Honing cross-correlation tools for inference on ultra-high-energy cosmic-ray composition

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F24%3A00585271" target="_blank" >RIV/68378271:_____/24:00585271 - isvavai.cz</a>

Výsledek na webu

<a href="https://hdl.handle.net/11104/0360130" target="_blank" >https://hdl.handle.net/11104/0360130</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1475-7516/2024/03/058" target="_blank" >10.1088/1475-7516/2024/03/058</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Honing cross-correlation tools for inference on ultra-high-energy cosmic-ray composition

Popis výsledku v původním jazyce

The chemical composition of the highest-energy cosmic rays, namely the atomic number Z of rays with energies E ≳ 40 EeV, remains to date largely unknown. Some information on the composition can be inferred from the deflections that charged ultra-high-energy cosmic rays experience while they traverse intervening magnetic fields. Indeed, such deflections distort and suppress the original anisotropy in the cosmic ray arrival directions, thus, given a source model, a measure of the anisotropy is also a measurement of the deflections, which in turn informs us on the chemical composition. In this work, we show that, by quantifying ultra-high-energy cosmic ray anisotropies through the angular cross-correlation between cosmic rays and galaxies, we would be able to exclude iron fractions fFe ≥ Script O(10%) assuming a fiducial hydrogen map at 2σ level, and even smaller fractions in the reverse case of hydrogen on an iron map, going well below fH ≈ 10% when we mask the Galactic Centre up to latitudes of 40°. This is an improvement of a factor of a few compared to our previous method, and is mostly ascribable to a new test statistics which is sensitive to each harmonic multipole individually. Our method can be applied to real data as an independent test of the recent claim that current cosmic-ray data can not be reproduced by any existing model of the Galactic magnetic field, as well as an additional handle to compare any realistic, competing, data-driven composition models.

Název v anglickém jazyce

Honing cross-correlation tools for inference on ultra-high-energy cosmic-ray composition

Popis výsledku anglicky

The chemical composition of the highest-energy cosmic rays, namely the atomic number Z of rays with energies E ≳ 40 EeV, remains to date largely unknown. Some information on the composition can be inferred from the deflections that charged ultra-high-energy cosmic rays experience while they traverse intervening magnetic fields. Indeed, such deflections distort and suppress the original anisotropy in the cosmic ray arrival directions, thus, given a source model, a measure of the anisotropy is also a measurement of the deflections, which in turn informs us on the chemical composition. In this work, we show that, by quantifying ultra-high-energy cosmic ray anisotropies through the angular cross-correlation between cosmic rays and galaxies, we would be able to exclude iron fractions fFe ≥ Script O(10%) assuming a fiducial hydrogen map at 2σ level, and even smaller fractions in the reverse case of hydrogen on an iron map, going well below fH ≈ 10% when we mask the Galactic Centre up to latitudes of 40°. This is an improvement of a factor of a few compared to our previous method, and is mostly ascribable to a new test statistics which is sensitive to each harmonic multipole individually. Our method can be applied to real data as an independent test of the recent claim that current cosmic-ray data can not be reproduced by any existing model of the Galactic magnetic field, as well as an additional handle to compare any realistic, competing, data-driven composition models.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/EF15_003%2F0000437" target="_blank" >EF15_003/0000437: Kosmologie, gravitace a temný sektor vesmíru</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Cosmology and Astroparticle Physics

ISSN

1475-7516

e-ISSN

1475-7516

Svazek periodika

2024

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

16

Strana od-do

058

Kód UT WoS článku

001195863300012

EID výsledku v databázi Scopus

2-s2.0-85188968369