Astrophysics and Astronomy Commons^™

Cosmological Initial Data For Numerical Relativity, David Garfinkle, Lawrence Mead

Faculty Publications

© 2020 American Physical Society. We find initial data for numerical relativity simulations of inhomogeneous cosmologies. This involves treating an exceptional case of the general relativity constraint equations. We devise analytic and numerical methods to treat this exceptional case. We apply the analytic method to the standard case of cosmology with a single scalar field. The numerical method is applied to the two-field ekpyrotic cosmology.

Gw190412: Observation Of A Binary-Black-Hole Coalescence With Asymmetric Masses, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, A. Aich, L. Aiello, A. Ain, P. Ajith, S. Akcay, G. Allen, A. Allocca, P. A. Altin, A. Amato, S. Anand, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Ansoldi, S. Antier, S. Appert, K. Arai, Tiffany Z. Summerscales

Faculty Publications

© 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. We report the observation of gravitational waves from a binary-black-hole coalescence during the first two weeks of LIGO's and Virgo's third observing run. The signal was recorded on April 12, 2019 at 05â¶30â¶44 UTC with a network signal-to-noise ratio of 19. The binary is different from observations during the first two observing runs most …

Modifications To Gravitational Wave Equation From Canonical Quantum Gravity, Andrea Dapor, Klaus Liegener

Faculty Publications

It is expected that the quantum nature of spacetime leaves its imprint in all semiclassical gravitational systems, at least in certain regimes, including gravitational waves. In this paper we investigate such imprints on gravitational waves within a specific framework: space is assumed to be discrete (in the form of a regular cubic lattice), and this discrete geometry is quantised following Dirac's canonical quantisation scheme. The semiclassical behavior is then extracted by promoting the expectation value of the Hamiltonian operator on a semiclassical state to an effective Hamiltonian. Considering a family of semiclassical states representing small tensor perturbations to Minkowski background, …

Lrg-Beasts: Ground-Based Detection Of Sodium And A Steep Optical Slope In The Atmosphere Of The Highly Inflated Hot-Saturn Wasp-21b, Lili Alderson, James Kirk, Mercedes López-Morales, Peter J. Wheatley, Ian Skillen, Gregory W. Henry, Chima Mcgruder, Matteo Brogi, Tom Louden, George King

Information Systems and Engineering Management Research Publications

We present the optical transmission spectrum of the highly inflated Saturn-mass exoplanet WASP-21b, using three transits obtained with the ACAM instrument on the William Herschel Telescope through the LRG-BEASTS survey (Low Resolution Ground-Based Exoplanet Atmosphere Survey using Transmission Spectroscopy). Our transmission spectrum covers a wavelength range of 4635–9000 Å, achieving an average transit depth precision of 197 ppm compared to one atmospheric scale height at 246 ppm. We detect Na i absorption in a bin width of 30 Å  at >4σ confidence, which extends over 100 Å. We see no evidence of absorption from K i. Atmospheric retrieval analysis of …

Are Conditions Right On Other Planets For The Existence Of Life As We Know It?, Nuri Park

International Programs

Understanding the origin of life is one fo the fundamental knowledge required to find life on extraterrestrial celestial. Among numerous phenomena that are driven by bio-molecules, self-assembly of the cellular membrane is considered as the most basic process in the origin of life. In water dominant environment of standard pressure and temperature, molecular interaction (Van der Waals force) among water molecules and phospholipids forces phospholopids to form lipid bilayer structure which is the proto structure of the cellular membrane. However, self-assembly of phospholopids in extremely pressurized wet environments has never been explored. Since liquid water in the solar system has …

Kinds Of Science And Exploring The Past, Channon Visscher

Faculty Work Comprehensive List

"Working alongside experimental and observational work, historical science helps us continue to learn the unfolding story of how a beautiful universe, created by a loving God, came to be as we see it today."

Posting about scientific methods from In All Things - an online journal for critical reflection on faith, culture, art, and every ordinary-yet-graced square inch of God’s creation.

https://inallthings.org/kinds-of-science-and-exploring-the-past/

Space Telescope And Optical Reverberation Mapping Project. Xi. Disk-Wind Characteristics And Contributions To The Very Broad Emission Lines Of Ngc 5547, M. Dehghanian, G. J. Ferland, G. A. Kriss, B. M. Peterson, K. T. Korista, M. R. Goad, M. Chatzikos, F. Guzmán, G. D. Rosa, M. Mehdipour, J. Kaastra, S. Mathur, M. Vestergaard, Daniel Proga, Tim Waters, M. C. Bentz, S. Bisogni, W. N. Brandt, E. D. Bontà, M. M. Fausnaugh, J. M. Gelbord, Keith Horne, I. M. Mchardy, R. W. Pogge, D. A. Starkey

Physics & Astronomy Faculty Research

In 2014 the NGC 5548 Space Telescope and Optical Reverberation Mapping campaign discovered a two-month anomaly when variations in the absorption and emission lines decorrelated from continuum variations. During this time the soft X-ray part of the intrinsic spectrum had been strongly absorbed by a line-of-sight (LOS) obscurer, which was interpreted as the upper part of a disk wind. Our first paper showed that changes in the LOS obscurer produces the decorrelation between the absorption lines and the continuum. A second study showed that the base of the wind shields the broad emission-line region (BLR), leading to the emission-line decorrelation. …

Volume I. Introduction To Dune, B. Abi, R. Acciarri, M.A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. Andrews, F. Andrianala, S. Andringa, A. Ankowski, M. Antonova, S. Antusch, A. Aranda-Fernandez, A. Ariga, L.O. Arnold, M.A. Arroyave, J. Asaadi, A. Aurisano, V. Aushev, D. Autiero, F. Azfar, H. Back, J.J. Back, C. Backhouse, P. Baesso, L. Bagby, R. Bajou, S. Balasubramanian, P. Baldi, B. Bambah, F. Barao, G. Barenboim, G. Barker, Wayne A. Barkhouse, C. Barnes, G. Barr, J. Barranco Monarca, N. Barros, J.L. Barrow, A. Bashyal, V. Basque, F. Bay, J. Bazo Alba, J.F. Beacom, E. Bechetoille, B. Behera, L. Bellantoni, G. Bellettini, V. Bellini, O. Beltramello, D. Belver, N. Benekos, F. Bento Neves, J. Berger, S. Berkman, P. Bernardini, R.M. Berner, H. Berns, S. Bertolucci, M. Betancourt, Y. Bezawada, M. Bhattacharjee, B. Bhuyan, S. Biagi, J. Bian, M. Biassoni, K. Biery, B. Bilki, M. Bishai, A. Bitadze, A. Blake, B. Blanco Siffert, F. Blaszczyk, G. Blazey, E. Blucher, J. Boissevain, S. Bolognesi, T. Bolton, M. Bonesini, M. Bongrand, F. Bonini, A. Booth, C. Booth, S. Bordoni, A. Borkum, T. Boschi, N. Bostan, P. Bour, S. Boyd, D. Boyden, J. Bracinik, D. Braga, D. Brailsford, A. Brandt, J. Bremer, C. Brew, E. Brianne, S.J. Brice, C. Brizzolari, C. Bromberg, G. Brooijmans, J. Brooke, A. Bross, G. Brunetti, N. Buchanan, H. Budd, D. Caiulo, P. Calafiura, J. Calcutt, M. Calin, S. Calvez, E. Calvo, L. Camilleri, A. Caminata, M. Campanelli, D. Caratelli, G. Carini, B. Carlus, P. Carniti, I. Caro Terrazas, H. Carranza, A. Castillo, C. Castromonte, C. Cattadori, F. Cavalier, F. Cavanna, S. Centro, G. Cerati, A. Cervelli, A. Cervera Villanueva, M. Chalifour, C. Chang, E. Chardonnet, A. Chatterjee, S. Chattopadhyay, J. Chaves, H. Chen, M. Chen, Y. Chen, D. Cherdack, C. Chi, S. Childress, A. Chiriacescu, K. Cho, S. Choubey, A. Christensen, D. Christian, G. Christodoulou, E. Church, P. Clarke, T.E. Coan, A.G. Cocco, J. Coelho, E. Conley, J. Conrad, M. Convery, L. Corwin, P. Cotte, L. Cremaldi, L. Cremonesi, J.I. Crespo-Anad, E. Cristaldo, R. Cross, C. Cuesta, Y. Cui, D. Cussans, M. Dabrowski, H. Da Motta, L. Da Silva Peres, Q. David, G.S. Davies, S. Davini, J. Dawson, K. De, R.M. De Almeida, P. Debbins, I. De Bonis, M. Decowski, A. De Gouvea, P.C. De Holanda, I.L. De Icaza Astiz, A. Deisting, P. De Jong, A. Delbart, D. Delepine, M. Delgado, A. Dell'acqua, P. De Lurgio, J.R. De Mello Neto, D.M. Demuth, S. Dennis, C. Densham, G. Deptuch, A. De Roeck, V. De Romeri, J. De Vries, R. Dharmapalan, M. Dias, F. Diaz, J. Diaz, S. Di Domizio, L. Di Giulio, P. Ding, L. Di Noto, C. Distefano, R. Diurba, M. Diwan, Z. Djurcic, N. Dokania, M. Dolinski, L. Domine, D. Douglas, F. Drielsma, D. Duchesneau, K. Duffy, P. Dunne, T. Durkin, H. Duyang, O. Dvornikov, D. Dwyer, A. Dyshkant, M. Eads, D. Edmunds, J. Eisch, S. Emery, A. Ereditato, C. Escobar, L. Escudero Sanchez, J.J. Evans, E. Ewart, A.C. Ezeribe, K. Fahey, A. Falcone, C. Farnese, Y. Farzan, J. Felix, E. Fernandez-Martinez, P. Fernandez Menendez, F. Ferraro, L. Fields, A. Filkins, F. Filthaut, R.S. Fitzpatrick, W. Flanagan, B. Fleming, R. Flight, J. Fowler, W. Fox, J. Franc, K. Francis, D. Franco, J. Freeman, J. Freestone, J. Fried, A. Friedland, S. Fuess, I. Furic, A.P. Furmanski, A. Gago, H. Gallagher, A. Gallego-Ros, N. Gallice, V. Galymov, E. Gamberini, T. Gamble, R. Gandhi, R. Gandrajula, S. Gao, D. Garcia-Gamez, M.Á. Garc𫑐Eris, S. Gardiner, D. Gastler, G. Ge, B. Gelli, A. Gendotti, S. Gent, Z. Ghorbani-Moghaddam, D. Gibin, I. Gil-Botella, C. Girerd, A. Giri, D. Gnani, O. Gogota, M. Gold, S. Gollapinni, K. Gollwitzer, R.A. Gomes, L. Gomez Bermeo, L.S. Gomez Fajardo, F. Gonnella, J. Gonzalez-Cuevas, M.C. Goodman, O. Goodwin, S. Goswami, C. Gotti, E. Goudzovski, C. Grace, M. Graham, E. Gramellini, R. Gran, E. Granados, A. Grant, C. Grant, D. Gratieri, P. Green, S. Green, L. Greenler, M. Greenwood, J. Greer, C. Griffith, M. Groh, J. Grudzinski, K. Grzelak, W. Gu, V. Guarino, R. Guenette, A. Guglielmi, B. Guo, K. Guthikonda, R. Gutierrez, P. Guzowski, M.M. Guzzo, S. Gwon, A. Habig, A. Hackenburg, H. Hadavand, R. Haenni, A. Hahn, J. Haigh, J. Haiston, T. Hamernik, P. Hamilton, J. Han, K. Harder, D.A. Harris, J. Hartnell, T. Hasegawa, R. Hatcher, E. Hazen, A. Heavey, K.M. Heeger, K. Hennessy, S. Henry, M. Hernandez Morquecho, K. Herner, L. Hertel, A.S. Hesam, J. Hewes, A. Higuera Pichardo, T. Hill, S.J. Hillier, A. Himmel, J. Hoff, C. Hohl, A. Holin, E. Hoppe, G.A. Horton-Smith, M. Hostert, A. Hourlier, B. Howard, R. Howell, J. Huang, J. Huang, J. Hugon, G. Iles, A.M. Iliescu, R. Illingworth, A. Ioannisian, R. Itay, A. Izmaylov, E. James, B. Jargowsky, F. Jediny, C. Jesús-Valls, X. Ji, L. Jiang, S. Jiménez, A. Jipa, A. Joglekar, C. Johnson, R. Johnson, B. Jones, S. Jones, C. Jung, T. Junk, Y. Jwa, M. Kabirnezhad, A. Kaboth, I. Kadenko, F. Kamiya, G. Karagiorgi, A. Karcher, M. Karolak, Y. Karyotakis, S. Kasai, S.P. Kasetti, L. Kashur, N. Kazaryan, E. Kearns, P. Keener, K.J. Kelly, E. Kemp, W. Ketchum, S. Kettell, M. Khabibullin, A. Khotjantsev, A. Khvedelidze, D. Kim, B. King, B. Kirby, M. Kirby, J. Klein, K. Koehler, L.W. Koerner, S. Kohn, P.P. Koller, M. Kordosky, T. Kosc, U. Kose, V. Kostelecky, K. Kothekar, F. Krennrich, I. Kreslo, Y. Kudenko, V. Kudryavtsev, S. Kulagin, J. Kumar, R. Kumar, C. Kuruppu, V. Kus, T. Kutter, A. Lambert, K. Lande, C.E. Lane, K. Lang, T. Langford, P. Lasorak, D. Last, C. Lastoria, A. Laundrie, A. Lawrence, I. Lazanu, R. Lazur, T. Le, J. Learned, P. Lebrun, G. Lehmann Miotto, R. Lehnert, M. Leigui De Oliveira, M. Leitner, M. Leyton, L. Li, S. Li, S. Li, T. Li, Y. Li, H. Liao, C. Lin, S. Lin, A. Lister, B.R. Littlejohn, J. Liu, S. Lockwitz, T. Loew, M. Lokajicek, I. Lomidze, K. Long, K. Loo, D. Lorca, T. Lord, J. Losecco, W.C. Louis, K. Luk, X. Luo, N. Lurkin, T. Lux, V.P. Luzio, D. Macfarland, A. Machado, P. Machado, C. Macias, J. Macier, A. Maddalena, P. Madigan, S. Magill, K. Mahn, A. Maio, J.A. Maloney, G. Mandrioli, J.C. Maneira, L. Manenti, S. Manly, A. Mann, K. Manolopoulos, M. Manrique Plata, A. Marchionni, W. Marciano, D. Marfatia, C. Mariani, J. Maricic, F. Marinho, A.D. Marino, M. Marshak, C. Marshall, J. Marshall, J. Marteau, J. Martin-Albo, N. Martinez, D.A. Martinez Caicedo, S. Martynenko, K. Mason, A. Mastbaum, M. Masud, S. Matsuno, J. Matthews, C. Mauger, N. Mauri, K. Mavrokoridis, R. Mazza, A. Mazzacane, E. Mazzucato, E. Mccluskey, N. Mcconkey, K.S. Mcfarland, C. Mcgrew, A. Mcnab, A. Mefodiev, P. Mehta, P. Melas, M. Mellinato, O. Mena, S. Menary, H. Mendez, A. Menegolli, G. Meng, M. Messier, W. Metcalf, M. Mewes, H. Meyer, T. Miao, G. Michna, T. Miedema, J. Migenda, R. Milincic, W. Miller, J. Mills, C. Milne, O. Mineev, O.G. Miranda, S. Miryala, C. Mishra, S. Mishra, A. Mislivec, D. Mladenov, I. Mocioiu, K. Moffat, N. Moggi, R. Mohanta, T.A. Mohayai, N. Mokhov, J.A. Molina, L. Molina Bueno, A. Montanari, C. Montanari, D. Montanari, L.M. Montano Zetina, J. Moon, M. Mooney, A. Moor, D. Moreno, B. Morgan, C. Morris, C. Mossey, E. Motuk, C.A. Moura, J. Mousseau, W. Mu, L. Mualem, J. Mueller, M. Muether, S. Mufson, F. Muheim, A. Muir, M. Mulhearn, H. Muramatsu, S. Murphy, J. Musser, J. Nachtman, S. Nagu, M. Nalbandyan, R. Nandakumar, D. Naples, S. Narita, D. Navas-Nicolas, N. Nayak, M. Nebot-Guinot, L. Necib, K. Negishi, J.K. Nelson, J. Nesbit, M. Nessi, D. Newbold, M. Newcomer, D. Newhart, R. Nichol, E. Niner, K. Nishimura, A. Norman, R. Northrop, P. Novella, J.A. Nowak, M. Oberling, A. Olivares Del Campo, A. Olivier, Y. Onel, Y. Onishchuk, J. Ott, L. Pagani, S. Pakvasa, O. Palamara, S. Palestini, J.M. Paley, M. Pallavicini, C. Palomares, E. Pantic, V. Paolone, V. Papadimitriou, R. Papaleo, A. Papanestis, S. Paramesvaran, S. Parke, Z. Parsa, M. Parvu, S. Pascoli, L. Pasqualini, J. Pasternak, J. Pater, C. Patrick, L. Patrizii, R.B. Patterson, S. Patton, T. Patzak, A. Paudel, B. Paulos, L. Paulucci, Z. Pavlovic, G. Pawloski, D. Payne, V. Pec, S.J. Peeters, Y. Penichot, E. Pennacchio, A. Penzo, O.L. Peres, J. Perry, D. Pershey, G. Pessina, G. Petrillo, C. Petta, R. Petti, F. Piastra, L. Pickering, F. Pietropaolo, J. Pillow, R. Plunkett, R. Poling, X. Pons, N. Poonthottathil, S. Pordes, M. Potekhin, R. Potenza, B.V. Potukuchi, J. Pozimski, M. Pozzato, S. Prakash, T. Prakash, S. Prince, G. Prior, D. Pugnere, K. Qi, X. Qian, J. Raaf, R. Raboanary, V. Radeka, J. Rademacker, B. Radics, A. Rafique, E. Raguzin, M. Rai, M. Rajaoalisoa, I. Rakhno, H. Rakotondramanana, L. Rakotondravohitra, Y. Ramachers, R. Rameika, M. Ramirez Delgado, B. Ramson, A. Rappoldi, G. Raselli, P. Ratoff, S. Ravat, H. Razafinime, J. Real, B. Rebel, D. Redondo, M. Reggiani-Guzzo, T. Rehak, J. Reichenbacher, S.D. Reitzner, A. Renshaw, S. Rescia, F. Resnati, A. Reynolds, G. Riccobene, L.C. Rice, K. Rielage, Y. Rigaut, D. Rivera, L. Rochester, M. Roda, P. Rodrigues, M. Rodriguez Alonso, J. Rodriguez Rondon, A. Roeth, H. Rogers, S. Rosauro-Alcaraz, M. Rossella, J. Rout, S. Roy, A. Rubbia, C. Rubbia, B. Russell, J. Russell, D. Ruterbories, R. Saakyan, S. Sacerdoti, T. Safford, N. Sahu, P. Sala, N. Samios, M. Sanchez, D.A. Sanders, D. Sankey, S. Santana, M. Santos-Maldonado, N. Saoulidou, P. Sapienza, C. Sarasty, I. Sarcevic, G. Savage, V. Savinov, A. Scaramelli, A. Scarff, A. Scarpelli, T. Schaffer, H. Schellman, P. Schlabach, D. Schmitz, K. Scholberg, A. Schukraft, E. Segreto, J. Sensenig, I. Seong, A. Sergi, F. Sergiampietri, D. Sgalaberna, M. Shaevitz, S. Shafaq, M. Shamma, H.R. Sharma, R. Sharma, T. Shaw, C. Shepherd-Themistocleous, S. Shin, D. Shooltz, R. Shrock, L. Simard, N. Simos, J. Sinclair, G. Sinev, J. Singh, J. Singh, V. Singh, R. Sipos, F. Sippach, G. Sirri, A. Sitraka, K. Siyeon, D. Smargianaki, A. Smith, A. Smith, E. Smith, P. Smith, J. Smolik, M. Smy, P. Snopok, M. Soares Nunes, H. Sobel, M. Soderberg, C.J. Solano Salinas, S. Söldner-Rembold, N. Solomey, V. Solovov, W.E. Sondheim, M. Sorel, J. Soto-Oton, A. Sousa, K. Soustruznik, F. Spagliardi, M. Spanu, J. Spitz, N.J. Spooner, K. Spurgeon, R. Staley, M. Stancari, L. Stanco, H. Steiner, J. Stewart, B. Stillwell, J. Stock, F. Stocker, T. Stokes, M. Strait, T. Strauss, S. Striganov, A. Stuart, D. Summers, A. Surdo, V. Susic, L. Suter, C. Sutera, R. Svoboda, B. Szczerbinska, A. Szelc, R. Talaga, H. Tanaka, B. Tapia Oregui, A. Tapper, S. Tariq, E. Tatar, R. Tayloe, A. Teklu, M. Tenti, K. Terao, C.A. Ternes, F. Terranova, G. Testera, A. Thea, J.L. Thompson, C. Thorn, S. Timm, A. Tonazzo, M. Torti, M. Tortola, F. Tortorici, D. Totani, M. Toups, C. Touramanis, J. Trevor, W.H. Trzaska, Y.T. Tsai, Z. Tsamalaidze, K. Tsang, N. Tsverava, S. Tufanli, C. Tull, E. Tyley, M. Tzanov, M.A. Uchida, J. Urheim, T. Usher, M. Vagins, P. Vahle, G. Valdiviesso, E. Valencia, Z. Vallari, J.W. Valle, S. Vallecorsa, R. Van Berg, R.G. Van De Water, D. Vanegas Forero, F. Varanini, D. Vargas, G. Varner, J. Vasel, G. Vasseur, K. Vaziri, S. Ventura, A. Verdugo, S. Vergani, M.A. Vermeulen, M. Verzocchi, H. Vieira De Souza, C. Vignoli, C. Vilela, B. Viren, T. Vrba, T. Wachala, A.V. Waldron, M. Wallbank, H. Wang, J. Wang, Y. Wang, Y. Wang, K. Warburton, D. Warner, M. Wascko, D. Waters, A. Watson, P. Weatherly, A. Weber, M. Weber, H. Wei, A. Weinstein, D. Wenman, M. Wetstein, M.R. While, A. White, L.H. Whitehead, D. Whittington, M.J. Wilking, C. Wilkinson, Z. Williams, F. Wilson, R.J. Wilson, J. Wolcott, T. Wongjirad, K. Wood, L. Wood, E. Worcester, M. Worcester, C. Wret, W. Wu, W. Wu, Y. Xiao, G. Yang, T. Yang, N. Yershov, K. Yonehara, Tim Young, B. Yu, J. Yu, J. Zalesak, L. Zambelli, B. Zamorano, A. Zani, L. Zazueta, G. Zeller, J. Zennamo, K. Zeug, C. Zhang, M. Zhao, E. Zhivun, G. Zhu, E.D. Zimmerman, M. Zito, S. Zucchelli, J. Zuklin, V. Zutshi, R. Zwaska

Physics Faculty Publications

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying …

Meteoroid Impacts As A Source Of Bennu's Particle Ejection Events, W. F. Bottke, A. V. Moorhead, Harold Connolly Jr., C. W. Hergenrother, J. L. Molaro, P. Michel

School of Earth & Environment Departmental Research

Asteroid (101955) Bennu, a near‐Earth object with a primitive carbonaceous chondrite‐like composition, was observed by the Origins, Spectral Interpretation, Resource Identification, and Security‐Regolith Explorer (OSIRIS‐REx) spacecraft to undergo multiple particle ejection events near perihelion between December 2018 and February 2019. The three largest events observed during this period, which all occurred 3.5 to 6 hr after local noon, placed numerous particles <10 cm on temporary orbits around Bennu. Here we examine whether these events could have been produced by sporadic meteoroid impacts using the National Aeronautics and Space Administration's (NASA) Meteoroid Engineering Model 3.0. Most projectiles that impact Bennu come from nearly isotropic or Jupiter‐family comets and have evolved toward the Sun by Poynting‐Robertson drag. We find that 7,000‐J impacts on Bennu occur with a biweekly cadence near perihelion, with a preference to strike in the late afternoon (~6 pm local time). This timing matches observations. Crater scaling laws also indicate that these impact energies can reproduce the sizes and masses of the largest observed particles, provided the surface has the cohesive properties of weak, porous materials. Bennu's ejection events could be caused by the same kinds of meteoroid impacts that created the Moon's asymmetric debris cloud observed by the Lunar Atmosphere and Dust Environment Explorer (LADEE). Our findings also suggest that fewer ejection events should take place as Bennu moves further away from the Sun, a result that can be tested with future observations.

Space Telescope And Optical Reverberation Mapping Project. Xi. Disk-Wind Characteristics And Contributions To The Very Broad Emission Lines Of Ngc 5548, Maryam Dehghanian, Gary J. Ferland, G. A. Kriss, B. M. Peterson, K. T. Korista, M. R. Goad, Marios Chatzikos, Francisco Guzmán, G. De Rosa, M. Mehdipour, J. Kaastra, S. Mathur, M. Vestergaard, D. Proga, T. Waters, M. C. Bentz, S. Bisogni, W. N. Brandt, E. Dalla Bontà, M. M. Fausnaugh, J. M. Gelbord, Keith Horne, I. M. Mchardy, R. W. Pogge, D. A. Starkey

Physics and Astronomy Faculty Publications

In 2014 the NGC 5548 Space Telescope and Optical Reverberation Mapping campaign discovered a two-month anomaly when variations in the absorption and emission lines decorrelated from continuum variations. During this time the soft X-ray part of the intrinsic spectrum had been strongly absorbed by a line-of-sight (LOS) obscurer, which was interpreted as the upper part of a disk wind. Our first paper showed that changes in the LOS obscurer produces the decorrelation between the absorption lines and the continuum. A second study showed that the base of the wind shields the broad emission-line region (BLR), leading to the emission-line decorrelation. …

Tess Reveals A Short-Period Sub-Neptune Sibling (Hd 86226c) To A Known Long-Period Giant Planet, J. Teske, M. R. Díaz, R. Luque, T. Močnik, J. V. Seidel, J. F. Otegi, F. Feng, J. S. Jenkins, E. Pallè, D. Ségransan, S. Udry, K. A. Collins, J. D. Eastman, G. R. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, D. R. Anderson, T. Barclay, F. Bouchy, J. A. Burt, R. P. Butler, D. A. Caldwell, K. I. Collins, J. D. Crane, C. Dorn, E. Flowers, J. Haldemann, R. Helled, C. Hellier, Eric L.N. Jensen, S. R. Kane, N. Law, J. J. Lissauer, A. W. Mann, M. Marmier, L. D. Nielsen, M. E. Rose, S. A. Shectman, A. Shporer, G. Torres, S. X. Wang, A. Wolfgang, I. Wong, C. Ziegler

Physics & Astronomy Faculty Works

The Transiting Exoplanet Survey Satellite mission was designed to find transiting planets around bright, nearby stars. Here, we present the detection and mass measurement of a small, short-period (≈4 days) transiting planet around the bright (V = 7.9), solar-type star HD 86226 (TOI-652, TIC 22221375), previously known to host a long-period (~1600 days) giant planet. HD 86226c (TOI-652.01) has a radius of 2.16 ± 0.08 R⊕ and a mass of ${7.25}_{-1.12}^{+1.19}$M⊕, based on archival and new radial velocity data. We also update the parameters of the longer-period, not-known-to-transit planet, and find it to be less eccentric and less massive than …

Multiband Polarimetric Imaging Of Hr 4796a With The Gemini Planet Imager, Pauline Arriaga, Michael P. Fitzgerald, Gaspard Duchêne, Paul Kalas, Maxwell A. Millar-Blanchaer, Marshall D. Perrin, Christine H. Chen, Johan Mazoyer, Mark Ammons, Vanessa P. Bailey, Trafis S. Barman, Joanna Bulger, Jeffrey K. Chilcote, Tara Cotten, Robert J. De Rosa, Rene Doyon, Thomas M. Esposito, Katherine B. Follette, Benjamin L. Gerard, Stephen Goodsell, James R. Graham, Alexandra Z. Greenbaum, Pascale Hibon, Justin Hom, Li Wei Hung, Patrick Ingraham, Quinn M. Konopacky, Bruce A. Macintosh, Jérôme Maire, Franck Marchis, Mark S. Marley, Christian Marois, Kimberly Ward-Duong, Et Al

Astronomy: Faculty Publications

HR4796A hosts a well-studied debris disk with a long history due to its high fractional luminosity and favorable inclination, which facilitate both unresolved and resolved observations. We present new J-and K 1-band images of the resolved debris disk HR4796A taken in the polarimetric mode of the Gemini Planet Imager (GPI). The polarized intensity features a strongly forward-scattered brightness distribution and is undetected at the far side of the disk. The total intensity is detected at all scattering angles and also exhibits a strong forward-scattering peak. We use a forward-modeled geometric disk in order to extract geometric parameters, polarized fraction, and …

Active Magnetic Radiation Shielding For Long-Duration Human Spaceflight, Kristine Ferrone

Dissertations and Theses (Open Access)

Exploration of interplanetary space presents dramatic hazards to human survival.

Space radiation hazards outside the protection of the Earth’s magnetosphere can

produce both acute and chronic health risks and thus become limiting factors for

NASA’s planned mission to Mars by the 2030s. Radiation exposure on a Mars mission

is delivered primarily by high energy ions from galactic cosmic rays and moderate

energy protons from solar particle events. The chronic radiation dose due to galactic

cosmic rays on a typical Mars mission is on the order of 1 Sv, and additional acute

radiation dose from solar flares can reach over 4 …

Diffuse Spectra Model Of Photoluminescence In Carbon Quantum Dots, S. E. Kumekov, N. K. Saitova, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

The attractive aspect of excitation related to fluorescence nature in carbon quantum dots (CQD) has guided to several assumptions correlated with clusters size distribution, shapes as well as presence of different emissive states. In this study, a dimer–excimer model of photoluminescence (PL) in CQD describing discrete multiple electronic states for the excitation-dependent emission is described. The functional dependence of the characteristic width of the diffuse spectra of PL on the size of a quantum dots are calculated. The effective width of PL spectrum can be tuned from 0.1 to 1 eV.

Modeling The Obscuring Features In Active Galactic Nuclei: An X-Ray Analysis Of Ngc 1052, Samantha E. Cabral

Graduate Masters Theses

We present a multi-epoch analysis of the X-ray spectrum of NGC 1052, a nearby galaxy notorious for its well-studied spectral variability. We utilize observations from NuSTAR, XMM-Newton, Chandra, Swift, Suzaku, BeppoSAX, and ASCA to create a comprehensive set of data that spans roughly 20 years. Organizing our data by observation date and grouping into specific epochs allows us to explore a model allowed to flex and accommodate any spectral changes that occur over time in the X-ray spectrum of NGC 1052. We find that the spectrum takes on a relatively flat nature and is best modeled with two neutral absorption …

Is Ngc 300 A Pure Exponential Disk Galaxy?, In Sung Jang, Roelof S. De Jong, Ivan Minchev, Eric F. Bell, Antonela Monachesi, Benne W. Holwerda, Jeremy Bailin, Adam Smercina, Richard D'Souza

Faculty and Staff Scholarship

NGC 300 is a low-mass disk galaxy in the Sculptor group. In the literature, it has been identified as a pure exponential disk galaxy, as its luminosity profile can be well fit with a single exponential law over many disk scale lengths (Type I). We investigate the stellar luminosity distribution of NGC 300 using Hubble Space Telescope archive data, reaching farther and deeper than any other previous studies. Color-magnitude diagrams show a significant population of old red giant branch (RGB) stars in all fields out to R ∼ 19 kpc (32′), as well as younger populations in the inner regions. …

Accumulation Of Polar Vorticity On Giant Planets: Towards A Three-Dimensional Theory, Shawn R. Brueshaber

Dissertations

My research investigates the polar atmospheric dynamics of the giant planets: Jupiter and Saturn (gas giants), and Uranus and Neptune (ice giants). I conduct my research modifying and applying the Explicit Planetary Isentropic Coordinate global circulation code to model the polar regions of the four giant planets.

The motivation behind my research is to uncover the reason why giant planet polar atmospheric dynamics differ. Jupiter features multiple circumpolar cyclones arranged in geometrical configurations, whereas Saturn features a single pole-centered cyclone. Uranus and Neptune also appear to have single pole-centered cyclones, albeit, larger than those on Saturn. …

Adaptive Spline Fitting With Particle Swarm Optimization, Soumya Mohanty, Ethan Fahnestock

Physics & Astronomy Faculty Publications

In fitting data with a spline, finding the optimal placement of knots can significantly improve the quality of the fit. However, the challenging high-dimensional and non-convex optimization problem associated with completely free knot placement has been a major roadblock in using this approach. We present a method that uses particle swarm optimization (PSO) combined with model selection to address this challenge. The problem of overfitting due to knot clustering that accompanies free knot placement is mitigated in this method by explicit regularization, resulting in a significantly improved performance on highly noisy data. The principal design choices available in the method …

A Simple Graphical Method For Calculating The Standing Wave Frequencies On A Rectangular Membrane, Joseph D. Romano, Richard H. Price

Physics & Astronomy Faculty Publications

In introductory physics courses, simple arguments based on traveling waves on a string are used to relate the frequency of standing waves to boundary conditions, e.g., the fixed ends of the string. Here, we extend that approach to two-dimensional waves such as the oscillations of a rectangular membrane with edges fixed at the boundary. This results in a graphical method that uses only simple geometry and is suitable for explaining two-dimensional standing-wave oscillations to non-science majors, e.g., in a physics of sound and music class.

Graphite Intercalation Compounds Derived By Green Chemistry As Oxygen Reduction Reaction Catalysts, Jianchao Zhao, Joseph H. Dumont, Ulises Martinez, Javier Macossay-Torres, Kateryna Artyushkova, Plamen Atanassov, Gautam Gupta

Physics & Astronomy Faculty Publications

Precious group metal (PGM) catalysts such as Pt supported on carbon supports are expensive catalysts utilized for the oxygen reduction reaction (ORR) due to their unmatched catalytic activity and durability. As an alternative, PGM-free ORR electrocatalysts that offer respectable catalytic activity are being pursued. Most of the notable PGM-free catalysts are obtained either from a bottom-up approach synthesis utilizing nitrogen-rich polymers as building blocks, or from a top down approach, where nitrogen and metal moieties are incorporated to carbonaceous matrixes. The systematic understanding of the origin of catalytic activity for either case is speculative and currently employed synthesis techniques typically …