Databases and web-based software tools for HR-pyPopStar models and MEGASTAR library Mollá Lorente, M. 1 ; García-Vargas, M. 2; Carrasco Licea, E. 3; Mujica Álvarez, E. 2 & Millán-Irigoyen, I. 1 1CIEMAT (Madrid, Spain), 2FRACTAL S.L.N.E. (Madrid, Spain), 3INAOE (Puebla, Mexico) MEGASTAR is a stellar spectral atlas for MEGARA (Multi Espectrógrafo en GTC de Alta Resolución para Astronomía). MEGARA is an optical (3650 – 9750 Å), fiber- fed, medium-high spectral resolution (R = 6000, 12000, 20000) instrument in operation on the GTC 10.4m telescope. The scientific exploitation of MEGARA demanded a stellar-spectra library to interpret galaxy data and to estimate the contribution of the stellar populations. MEGASTAR atlas is focused on the highest resolution setups, HR-R and HR-I, and already has almost 1000 stars (twice spectra) thanks to the filler-type OpenTime obtained up to now in 7 semesters. We have developed a web- based tool and a database that allow working in the project (for MEGASTAR team) and making the observations and products available to the scientific community. MEGASTAR WebApp Functionalities: § Visualization and search of the sources involved in the project (link to the SIMBAD database). § Visualization, search, download and plot the data product files (by using a java tool) of the observations. § Paint a graph of the stars grouped by three ranges of [Fe/H] as follows: all stars of the library, the observed stars of the library or the user stars uploaded by a file. § Download the releases of the reduced star spectra. § Download the statistics files: observations statistics by VPH and by stellar physical parameters. MEGASTAR WebApp Technologies: § Web Servers: Apache and Tomcat § Database: MySQL § Languages: Java, Java Servlets, HTML and JavaScript § Libraries: JFreeChart, Plotly and nom.tam FITS HR-pyPopStar WebApp Functionalities: § Detailed description of the HR-pyPopStar models. § Models Download. § Plot spectra from the HR-pyPopStar Library. § Plot synthetic properties resulting from SSP SEDs. § Combine spectra from the HR-pyPopStar Library. HR-pyPopStar WebApp Technologies: § Web Servers: Apache and Tomcat. § Database: MySQL. § Framework: Google Web Toolkit (GWT). § Languages: Java, Java Servlets, HTML and JavaScript. § Libraries: JFreeChart and nom.tam FITS. HR-pyPopStar model provides a complete set of high resolution (HR) Spectral Energy Distributions (SEDs) of Single Stellar Populations. The model uses the most recent high wavelength-resolution theoretical atmosphere libraries for main sequence, post-AGB/planetary nebulae and Wolf-Rayet stars. The SEDs are given for more than a hundred ages ranging from 0.1 Myr to 13.8 Gyr, four different values of the metallicity (Z = 0.004, 0.008, 0.02 and 0.05), and four different IMFs. We have developed a public web-based software tools and a database to manage HR-pyPopStar models and to make this available to the users community. References: García-Vargas et al. , 2020, MNRAS, 493, 871. DOI: 10.1093/mnras/staa126; Carrasco et al., 2021, MNRAS, 501, 3568. DOI: 10.1093/mnras/staa3704; Mollá et al. 2022, submitted. References: Millán-Irigoyen et al. (2021), MNRAS, 506, 4781. https://doi.org/10.1093/mnras/stab1969