Reduced bispectrum seeded by helical primordial magnetic fields
Abstract
In this paper, we investigate the effects of helical primordial magnetic fields (PMFs) on the cosmic microwave background (CMB) reduced bispectrum. We derive the full threepoint statistics of helical magnetic fields and numerically calculate the even contribution in the collinear configuration. We then numerically compute the CMB reduced bispectrum induced by passive and compensated PMF modes on large angular scales. There is a negative signal on the bispectrum due to the helical terms of the fields and we also observe that the biggest contribution to the bispectrum comes from the nonzero IR cutoff for causal fields, unlike the twopoint correlation case. For negative spectral indices, the reduced bispectrum is enhanced by the passive modes. This gives a lower value of the upper limit for the mean amplitude of the magnetic field on a given characteristic scale. However, high values of IR cutoff in the bispectrum, and the helical terms of the magnetic field relaxes this bound. This demonstrates the importance of the IR cutoff and helicity in the study of the nature of PMFs from CMB observations.
 Authors:
 Universidad Nacional de ColombiaBogotá, Facultad de Ciencias, Departamento de Física, Carrera 30 Calle 4503, C.P. 111321 Bogotá (Colombia)
 Grupo de Gravitación y Cosmología, Observatorio Astronómico Nacional, Universidad Nacional de Colombia, cra 45 No 2685, Edificio Uriel Gutierréz, Bogotá, D.C. (Colombia)
 Publication Date:
 OSTI Identifier:
 22676166
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2017; Journal Issue: 06; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; COMPUTERIZED SIMULATION; CORRELATIONS; HELICITY; MAGNETIC FIELDS; RELICT RADIATION; STATISTICS
Citation Formats
Hortúa, Héctor Javier, and Castañeda, Leonardo, Email: hjhortuao@unal.edu.co, Email: lcastanedac@unal.edu.co. Reduced bispectrum seeded by helical primordial magnetic fields. United States: N. p., 2017.
Web. doi:10.1088/14757516/2017/06/020.
Hortúa, Héctor Javier, & Castañeda, Leonardo, Email: hjhortuao@unal.edu.co, Email: lcastanedac@unal.edu.co. Reduced bispectrum seeded by helical primordial magnetic fields. United States. doi:10.1088/14757516/2017/06/020.
Hortúa, Héctor Javier, and Castañeda, Leonardo, Email: hjhortuao@unal.edu.co, Email: lcastanedac@unal.edu.co. Thu .
"Reduced bispectrum seeded by helical primordial magnetic fields". United States.
doi:10.1088/14757516/2017/06/020.
@article{osti_22676166,
title = {Reduced bispectrum seeded by helical primordial magnetic fields},
author = {Hortúa, Héctor Javier and Castañeda, Leonardo, Email: hjhortuao@unal.edu.co, Email: lcastanedac@unal.edu.co},
abstractNote = {In this paper, we investigate the effects of helical primordial magnetic fields (PMFs) on the cosmic microwave background (CMB) reduced bispectrum. We derive the full threepoint statistics of helical magnetic fields and numerically calculate the even contribution in the collinear configuration. We then numerically compute the CMB reduced bispectrum induced by passive and compensated PMF modes on large angular scales. There is a negative signal on the bispectrum due to the helical terms of the fields and we also observe that the biggest contribution to the bispectrum comes from the nonzero IR cutoff for causal fields, unlike the twopoint correlation case. For negative spectral indices, the reduced bispectrum is enhanced by the passive modes. This gives a lower value of the upper limit for the mean amplitude of the magnetic field on a given characteristic scale. However, high values of IR cutoff in the bispectrum, and the helical terms of the magnetic field relaxes this bound. This demonstrates the importance of the IR cutoff and helicity in the study of the nature of PMFs from CMB observations.},
doi = {10.1088/14757516/2017/06/020},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 06,
volume = 2017,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}

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