, MacMahon, David, additional, Malan, Lourence, additional, Malgas, Cresshim, additional, Maree, Matthys, additional, Matsetela, Eunice, additional, Mesinger, Andrei, additional, Molewa, Mathakane, additional, Morales, Miguel F., additional, Mosiane, Tshegofalang, additional, Neben, Abraham R., additional, Nikolic, Bojan, additional, Parsons, Aaron R., additional, Patra, Nipanjana, additional, Pieterse, Samantha, additional, Pober, Jonathan C., additional, Razavi-Ghods, Nima, additional, Ringuette, Jon, additional, Robnett, James, additional, Rosie, Kathryn, additional, Santos, Mario G., additional, Sims, Peter, additional, Singh, Saurabh, additional, Smith, Craig, additional, Syce, Angelo, additional, Thyagarajan, Nithyanandan, additional, Williams, Peter K. G., additional, and Zheng, Haoxuan, additional

Published
2022
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39. HERA Phase I Limits on the Cosmic 21 cm Signal: Constraints on Astrophysics and Cosmology during the Epoch of Reionization

Author

Abdurashidova, Zara, primary, Aguirre, James E., additional, Alexander, Paul, additional, Ali, Zaki S., additional, Balfour, Yanga, additional, Barkana, Rennan, additional, Beardsley, Adam P., additional, Bernardi, Gianni, additional, Billings, Tashalee S., additional, Bowman, Judd D., additional, Bradley, Richard F., additional, Bull, Philip, additional, Burba, Jacob, additional, Carey, Steve, additional, Carilli, Chris L., additional, Cheng, Carina, additional, DeBoer, David R., additional, Dexter, Matt, additional, de Lera Acedo, Eloy, additional, Dillon, Joshua S., additional, Ely, John, additional, Ewall-Wice, Aaron, additional, Fagnoni, Nicolas, additional, Fialkov, Anastasia, additional, Fritz, Randall, additional, Furlanetto, Steven R., additional, Gale-Sides, Kingsley, additional, Glendenning, Brian, additional, Gorthi, Deepthi, additional, Greig, Bradley, additional, Grobbelaar, Jasper, additional, Halday, Ziyaad, additional, Hazelton, Bryna J., additional, Heimersheim, Stefan, additional, Hewitt, Jacqueline N., additional, Hickish, Jack, additional, Jacobs, Daniel C., additional, Julius, Austin, additional, Kern, Nicholas S., additional, Kerrigan, Joshua, additional, Kittiwisit, Piyanat, additional, Kohn, Saul A., additional, Kolopanis, Matthew, additional, Lanman, Adam, additional, La Plante, Paul, additional, Lekalake, Telalo, additional, Lewis, David, additional, Liu, Adrian, additional, Ma, Yin-Zhe, additional, MacMahon, David, additional, Malan, Lourence, additional, Malgas, Cresshim, additional, Maree, Matthys, additional, Martinot, Zachary E., additional, Matsetela, Eunice, additional, Mesinger, Andrei, additional, Mirocha, Jordan, additional, Molewa, Mathakane, additional, Morales, Miguel F., additional, Mosiane, Tshegofalang, additional, Muñoz, Julian B., additional, Murray, Steven G., additional, Neben, Abraham R., additional, Nikolic, Bojan, additional, Nunhokee, Chuneeta D., additional, Parsons, Aaron R., additional, Patra, Nipanjana, additional, Pieterse, Samantha, additional, Pober, Jonathan C., additional, Qin, Yuxiang, additional, Razavi-Ghods, Nima, additional, Reis, Itamar, additional, Ringuette, Jon, additional, Robnett, James, additional, Rosie, Kathryn, additional, Santos, Mario G., additional, Sikder, Sudipta, additional, Sims, Peter, additional, Smith, Craig, additional, Syce, Angelo, additional, Thyagarajan, Nithyanandan, additional, Williams, Peter K. G., additional, and Zheng, Haoxuan, additional

Published
2022
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41. Effects of model incompleteness on the drift-scan calibration of radio telescopes

Author

Gehlot, Bharat K, primary, Jacobs, Daniel C, additional, Bowman, Judd D, additional, Mahesh, Nivedita, additional, Murray, Steven G, additional, Kolopanis, Matthew, additional, Beardsley, Adam P, additional, Abdurashidova, Zara, additional, Aguirre, James E, additional, Alexander, Paul, additional, Ali, Zaki S, additional, Balfour, Yanga, additional, Bernardi, Gianni, additional, Billings, Tashalee S, additional, Bradley, Richard F, additional, Bull, Phil, additional, Burba, Jacob, additional, Carey, Steve, additional, Carilli, Chris L, additional, Cheng, Carina, additional, DeBoer, David R, additional, Dexter, Matt, additional, de Lera Acedo, Eloy, additional, Dillon, Joshua S, additional, Ely, John, additional, Ewall-Wice, Aaron, additional, Fagnoni, Nicolas, additional, Fritz, Randall, additional, Furlanetto, Steven R, additional, Gale-Sides, Kingsley, additional, Glendenning, Brian, additional, Gorthi, Deepthi, additional, Greig, Bradley, additional, Grobbelaar, Jasper, additional, Halday, Ziyaad, additional, Hazelton, Bryna J, additional, Hewitt, Jacqueline N, additional, Hickish, Jack, additional, Julius, Austin, additional, Kern, Nicholas S, additional, Kerrigan, Joshua, additional, Kittiwisit, Piyanat, additional, Kohn, Saul A, additional, Lanman, Adam, additional, La Plante, Paul, additional, Lekalake, Telalo, additional, Lewis, David, additional, Liu, Adrian, additional, Ma, Yin-Zhe, additional, MacMahon, David, additional, Malan, Lourence, additional, Malgas, Cresshim, additional, Maree, Matthys, additional, Martinot, Zachary E, additional, Matsetela, Eunice, additional, Mesinger, Andrei, additional, Molewa, Mathakane, additional, Monsalve, Raul A, additional, Morales, Miguel F, additional, Mosiane, Tshegofalang, additional, Neben, Abraham R, additional, Nikolic, Bojan, additional, Parsons, Aaron R, additional, Pascua, Robert, additional, Patra, Nipanjana, additional, Pieterse, Samantha, additional, Pober, Jonathan C, additional, Razavi-Ghods, Nima, additional, Ringuette, Jon, additional, Robnett, James, additional, Rosie, Kathryn, additional, Santos, Mario G, additional, Sims, Peter, additional, Smith, Craig, additional, Syce, Angelo, additional, Tegmark, Max, additional, Thyagarajan, Nithyanandan, additional, Williams, Peter K G, additional, and Zheng, Haoxuan, additional

Published
2021
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43. Integrated care for people with diabetes in South London

Author

Mohiddin, Abdu, Carey, Steve, Costa, Dominic, and Jones, Richard

Subjects
Diabetes -- Care and treatment -- Research, Health care industry -- Services, Nurses -- Practice -- Services -- Research, Health, Health care industry, Practice, Care and treatment, Research, Services
Abstract

Introduction This article describes an intervention to improve diabetes care services in a deprived multi-ethnic inner-city area of south London with the long-term aim of building a local service model. [...]

Published
2004

44. Storage and distribution of pathology digital images using integrated Web-based viewing systems. (Special Article)

Author

Marchevsky, Alberto M., Dulbandzhyan, Ronda, Seely, Kevin, Carey, Steve, and Duncan, Raymond G.

Subjects
Internet -- Usage, Health care industry -- Information management, Image processing -- Methods
Abstract

* Context.--Health care providers have expressed increasing interest in incorporating digital images of gross pathology specimens and photomicrographs in routine pathology reports. Objective.--To describe the multiple technical and logistical challenges involved in the integration of the various components needed for the development of a system for integrated Web-based viewing, storage, and distribution of digital images in a large health system. Design.--An Oracle version 8.1.6 database was developed to store, index, and deploy pathology digital photographs via our Intranet. The database allows for retrieval of images by patient demographics or by SNOMED code information. Setting.--The Intranet of a large health system accessible from multiple computers located within the medical center and at distant private physician offices. Results.--The images can be viewed using any of the workstations of the health system that have authorized access to our Intranet, using a standard browser or a browser configured with an external viewer or inexpensive plug-in software, such as Prizm 2.0. The images can be printed on paper or transferred to film using a digital film recorder. Digital images can also be displayed at pathology conferences by using wireless local area network (LAN) and secure remote technologies. Conclusions.--The standardization of technologies and the adoption of a Web interface for all our computer systems allows us to distribute digital images from a pathology database to a potentially large group of users distributed in multiple locations throughout a large medical center., Health care providers have expressed increasing interest in the use of digital images as a substitute for gross photography and microphotography, image analysis, telepathology, and other medical applications. (1-21) Megapixel [...]

Published
2002

45. Detection of cosmic structures using the bispectrum phase. II. First results from application to cosmic reionization using the Hydrogen Epoch of Reionization Array

Author

Thyagarajan, Nithyanandan, primary, Carilli, Chris L., additional, Nikolic, Bojan, additional, Kent, James, additional, Mesinger, Andrei, additional, Kern, Nicholas S., additional, Bernardi, Gianni, additional, Matika, Siyanda, additional, Abdurashidova, Zara, additional, Aguirre, James E., additional, Alexander, Paul, additional, Ali, Zaki S., additional, Balfour, Yanga, additional, Beardsley, Adam P., additional, Billings, Tashalee S., additional, Bowman, Judd D., additional, Bradley, Richard F., additional, Burba, Jacob, additional, Carey, Steve, additional, Cheng, Carina, additional, DeBoer, David R., additional, Dexter, Matt, additional, Acedo, Eloy de Lera, additional, Dillon, Joshua S., additional, Ely, John, additional, Ewall-Wice, Aaron, additional, Fagnoni, Nicolas, additional, Fritz, Randall, additional, Furlanetto, Steven R., additional, Gale-Sides, Kingsley, additional, Glendenning, Brian, additional, Gorthi, Deepthi, additional, Greig, Bradley, additional, Grobbelaar, Jasper, additional, Halday, Ziyaad, additional, Hazelton, Bryna J., additional, Hewitt, Jacqueline N., additional, Hickish, Jack, additional, Jacobs, Daniel C., additional, Julius, Austin, additional, Kerrigan, Joshua, additional, Kittiwisit, Piyanat, additional, Kohn, Saul A., additional, Kolopanis, Matthew, additional, Lanman, Adam, additional, La Plante, Paul, additional, Lekalake, Telalo, additional, Lewis, David, additional, Liu, Adrian, additional, MacMahon, David, additional, Malan, Lourence, additional, Malgas, Cresshim, additional, Maree, Matthys, additional, Martinot, Zachary E., additional, Matsetela, Eunice, additional, Molewa, Mathakane, additional, Morales, Miguel F., additional, Mosiane, Tshegofalang, additional, Neben, Abraham R., additional, Parsons, Aaron R., additional, Patra, Nipanjana, additional, Pieterse, Samantha, additional, Pober, Jonathan C., additional, Razavi-Ghods, Nima, additional, Ringuette, Jon, additional, Robnett, James, additional, Rosie, Kathryn, additional, Sims, Peter, additional, Smith, Craig, additional, Syce, Angelo, additional, Williams, Peter K. G., additional, and Zheng, Haoxuan, additional

Published
2020
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50. Influence of magma composition on the eruptive activity of Mount St. Helens,Washington

Author

Gardner, James E., Carey, Steve, Sigurdsson, Haraldur, and Rutherford, Malcolm J.

Subjects
Mount Saint Helens -- Natural history, Magma -- Composition, Volcanism -- Research, Volcanoes -- Washington, Earth sciences
Abstract

The relation of eruptive intensity with magma composition and viscosity has been investigated for Mount St. Helens, Washington, where eruptive activity has ranged from basaltic lava flows to dacitic Plinian eruptions. The Plinian eruptions have varied in eruptive intensity from [10.sup.6] to [10.sup.8] kg/s, yet all erupted dacitic magma. These dacites, however, differ greatly in temperature, water content, and crystallinity, and thus magma viscosity varies by two orders of magnitude. The variation in viscosity is correlated inversely with intensity, demonstrating the control of composition on intensity. In addition, more mafic magmas erupted at lower intensities, showing that the wide range in eruptive behavior is linked to magma composition. Changes in composition result mainly from mixing of basaltic and dacitic magmas and occur in cycles. The rate of change during a cycle depends upon the length of the preceding repose period and the flux of basalt to the reservoir, because the supply of dacite has been relatively constant. When the flux of basalt is low, cycles progress from dacite to andesite over extended periods, whereas a higher flux leads to more rapid changes. Because composition controls eruptive intensity, the eruptive behavior of the volcano also varies through a cycle.

Published
1995

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