Revisiting the NVSS number count dipole

We present a realistic modeling of the dipole component of the projected sky distribution of NVSS radio galaxies. The modeling relies on mock catalogs generated within the context of $\mathrm{\Lambda }$CDM cosmology, in the linear regime of structure formation. After removing the contribution from the solar motion, the mocks show that the remaining observed signal is mostly (70%) due to structures within $z\lesssim 0.1$. The amplitude of the model signal depends on the bias factor $b$ of the NVSS mock galaxies. For sources with flux density, $S>15\mathrm{m}\mathrm{J}\mathrm{y}$, the bias recipe inferred from higher order moments is consistent with the observed dipole signal at $2.12\sigma$. Flux thresholds above $20\mathrm{m}\mathrm{J}\mathrm{y}$ yield a disagreement close to the $3\sigma$ level. A constant high bias, $b=3$ is needed to mitigate the tension to the $\sim 2.3\sigma$ level.