Cosmological constraints from the redshift-space galaxy skew spectra

Abstract

Extracting the non-Gaussian information of the cosmic large-scale structure (LSS) is vital in unlocking the full potential of the rich datasets from the upcoming stage-IV galaxy surveys. Galaxy skew spectra serve as efficient beyond-two-point statistics, encapsulating essential bispectrum information with computational efficiency akin to power spectrum analysis. This paper presents the first cosmological constraints from analyzing the full set of redshift-space galaxy skew spectra of the data from the SDSS-III BOSS, accessing cosmological information down to nonlinear scales. Employing the forward modeling framework and simulation-based inference via normalizing flows, we analyze the CMASS-SGC subsample, which constitute approximately 10% of the full BOSS data. Analyzing the scales up to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>k</a:mi></a:mrow><a:mrow><a:mi>max</a:mi></a:mrow></a:msub><a:mo>=</a:mo><a:mn>0.5</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mrow><a:msup><a:mrow><a:mi>h</a:mi></a:mrow><a:mrow><a:mo>−</a:mo><a:mn>1</a:mn></a:mrow></a:msup><a:mtext> </a:mtext><a:mi>Mpc</a:mi></a:mrow></a:mrow></a:math>, we find that the skew spectra improve the constraints on <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msub><c:mi mathvariant="normal">Ω</c:mi><c:mi mathvariant="normal">m</c:mi></c:msub><c:mo>,</c:mo><c:msub><c:mi mathvariant="normal">Ω</c:mi><c:mi mathvariant="normal">b</c:mi></c:msub><c:mo>,</c:mo><c:mi>h</c:mi></c:math>, and <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:msub><i:mi>n</i:mi><i:mi>s</i:mi></i:msub></i:math> by 34%, 35%, 18%, 10%, respectively, compared to constraints from previous power spectrum multipoles analysis, yielding <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mrow><k:msub><k:mrow><k:mi mathvariant="normal">Ω</k:mi></k:mrow><k:mrow><k:mi mathvariant="normal">m</k:mi></k:mrow></k:msub><k:mo>=</k:mo><k:mn>0.28</k:mn><k:msubsup><k:mrow><k:mn>8</k:mn></k:mrow><k:mrow><k:mo>−</k:mo><k:mn>0.034</k:mn></k:mrow><k:mrow><k:mo>+</k:mo><k:mn>0.024</k:mn></k:mrow></k:msubsup></k:mrow></k:math>, <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:msub><o:mi mathvariant="normal">Ω</o:mi><o:mi mathvariant="normal">b</o:mi></o:msub><o:mo>=</o:mo><o:mn>0.04</o:mn><o:msubsup><o:mn>3</o:mn><o:mrow><o:mo>−</o:mo><o:mn>0.007</o:mn></o:mrow><o:mrow><o:mo>+</o:mo><o:mn>0.005</o:mn></o:mrow></o:msubsup></o:math>, <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mi>h</s:mi><s:mo>=</s:mo><s:mn>0.75</s:mn><s:msubsup><s:mn>9</s:mn><s:mrow><s:mo>−</s:mo><s:mn>0.050</s:mn></s:mrow><s:mrow><s:mo>+</s:mo><s:mn>0.104</s:mn></s:mrow></s:msubsup></s:math>, <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:msub><u:mi>n</u:mi><u:mi mathvariant="normal">s</u:mi></u:msub><u:mo>=</u:mo><u:mn>0.91</u:mn><u:msubsup><u:mn>8</u:mn><u:mrow><u:mo>−</u:mo><u:mn>0.090</u:mn></u:mrow><u:mrow><u:mo>+</u:mo><u:mn>0.041</u:mn></u:mrow></u:msubsup></u:math> (at 68% confidence limit). On the other hand, the constraints on <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:msub><x:mi>σ</x:mi><x:mn>8</x:mn></x:msub></x:math> are weaker than from the power spectrum. Including the big bang nucleosynthesis (BBN) prior on baryon density reduces the uncertainty on the Hubble parameter further, achieving <z:math xmlns:z="http://www.w3.org/1998/Math/MathML" display="inline"><z:mi>h</z:mi><z:mo>=</z:mo><z:mn>0.75</z:mn><z:msubsup><z:mn>0</z:mn><z:mrow><z:mo>−</z:mo><z:mn>0.032</z:mn></z:mrow><z:mrow><z:mo>+</z:mo><z:mn>0.034</z:mn></z:mrow></z:msubsup></z:math>, which is a 38% improvement over the constraint from the power spectrum with the same prior. Compared to the bispectrum (monopole) analysis, skew spectra offer comparable constraints on larger scales (<bb:math xmlns:bb="http://www.w3.org/1998/Math/MathML" display="inline"><bb:mrow><bb:msub><bb:mrow><bb:mi>k</bb:mi></bb:mrow><bb:mrow><bb:mi>max</bb:mi></bb:mrow></bb:msub><bb:mo>&lt;</bb:mo><bb:mn>0.3</bb:mn><bb:mtext> </bb:mtext><bb:mtext> </bb:mtext><bb:mrow><bb:msup><bb:mrow><bb:mi>h</bb:mi></bb:mrow><bb:mrow><bb:mo>−</bb:mo><bb:mn>1</bb:mn></bb:mrow></bb:msup><bb:mtext> </bb:mtext><bb:mi>Mpc</bb:mi></bb:mrow></bb:mrow></bb:math>) for most parameters except for <db:math xmlns:db="http://www.w3.org/1998/Math/MathML" display="inline"><db:msub><db:mi>σ</db:mi><db:mn>8</db:mn></db:msub></db:math>. Published by the American Physical Society 2024

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