Running summarizing tools on a new article

Abstract: Gaia-4b is the first confirmed exoplanet discovered with Gaia astrometry, based on its identification as a possible exoplanet in the solution in Gaia Data Release 3 and subsequent confirmation with radial velocity. In this work we present a \texttt{python} framework called \texttt{pyGaiafits} that can jointly analyze astrometric time series and radial velocities. We use this to combine the precise along-scan astrometric time series for Gaia-4 from the Gaia DR4 pre-release with 44 radial velocities (RVs) obtained over three years from four independent spectrographs (HPF, HARPS-N, NEID, and FIES). By jointly fitting these two complementary datasets that collectively span a 12-year baseline ($\sim$7 orbital periods of Gaia-4b), we refine the system parameters and determine the true mass of Gaia-4b to be $10.70\pm0.32$~$M_J$. Critically, we do not find significant evidence for the long-term quadratic RV trend previously reported in the literature, recovering $\ddotγ = 5.5^{+8.3}_{-6.7}\;\mathrm{m\,s^{-1}\,yr^{-2}}$ consistent with zero. We discuss how this discrepancy likely arises from a degeneracy between orbital period and long-term trends when RVs span only $\sim$1.5 orbital cycles --- a degeneracy that is broken by anchoring the ephemeris with early Gaia astrometry.