TESS exoplanet candidates validated with HARPS archival data. A massive Neptune around GJ143 and two Neptunes around HD23472

We aim at the discovery of new planetary systems by exploiting the transit light curve results from TESS orbital observatory's Sector 1 and 2 observations and validating them with precise Doppler measurements obtained from archival HARPS data. Taking advantage of the reported TESS transit events around GJ143 (TOI 186) and HD23472 (TOI 174) we model their HARPS precise Doppler measurements and derive orbital parameters for these two systems. For the GJ143 system TESS has reported only a single transit, and thus its period is unconstrained from photometry. Our RV analysis of GJ143 reveal the full Keplerian solution of the system, which is consistent with an eccentric planet with a mass almost twice that of Neptune and a period of $P_{\rm b}$ = $35.59_{-0.01}^{+0.01}$ days. Our estimates of the GJ143 b planet are fully consistent with the transit timing from TESS. We confirm the two-planet system around HD23472, which according to our analysis is composed of two Neptune mass planets in a possible 5:3 MMR.