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Your search keyword '"Acedo, Eloy de Lera"' showing total 4 results
Start Over Author "Acedo, Eloy de Lera" Topic reionization
4 results on '"Acedo, Eloy de Lera"'

1. Foreground modelling via Gaussian process regression: an application to HERA data

Author

Ghosh, Abhik, Mertens, Florent, Bernardi, Gianni, Santos, Mário G, Kern, Nicholas S, Carilli, Christopher L, Grobler, Trienko L, Koopmans, Léon VE, Jacobs, Daniel C, Liu, Adrian, Parsons, Aaron R, Morales, Miguel F, Aguirre, James E, Dillon, Joshua S, Hazelton, Bryna J, Smirnov, Oleg M, Gehlot, Bharat K, Matika, Siyanda, Alexander, Paul, Ali, Zaki S, Beardsley, Adam P, Benefo, Roshan K, Billings, Tashalee S, Bowman, Judd D, Bradley, Richard F, Cheng, Carina, Chichura, Paul M, DeBoer, David R, Acedo, Eloy de Lera, Ewall-Wice, Aaron, Fadana, Gcobisa, Fagnoni, Nicolas, Fortino, Austin F, Fritz, Randall, Furlanetto, Steve R, Gallardo, Samavarti, Glendenning, Brian, Gorthi, Deepthi, Greig, Bradley, Grobbelaar, Jasper, Hickish, Jack, Josaitis, Alec, Julius, Austin, Igarashi, Amy S, Kariseb, MacCalvin, Kohn, Saul A, Kolopanis, Matthew, Lekalake, Telalo, Loots, Anita, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E, Mathison, Nathan, Matsetela, Eunice, Mesinger, Andrei, Neben, Abraham R, Nikolic, Bojan, Nunhokee, Chuneeta D, Patra, Nipanjana, Pieterse, Samantha, Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sell, Raddwine, Smith, Craig, Syce, Angelo, Tegmark, Max, Thyagarajan, Nithyanandan, Williams, Peter KG, and Zheng, Haoxuan

Subjects
instrumentation: interferometers, methods: statistical, dark ages, reionization, first stars, diffuse radiation, large-scale structure of Universe, cosmology: observations, astro-ph.CO, Astronomical and Space Sciences, Astronomy & Astrophysics
Abstract

The key challenge in the observation of the redshifted 21-cm signal from cosmic reionization is its separation from the much brighter foreground emission. Such separation relies on the different spectral properties of the two components, although, in real life, the foreground intrinsic spectrum is often corrupted by the instrumental response, inducing systematic effects that can further jeopardize the measurement of the 21-cm signal. In this paper, we use Gaussian Process Regression to model both foreground emission and instrumental systematics in ∼2 h of data from the Hydrogen Epoch of Reionization Array. We find that a simple co-variance model with three components matches the data well, giving a residual power spectrum with white noise properties. These consist of an 'intrinsic' and instrumentally corrupted component with a coherence scale of 20 and 2.4 MHz, respectively (dominating the line-of-sight power spectrum over scales kâ ≤ 0.2 h cMpc-1) and a baseline-dependent periodic signal with a period of ∼1 MHz (dominating over kâ ∼0.4-0.8 h cMpc-1), which should be distinguishable from the 21-cm Epoch of Reionization signal whose typical coherence scale is ∼0.8 MHz.

Published
2020

2. On the use of temporal filtering for mitigating galactic synchrotron calibration bias in 21 cm reionization observations.

Author

Charles, Ntsikelelo, Kern, Nicholas, Bernardi, Gianni, Bester, Landman, Smirnov, Oleg, Fagnoni, Nicolas, and Acedo, Eloy de Lera

Subjects
CALIBRATION, SYNCHROTRONS, ANTENNAS (Electronics)
Abstract

Precision antenna calibration is required for mitigating the impact of foreground contamination in 21 cm cosmological radio surveys. One widely studied source of error is the effect of missing point sources in the calibration sky model; however, poorly understood diffuse galactic emission also creates a calibration bias that can complicate the clean separation of foregrounds from the 21 cm signal. In this work, we present a technique for suppressing this bias with temporal filtering of radio interferometric visibilities observed in a drift-scan mode. We demonstrate this technique on mock simulations of the Hydrogen Epoch of Reionization Array (HERA) experiment. Inspecting the recovered calibration solutions, we find that our technique reduces spurious errors by over an order of magnitude. This improved accuracy approaches the required accuracy needed to make a fiducial detection of the 21 cm signal with HERA, but is dependent on a number of external factors that we discuss. We also explore different types of temporal filtering techniques and discuss their relative performance and trade-offs. [ABSTRACT FROM AUTHOR]

Published
2023
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3. Imaging and Modeling Data from the Hydrogen Epoch of Reionization Array

Author

Juan Mena Parra, Piyanat Kittiwisit, Kingsley Gale-Sides, Joshua Kerrigan, Honggeun Kim, Adrian Liu, Phil Bull, Nipanjana Patra, Ziyaad Halday, Matthys Maree, James E. Aguirre, Bryna J. Hazelton, Jacqueline N. Hewitt, Zara Abdurashidova, Saul A. Kohn, Judd D. Bowman, Matt Dexter, K. Gale-Sides, Samantha Pieterse, Paul La Plante, Mathakane Molewa, James Kent, Nithyanandan Thyagarajan, Eunice Matsetela, Nicolas Fagnoni, Adam P. Beardsley, Alec Josaitis, Kathryn Rosie, David MacMahon, Jonathan C. Pober, Andrei Mesinger, Jasper Grobbelaar, Tashalee S. Billings, Zachary E. Martinot, Tshegofalang Mosiane, Abraham R. Neben, Austin Julius, Randall Fritz, Siyanda Matika, Brian Glendenning, Carina Cheng, Peter Sims, Paul Alexander, Daniel C. Jacobs, Steve R. Furlanetto, Gianni Bernardi, Bradley Greig, Lourence Malan, Nima Razavi-Ghods, Cresshim Malgas, Yanga Balfour, Nicholas S. Kern, Telalo Lekalake, David DeBoer, Aaron R. Parsons, Richard F. Bradley, Matthew Kolopanis, Deepthi Gorthi, Peter K. G. Williams, James Robnett, Joshua S. Dillon, Chris Carilli, Eloy de Lera Acedo, Miguel F. Morales, Zaki S. Ali, Bojan Nikolic, Aaron Ewall-Wice, Jack Hickish, Jacob Burba, Angelo Syce, Haoxuan Zheng, Adam Lanman, ITA, USA, ZAF, Carilli, C. L., Thyagarajan, N., Kent, J., Nikolic, B., Gale-Sides, K., Kern, N. S., Bernardi, G., Mesinger, A., Matika, S., Abdurashidova, Zara, Aguirre, James E., Paul, Alexander Christian, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Phil, Burba, Jacob, Cheng, Carina, Deboer, David R., Dexter, Matt, Acedo, Eloy de Lera, Dillon, Joshua S., Ewall-Wice, Aaron, Fagnoni, Nicola, Fritz, Randall, Furlanetto, Steve 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., Josaitis, Alec, Julius, Austin, Kerrigan, Joshua, Kim, Honggeun, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, Plante, Paul La, Lekalake, Telalo, Liu, Adrian, Macmahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthy, Martinot, Zachary E., Matsetela, Eunice, Molewa, Mathakane, Morales, Miguel F., Mosiane, Tshegofalang, Neben, Abraham R., Parra, Juan Mena, Parsons, Aaron R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Robnett, Jame, Rosie, Kathryn, Sims, Peter, Syce, Angelo, Williams, Peter K. G., Zheng, Haoxuan, Carilli, CL [0000-0001-6647-3861], Thyagarajan, N [0000-0003-1602-7868], Kern, NS [0000-0002-8211-1892], Bernardi, G [0000-0002-0916-7443], Aguirre, JE [0000-0002-4810-666X], Beardsley, AP [0000-0001-9428-8233], Bowman, JD [0000-0002-8475-2036], Bull, P [0000-0001-5668-3101], Dillon, JS [0000-0003-3336-9958], Ewall-Wice, A [0000-0002-0086-7363], Furlanetto, SR [0000-0002-0658-1243], Hazelton, BJ [0000-0001-7532-645X], Jacobs, DC [0000-0002-0917-2269], Kerrigan, J [0000-0002-1876-272X], Kittiwisit, P [0000-0003-0953-313X], Kohn, SA [0000-0001-6744-5328], Kolopanis, M [0000-0002-2950-2974], Liu, A [0000-0001-6876-0928], Morales, MF [0000-0001-7694-4030], Neben, AR [0000-0001-7776-7240], Patra, N [0000-0002-9457-1941], Pober, JC [0000-0002-3492-0433], Williams, PKG [0000-0003-3734-3587], and Apollo - University of Cambridge Repository

Subjects
Physics, Cosmological evolution, Hydrogen, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, chemistry.chemical_element, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Cosmology, Data modeling, chemistry, Reionization, Space and Planetary Science, 0103 physical sciences, Radio interferometry, Astrophysics - Instrumentation and Methods for Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

We analyze data from the Hydrogen Epoch of Reionization Array. This is the third in a series of papers on the closure phase delay-spectrum technique designed to detect the HI 21cm emission from cosmic reionization. We present the details of the data and models employed in the power spectral analysis, and discuss limitations to the process. We compare images and visibility spectra made with HERA data, to parallel quantities generated from sky models based on the GLEAM survey, incorporating the HERA telescope model. We find reasonable agreement between images made from HERA data, with those generated from the models, down to the confusion level. For the visibility spectra, there is broad agreement between model and data across the full band of $\sim 80$MHz. However, models with only GLEAM sources do not reproduce a roughly sinusoidal spectral structure at the tens of percent level seen in the observed visibility spectra on scales $\sim 10$ MHz on 29 m baselines. We find that this structure is likely due to diffuse Galactic emission, predominantly the Galactic plane, filling the far sidelobes of the antenna primary beam. We show that our current knowledge of the frequency dependence of the diffuse sky radio emission, and the primary beam at large zenith angles, is inadequate to provide an accurate reproduction of the diffuse structure in the models. We discuss implications due to this missing structure in the models, including calibration, and in the search for the HI 21cm signal, as well as possible mitigation techniques., Comment: 17 pages, 10 figures, accepted for the ApJ Supplement

Published
2020

4. Hydrogen Epoch of Reionization Array (HERA)

Author

Paul Alexander, Lourence Malan, David MacMahon, Daniel C. Jacobs, Jon Ringuette, C. H. Smith, Angelo Syce, Cresshim Malgas, Aaron R. Parsons, Nicolas Fagnoni, Joshua S. Dillon, Miguel F. Morales, Nithyanandan Thyagarajan, Richard F. Bradley, Peter Williams, Zaki S. Ali, Telalo Lekalake, Aaron Ewall-Wice, Nipanjana Patra, Eloy de Lera Acedo, Jonathan C. Pober, Nathan Mathison, Andrei Mesinger, Nima Razavi-Ghods, Gianni Bernardi, Bradley Greig, Steve R. Furlanetto, Jasper Grobbelaar, David DeBoer, Adrian Liu, Matthys Maree, Saul A. Kohn, Zachary E. Martinot, Anita Loots, Brian Glendenning, Carina Cheng, Judd D. Bowman, Raddwine Sell, Kathryn Rosie, Samantha Pieterse, Adam P. Beardsley, Gcobisa Fadana, Bryna J. Hazelton, Jacqueline N. Hewitt, Haoxuan Zheng, James E. Aguirre, James Robnett, Abraham R. Neben, Randall Fritz, Austin Julius, Chris L. Carilli, Jack Hickish, Eunice Matsetela, MacCalvin Kariseb, Max Tegmark, ITA, USA, Deboer, David R., Parsons, Aaron R., Aguirre, James E., Alexander, Paul, Ali, Zaki S., Beardsley, Adam P., Bernardi, Gianni, Bowman, Judd D., Bradley, Richard F., Carilli, Chris L., Cheng, Carina, Acedo, Eloy de Lera, Dillon, Joshua S., Ewall-Wice, Aaron, Fadana, Gcobisa, Fagnoni, Nicola, Fritz, Randall, Furlanetto, Steve R., Glendenning, Brian, Greig, Bradley, Grobbelaar, Jasper, Hazelton, Bryna J., Hewitt, Jacqueline N., Hickish, Jack, Jacobs, Daniel C., Julius, Austin, Kariseb, Maccalvin, Kohn, Saul A., Lekalake, Telalo, Liu, Adrian, Loots, Anita, Macmahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthy, Martinot, Zachary, Mathison, Nathan, Matsetela, Eunice, Mesinger, Andrei, Morales, Miguel F., Neben, Abraham R., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, Jame, Rosie, Kathryn, Sell, Raddwine, Smith, Craig, Syce, Angelo, Tegmark, Max, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Bryna, Dark age, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, 01 natural sciences, Reionization, Settore FIS/05 - Astronomia e Astrofisica, First star, 0103 physical sciences, Physical Sciences and Mathematics, Theology, Telescope, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, biology, 010308 nuclear & particles physics, Philosophy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, HERA, biology.organism_classification, Space and Planetary Science, Interferometer [Instrumentation], Interferometric [Techniques], Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization ($z=6-12$), and to explore earlier epochs of our Cosmic Dawn ($z\sim30$). During these epochs, early stars and black holes heated and ionized the IGM, introducing fluctuations in 21 cm emission. HERA is designed to characterize the evolution of the 21 cm power spectrum to constrain the timing and morphology of reionization, the properties of the first galaxies, the evolution of large-scale structure, and the early sources of heating. The full HERA instrument will be a 350-element interferometer in South Africa consisting of 14-m parabolic dishes observing from 50 to 250 MHz. Currently, 19 dishes have been deployed on site and the next 18 are under construction. HERA has been designated as an SKA Precursor instrument. In this paper, we summarize HERA's scientific context and provide forecasts for its key science results. After reviewing the current state of the art in foreground mitigation, we use the delay-spectrum technique to motivate high-level performance requirements for the HERA instrument. Next, we present the HERA instrument design, along with the subsystem specifications that ensure that HERA meets its performance requirements. Finally, we summarize the schedule and status of the project. We conclude by suggesting that, given the realities of foreground contamination, current-generation 21 cm instruments are approaching their sensitivity limits. HERA is designed to bring both the sensitivity and the precision to deliver its primary science on the basis of proven foreground filtering techniques, while developing new subtraction techniques to unlock new capabilities. The result will be a major step toward realizing the widely recognized scientific potential of 21 cm cosmology., Comment: 26 pages, 24 figures, 2 tables

Published
2016
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