Speakers
Description
SPHEREx is a full-sky galaxy survey that will launch in early 2025. It will detect ~500 Million galaxies over a redshift range 0 to ~4 with spectro-photometric redshifts. SPHEREx is designed to measure the scale-dependent galaxy bias due to primordial non-Gaussianity on large scales. However, general relativistic effects show a similar scale dependence in the power spectrum and are projected to have similar signal size as non-Gaussianity. Furthermore, typical power spectrum estimators are afflicted by wide-angle effects stemming from the geometry of the curved sky, and these wide-angle effects interact with relativistic effects. To avoid wide-angle effects, we use the spherical Fourier Bessel basis that is the harmonic basis in spherical coordinates, thus having a natural separation of angular and line-of-sight effects. This makes it the ideal basis for measuring large-scale perturbations and relativistic effects. I will present how GR effects such as lensing magnification enter the SFB power spectrum and how it affects the non-Gaussianity measurement, especially with an eye towards the SPHEREx mission.
