The Hunt for Primordial Interactions in the Large-Scale Structures of the Universe

Biagetti, Matteo

doi:10.3390/galaxies7030071

Cited by 50 publications

(40 citation statements)

References 403 publications

(679 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The clear cosine-dependence between the asymmetry and the direction of observation might be an indication of a rotating universe (Gödel 2000). The asymmetry between galaxies with opposite spin patterns can be also used as an additional messenger and source of information about the large-scale structure, in addition to other sources of information related to galaxies such as stellar mass growth (Alpaslan et al 2016), the density distribution, galaxy shape, and the frequency of rare objects (Biagetti 2019). The indifference in the absolute magnitude of the galaxies might indicate on differences in the distribution of clockwise and counterclockwise galaxies in different redshift ranges, which can be related to chiral gravitational waves (Biagetti & Orlando 2020).…”

Section: Bandmentioning

confidence: 99%

Asymmetry between galaxies with different spin patterns: A comparison between COSMOS, SDSS, and Pan-STARRS

Shamir

2020

Open Astronomy

View full text Add to dashboard Cite

Previous observations of a large number of galaxies show differences between the photometry of spiral galaxies with clockwise spin patterns and spiral galaxies with counterclockwise spin patterns. In this study the mean magnitude of a large number of clockwise galaxies is compared to the mean magnitude of a large number of counterclockwise galaxies. The observed difference between clockwise and counterclockwise spiral galaxies imaged by the space-based COSMOS survey is compared to the differences between clockwise and counterclockwise galaxies imaged by the Earth-based SDSS and Pan-STARRS around the same field. The annotation of clockwise and counterclockwise galaxies is a fully automatic process that does not involve human intervention, and in all experiments both clockwise and counterclockwise galaxies are separated from the same fields. The comparison shows that the same asymmetry was identified by all three telescopes, providing strong evidence that the rotation direction of a spiral galaxy is linked to its luminosity as measured from Earth. Analysis of the luminosity difference using a large number of galaxies from different parts of the sky shows that the difference between clockwise and counterclockwise galaxies changes with the direction of observation, and oriented around an axis.

show abstract

Section: Bandmentioning

confidence: 99%

Asymmetry between galaxies with different spin patterns: A comparison between COSMOS, SDSS, and Pan-STARRS

Shamir

2020

Open Astronomy

View full text Add to dashboard Cite

show abstract

“…That is why we expect our findings to be particularly important for this parameter. The modeling of how the primordial signature of φ is imprinted in galaxy clustering has been extensively studied in the literature, both for the power spectrum ( [96][97][98], see [99] for a recent review and references therein) and for the bispectrum [53,57,64,[100][101][102][103][104][105][106][107][108][109][110][111][112][113][114][115].…”

Section: Local Primordial Non-gaussianitymentioning

confidence: 99%

The Covariance of Squeezed Bispectrum Configurations

Biagetti,

Castiblanco,

Noreña

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

We measure the halo bispectrum covariance in a large set of N-body simulations and compare it with theoretical expectations. We find a large correlation among (even mildly) squeezed halo bispectrum configurations. A similarly large correlation can be found between squeezed triangles and the long-wavelength halo power spectrum. This shows that the diagonal Gaussian contribution fails to describe, even approximately, the full covariance in these cases. We compare our numerical estimate with a model that includes, in addition to the Gaussian one, only the non-Gaussian terms that are large for squeezed configurations. We find that accounting for these large terms in the modeling greatly improves the agreement of the full covariance with simulations. We apply these results to a simple Fisher matrix forecast, and find that constraints on primordial non-Gaussianity are degraded by a factor of ∼ 2 when a non-Gaussian covariance is assumed instead of the diagonal, Gaussian approximation.

show abstract

“…where b g is the linear galaxy bias, M(k) ∝ k 2 at large scales is the transfer function relating the primordial curvature perturbation ζ to the linear dark matter density field δ, and b ζ is the bias associated to primordial non-Gaussianity (see [77][78][79] and [80] for a review). While in the absence of primordial non-Gaussianity, the galaxy power spectrum at large scales should relate to the matter power spectrum via a constant, the second term in Eq.…”

Section: Local Non-gaussianity and Scale-dependent Biasmentioning

confidence: 99%

The Persistence of Large Scale Structures I: Primordial non-Gaussianity

Biagetti,

Cole,

Shiu

2020

Preprint

Self Cite

View full text Add to dashboard Cite

We develop an analysis pipeline for characterizing the topology of large scale structure and extracting cosmological constraints based on persistent homology. Persistent homology is a technique from topological data analysis that quantifies the multiscale topology of a data set, in our context unifying the contributions of clusters, filament loops, and cosmic voids to cosmological constraints. We describe how this method captures the imprint of primordial local non-Gaussianity on the late-time distribution of dark matter halos, using a set of N-body simulations as a proxy for real data analysis. For our best single statistic, running the pipeline on several cubic volumes of size 40 (Gpc/h) 3 , we detect f loc NL = 10 at 97.5% confidence on ∼ 85% of the volumes. Additionally we test our ability to resolve degeneracies between the topological signature of f loc NL and variation of σ 8 and argue that correctly identifying nonzero f loc NL in this case is possible via an optimal template method. Our method relies on information living at O(10) Mpc/h, a complementary scale with respect to commonly used methods such as the scale-dependent bias in the halo/galaxy power spectrum. Therefore, while still requiring a large volume, our method does not require sampling long-wavelength modes to constrain primordial non-Gaussianity. Moreover, our statistics are interpretable: we are able to reproduce previous results in certain limits and we make new predictions for unexplored observables, such as filament loops formed by dark matter halos in a simulation box.

show abstract

The Hunt for Primordial Interactions in the Large-Scale Structures of the Universe

Cited by 50 publications

References 403 publications

Asymmetry between galaxies with different spin patterns: A comparison between COSMOS, SDSS, and Pan-STARRS

Asymmetry between galaxies with different spin patterns: A comparison between COSMOS, SDSS, and Pan-STARRS

The Covariance of Squeezed Bispectrum Configurations

The Persistence of Large Scale Structures I: Primordial non-Gaussianity

Contact Info

Product

Resources

About