Dumusque, X.X.DumusqueCretignier, M.M.CretignierSosnowska, D.D.SosnowskaBuchschacher, N.N.BuchschacherLovis, C.C.LovisPhillips, D. F.D. F.PhillipsPepe, F.F.PepeAlesina, F.F.AlesinaBuchhave, L. A.L. A.BuchhaveBurnier, J.J.BurnierCecconi, M.M.CecconiCegla, H. M.H. M.CeglaCloutier, R.R.CloutierCollier Cameron, A.A.Collier CameronCOSENTINO, RosarioRosarioCOSENTINOGhedina, A.A.GhedinaGonzález, M.M.GonzálezHaywood, R. D.R. D.HaywoodLatham, D. W.D. W.LathamLodi, M.M.LodiLópez-Morales, M.M.López-MoralesMALDONADO PRADO, JesusJesusMALDONADO PRADOMalavolta, L.L.MalavoltaMICELA, GiuseppinaGiuseppinaMICELAMOLINARI, Emilio CarloEmilio CarloMOLINARIMortier, A.A.MortierPérez Ventura, H.H.Pérez VenturaPinamonti, MatteoMatteoPinamontiPORETTI, EnnioEnnioPORETTIRice, K.K.RiceRiverol, L.L.RiverolRiverol, C.C.RiverolSan Juan, J.J.San JuanSégransan, D.D.SégransanSOZZETTI, AlessandroAlessandroSOZZETTIThompson, S. J.S. J.ThompsonUdry, S.S.UdryWilson, T. G.T. G.Wilson2022-05-312022-05-3120210004-6361http://hdl.handle.net/20.500.12386/32125Context. The solar telescope connected to HARPS-N has been observing the Sun since the summer of 2015. Such a high-cadence, long-baseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. On the instrumental side, this data set allowed us to detect sub- m s<SUP>−1</SUP> systematics that needed to be corrected for. <BR /> Aims: The goals of this manuscript are to (i) present a new data reduction software for HARPS-N, (ii) demonstrate the improvement brought by this new software during the first three years of the HARPS-N solar data set, and (iii) release all the obtained solar products, from extracted spectra to precise radial velocities. <BR /> Methods: To correct for the instrumental systematics observed in the data reduced with the current version of the HARPS-N data reduction software (DRS version 3.7), we adapted the newly available ESPRESSO DRS (version 2.2.3) to HARPS-N and developed new optimised recipes for the spectrograph. We then compared the first three years of HARPS-N solar data reduced with the current and new DRS. <BR /> Results: The most significant improvement brought by the new DRS is a strong decrease in the day-to-day radial-velocity scatter, from 1.27 to 1.07 m s<SUP>−1</SUP>; this is thanks to a more robust method to derive wavelength solutions, but also to the use of calibrations closer in time. The newly derived solar radial-velocities are also better correlated with the chromospheric activity level of the Sun in the long term, with a Pearson correlation coefficient of 0.93 compared to 0.77 before, which is expected from our understanding of stellar signals. Finally, we also discuss how HARPS-N spectral ghosts contaminate the measurement of the calcium activity index, and we present an efficient technique to derive an index free of instrumental systematics. <BR /> Conclusions: This paper presents a new data reduction software for HARPS-N and demonstrates its improvements, mainly in terms of radial-velocity precision, when applied to the first three years of the HARPS-N solar data set. Those newly reduced solar data, representing an unprecedented time series of 34 550 high-resolution spectra and precise radial velocities, are released alongside this paper. Those data are crucial to understand stellar activity signals in solar-type stars further and develop the mitigating techniques that will allow us to detect other Earths. <P />The thorium line list discussed in Appendix C and presented in Table C.1 is only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr/">cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/648/A103">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/648/A103</A>STAMPAenArticle10.1051/0004-6361/2020393502-s2.0-85104681159http://arxiv.org/abs/2009.01945v2https://www.aanda.org/articles/aa/full_html/2021/04/aa39350-20/aa39350-20.html2021A&A...648A.103DFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation