A standard ruler akin in application to standard candles, Baryon Acoustic Oscillations (BAO) are a main feature of the matter power spectrum, depending on fundamental quantities cosmologists are striving to measure. The SKA Observatory (SKAO) will look for their signal in the post-reionisation universe via neutral hydrogen Intensity Mapping, a task made challenging by astrophysical foregrounds and resolution limitations. To tackle these issues, we investigate the results emerging from the multipole expansion approach as a mitigation of such limitations and we showcase the gains made from cross-correlating the HI intensity mapping with spectroscopic galaxy observations. This is to be intended as an anticipation of future synergies between the SKAO Project and LSS Stage 4- or DESI-like instruments. Adding then the information from the quadrupole term allows for a detection of the BAO feature up to 4.5-6 σ at the lowest redshifts, providing robust constraints on the radial Alcock-Paczyński parameter (a proxy for the Hubble parameter). On the other hand, the corresponding perpendicular parameter remains unconstrained and prior dominated due to beam effects.

BAO from HI intensity mapping: The role of multipoles and cross-correlations / Rubiola, Andrea Maria. - In: IL NUOVO CIMENTO C. - ISSN 2037-4909. - 2023, 46:4(2023), p. 124. [10.1393/ncc/i2023-23124-8]

BAO from HI intensity mapping: The role of multipoles and cross-correlations

Rubiola, Andrea Maria
2023-01-01

Abstract

A standard ruler akin in application to standard candles, Baryon Acoustic Oscillations (BAO) are a main feature of the matter power spectrum, depending on fundamental quantities cosmologists are striving to measure. The SKA Observatory (SKAO) will look for their signal in the post-reionisation universe via neutral hydrogen Intensity Mapping, a task made challenging by astrophysical foregrounds and resolution limitations. To tackle these issues, we investigate the results emerging from the multipole expansion approach as a mitigation of such limitations and we showcase the gains made from cross-correlating the HI intensity mapping with spectroscopic galaxy observations. This is to be intended as an anticipation of future synergies between the SKAO Project and LSS Stage 4- or DESI-like instruments. Adding then the information from the quadrupole term allows for a detection of the BAO feature up to 4.5-6 σ at the lowest redshifts, providing robust constraints on the radial Alcock-Paczyński parameter (a proxy for the Hubble parameter). On the other hand, the corresponding perpendicular parameter remains unconstrained and prior dominated due to beam effects.
2023
4
Rubiola, Andrea Maria
BAO from HI intensity mapping: The role of multipoles and cross-correlations / Rubiola, Andrea Maria. - In: IL NUOVO CIMENTO C. - ISSN 2037-4909. - 2023, 46:4(2023), p. 124. [10.1393/ncc/i2023-23124-8]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/406889
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