Search

Your search keyword '"BOWMAN, JUDD"' showing total 779 results
Start Over Author "BOWMAN, JUDD"

Refine your results

779 results on '"BOWMAN, JUDD"'

201. Cosmology with the Highly Redshifted 21 cm Line

Author

Liu, Adrian, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Carucci, Isabella P., Chang, Tzu-Ching, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dillon, Joshua, Dvorkin, Cora, Fialkov, Anastasia, Furlanetto, Steven, Gnedin, Nick, Hazelton, Bryna, Jacobs, Daniel, Wolt, Marc Klein, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, Mesinger, Andrei, Mirocha, Jordan, Munoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, Zaldarriaga, Matias, and Astronomy

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The 21cm line can be used to conduct large-volume surveys of the high-z universe, probing both astrophysics and cosmology. We highlight the promise of using the 21cm line to constrain cosmology via z>6 observations, emphasizing the key advances and investments required to access the potentially vast information content of future surveys.

Published
2019

202. Insights Into the Epoch of Reionization with the Highly-Redshifted 21-cm Line

Author

Furlanetto, Steven, Carilli, Chris L., Mirocha, Jordan, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Bowman, Judd D., Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Carucci, Isabella P., Chang, Tzu-Ching, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, Davies, Frederick, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Gnedin, Nick, Hazelton, Bryna, Jacobs, Daniel, Karkare, Kirit, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mesinger, Andrew, Munoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Switzer, Eric, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, Zaldarriaga, Matias, and Astronomy

Subjects
Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics
Abstract

We describe how direct measurements of the reionization process with the 21-cm line of neutral hydrogen will enable science investigations of that era.

Published
2019

203. The Murchison Widefield Array Commissioning Survey: A Low-Frequency Catalogue of 14,110 Compact Radio Sources over 6,100 Square Degrees

Author

Haystack Observatory, MIT Kavli Institute for Astrophysics and Space Research, Hurley-Walker, Natasha, Morgan, John, Wayth, Randall B., Hancock, Paul J., Bell, Martin E., Bernardi, Gianni, Bhat, Ramesh, Briggs, Frank, Deshpande, Avinash A., Ewall-Wice, Aaron Michael, Feng, Lu, Hazelton, Bryna J., Hindson, Luke, Jacobs, Daniel C., Kaplan, David L., Kudryavtseva, Nadia, Lenc, Emil, McKinley, Benjamin, Mitchell, Daniel, Pindor, Bart, Procopio, Pietro, Oberoi, Divya, Offringa, Andre, Ord, Stephen, Riding, Jennifer, Bowman, Judd D., Cappallo, Roger, Corey, Brian, Emrich, David, Gaensler, B. M., Goeke, Robert F, Greenhill, Lincoln, Hewitt, Jacqueline, Johnston-Hollitt, Melanie, Kasper, Justin, Kratzenberg, Eric, Lonsdale, Colin, Lynch, Mervyn, McWhirter, Russell, Morales, Miguel F., Morgan, Edward H, Prabu, Thiagaraj, Rogers, Alan, Roshi, Anish, Shankar, Udaya, Srivani, K., Subrahmanyan, Ravi, Tingay, Steven, Waterson, Mark, Webster, Rachel, Whitney, Alan, Williams, Andrew, Williams, Chris, Haystack Observatory, MIT Kavli Institute for Astrophysics and Space Research, Hurley-Walker, Natasha, Morgan, John, Wayth, Randall B., Hancock, Paul J., Bell, Martin E., Bernardi, Gianni, Bhat, Ramesh, Briggs, Frank, Deshpande, Avinash A., Ewall-Wice, Aaron Michael, Feng, Lu, Hazelton, Bryna J., Hindson, Luke, Jacobs, Daniel C., Kaplan, David L., Kudryavtseva, Nadia, Lenc, Emil, McKinley, Benjamin, Mitchell, Daniel, Pindor, Bart, Procopio, Pietro, Oberoi, Divya, Offringa, Andre, Ord, Stephen, Riding, Jennifer, Bowman, Judd D., Cappallo, Roger, Corey, Brian, Emrich, David, Gaensler, B. M., Goeke, Robert F, Greenhill, Lincoln, Hewitt, Jacqueline, Johnston-Hollitt, Melanie, Kasper, Justin, Kratzenberg, Eric, Lonsdale, Colin, Lynch, Mervyn, McWhirter, Russell, Morales, Miguel F., Morgan, Edward H, Prabu, Thiagaraj, Rogers, Alan, Roshi, Anish, Shankar, Udaya, Srivani, K., Subrahmanyan, Ravi, Tingay, Steven, Waterson, Mark, Webster, Rachel, Whitney, Alan, Williams, Andrew, and Williams, Chris

Abstract

We present the results of an approximately 6,100 deg[superscript 2] 104-196 MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December: the MWACS. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The survey covers approximately 20.5 h < RA < 8.5 h, -58° < Dec < -14°over three frequency bands centred on 119, 150 and 180 MHz, with image resolutions of 6-3 arcmin. The catalogue has 3 arcmin angular resolution and a typical noise level of 40 mJy beam [superscript -1], with reduced sensitivity near the field boundaries and bright sources. We describe the data reduction strategy, based upon mosaicked snapshots, flux density calibration, and source-finding method. We present a catalogue of flux density and spectral index measurements for 14,110 sources, extracted from the mosaic, 1,247 of which are sub-components of complexes of sources. Keywords: surveys; radio continuum; general - surveys - techniques; interferometric

Published
2020

204. Photo-realistic Terrain Modeling and Visualization for Mars Exploration Rover Science Operations

Author

Edwards, Laurence, Sims, Michael, Kunz, Clayton, Lees, David, and Bowman, Judd

Subjects
Computer Programming And Software
Abstract

Modern NASA planetary exploration missions employ complex systems of hardware and software managed by large teams of. engineers and scientists in order to study remote environments. The most complex and successful of these recent projects is the Mars Exploration Rover mission. The Computational Sciences Division at NASA Ames Research Center delivered a 30 visualization program, Viz, to the MER mission that provides an immersive, interactive environment for science analysis of the remote planetary surface. In addition, Ames provided the Athena Science Team with high-quality terrain reconstructions generated with the Ames Stereo-pipeline. The on-site support team for these software systems responded to unanticipated opportunities to generate 30 terrain models during the primary MER mission. This paper describes Viz, the Stereo-pipeline, and the experiences of the on-site team supporting the scientists at JPL during the primary MER mission.

Published
2005

206. Absolute Calibration Strategies for the Hydrogen Epoch of Reionization Array and Their Impact on the 21 cm Power Spectrum

Author

Kern, Nicholas S., primary, Dillon, Joshua S., additional, Parsons, Aaron R., additional, Carilli, Christopher L., additional, Bernardi, Gianni, 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, Bull, Philip, additional, Burba, Jacob, additional, Carey, Steven, 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, Steve 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, 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, 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, Thyagarajan, Nithyanandan, additional, Williams, Peter K. G., additional, and Zheng, Haoxuan, additional

Published
2020
Full Text
View/download PDF

207. Mitigating Internal Instrument Coupling for 21 cm Cosmology. II. A Method Demonstration with the Hydrogen Epoch of Reionization Array

Author

Kern, Nicholas S., primary, Parsons, Aaron R., additional, Dillon, Joshua S., additional, Lanman, Adam E., additional, Liu, Adrian, additional, Bull, Philip, additional, Ewall-Wice, Aaron, additional, Abdurashidova, Zara, additional, Aguirre, James E., additional, Alexander, Paul, additional, Ali, Zaki S., additional, Balfour, Yanga, additional, Beardsley, Adam P., additional, Bernardi, Gianni, additional, Bowman, Judd D., additional, Bradley, Richard F., additional, Burba, Jacob, additional, Carilli, Chris L., additional, Cheng, Carina, additional, DeBoer, David R., additional, Dexter, Matt, additional, de Lera Acedo, Eloy, additional, Fagnoni, Nicolas, additional, Fritz, Randall, additional, Furlanetto, Steve R., 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, La Plante, Paul, additional, Lekalake, Telalo, 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, 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, Thyagarajan, Nithyanandan, additional, Williams, Peter K. G., additional, and Zheng, Haoxuan, additional

Published
2020
Full Text
View/download PDF

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

Author

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

Published
2020
Full Text
View/download PDF

209. The Star-Planet Activity Research CubeSat (SPARCS): A Mission to Understand the Impact of Stars in Exoplanets

Author

Ardila, David, Shkolnik, Evgenya, Scowen, Paul, Jewell, April, Nikzad, Shouleh, Bowman, Judd, Fitzgerald, Michael, and Jacobs, Daniel

Abstract

The Star-Planet Activity Research CubeSat (SPARCS) is a NASA-funded astrophysics mission, devoted to the study of the ultraviolet (UV) time-domain behavior in low-mass stars. Given their abundance and size, low-mass stars are important targets in the search for habitable-zone, exoplanets. However, not enough is known about the stars flare and quiescent emission, which powers photochemical reactions on the atmospheres of possible planets. Over its initial 1- year mission, SPARCS will stare at ≈10 stars in order to measure short- (minutes) and long- (months) term variability simultaneously in the near-UV (NUV – lc = 280 nm) and far-UV (FUV – lc = 162 nm). The SPARCS payload consists of a 9-cm reflector telescope paired with two high-sensitivity 2D-doped CCDs. The detectors are kept passively cooled at 238K, in order to reduce dark-current contribution. The filters have been selected to provide strong rejection of longer wavelengths, where most of the starlight is emitted. The payload will be integrated within a 6U CubeSat to be placed on a Sun-synchronous terminator orbit, allowing for long observing stares for all targets. Launch is expected to occur not earlier than October 2021.

Published
2018

212. Optimizing sparse RFI prediction using deep learning

Author

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

Published
2019
Full Text
View/download PDF

216. Peering into the dark (ages) with low-frequency space interferometers: Using the 21-cm signal of neutral hydrogen from the infant universe to probe fundamental (Astro)physics.

Author

Koopmans, Léon V. E., Barkana, Rennan, Bentum, Mark, Bernardi, Gianni, Boonstra, Albert-Jan, Bowman, Judd, Burns, Jack, Chen, Xuelei, Datta, Abhirup, Falcke, Heino, Fialkov, Anastasia, Gehlot, Bharat, Gurvits, Leonid, Jelić, Vibor, Klein-Wolt, Marc, Lazio, Joseph, Meerburg, Daan, Mellema, Garrelt, Mertens, Florent, and Mesinger, Andrei

Subjects
INFANTS, MIDDLE Ages, PHYSICS, RADIO telescopes, INTERFEROMETERS, REDSHIFT
Abstract

The Dark Ages and Cosmic Dawn are largely unexplored windows on the infant Universe (z ~ 200–10). Observations of the redshifted 21-cm line of neutral hydrogen can provide valuable new insight into fundamental physics and astrophysics during these eras that no other probe can provide, and drives the design of many future ground-based instruments such as the Square Kilometre Array (SKA) and the Hydrogen Epoch of Reionization Array (HERA). We review progress in the field of high-redshift 21-cm Cosmology, in particular focussing on what questions can be addressed by probing the Dark Ages at z > 30. We conclude that only a space- or lunar-based radio telescope, shielded from the Earth's radio-frequency interference (RFI) signals and its ionosphere, enable the 21-cm signal from the Dark Ages to be detected. We suggest a generic mission design concept, CoDEX, that will enable this in the coming decades. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

217. Cosmology with the Highly Redshifted 21cm Line

Author

Liu, Adrian, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Carucci, Isabella P., Chang, Tzu-Ching, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Furlanetto, Steven, Gnedin, Nick, Hazelton, Bryna, Hewitt, Jacqueline, Jacobs, Daniel, Karkare, Kirit, Wolt, Marc Klein, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, Plante, Paul La, Lidz, Adam, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, Mesinger, Andrei, Mirocha, Jordan, Munoz, Julian, Murray, Steven, Newburgh, Laura, Parsons, Aaron, Pober, Jonathan, Pritchard, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, Zaldarriaga, Matias, Liu, Adrian, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Carucci, Isabella P., Chang, Tzu-Ching, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Furlanetto, Steven, Gnedin, Nick, Hazelton, Bryna, Hewitt, Jacqueline, Jacobs, Daniel, Karkare, Kirit, Wolt, Marc Klein, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, Plante, Paul La, Lidz, Adam, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, Mesinger, Andrei, Mirocha, Jordan, Munoz, Julian, Murray, Steven, Newburgh, Laura, Parsons, Aaron, Pober, Jonathan, Pritchard, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, and Zaldarriaga, Matias

Abstract

In addition to being a probe of Cosmic Dawn and Epoch of Reionization astrophysics, the 21cm line at z>6 is also a powerful way to constrain cosmology. Its power derives from several unique capabilities. First, the 21cm line is sensitive to energy injections into the intergalactic medium at high redshifts. It also increases the number of measurable modes compared to existing cosmological probes by orders of magnitude. Many of these modes are on smaller scales than are accessible via the CMB, and moreover have the advantage of being firmly in the linear regime (making them easy to model theoretically). Finally, the 21cm line provides access to redshifts prior to the formation of luminous objects. Together, these features of 21cm cosmology at z>6 provide multiple pathways toward precise cosmological constraints. These include the "marginalizing out" of astrophysical effects, the utilization of redshift space distortions, the breaking of CMB degeneracies, the identification of signatures of relative velocities between baryons and dark matter, and the discovery of unexpected signs of physics beyond the ΛCDM paradigm at high redshifts.

Published
2019

218. A Roadmap for Astrophysics and Cosmology with High-Redshift 21 cm Intensity Mapping

Author

Array, The Hydrogen Epoch of Reionization, Array, The Hydrogen Epoch of Reionization, Collaboration, Aguirre, James E, Beardsley, Adam P, Bernardi, Gianni, Bowman, Judd D, Bull, Philip, Carilli, Chris L, Dai, Wei-Ming, DeBoer, David R, Dillon, Joshua S, Ewall-Wice, Aaron, Furlanetto, Steve R, Gehlot, Bharat K, Gorthi, Deepthi, Greig, Bradley, Hazelton, Bryna J, Hewitt, Jacqueline N, Jacobs, Daniel C, Kern, Nicholas S, Kittiwisit, Piyanat, Kolopanis, Matthew, Plante, Paul La, Liu, Adrian, Ma, Yin-Zhe, Mdlalose, Mthokozisi, Mirocha, Jordan, Murray, Steven G, Parsons, Aaron R, Pober, Jonathan C, Sims, Peter H, Thyagarajan, Nithyanandan, Array, The Hydrogen Epoch of Reionization, Array, The Hydrogen Epoch of Reionization, Collaboration, Aguirre, James E, Beardsley, Adam P, Bernardi, Gianni, Bowman, Judd D, Bull, Philip, Carilli, Chris L, Dai, Wei-Ming, DeBoer, David R, Dillon, Joshua S, Ewall-Wice, Aaron, Furlanetto, Steve R, Gehlot, Bharat K, Gorthi, Deepthi, Greig, Bradley, Hazelton, Bryna J, Hewitt, Jacqueline N, Jacobs, Daniel C, Kern, Nicholas S, Kittiwisit, Piyanat, Kolopanis, Matthew, Plante, Paul La, Liu, Adrian, Ma, Yin-Zhe, Mdlalose, Mthokozisi, Mirocha, Jordan, Murray, Steven G, Parsons, Aaron R, Pober, Jonathan C, Sims, Peter H, and Thyagarajan, Nithyanandan

Abstract

In this white paper, we lay out a US roadmap for high-redshift 21 cm cosmology (30 < z < 6) in the 2020s. Beginning with the currently-funded HERA and MWA Phase II projects and advancing through the decade with a coordinated program of small-scale instrumentation, software, and analysis projects targeting technology development, this roadmap incorporates our current best understanding of the systematics confronting 21 cm cosmology into a plan for overcoming them, enabling next-generation, mid-scale 21 cm arrays to be proposed late in the decade. Submitted for consideration by the Astro2020 Decadal Survey Program Panel for Radio, Millimeter, and Submillimeter Observations from the Ground as a Medium-Sized Project.

Published
2019

219. Absolute Calibration Strategies for the Hydrogen Epoch of Reionization Array and Their Impact on the 21 cm Power Spectrum

Author

Kern, Nicholas S., Dillon, Joshua S., Parsons, Aaron R., Carilli, Christopher L., Bernardi, Gianni, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, 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., Julius, Austin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, 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., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., Zheng, Haoxuan, Kern, Nicholas S., Dillon, Joshua S., Parsons, Aaron R., Carilli, Christopher L., Bernardi, Gianni, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Billings, Tashalee S., Bowman, Judd D., Bradley, Richard F., Bull, Philip, Burba, Jacob, Carey, Steven, Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Ely, John, Ewall-Wice, Aaron, Fagnoni, Nicolas, 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., Julius, Austin, Kerrigan, Joshua, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, 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., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

We discuss absolute calibration strategies for Phase I of the Hydrogen Epoch of Reionization Array (HERA), which aims to measure the cosmological 21 cm signal from the Epoch of Reionization (EoR). HERA is a drift-scan array with a 10 degree wide field of view, meaning bright, well-characterized point source transits are scarce. This, combined with HERA's redundant sampling of the uv plane and the modest angular resolution of the Phase I instrument, make traditional sky-based and self-calibration techniques difficult to implement with high dynamic range. Nonetheless, in this work we demonstrate calibration for HERA using point source catalogues and electromagnetic simulations of its primary beam. We show that unmodeled diffuse flux and instrumental contaminants can corrupt the gain solutions, and present a gain smoothing approach for mitigating their impact on the 21 cm power spectrum. We also demonstrate a hybrid sky and redundant calibration scheme and compare it to pure sky-based calibration, showing only a marginal improvement to the gain solutions at intermediate delay scales. Our work suggests that the HERA Phase I system can be well-calibrated for a foreground-avoidance power spectrum estimator by applying direction-independent gains with a small set of degrees of freedom across the frequency and time axes., Comment: Accepted to ApJ

Published
2019
Full Text
View/download PDF

220. NASA Probe Study Report: Farside Array for Radio Science Investigations of the Dark ages and Exoplanets (FARSIDE)

Author

Burns, Jack O., Hallinan, Gregg, Lux, Jim, Teitelbaum, Lawrence, Kocz, Jonathon, MacDowall, Robert, Bradley, Richard, Rapetti, David, Wu, Wenbo, Furlanetto, Steven, Austin, Alex, Romero-Wolf, Andres, Chang, Tzu-Ching, Bowman, Judd, Kasper, Justin, Anderson, Marin, Zhen, Zhongwen, Pober, Jonathan, Mirocha, Jordan, Burns, Jack O., Hallinan, Gregg, Lux, Jim, Teitelbaum, Lawrence, Kocz, Jonathon, MacDowall, Robert, Bradley, Richard, Rapetti, David, Wu, Wenbo, Furlanetto, Steven, Austin, Alex, Romero-Wolf, Andres, Chang, Tzu-Ching, Bowman, Judd, Kasper, Justin, Anderson, Marin, Zhen, Zhongwen, Pober, Jonathan, and Mirocha, Jordan

Abstract

This is the final report submitted to NASA for a Probe-class concept study of the "Farside Array for Radio Science Investigations of the Dark ages and Exoplanets" (FARSIDE), a low radio frequency interferometric array on the farside of the Moon. The design study focused on the instrument, a deployment rover, the lander and base station, and delivered an architecture broadly consistent with the requirements for a Probe mission. This notional architecture consists of 128 dipole antennas deployed across a 10 km area by a rover, and tethered to a base station for central processing, power and data transmission to the Lunar Gateway, or an alternative relay satellite. FARSIDE would provide the capability to image the entire sky each minute in 1400 channels spanning frequencies from 150 kHz to 40 MHz, extending down two orders of magnitude below bands accessible to ground-based radio astronomy. The lunar farside can simultaneously provide isolation from terrestrial radio frequency interference, auroral kilometric radiation, and plasma noise from the solar wind. This would enable near-continuous monitoring of the nearest stellar systems in the search for the radio signatures of coronal mass ejections and energetic particle events, and would also detect the magnetospheres for the nearest candidate habitable exoplanets. Simultaneously, FARSIDE would be used to characterize similar activity in our own solar system, from the Sun to the outer planets. Through precision calibration via an orbiting beacon, and exquisite foreground characterization, FARSIDE would also measure the Dark Ages global 21-cm signal at redshifts from 50-100. It will also be a pathfinder for a larger 21-cm power spectrum instrument by carefully measuring the foreground with high dynamic range., Comment: 50 pages, NASA Probe final study report. arXiv admin note: text overlap with arXiv:1907.05407

Published
2019

221. Mitigating Internal Instrument Coupling II: A Method Demonstration with the Hydrogen Epoch of Reionization Array

Author

Kern, Nicholas S., Parsons, Aaron R., Dillon, Joshua S., Lanman, Adam E., Liu, Adrian, Bull, Philip, Ewall-Wice, Aaron, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steve R., 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, La Plante, Paul, Lekalake, Telalo, 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., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., Zheng, Haoxuan, Kern, Nicholas S., Parsons, Aaron R., Dillon, Joshua S., Lanman, Adam E., Liu, Adrian, Bull, Philip, Ewall-Wice, Aaron, Abdurashidova, Zara, Aguirre, James E., Alexander, Paul, Ali, Zaki S., Balfour, Yanga, Beardsley, Adam P., Bernardi, Gianni, Bowman, Judd D., Bradley, Richard F., Burba, Jacob, Carilli, Chris L., Cheng, Carina, DeBoer, David R., Dexter, Matt, Acedo, Eloy de Lera, Fagnoni, Nicolas, Fritz, Randall, Furlanetto, Steve R., 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, La Plante, Paul, Lekalake, Telalo, 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., Patra, Nipanjana, Pieterse, Samantha, Pober, Jonathan C., Razavi-Ghods, Nima, Ringuette, Jon, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

We present a study of internal reflection and cross coupling systematics in Phase I of the Hydrogen Epoch of Reionization Array (HERA). In a companion paper, we outlined the mathematical formalism for such systematics and presented algorithms for modeling and removing them from the data. In this work, we apply these techniques to data from HERA's first observing season as a method demonstration. The data show evidence for systematics that, without removal, would hinder a detection of the 21 cm power spectrum for the targeted EoR line-of-sight modes in the range 0.2 < k_parallel < 0.5\ h^-1 Mpc. After systematic removal, we find we can recover these modes in the power spectrum down to the integrated noise-floor of a nightly observation, achieving a dynamic range in the EoR window of 10^-6 in power (mK^2 units) with respect to the bright galactic foreground signal. In the absence of other systematics and assuming the systematic suppression demonstrated here continues to lower noise levels, our results suggest that fully-integrated HERA Phase I may have the capacity to set competitive upper limits on the 21 cm power spectrum. For future observing seasons, HERA will have upgraded analog and digital hardware to better control these systematics in the field., Comment: Submitted to ApJ

Published
2019
Full Text
View/download PDF

222. Peering into the Dark (Ages) with Low-Frequency Space Interferometers

Author

Koopmans, Leon, Barkana, Rennan, Bentum, Mark, Bernardi, Gianni, Boonstra, Albert-Jan, Bowman, Judd, Burns, Jack, Chen, Xuelei, Datta, Abhirup, Falcke, Heino, Fialkov, Anastasia, Gehlot, Bharat, Gurvits, Leonid, Jelić, Vibor, Klein-Wolt, Marc, Koopmans, Léon, Lazio, Joseph, Meerburg, Daan, Mellema, Garrelt, Mertens, Florent, Mesinger, Andrei, Offringa, André, Pritchard, Jonathan, Semelin, Benoit, Subrahmanyan, Ravi, Silk, Joseph, Trott, Cathryn, Vedantham, Harish, Verde, Licia, Zaroubi, Saleem, Zarka, Philippe, Koopmans, Leon, Barkana, Rennan, Bentum, Mark, Bernardi, Gianni, Boonstra, Albert-Jan, Bowman, Judd, Burns, Jack, Chen, Xuelei, Datta, Abhirup, Falcke, Heino, Fialkov, Anastasia, Gehlot, Bharat, Gurvits, Leonid, Jelić, Vibor, Klein-Wolt, Marc, Koopmans, Léon, Lazio, Joseph, Meerburg, Daan, Mellema, Garrelt, Mertens, Florent, Mesinger, Andrei, Offringa, André, Pritchard, Jonathan, Semelin, Benoit, Subrahmanyan, Ravi, Silk, Joseph, Trott, Cathryn, Vedantham, Harish, Verde, Licia, Zaroubi, Saleem, and Zarka, Philippe

Abstract

Neutral hydrogen pervades the infant Universe, and its redshifted 21-cm signal allows one to chart the Universe. This signal allows one to probe astrophysical processes such as the formation of the first stars, galaxies, (super)massive black holes and enrichment of the pristine gas from z~6 to z~30, as well as fundamental physics related to gravity, dark matter, dark energy and particle physics at redshifts beyond that. As one enters the Dark Ages (z>30), the Universe becomes pristine. Ground-based low-frequency radio telescopes aim to detect the spatial fluctuations of the 21-cm signal. Complementary, global 21-cm experiments aim to measure the sky-averaged 21-cm signal. Escaping RFI and the ionosphere has motivated space-based missions, such as the Dutch-Chinese NCLE instrument (currently in lunar L2), the proposed US-driven lunar or space-based instruments DAPPER and FARSIDE, the lunar-orbit interferometer DSL (China), and PRATUSH (India). To push beyond the current z~25 frontier, though, and measure both the global and spatial fluctuations (power-spectra/tomography) of the 21-cm signal, low-frequency (1-100MHz; BW~50MHz; z>13) space-based interferometers with vast scalable collecting areas (1-10-100 km2), large filling factors (~1) and large fields-of-view (4pi sr.) are needed over a mission lifetime of >5 years. In this ESA White Paper, we argue for the development of new technologies enabling interferometers to be deployed, in space (e.g. Earth-Sun L2) or in the lunar vicinity (e.g. surface, orbit or Earth-Moon L2), to target this 21-cm signal. This places them in a stable environment beyond the reach of most RFI from Earth and its ionospheric corruptions, enabling them to probe the Dark Ages as well as the Cosmic Dawn, and allowing one to investigate new (astro)physics that is inaccessible in any other way in the coming decades. [Abridged], Comment: 24 pages, 8 figures, 3 tables; White paper submitted to ESA Voyage 2050

Published
2019

223. Understanding the HERA Phase I receiver system with simulations and its impact on the detectability of the EoR delay power spectrum

Author

Fagnoni, Nicolas, Acedo, Eloy de Lera, DeBoer, David R., 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, Phil, Burba, Jacob, Carilli, Chris L., Cheng, Carina, Dexter, Matt, Dillon, Joshua S., Ewall-Wice, Aaron, 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, Kern, Nicholas S., Kerrigan, Joshua, Kim, Honggeun, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Parra, Juan Mena, 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, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., Zheng, Haoxuan, Fagnoni, Nicolas, Acedo, Eloy de Lera, DeBoer, David R., 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, Phil, Burba, Jacob, Carilli, Chris L., Cheng, Carina, Dexter, Matt, Dillon, Joshua S., Ewall-Wice, Aaron, 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, Kern, Nicholas S., Kerrigan, Joshua, Kim, Honggeun, Kittiwisit, Piyanat, Kohn, Saul A., Kolopanis, Matthew, Lanman, Adam, La Plante, Paul, Lekalake, Telalo, Liu, Adrian, MacMahon, David, Malan, Lourence, Malgas, Cresshim, Maree, Matthys, Martinot, Zachary E., Matsetela, Eunice, Parra, Juan Mena, 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, Robnett, James, Rosie, Kathryn, Sims, Peter, Smith, Craig, Syce, Angelo, Thyagarajan, Nithyanandan, Williams, Peter K. G., and Zheng, Haoxuan

Abstract

The detection of the Epoch of Reionization (EoR) delay power spectrum using a "foreground avoidance method" highly depends on the instrument chromaticity. The systematic effects induced by the radio-telescope spread the foreground signal in the delay domain, which contaminates the EoR window theoretically observable. Applied to the Hydrogen Epoch of Reionization Array (HERA), this paper combines detailed electromagnetic and electrical simulations in order to model the chromatic effects of the instrument, and quantify its frequency and time responses. In particular, the effects of the analogue receiver, transmission cables, and mutual coupling are included. These simulations are able to accurately predict the intensity of the reflections occurring in the 150-m cable which links the antenna to the back-end. They also show that electromagnetic waves can propagate from one dish to another one through large sections of the array due to mutual coupling. The simulated system time response is attenuated by a factor $10^{4}$ after a characteristic delay which depends on the size of the array and on the antenna position. Ultimately, the system response is attenuated by a factor $10^{5}$ after 1400 ns because of the reflections in the cable, which corresponds to characterizable ${k_\parallel}$-modes above 0.7 $h\;\rm{Mpc}^{-1}$ at 150 MHz. Thus, this new study shows that the detection of the EoR signal with HERA Phase I will be more challenging than expected. On the other hand, it improves our understanding of the telescope, which is essential to mitigate the instrument chromaticity., Comment: 13 pages, 17 figures - Submitted to MNRAS - 2nd revision

Published
2019
Full Text
View/download PDF

224. FARSIDE: A Low Radio Frequency Interferometric Array on the Lunar Farside

Author

Burns, Jack, Hallinan, Gregg, Lux, Jim, Romero-Wolf, Andres, Chang, Tzu-Ching, Kocz, Jonathan, Bowman, Judd, MacDowall, Robert, Kasper, Justin, Bradley, Richard, Anderson, Marin, Rapetti, David, Burns, Jack, Hallinan, Gregg, Lux, Jim, Romero-Wolf, Andres, Chang, Tzu-Ching, Kocz, Jonathan, Bowman, Judd, MacDowall, Robert, Kasper, Justin, Bradley, Richard, Anderson, Marin, and Rapetti, David

Abstract

FARSIDE (Farside Array for Radio Science Investigations of the Dark ages and Exoplanets) is a Probe-class concept to place a low radio frequency interferometric array on the farside of the Moon. A NASA-funded design study, focused on the instrument, a deployment rover, the lander and base station, delivered an architecture broadly consistent with the requirements for a Probe mission. This notional architecture consists of 128 dual polarization antennas deployed across a 10 km area by a rover, and tethered to a base station for central processing, power and data transmission to the Lunar Gateway. FARSIDE would provide the capability to image the entire sky each minute in 1400 channels spanning frequencies from 100 kHz to 40 MHz, extending down two orders of magnitude below bands accessible to ground-based radio astronomy. The lunar farside can simultaneously provide isolation from terrestrial radio frequency interference, auroral kilometric radiation, and plasma noise from the solar wind. This would enable near-continuous monitoring of the nearest stellar systems in the search for the radio signatures of coronal mass ejections and energetic particle events, and would also detect the magnetospheres for the nearest candidate habitable exoplanets. Simultaneously, FARSIDE would be used to characterize similar activity in our own solar system, from the Sun to the outer planets, including the hypothetical Planet Nine. Through precision calibration via an orbiting beacon, and exquisite foreground characterization, FARSIDE would also measure the Dark Ages global 21-cm signal at redshifts z=50-100. The unique observational window offered by FARSIDE would enable an abundance of additional science ranging from sounding of the lunar subsurface to characterization of the interstellar medium in the solar system neighborhood., Comment: 13 pages, 9 figures, 2 tables, Astro2020 Decadal Survey whitepaper

Published
2019

225. Direct Wide-Field Radio Imaging in Real-Time at High Time Resolution using Antenna Electric Fields

Author

Kent, James, Beardsley, Adam P., Bester, Landman, Gull, Steve F., Nikolic, Bojan, Dowell, Jayce, Thyagarajan, Nithyanandan, Taylor, Greg B., Bowman, Judd, Kent, James, Beardsley, Adam P., Bester, Landman, Gull, Steve F., Nikolic, Bojan, Dowell, Jayce, Thyagarajan, Nithyanandan, Taylor, Greg B., and Bowman, Judd

Abstract

The recent demonstration of a real-time direct imaging radio interferometry correlator represents a new capability in radio astronomy. However wide field imaging with this method is challenging since wide-field effects and array non-coplanarity degrade image quality if not compensated for. Here we present an alternative direct imaging correlation strategy using a Direct Fourier Transform (DFT), modelled as a linear operator facilitating a matrix multiplication between the DFT matrix and a vector of the electric fields from each antenna. This offers perfect correction for wide field and non-coplanarity effects. When implemented with data from the Long Wavelength Array (LWA), it offers comparable computational performance to previously demonstrated direct imaging techniques, despite having a theoretically higher floating point cost. It also has additional benefits, such as imaging sparse arrays and control over which sky co-ordinates are imaged, allowing variable pixel placement across an image. It is in practice a highly flexible and efficient method of direct radio imaging when implemented on suitable arrays. A functioning Electric Field Direct imaging architecture using the DFT is presented, alongside an exploration of techniques for wide-field imaging similar to those in visibility based imaging, and an explanation of why they do not fit well to imaging directly with the digitized electric field data. The DFT imaging method is demonstrated on real data from the LWA telescope, alongside a detailed performance analysis, as well as an exploration of its applicability to other arrays., Comment: 12 pages, 8 figures, 2 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society

Published
2019
Full Text
View/download PDF

226. A Real-Time, All-Sky, High Time Resolution, Direct Imager for the Long Wavelength Array

Author

Kent, James, Dowell, Jayce, Beardsley, Adam, Thyagarjan, Nithyanandan, Taylor, Greg, Bowman, Judd, Kent, James, Dowell, Jayce, Beardsley, Adam, Thyagarjan, Nithyanandan, Taylor, Greg, and Bowman, Judd

Abstract

The future of radio astronomy will require instruments with large collecting areas for higher sensitivity, wide fields of view for faster survey speeds, and efficient computing and data rates relative to current capabilities. We describe the first successful deployment of the E-field Parallel Imaging Correlator (EPIC) on the LWA station in Sevilleta, New Mexico, USA (LWA-SV). EPIC is a solution to the computational problem of large interferometers. By gridding and spatially Fourier transforming channelised electric fields from the antennas in real-time, EPIC removes the explicit cross multiplication of all pairs of antenna voltages to synthesize an aperture, reducing the computational scaling from $\mathcal{O}(n_a^2)$ to $\mathcal{O}(n_g \log_2 n_g)$, where $n_a$ is the number of antennas and $n_g$ is the number of grid points. Not only does this save computational costs for dense arrays but it produces very high time resolution images in real time. The GPU-based implementation uses existing LWA-SV hardware and the high performance streaming framework, Bifrost. We examine the practical details of the EPIC deployment and verify the imaging performance by detecting a meteor impact on the atmosphere using continuous all-sky imaging at 50 ms time resolution., Comment: 10 pages

Published
2019
Full Text
View/download PDF

227. Mapping Cosmic Dawn and Reionization: Challenges and Synergies

Author

Alvarez, Marcelo A., Fialkov, Anastasia, La Plante, Paul, Aguirre, James, Ali-Haïmoud, Yacine, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Cappelluti, Nico, Carucci, Isabella, Chang, Tzu-Ching, Cleary, Kieran, Cooray, Asantha, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Ferraro, Simone, Furlanetto, Steven, Hazelton, Bryna, Hill, J. Colin, Jacobs, Daniel, Karkare, Kirit, Keating, Garrett K., Koopmans, Léon, Kovetz, Ely, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mirocha, Jordan, Muñoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Vikhlinin, Alexey, Visbal, Eli, Zaldarriaga, Matias, Alvarez, Marcelo A., Fialkov, Anastasia, La Plante, Paul, Aguirre, James, Ali-Haïmoud, Yacine, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Cappelluti, Nico, Carucci, Isabella, Chang, Tzu-Ching, Cleary, Kieran, Cooray, Asantha, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Ferraro, Simone, Furlanetto, Steven, Hazelton, Bryna, Hill, J. Colin, Jacobs, Daniel, Karkare, Kirit, Keating, Garrett K., Koopmans, Léon, Kovetz, Ely, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mirocha, Jordan, Muñoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Vikhlinin, Alexey, Visbal, Eli, and Zaldarriaga, Matias

Abstract

Cosmic dawn and the Epoch of Reionization (EoR) are among the least explored observational eras in cosmology: a time at which the first galaxies and supermassive black holes formed and reionized the cold, neutral Universe of the post-recombination era. With current instruments, only a handful of the brightest galaxies and quasars from that time are detectable as individual objects, due to their extreme distances. Fortunately, a multitude of multi-wavelength intensity mapping measurements, ranging from the redshifted 21 cm background in the radio to the unresolved X-ray background, contain a plethora of synergistic information about this elusive era. The coming decade will likely see direct detections of inhomogenous reionization with CMB and 21 cm observations, and a slew of other probes covering overlapping areas and complementary physical processes will provide crucial additional information and cross-validation. To maximize scientific discovery and return on investment, coordinated survey planning and joint data analysis should be a high priority, closely coupled to computational models and theoretical predictions., Comment: 5 pages, 1 figure, submitted to the Astro2020 Decadal Survey Science White Paper call

Published
2019

228. Optimizing Sparse RFI Prediction using Deep Learning

Author

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

Abstract

Radio Frequency Interference (RFI) is an ever-present limiting factor among radio telescopes even in the most remote observing locations. When looking to retain the maximum amount of sensitivity and reduce contamination for Epoch of Reionization studies, the identification and removal of RFI is especially important. In addition to improved RFI identification, we must also take into account computational efficiency of the RFI-Identification algorithm as radio interferometer arrays such as the Hydrogen Epoch of Reionization Array grow larger in number of receivers. To address this, we present a Deep Fully Convolutional Neural Network (DFCN) that is comprehensive in its use of interferometric data, where both amplitude and phase information are used jointly for identifying RFI. We train the network using simulated HERA visibilities containing mock RFI, yielding a known "ground truth" dataset for evaluating the accuracy of various RFI algorithms. Evaluation of the DFCN model is performed on observations from the 67 dish build-out, HERA-67, and achieves a data throughput of 1.6$\times 10^{5}$ HERA time-ordered 1024 channeled visibilities per hour per GPU. We determine that relative to an amplitude only network including visibility phase adds important adjacent time-frequency context which increases discrimination between RFI and Non-RFI. The inclusion of phase when predicting achieves a Recall of 0.81, Precision of 0.58, and $F_{2}$ score of 0.75 as applied to our HERA-67 observations., Comment: 11 pages, 7 figures

Published
2019
Full Text
View/download PDF

229. Astro2020 Science White Paper: First Stars and Black Holes at Cosmic Dawn with Redshifted 21-cm Observations

Author

Mirocha, Jordan, Jacobs, Daniel, Dillon, Josh, Furlanetto, Steve, Pober, Jonathan, Liu, Adrian, Aguirre, James, Ali-Haïmoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Burns, Jack, Chen, Xuelei, Chang, Tzu-Ching, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dvorkin, Cora, Fialkov, Anastasia, Gnedin, Nick, Hazelton, Bryna, Kiyoshi, Masui, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Ma, Yin-Zhe, Mao, Yi, Mesinger, Andrei, Muñoz, Julian, Murray, Steven, Parsons, Aaron, Pritchard, Jonathan, Sievers, Jonathan, Switzer, Eric, Thyagarajan, Nithyanandan, Visbal, Eli, Zaldarriaga, Matias, Mirocha, Jordan, Jacobs, Daniel, Dillon, Josh, Furlanetto, Steve, Pober, Jonathan, Liu, Adrian, Aguirre, James, Ali-Haïmoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Burns, Jack, Chen, Xuelei, Chang, Tzu-Ching, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dvorkin, Cora, Fialkov, Anastasia, Gnedin, Nick, Hazelton, Bryna, Kiyoshi, Masui, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Ma, Yin-Zhe, Mao, Yi, Mesinger, Andrei, Muñoz, Julian, Murray, Steven, Parsons, Aaron, Pritchard, Jonathan, Sievers, Jonathan, Switzer, Eric, Thyagarajan, Nithyanandan, Visbal, Eli, and Zaldarriaga, Matias

Abstract

The "cosmic dawn" refers to the period of the Universe's history when stars and black holes first formed and began heating and ionizing hydrogen in the intergalactic medium (IGM). Though exceedingly difficult to detect directly, the first stars and black holes can be constrained indirectly through measurements of the cosmic 21-cm background, which traces the ionization state and temperature of intergalactic hydrogen gas. In this white paper, we focus on the science case for such observations, in particular those targeting redshifts z $\gtrsim$ 10 when the IGM is expected to be mostly neutral. 21-cm observations provide a unique window into this epoch and are thus critical to advancing first star and black hole science in the next decade., Comment: White paper submitted to the Astro2020 Decadal Survey

Published
2019

230. Astro2020 Science White Paper: Synergies Between Galaxy Surveys and Reionization Measurements

Author

Furlanetto, Steven, Beardsley, Adam, Carilli, Chris L., Mirocha, Jordan, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Becker, George, Bowman, Judd D., Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Carucci, Isabella P., Chang, Tzu-Ching, Chiang, Hsin, Cohn, Joanne, Davies, Frederick, DeBoer, David, Dickinson, Mark, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Finkelstein, Steven, Gnedin, Nick, Hazelton, Bryna, Jacobs, Daniel, Karkare, Kirit, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mesinger, Andrei, Munoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Robertson, Brant, Sievers, Jonathan, Switzer, Eric, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, Zaldarriaga, Matias, Furlanetto, Steven, Beardsley, Adam, Carilli, Chris L., Mirocha, Jordan, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Becker, George, Bowman, Judd D., Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Carucci, Isabella P., Chang, Tzu-Ching, Chiang, Hsin, Cohn, Joanne, Davies, Frederick, DeBoer, David, Dickinson, Mark, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Finkelstein, Steven, Gnedin, Nick, Hazelton, Bryna, Jacobs, Daniel, Karkare, Kirit, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mesinger, Andrei, Munoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Robertson, Brant, Sievers, Jonathan, Switzer, Eric, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, and Zaldarriaga, Matias

Abstract

The early phases of galaxy formation constitute one of the most exciting frontiers in astrophysics. It is during this era that the first luminous sources reionize the intergalactic medium - the moment when structure formation affects every baryon in the Universe. Here we argue that we will obtain a complete picture of this era by combining observations of galaxies with direct measurements of the reionization process: the former will provide a detailed understanding of bright sources, while the latter will constrain the (substantial) faint source population. We further describe how optimizing the comparison of these two measurements requires near-infrared galaxy surveys covering large volumes and retaining redshift information and also improvements in 21-cm analysis, moving those experiments into the imaging regime., Comment: 9 pages, 3 figures

Published
2019

231. Cosmic Dawn and Reionization: Astrophysics in the Final Frontier

Author

Cooray, Asantha, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Appleton, Phil, Armus, Lee, Becker, George, Bock, Jamie, Bowler, Rebecca, Bowman, Judd, Bradford, Matt, Breysse, Patrick, Bromm, Volker, Burns, Jack, Caputi, Karina, Castellano, Marco, Chang, Tzu-Ching, Chary, Ranga, Chiang, Hsin, Cohn, Joanne, Conselice, Chris, Cuby, Jean-Gabriel, Davies, Frederick, Dayal, Pratika, Dore, Olivier, Farrah, Duncan, Ferrara, Andrea, Finkelstein, Steven, Furlanetto, Steven, Hazelton, Bryna, Heneka, Caroline, Hutter, Anne, Jacobs, Daniel, Koopmans, Leon, Kovetz, Ely, La Piante, Paul, Fevre, Olivier Le, Liu, Adrian, Ma, Jingzhe, Ma, Yin-Zhe, Malhotra, Sangeeta, Mao, Yi, Marrone, Dan, Masui, Kiyoshi, McQuinn, Matthew, Mirocha, Jordan, Mortlock, Daniel, Murphy, Eric, Nayyeri, Hooshang, Natarajan, Priya, Nithyanandan, Thyagarajan, Parsons, Aaron, Pello, Roser, Pope, Alexandra, Rhoads, James, Rhodes, Jason, Riechers, Dominik, Robertson, Brant, Scarlata, Claudia, Serjeant, Stephen, Saliwanchik, Benjamin, Salvaterra, Ruben, Schneider, Rafffaella, Silva, Marta, Sahlén, Martin, Santos, Mario G., Switzer, Eric, Temi, Pasquale, Trac, Hy, Venkatesan, Aparna, Visbal, Eli, Zaldarriaga, Matias, Zemcov, Michael, Zheng, Zheng, Cooray, Asantha, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Appleton, Phil, Armus, Lee, Becker, George, Bock, Jamie, Bowler, Rebecca, Bowman, Judd, Bradford, Matt, Breysse, Patrick, Bromm, Volker, Burns, Jack, Caputi, Karina, Castellano, Marco, Chang, Tzu-Ching, Chary, Ranga, Chiang, Hsin, Cohn, Joanne, Conselice, Chris, Cuby, Jean-Gabriel, Davies, Frederick, Dayal, Pratika, Dore, Olivier, Farrah, Duncan, Ferrara, Andrea, Finkelstein, Steven, Furlanetto, Steven, Hazelton, Bryna, Heneka, Caroline, Hutter, Anne, Jacobs, Daniel, Koopmans, Leon, Kovetz, Ely, La Piante, Paul, Fevre, Olivier Le, Liu, Adrian, Ma, Jingzhe, Ma, Yin-Zhe, Malhotra, Sangeeta, Mao, Yi, Marrone, Dan, Masui, Kiyoshi, McQuinn, Matthew, Mirocha, Jordan, Mortlock, Daniel, Murphy, Eric, Nayyeri, Hooshang, Natarajan, Priya, Nithyanandan, Thyagarajan, Parsons, Aaron, Pello, Roser, Pope, Alexandra, Rhoads, James, Rhodes, Jason, Riechers, Dominik, Robertson, Brant, Scarlata, Claudia, Serjeant, Stephen, Saliwanchik, Benjamin, Salvaterra, Ruben, Schneider, Rafffaella, Silva, Marta, Sahlén, Martin, Santos, Mario G., Switzer, Eric, Temi, Pasquale, Trac, Hy, Venkatesan, Aparna, Visbal, Eli, Zaldarriaga, Matias, Zemcov, Michael, and Zheng, Zheng

Abstract

The cosmic dawn and epoch of reionization mark the time period in the universe when stars, galaxies, and blackhole seeds first formed and the intergalactic medium changed from neutral to an ionized one. Despite substantial progress with multi-wavelength observations, astrophysical process during this time period remain some of the least understood with large uncertainties on our existing models of galaxy, blackhole, and structure formation. This white paper outlines the current state of knowledge and anticipated scientific outcomes with ground and space-based astronomical facilities in the 2020s. We then propose a number of scientific goals and objectives for new facilities in late 2020s to mid 2030s that will lead to definitive measurements of key astrophysical processes in the epoch of reionization and cosmic dawn., Comment: Science White paper submitted to Astro2020 Decadal Survey

Published
2019

232. Astro2020 Science White Paper: Insights Into the Epoch of Reionization with the Highly-Redshifted 21-cm Line

Author

Furlanetto, Steven, Carilli, Chris L., Mirocha, Jordan, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Bowman, Judd D., Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Carucci, Isabella P., Chang, Tzu-Ching, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, Davies, Frederick, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Gnedin, Nick, Hazelton, Bryna, Jacobs, Daniel, Karkare, Kirit, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mesinger, Andrei, Munoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Switzer, Eric, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, Zaldarriaga, Matias, Furlanetto, Steven, Carilli, Chris L., Mirocha, Jordan, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Bowman, Judd D., Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Carucci, Isabella P., Chang, Tzu-Ching, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, Davies, Frederick, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Gnedin, Nick, Hazelton, Bryna, Jacobs, Daniel, Karkare, Kirit, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mesinger, Andrei, Munoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Switzer, Eric, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, and Zaldarriaga, Matias

Abstract

The epoch of reionization, when photons from early galaxies ionized the intergalactic medium about a billion years after the Big Bang, is the last major phase transition in the Universe's history. Measuring the characteristics of the transition is important for understanding early galaxies and the cosmic web and for modeling dwarf galaxies in the later Universe. But such measurements require probes of the intergalactic medium itself. Here we describe how the 21-cm line of neutral hydrogen provides a powerful probe of the reionization process and therefore important constraints on both the galaxies and intergalactic absorbers at that time. While existing experiments will make precise statistical measurements over the next decade, we argue that improved 21-cm analysis techniques - allowing imaging of the neutral gas itself - as well as improved theoretical models, are crucial for testing our understanding of this important era., Comment: 8 pages, 4 figures

Published
2019

233. Astro 2020 Science White Paper: Fundamental Cosmology in the Dark Ages with 21-cm Line Fluctuations

Author

Furlanetto, Steven, Bowman, Judd D., Mirocha, Jordan, Pober, Jonathan C., Burns, Jack, Carilli, Chris L., Munoz, Julian, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Breysse, Patrick, Bromm, Volker, Bull, Philip, Chang, Tzu-Ching, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, Davies, Frederick, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Hazelton, Bryna, Jacobs, Daniel, Karkare, Kirit, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, Mesinger, Andrew, Murray, Steven, Parsons, Aaron, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, Zaldarriaga, Matias, Furlanetto, Steven, Bowman, Judd D., Mirocha, Jordan, Pober, Jonathan C., Burns, Jack, Carilli, Chris L., Munoz, Julian, Aguirre, James, Ali-Haimoud, Yacine, Alvarez, Marcelo, Beardsley, Adam, Becker, George, Breysse, Patrick, Bromm, Volker, Bull, Philip, Chang, Tzu-Ching, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, Davies, Frederick, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Fialkov, Anastasia, Hazelton, Bryna, Jacobs, Daniel, Karkare, Kirit, Kohn, Saul, Koopmans, Leon, Kovetz, Ely, La Plante, Paul, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, Mesinger, Andrew, Murray, Steven, Parsons, Aaron, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Visbal, Eli, and Zaldarriaga, Matias

Abstract

The Dark Ages are the period between the last scattering of the cosmic microwave background and the appearance of the first luminous sources, spanning approximately 1100 < z < 30. The only known way to measure fluctuations in this era is through the 21-cm line of neutral hydrogen. Such observations have enormous potential for cosmology, because they span a large volume while the fluctuations remain linear even on small scales. Observations of 21-cm fluctuations during this era can therefore constrain fundamental aspects of our Universe, including inflation and any exotic physics of dark matter. While the observational challenges to these low-frequency 21-cm observations are enormous, especially from the terrestrial environment, they represent an important goal for cosmology., Comment: 10 pages, 4 figures

Published
2019

234. Results from EDGES High-Band: III. New Constraints on Parameters of the Early Universe

Author

Monsalve, Raul A., Fialkov, Anastasia, Bowman, Judd D., Rogers, Alan E. E., Mozdzen, Thomas J., Cohen, Aviad, Barkana, Rennan, Mahesh, Nivedita, Monsalve, Raul A., Fialkov, Anastasia, Bowman, Judd D., Rogers, Alan E. E., Mozdzen, Thomas J., Cohen, Aviad, Barkana, Rennan, and Mahesh, Nivedita

Abstract

We present new constraints on parameters of cosmic dawn and the epoch of reionization derived from the EDGES High-Band spectrum ($90-190$ MHz). The parameters are probed by evaluating global $21$ cm signals generated with the recently developed Global21cm tool. This tool uses neural networks trained and tested on $\sim 30,000$ spectra produced with semi-numerical simulations that assume the standard thermal evolution of the cosmic microwave background and the intergalactic medium. From our analysis, we constrain at $68\%$ (1) the minimum virial circular velocity of star-forming halos to $V_{\rm c}<19.3$ km s$^{-1}$, (2) the X-ray heating efficiency of early sources to $f_{\rm X}>0.0042$, and (3) the low-energy cutoff of the X-ray spectral energy distribution to $\nu_{\rm min}<2.3$ keV. We also constrain the star-formation efficiency ($f_*$), the electron scattering optical depth ($\tau_{\rm e}$), and the mean-free path of ionizing photons ($R_{\rm mfp}$). We re-compute the constraints after incorporating into the analysis four estimates for the neutral hydrogen fraction from high-$z$ quasars and galaxies, and a prior on $\tau_{\rm e}$ from Planck $2018$. The largest impact of the external observations is on the parameters that most directly characterize reionization. Specifically, we derive the combined $68\%$ constraints $\tau_{\rm e}<0.063$ and $R_{\rm mfp}>27.5$ Mpc. The external observations also have a significant effect on $V_{\rm c}$ due to its degeneracy with $\tau_{\rm e}$, while the constraints on $f_*$, $f_{\rm X}$, and $\nu_{\rm min}$, remain primarily determined by EDGES.

Published
2019
Full Text
View/download PDF

235. Mapping Cosmic Dawn and Reionization: Challenges and Synergies

Author

Alvarez, Marcelo A, Alvarez, Marcelo A, Fialkov, Anastasia, Plante, Paul La, Aguirre, James, Ali-Haïmoud, Yacine, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Cappelluti, Nico, Carucci, Isabella, Chang, Tzu-Ching, Cleary, Kieran, Cooray, Asantha, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Ferraro, Simone, Furlanetto, Steven, Hazelton, Bryna, Hill, J Colin, Jacobs, Daniel, Karkare, Kirit, Keating, Garrett K, Koopmans, Léon, Kovetz, Ely, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mirocha, Jordan, Muñoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Vikhlinin, Alexey, Visbal, Eli, Zaldarriaga, Matias, Alvarez, Marcelo A, Alvarez, Marcelo A, Fialkov, Anastasia, Plante, Paul La, Aguirre, James, Ali-Haïmoud, Yacine, Becker, George, Bowman, Judd, Breysse, Patrick, Bromm, Volker, Bull, Philip, Burns, Jack, Cappelluti, Nico, Carucci, Isabella, Chang, Tzu-Ching, Cleary, Kieran, Cooray, Asantha, Chen, Xuelei, Chiang, Hsin, Cohn, Joanne, DeBoer, David, Dillon, Joshua, Doré, Olivier, Dvorkin, Cora, Ferraro, Simone, Furlanetto, Steven, Hazelton, Bryna, Hill, J Colin, Jacobs, Daniel, Karkare, Kirit, Keating, Garrett K, Koopmans, Léon, Kovetz, Ely, Lidz, Adam, Liu, Adrian, Ma, Yin-Zhe, Mao, Yi, Masui, Kiyoshi, McQuinn, Matthew, Mirocha, Jordan, Muñoz, Julian, Murray, Steven, Parsons, Aaron, Pober, Jonathan, Saliwanchik, Benjamin, Sievers, Jonathan, Thyagarajan, Nithyanandan, Trac, Hy, Vikhlinin, Alexey, Visbal, Eli, and Zaldarriaga, Matias

Abstract

Cosmic dawn and the Epoch of Reionization (EoR) are among the least explored observational eras in cosmology: a time at which the first galaxies and supermassive black holes formed and reionized the cold, neutral Universe of the post-recombination era. With current instruments, only a handful of the brightest galaxies and quasars from that time are detectable as individual objects, due to their extreme distances. Fortunately, a multitude of multi-wavelength intensity mapping measurements, ranging from the redshifted 21 cm background in the radio to the unresolved X-ray background, contain a plethora of synergistic information about this elusive era. The coming decade will likely see direct detections of inhomogenous reionization with CMB and 21 cm observations, and a slew of other probes covering overlapping areas and complementary physical processes will provide crucial additional information and cross-validation. To maximize scientific discovery and return on investment, coordinated survey planning and joint data analysis should be a high priority, closely coupled to computational models and theoretical predictions.

Published
2019

236. FARSIDE: A Low Radio Frequency Interferometric Array on the Lunar Farside

Author

Burns, Jack O., Hallinan, Gregg, Lux, Jim, Romero-Wolf, Andres, Chang, Tzu-Ching, Kocz, Jonathon, Bowman, Judd, MacDowall, Robert, Kasper, Justin, Bradley, Richard, Anderson, Marin, Rapetti, David, Teitelbaum, Lawrence, Burns, Jack O., Hallinan, Gregg, Lux, Jim, Romero-Wolf, Andres, Chang, Tzu-Ching, Kocz, Jonathon, Bowman, Judd, MacDowall, Robert, Kasper, Justin, Bradley, Richard, Anderson, Marin, Rapetti, David, and Teitelbaum, Lawrence

Abstract

FARSIDE (Farside Array for Radio Science Investigations of the Dark ages and Exoplanets) is a Probe-class concept to place a low radio frequency interferometric array on the farside of the Moon. A NASA-funded design study, focused on the instrument, a deployment rover, the lander and base station, delivered an architecture broadly consistent with the requirements for a Probe mission. This notional architecture consists of 128 dual polarization antennas deployed across a 10 km area by a rover, and tethered to a base station for central processing, power and data transmission to the Lunar Gateway. FARSIDE would provide the capability to image the entire sky each minute in 1400 channels spanning frequencies from 100 kHz to 40 MHz, extending down two orders of magnitude below bands accessible to ground-based radio astronomy. The lunar farside can simultaneously provide isolation from terrestrial radio frequency interference, auroral kilometric radiation, and plasma noise from the solar wind. This would enable near-continuous monitoring of the nearest stellar systems in the search for the radio signatures of coronal mass ejections and energetic particle events, and would also detect the magnetospheres for the nearest candidate habitable exoplanets. Simultaneously, FARSIDE would be used to characterize similar activity in our own solar system, from the Sun to the outer planets, including the hypothetical Planet Nine. Through precision calibration via an orbiting beacon, and exquisite foreground characterization, FARSIDE would also measure the Dark Ages global 21-cm signal at redshifts z=50-100. The unique observational window offered by FARSIDE would enable an abundance of additional science ranging from sounding of the lunar subsurface to characterization of the interstellar medium in the solar system neighborhood.

Published
2019

237. The Star-Planet Activity Research CubeSat (SPARCS): A Mission to Understand the Impact of Stars in Exoplanets

Author

Ardila, David R., Shkolnik, Evgenya, Scowen, Paul, Jewell, April, Nikzad, Shouleh, Bowman, Judd, Fitzgerald, Michael, Jacobs, Daniel, Spittler, Constance, Barman, Travis, Peackock, Sarah, Beasley, Matthew, Gorgian, Varoujan, Llama, Joe, Meadows, Victoria, Swain, Mark, and Zellem, Robert

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

The Star-Planet Activity Research CubeSat (SPARCS) is a NASA-funded astrophysics mission, devoted to the study of the ultraviolet (UV) time-domain behavior in low-mass stars. Given their abundance and size, low-mass stars are important targets in the search for habitable-zone, exoplanets. However, not enough is known about the stars flare and quiescent emission, which powers photochemical reactions on the atmospheres of possible planets. Over its initial 1-year mission, SPARCS will stare at ~10 stars in order to measure short- (minutes) and long- (months) term variability simultaneously in the near-UV (NUV - lam = 280 nm) and far-UV (FUV - lam = 162 nm). The SPARCS payload consists of a 9-cm reflector telescope paired with two high-sensitivity 2D-doped CCDs. The detectors are kept passively cooled at 238K, in order to reduce dark-current contribution. The filters have been selected to provide strong rejection of longer wavelengths, where most of the starlight is emitted. The payload will be integrated within a 6U CubeSat to be placed on a Sun-synchronous terminator orbit, allowing for long observing stares for all targets. Launch is expected to occur not earlier than October 2021., Comment: Original Reference: Ardila, D. R. et al. 2018, "The Star-Planet Activity Research CubeSat (SPARCS): A Mission to Understand the Impact of Stars in Exoplanets," Proceedings of the AIAA/USU Conference on Small Satellites, Instruments / Science I, SSC18-WKIV-02. https://digitalcommons.usu.edu/smallsat/2018/all2018/439/

Published
2018
Full Text
View/download PDF

239. Understanding the HERA Phase I receiver system with simulations and its impact on the detectability of the EoR delay power spectrum.

Author

Fagnoni, Nicolas, de Lera Acedo, Eloy, DeBoer, David R, 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, Phil, Burba, Jacob, Carilli, Chris L, Cheng, Carina, Dexter, Matt, Dillon, Joshua S, and Ewall-Wice, Aaron

Subjects
POWER spectra, RADIO telescopes, SIMULATION methods & models, ANTENNA arrays, SIGNAL detection, ELECTROMAGNETIC waves
Abstract

The detection of the Epoch of Reionization (EoR) delay power spectrum using a 'foreground avoidance method' highly depends on the instrument chromaticity. The systematic effects induced by the radio telescope spread the foreground signal in the delay domain, which contaminates the EoR window theoretically observable. Applied to the Hydrogen Epoch of Reionization Array (HERA), this paper combines detailed electromagnetic and electrical simulations in order to model the chromatic effects of the instrument, and quantify its frequency and time responses. In particular, the effects of the analogue receiver, transmission cables, and mutual coupling are included. These simulations are able to accurately predict the intensity of the reflections occurring in the 150-m cable which links the antenna to the backend. They also show that electromagnetic waves can propagate from one dish to another one through large sections of the array due to mutual coupling. The simulated system time response is attenuated by a factor 104 after a characteristic delay which depends on the size of the array and on the antenna position. Ultimately, the system response is attenuated by a factor 105 after 1400 ns because of the reflections in the cable, which corresponds to characterizable k ∥-modes above 0.7 |$h\,\,\rm {Mpc}^{-1}$| at 150 MHz. Thus, this new study shows that the detection of the EoR signal with HERA Phase I will be more challenging than expected. On the other hand, it improves our understanding of the telescope, which is essential to mitigate the instrument chromaticity. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

240. Assembly, integration, and testing of the Star-Planet Activity Research CubeSat (SPARCS)

Author

den Herder, Jan-Willem A., Nikzad, Shouleh, Nakazawa, Kazuhiro, Jensen, Logan, Gamaunt, John, Scowen, Paul, Struebel, Nathaniel, O'Mara, Liam, Naik, Neil, Ardila, David, Austin, Jim, Barman, Travis, Basset, Christophe, Beasley, Matthew, Bernard, Lee, Bowman, Judd, Butler, Nathaniel, Gregory, Dawn, Jewell, April, Knapp, Mary, Jacobs, Daniel, Kolopanis, Matthew, Ladwig, Cristy, Llama, Joe, Meadows, Victoria, Nikzad, Shouleh, Peacock, Sarah, Ramiaramanantsoa, Tahina, Samson, Titu, Shkolnik, Evgenya, Swain, Mark, and Veach, Todd

Published
2024
Full Text
View/download PDF

241. Photometric calibration in the ultraviolet of the Star-Planet Activity Research CubeSat (SPARCS)

Author

den Herder, Jan-Willem A., Nikzad, Shouleh, Nakazawa, Kazuhiro, Ardila, David R., Shkolnik, Evgenya, Scowen, Paul, Ramiaramanantsoa, Tahina, Barman, Travis, Bowman, Judd, Basset, Christophe, Gamaunt, Jonathan, Gregory, Dawn, Jacobs, Daniel, Jensen, Logan, Jewell, April, Kolopanis, Matthew, Knapp, Mary, Kyne, Gillian, Ladwig, Cristy, Llama, Joe, Meadows, Victoria, Nikzad, Shouleh, Peacock, Sarah, Struebel, Nathaniel, and Swain, Mark

Published
2024
Full Text
View/download PDF

242. Performance of the SPARCS UV camera and detectors

Author

den Herder, Jan-Willem A., Nikzad, Shouleh, Nakazawa, Kazuhiro, Jewell, April D., Basset, Christophe, Nikzad, Shouleh, Kyne, Gillian, Maruyama, Yuki, Bush, Nathan, Hennessy, John, Jones, Todd J., Klein, Matthew, Monacos, Steve, Rodriguez, Robin E., Ardila, David, Bowman, Judd, Gamaunt, Jonathan, Gregory, Dawn, Jacobs, Daniel, Jensen, Logan, Kolopanis, Matthew, Ladwig, Cristy, Ramiaramanantsoa, Tahina, Scowen, Paul, Strubel, Nathaniel, and Shkolnik, Evgenya

Published
2024
Full Text
View/download PDF

243. 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, and Carey, Steve

Subjects
CALIBRATION, HYDROGEN, REDUNDANCY in engineering, DEGREES of freedom
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. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

244. Differences in visitor characteristics and experiences on episodic free admission days.

Author

Bowman, Catherine D. D., Adkins, Adrianna, Owen, Brooke L., Rogers, Kyle J., Escalante, Edgar, Bowman, Judd D., Nelson, Brian C., and Stoltman, Alison

Subjects
NATURAL history museums, DECISION making
Abstract

To increase access, most U.S. museums provide free admission opportunities, either through episodic free days or other means. Although studies document the effects of museums transitioning from paid to free entry for museums considering a less extreme change, such as adding (or subtracting) a free day, detailed comparative data on the characteristics and experiences of visitors attending episodic free days and standard days are needed to inform decision making. This post-hoc analysis of data (n = 370) from the control condition of a larger study [authors] outlines significant differences in visitor characteristics, group composition, group behavior, and interest in and experience with the exhibit on free and standard days at a mid-sized natural history museum, highlighting the affordances and drawbacks of offering episodic free days. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

246. Monitoring the high-energy radiation environment of exoplanets around low-mass stars with SPARCS (Star-Planet Activity Research CubeSat)

Author

Scowen, Paul A., primary, Shkolnik, Evgenya, primary, Ardila, David, primary, Bowman, Judd, primary, Jacobs, Danny, primary, Jewell, April D., primary, Beasley, Matthew, primary, Swain, Mark, primary, Gorjian, Varoujan, primary, Nikzad, Shouleh, primary, Meadows, Victoria, primary, Barman, Travis, primary, Zellem, Robert, primary, Llama, Joe, primary, Fitzgerald, Michael, primary, and Spittler, Constance, primary

Published
2018
Full Text
View/download PDF

249. The hydrogen epoch of reionization array dish III: measuring chromaticity of prototype element with reflectometry

Author

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

Published
2018
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results