Um pipeline de redução de dados espectroscópicos para eventos de quilonova

Abstract

This work presents the process of making a pipeline for the reduction of longslit spectroscopic data, acquired with the GMOS instrument of the Gemini Observatory as part of the optical follow-up of kilonovae candidates. The data was acquired as part of an international effort for the detection of the electromagnetic counterpart signal from mergers between compact objects, detected over the third cycle of operations of the LIGO and Virgo observatories. The observations aim to answer some of the open questions on the nature of this kind of event. A fast reduction of the acquired data is extremely important for a quick classification and observation of the early moments after the merger. The pipeline presented here was built on a Pyraf environment, joining Python functions with data reduction commands from the GEMINI IRAF package, to establish an automated reduction process, therefore decreasing the total amount of time for the operation. To guarantee the good quality of the automatic processes, diagnostic figures are made, allowing the identification and correction of eventual problems. The pipeline operated in the reduction of the data acquired by the GMOS during the observation of four candidates to the optical counterpart of the event S200115j, detected in gravitational waves on January 15, 2020. The methods presented in this work were able to establish a homogeneous reduction of this data set, substantially decreasing the total amount of time for the analysis of the observed candidates. The transients did not present the expected spectral features of kilonovae, being related to supernova emissions. Although the observed transients were not confirmed as the optical counterpart of the gravitational wave event, the excellent performance of the pipeline places it as a promising tool for the reduction of forthcoming spectroscopic data from optical follow-up programs with the Gemini/GMOS.