Effect of peak absolute magnitude of Type Ia supernovae and sound horizon values on the Hubble constant using DESI Data Release 1 results

Abstract We apply data-motivated priors on the peak absolute magnitude of Type Ia supernovae ( M ) and the sound horizon at the drag epoch ( $$r_d$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>r</mml:mi> <mml:mi>d</mml:mi> </mml:msub> </mml:math> ), to study how the $$ M-r_d$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>M</mml:mi> <mml:mo>-</mml:mo> <mml:msub> <mml:mi>r</mml:mi> <mml:mi>d</mml:mi> </mml:msub> </mml:mrow> </mml:math> degeneracy affects low redshift measurements of the Hubble constant, and then compare these estimates to the Planck estimated value of the Hubble constant. We use the data from Pantheon $$+$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>+</mml:mo> </mml:math> , Cosmic Chronometers, and the Dark Energy Spectroscopic Instrument Data Release 1 (DESI DR1) Baryon Acoustic Oscillations (BAO) results for this purpose. We reaffirm the fact that there is a degeneracy between M and $$r_d$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>r</mml:mi> <mml:mi>d</mml:mi> </mml:msub> </mml:math> , and modifying the $$r_d$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>r</mml:mi> <mml:mi>d</mml:mi> </mml:msub> </mml:math> values to reconcile the discrepancy in Hubble constant values also requires a change in the peak absolute magnitude M . For certain M and $$r_d$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>r</mml:mi> <mml:mi>d</mml:mi> </mml:msub> </mml:math> priors, the discrepancy is found to reduce to be as low as (1.2–2) $$\sigma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> </mml:math> when considering the spatially flat $$\Lambda $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>Λ</mml:mi> </mml:math> CDM model . We also notice that for our datasets considered, the Gaussian prior combination of $$M \in \mathcal {N} (-\,19.253,0.027)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>M</mml:mi> <mml:mo>∈</mml:mo> <mml:mi>N</mml:mi> <mml:mo>(</mml:mo> <mml:mo>-</mml:mo> <mml:mspace/> <mml:mn>19.253</mml:mn> <mml:mo>,</mml:mo> <mml:mn>0.027</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> (obtained from SH0ES) and $$r_d \in \mathcal {N} (147.05,0.3)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>r</mml:mi> <mml:mi>d</mml:mi> </mml:msub> <mml:mo>∈</mml:mo> <mml:mi>N</mml:mi> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>147.05</mml:mn> <mml:mo>,</mml:mo> <mml:mn>0.3</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> </mml:mrow> </mml:math> Mpc (determined from Planck CMB measurements) is least favored as compared to other prior combinations for the $$\Lambda $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>Λ</mml:mi> </mml:math> CDM model.