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Large-scale alignments of quasar polarisations: a detailed study of the spinless-particle scenario
Cosmology and Nongalactic Astrophysics · Submitted 29 Aug 2013
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim After a systematic investigation, we conclude that it is very unlikely that these observations can be accounted for by axion-like particles, given current data and constraints.
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The abstract, sentence by sentence
The main motivation for our work has been a puzzling observation concerning quasars. No one expected the existence of correlations in the polarisation of visible light coming from objects separated by gigaparsecs, until they were first reported in the form of a redshift-dependent effect that has become more and more significant with the growth of the data sample. In close connection with the observational group, we have studied in detail the most widely considered scenario, involving axion-photon mixing in extragalactic magnetic fields. After a systematic investigation, we conclude that it is very unlikely that these observations can be accounted for by axion-like particles, given current data and constraints. We also derive new limits on the parameters describing these particles. This thesis gives in particular a detailed account of the consequences of axion-photon mixing on polarisation, studies the influence of averages over the frequency (including a wave-packet treatment of the mixing), and discusses the consequences of different magnetic-field morphologies.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | The main motivation for our work has been a puzzling observation concerning quasars. | background 0.97 | 0.13 | 0.02 | asserted 0.89 |
| s1 | No one expected the existence of correlations in the polarisation of visible light coming from objects separated by gigaparsecs, until they were first reported in the form of a redshift-dependent effect that has become more and more significant with the growth of the data sample. | background 0.98 | 0.06 | 0.03 | asserted 1.00 |
| s2 | In close connection with the observational group, we have studied in detail the most widely considered scenario, involving axion-photon mixing in extragalactic magnetic fields. | contribution 0.70 | 0.87 | 0.02 | asserted 0.97 |
| s3 | After a systematic investigation, we conclude that it is very unlikely that these observations can be accounted for by axion-like particles, given current data and constraints. | result 0.88 | 0.91 | 0.92 | asserted 0.54 |
| s4 | We also derive new limits on the parameters describing these particles. | result 0.89 | 0.95 | 0.05 | asserted 0.99 |
| s5 | This thesis gives in particular a detailed account of the consequences of axion-photon mixing on polarisation, studies the influence of averages over the frequency (including a wave-packet treatment of the mixing), and discusses the consequences of different magnetic-field morphologies. | contribution 0.96 | 0.82 | 0.03 | asserted 0.93 |
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The paper
Original abstract
The main motivation for our work has been a puzzling observation concerning quasars. No one expected the existence of correlations in the polarisation of visible light coming from objects separated by gigaparsecs, until they were first reported in the form of a redshift-dependent effect that has become more and more significant with the growth of the data sample. In close connection with the observational group, we have studied in detail the most widely considered scenario, involving axion-photon mixing in extragalactic magnetic fields. After a systematic investigation, we conclude that it is very unlikely that these observations can be accounted for by axion-like particles, given current data and constraints. We also derive new limits on the parameters describing these particles. This thesis gives in particular a detailed account of the consequences of axion-photon mixing on polarisation, studies the influence of averages over the frequency (including a wave-packet treatment of the mixing), and discusses the consequences of different magnetic-field morphologies.
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How the literature uses it
1 arXiv paper cite this in 2 sentences
Papers whose main result relates to this one's
States the same result 1 paper
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The standard axion-like particle explanation of the observed large-scale coherent orientations of quasar polarisation vectors is ruled out by the recent measurements of vanishing of circular polarisation.
Can axion-like particles explain the alignments of the polarisations of light from quasars? · 0.89
States a conflicting result 2 papers
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Interpreted in terms of a cosmological-size effect, we show that the dichroism and birefringence predicted by a mixing between photons and very light pseudoscalar particles within a magnetic field can qualitatively reproduce the observations.
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We present results showing that, thanks to axion-photon mixing in external magnetic fields, it is actually possible to produce an effect similar to the one needed to explain the large-scale coherent orientations of quasar polarisation vectors in visible light that have been observed in some regions of the sky.
Papers citing it · 1 sentence without a confident label
Cites it as background 1 paper
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For a recent summary of the motivations for these particles from theory and of their implications, see Refs. [ref] and references therein.
Constraining ALPs with linear and circular polarisation measurements of quasar light · Introduction · 0.96
What it cites · 103 sentences without a confident label
Uses the method or tool of 2 papers
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Departure from isotropy in a $(q,u)$ space A simple method that we have proposed [ref] is to check how the alignment tendency in a given region looks like in a linear polarisation space $(q,u)$, and to highlight it using averages.
Can axion-like particles explain the alignments of the polarisations of light from quasars? · Highlighting non-random orientations of polarisation · 0.91
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A simpler approach [ref] is to use direct averages of the plane-wave Stokes parameters of Eq. [ref] over frequency, instead of wave packets.
When the Wavepacket is Unnecessary · Results for white light · 0.93
Uses data or values from 10 papers
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As estimated in Ref. [ref] , this has to be at least 0.5% and certainly not more than 2% to explain the observations.
Optical circular polarization in quasars · Alignments due to dichroism · 0.80
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In the latest sample [ref] , 42 quasars out of 56 from this region actually have their polarisation position angles in that given $[146,46]$ range.[In the corresponding low-$z$ region shown in Fig. [ref], the authors have noted that 35 objects out of 43 have their polarisation position angles in a 90$$ interval, $[30,120]$.] To apply the binomial test specifically, the authors removed the objects used to define the predicted range in this region, leaving 27 objects oriented accordingly out of 40, and found a probability of uniform distribution equal to $2.8×10^-3$ [ref] .
Mapping extreme-scale alignments of quasar polarization vectors · Highlighting non-random orientations of polarisation · 0.95
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In our case, the influence of our galactic magnetic field can be neglected because the mixing with nearly massless pseudoscalars would be inefficient at the optical frequencies at which the alignments have been detected (we use the values for $ℬ$ and $ω_p$ considered in Ref. [ref] ).
Axion-like particle effects on the polarization of cosmic high-energy gamma sources · Motivation · 0.95
Compares with 4 papers
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In the observational paper [ref] and in Ref. [ref] , another analysis was done, leading to the preferred angles one finds when considering only the angular information (those shown in Fig. [ref]), which are indicated with straight lines.
Large-scale coherent orientations of quasar polarisation vectors: interpretation in terms of axion-like particles · Highlighting non-random orientations of polarisation · 0.92
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In the observational paper [ref] and in Ref. [ref] , another analysis was done, leading to the preferred angles one finds when considering only the angular information (those shown in Fig. [ref]), which are indicated with straight lines.
Mapping extreme-scale alignments of quasar polarization vectors · Highlighting non-random orientations of polarisation · 0.92
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This contrasts with what one can expect from photons of higher energies; see, e.g. Ref. [ref] .
The Milky Way as a Kiloparsec-Scale Axionscope · Motivation · 0.82
Cites as support 4 papers
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Full analyses [ref] indeed indicate that the effect is not likely to be explained by local causes (influence of our galaxy, dust, etc.), which would similarly affect both low- and high-redshift samples, and suggest that it requires something more exotic.
Confirmation of the existence of coherent orientations of quasar polarization vectors on cosmological scales · Quasar polarisations coherently oriented on large scales · 0.98
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Full analyses [ref] indeed indicate that the effect is not likely to be explained by local causes (influence of our galaxy, dust, etc.), which would similarly affect both low- and high-redshift samples, and suggest that it requires something more exotic.
Large Scale Alignment of Optical Polarizations from Distant QSOs using Coordinate Invariant Statistics · Quasar polarisations coherently oriented on large scales · 0.98
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Full analyses [ref] indeed indicate that the effect is not likely to be explained by local causes (influence of our galaxy, dust, etc.), which would similarly affect both low- and high-redshift samples, and suggest that it requires something more exotic.
Mapping extreme-scale alignments of quasar polarization vectors · Quasar polarisations coherently oriented on large scales · 0.98
Cites as background 21 papers
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Discussed as an interesting possibility already in the first of these papers, the mixing of light with spinless particles has soon become the favourite scenario, and has been claimed as naturally able to account qualitatively for most of the properties of the observations of linear polarisation [ref] .
Mapping extreme-scale alignments of quasar polarization vectors · Towards a spinless-particle interpretation · 0.87
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Among the various ideas proposed to explain the observations, the one that has been the most widely considered in the literature is related to particle physics and involves the existence of new light spinless particles, see e.g. Refs. [ref] .
Axions and polarisation of quasars · How can we understand this effect? · 0.90
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Among the various ideas proposed to explain the observations, the one that has been the most widely considered in the literature is related to particle physics and involves the existence of new light spinless particles, see e.g. Refs. [ref] .
Large-Scale Alignments of Quasar Polarization Vectors: Evidence at Cosmological Scales for Very Light Pseudoscalar Particles Mixing with Photons? · How can we understand this effect? · 0.90
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