J-PLUS: Tomographic analysis of galaxy angular density and redshift fluctuations in Data Release 3. Constraints on photo-\(z\) errors, linear bias, and peculiar velocities

The Javalambre Photometric Local Universe Survey (J-PLUS) is a spectro-photometricsurvey covering about 3,000~deg\(^2\) in its third data release (DR3), and containing about 300,000 galaxies with high quality ({\it odds}\(>0.8\)) photometric redshifts (hereafter photo-\(z\)s). We use this galaxy sample to conduct a tomographic study of the counts and redshift angular fluctuations under Gaussian shells sampling the redshift range \(z\in[0.05,0.25]\). We confront the angular power spectra of these observables measured under shells centered on 11 different redshifts with theoretical expectations derived from a linear Boltzmann code ({\tt ARFCAMB}). Overall we find that J-PLUS DR3 data are well reproduced by our linear, simplistic model. We obtain that counts (or density) angular fluctuations (hereafter ADF) are very sensitive to the linear galaxy bias \(b_g(z)\), although weakly sensitive to radial peculiar velocities of the galaxy field, while suffering from systematics residuals for \(z>0.15\). Angular redshift fluctuations (ARF), instead, show higher sensitivity to radial peculiar velocities and also higher sensitivity to the average uncertainty in photo-\(z\)s (\(\sigma_{\rm Err}\)), with no obvious impact from systematics. For \(z<0.15\) both ADF and ARF agree on measuring a monotonically increasing linear bias varying from \(b_g(z=0.05)\simeq 0.9\pm 0.06\) up to \(b_g(z=0.15)\simeq 1.5\pm 0.05\), while, by first time, providing consistent measurements of \(\sigma_{\rm Err}(z)\sim 0.014\) that are \(\sim 40~\%\) higher than estimates from the photo-\(z\) code {\tt LePhare}, (\(\sigma_{\rm Err}^{\rm LePhare}=0.010\)). As expected, this photo-\(z\) uncertainty level prevents the detection of radial peculiar velocities in the modest volume sampled by J-PLUS DR3, although prospects for larger galaxy surveys of similar (and higher) photo-\(z\) precision are promising.