☆ 4.6 Article

Issues on generating primordial anisotropies at the end of inflation

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS (2012)

Journal

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

Volume -, Issue 1, Pages -

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IOP Publishing Ltd

DOI: 10.1088/1475-7516/2012/01/022

Keywords

inflation; cosmological perturbation theory

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Astronomy & Astrophysics Physics, Particles & Fields

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Abstract

We revisit the idea of generating primordial anisotropies at the end of inflation in models of inflation with gauge fields. To be specific we consider the charged hybrid inflation model where the waterfall field is charged under a U(1) gauge field so the surface of end of inflation is controlled both by inflaton and the gauge fields. Using delta N formalism properly we find that the anisotropies generated at the end of inflation from the gauge field fluctuations are exponentially suppressed on cosmological scales. This is because the gauge field evolves exponentially during inflation while in order to generate appreciable anisotropies at the end of inflation the spectator gauge field has to be frozen and scale invariant. We argue that this is a generic feature, that is, one can not generate observable anisotropies at the end of inflation within an FRW background.

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Comparison of Polarized Radiative Transfer Codes Used by the EHT Collaboration

Ben S. Prather, Jason Dexter, Monika Moscibrodzka, Hung-Yi Pu, Thomas Bronzwaer, Jordy Davelaar, Ziri Younsi, Charles F. Gammie, Roman Gold, George N. Wong, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, Keiichi Asada, Rebecca Azulay, Uwe Bach, Anne-Kathrin Baczko, David Ball, Mislav Balokovic, John Barrett, Michi A. Bauboeck, Bradford Benson, Dan Bintley, Lindy Blackburn, Raymond L. Blundell, Katherine C. Bouman, Geoffrey Bower, Hope Boyce, Michael D. Bremer, Christiaan Brinkerink, Roger Brissenden, Silke E. Britzen, Avery Broderick, Dominique Broguiere, Sandra Bustamante, Do-Young E. Byun, John Carlstrom, Chiara Ceccobello, Andrew Chael, Chi-kwan O. Chan, Dominic Chang, Koushik Chatterjee, Shami Chatterjee, Ming-Tang Chen, Yongjun Chen, Xiaopeng Cheng, Ilje Cho, Pierre S. Christian, Nicholas E. Conroy, John M. Conway, James M. Cordes, Thomas B. Crawford, Geoffrey Crew, Alejandro Cruz-Osorio, Yuzhu Cui, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Vedant S. Dhruv, Sheperd Doeleman, Sean A. Dougal, Sergio P. Dzib, Ralph Eatough, Razieh Emami, Heino Falcke, Joseph L. Farah, Vincent Fish, Ed Fomalont, H. Alyson Ford, Raquel T. Fraga-Encinas, William Freeman, Per M. Friberg, Christian Fromm, Antonio Fuentes, Peter Galison, Roberto Garcia, Olivier Gentaz, Boris Georgiev, Ciriaco I. Goddi, Arturo Gomez-Ruiz, Jose L. Gomez, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Daryl Haggard, Kari H. Haworth, Michael Hecht, Ronald Hesper, Dirk C. Heumann, Luis C. Ho, Paul Ho, Mareki Honma, Chih-Wei L. Huang, Lei H. Huang, David Hughes, Shiro Ikeda, C. M. Violette Impellizzeri, Makoto Inoue, Sara J. Issaoun, David T. James, Buell Jannuzi, Michael Janssen, Britton Jeter, Wu Jiang, Alejandra D. Jimenez-Rosales, Michael Johnson, Svetlana V. Jorstad, Abhishek Joshi, Taehyun Jung, Mansour Karami, Ramesh Karuppusamy, Tomohisa K. Kawashima, Garrett Keating, Mark Kettenis, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kim, Motoki Kino, Jun Yi Koay, Prashant Kocherlakota, Yutaro Kofuji, Shoko Koyama, Carsten Kramer, Michael P. Kramer, Thomas Krichbaum, Cheng-Yu Kuo, Noemi R. La Bella, Tod Lauer, Daeyoung Lee, Sang-Sung Lee, Po Kin Leung, Aviad Levis, Zhiyuan Li, Rocco Lico, Greg Lindahl, Michael Lindqvist, Mikhail Lisakov, Jun Liu, Kuo Liu, Elisabetta Liuzzo, Wen-Ping P. Lo, Andrei Lobanov, Laurent J. Loinard, Colin Lonsdale, Ru-Sen R. Lu, Nicholas MacDonald, Jirong Mao, Nicola Marchili, Sera P. Markoff, Daniel P. Marrone, Alan Marscher, Ivan Marti-Vidal, Satoki D. Matsushita, Lynn Matthews, Lia M. Medeiros, Karl Menten, Daniel Michalik, Izumi Mizuno, Yosuke M. Mizuno, James Moran, Kotaro Moriyama, Cornelia Mueller, Alejandro Mus, Gibwa Musoke, Ioannis Myserlis, Andrew Nadolski, Hiroshi M. Nagai, Neil Nagar, Masanori Nakamura, Ramesh Narayan, Gopal Narayanan, Iniyan Natarajan, Antonios Nathanail, Santiago Navarro Fuentes, Joey Neilsen, Roberto Neri, Chunchong Ni, Aristeidis A. Noutsos, Michael Nowak, Junghwan Oh, Hiroki Okino, Hector N. Olivares, Gisela Ortiz-Leon, Tomoaki Oyama, Feryal oezel, Daniel C. M. Palumbo, Georgios Filippos Paraschos, Jongho Park, Harriet Parsons, Nimesh Patel, Ue-Li W. Pen, Dominic Pesce, Vincent Pietu, Richard Plambeck, Aleksandar PopStefanija, Oliver M. Porth, Felix A. Poetzl, Jorge Preciado-Lopez, Dimitrios Psaltis, Venkatessh Ramakrishnan, Ramprasad G. Rao, Mark W. Rawlings, Alexander Raymond, Luciano Rezzolla, Angelo Ricarte, Bart Ripperda, Freek Roelofs, Alan Rogers, Eduardo Ros, Cristina Romero-Canizales, Arash Roshanineshat, Helge L. Rottmann, Alan Roy, Ignacio Ruiz, Chet Ruszczyk, Kazi L. J. Rygl, Salvador Sanchez, David Sanchez-Argueelles, Miguel Sanchez-Portal, Mahito Sasada, Kaushik Satapathy, Tuomas Savolainen, F. Peter Schloerb, Jonathan Schonfeld, Karl-Friedrich Schuster, Lijing Shao, Zhiqiang Shen, Des Small, Bong Won Sohn, Jason SooHoo, Kamal Souccar, He Sun, Fumie J. Tazaki, Alexandra Tetarenko, Paul Tiede, Remo P. J. Tilanus, Michael Titus, Pablo Torne, Efthalia Traianou, Tyler Trent, Sascha Trippe, Matthew Turk, Ilse van Bemmel, Huib Jan R. van Langevelde, Daniel van Rossum, Jesse Vos, Jan Wagner, Derek Ward-Thompson, John Wardle, Jonathan Weintroub, Norbert Wex, Robert Wharton, Maciek Wielgus, Kaj Wiik, Gunther F. Witzel, Michael Wondrak, Qingwen Wu, Paul Yamaguchi, Aristomenis Yfantis, Doosoo Yoon, Andre Young, Ken Young, Wei Yu, Feng Yuan, Ye-Fei Yuan, J. Anton Zensus, Shuo Zhang, Guang-Yao Zhao, Shan-Shan Zhao

Summary: Interpretation of resolved polarized images of black holes by the EHT relies on predicting the polarized emission observable by Earth-based instruments for a specific black hole accretion model. GRRT codes used within the EHT Collaboration are evaluated for accuracy and consistency in producing test images, demonstrating high consistency in various methods and implementations of radiative transfer calculations. The comparison shows similar images with a pixel-wise normalized mean squared error (NMSE) of 0.012 for an analytic accretion model, and NMSEs of 0.02, 0.04, 0.04, and 0.12 in Stokes I, Q, U, and V for a cell-based magnetohydrodynamic simulation snapshot. The agreement between the image metrics and published EHT results is better than measurement uncertainties.

ASTROPHYSICAL JOURNAL (2023)

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Article Astronomy & Astrophysics

Einstein rings modulated by wavelike dark matter from anomalies in gravitationally lensed images

Alfred Amruth, Tom Broadhurst, Jeremy Lim, Masamune Oguri, George F. F. Smoot, Jose M. M. Diego, Enoch Leung, Razieh Emami, Juno Li, Tzihong Chiueh, Hsi-Yu Schive, Michael C. H. Yeung, Sung Kei Li

Summary: Unveiling the true nature of dark matter, which only interacts gravitationally, is a major goal in physics. Weakly interacting massive particles and ultralight bosons (axions) are leading candidates for dark matter, postulated to address deficiencies in the Standard Model of particle physics. By examining the lensing signatures in multiply lensed images of background galaxies, researchers can distinguish between rho DM and psi DM halos, with rho DM models showing discrepancies in brightness and position predictions. In the case of the system HS 0810+2554, psi DM successfully reproduces all aspects of the lensed triplet images, while rho DM often fails. This, combined with its ability to resolve lensing anomalies, supports the idea of wavelike dark matter involving axions.

NATURE ASTRONOMY (2023)

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Article Astronomy & Astrophysics

Accretion Flow Morphology in Numerical Simulations of Black Holes from the ngEHT Model Library: The Impact of Radiation Physics

Koushik Chatterjee, Andrew Chael, Paul Tiede, Yosuke Mizuno, Razieh Emami, Christian Fromm, Angelo Ricarte, Lindy Blackburn, Freek Roelofs, Michael D. D. Johnson, Sheperd S. S. Doeleman, Philipp Arras, Antonio Fuentes, Jakob Knollmueller, Nikita Kosogorov, Greg Lindahl, Hendrik Mueller, Nimesh Patel, Alexander Raymond, Efthalia Traianou, Justin Vega

Summary: In the past few years, the Event Horizon Telescope (EHT) has successfully captured images of supermassive black holes M87* and Sgr A* for the first time, providing valuable insights into their structures. The upcoming ngEHT project aims to improve the resolution and sensitivity of the EHT array to better understand the accretion flow and jet in these black holes. Different numerical simulations have been compared to analyze the similarities and differences in the accretion flow structure and dynamics. The results show that despite some variations in electron temperature, the models exhibit remarkable similarities in temporal and spatial properties.

GALAXIES (2023)

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Article Astronomy & Astrophysics

Rapid Quenching of Galaxies at Cosmic Noon

Minjung Park, Sirio Belli, Charlie Conroy, Sandro Tacchella, Joel Leja, Sam E. Cutler, Benjamin D. Johnson, Erica J. Nelson, Razieh Emami

Summary: The study investigates the rapid quenching of young quiescent galaxies at high redshifts and identifies physical mechanisms involved. The results show that these galaxies experienced intense starbursts prior to rapid quenching and that AGN activity plays a role in some cases. Gas removal or depletion is observed in other galaxies, indicating a central starburst in the recent past. The study concludes that these galaxies are not only rapidly quenched but also formed through major starbursts, potentially driven by mergers and AGN feedback.

ASTROPHYSICAL JOURNAL (2023)

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