Análisis espectro/temporal de la emisión de rayos X de la binaria XTE J1739-285 observada por NuSTAR

SAAVEDRA, ENZO; FOGANTINI, FEDERICO A.; COMBI, J A; GARCÍA, F.; MANCUSO, G C

Congreso; Reunión Anual de la de la Asociación Argentina de Astronomía; 2021

This paper presents the results of the study of the X-ray emission of the low-mass X-ray binary XTE J1739--285 detected with NuSTAR. The source was observed on February 19, 2020 with an exposure time of ≈ 29 ks. Light curves in the energy range 3-79 keV are dominated by persistent emission of ≈ 27 c s-1. They present two type-I X-ray bursts whose maximum intensity reaches ≈ 700 c s-1 and the emission above the continuum can be detected up to ≈ 25 keV. Both bursts have an average decay time of ≈ 50 s. Hardness-intensity diagrams between different energy bands of the bursts present a counter-clockwise evolution, showing histeresis. The spectra of the bursts and the continuum were modelled using a thermally comptonised continuum and a blackbody component. The observed fluxes during the bursts are ≈ 139 % times greater than those measured during the persistent periods. The source reaches an unabsorbed luminosity of the order L* ≈ 1036 erg s-1 during the bursts, assuming a distance of 4 kpc.