Digital archival spectral data for Seyfert galaxies and their use in conjunction with modern FAI spectral data

Abstract

The paper presents a methodology for the digitization and processing of our own spectral data archive and the results of comparing the obtained data with those of modern observations. An Epson Perfection V850 Pro scanner with optional SilverFast8 software was used to scan photographic films. More than 2,000 archive spectra of Seyfert galaxies obtained in 1970–1990 with the AZT-8 telescope have been scanned to date (resolution 2400 dpi). The work describes the reduction of distortion for the scanned spectra using the program code, created in Python. Our code has been registered on the web service “GitHub” and a link to the code is given in the work. The results of digitization and subsequent spectra processing are presented in the example of the Seyfert galaxy Mrk 3. For the absolute calibration of the early spectra (Jan. 25, 1976) the radiation fluxes in the emission lines of [SII] were used. The lines were measured on the modern spectrogram obtained in 2023 on telescope AZT-8 (Mar. 14, 2023)