Study of UV line and continuum variabilities in the Broadline Seyfert 1 Galaxy ESO 141-G55

TL;DR

This study analyzes three years of UV observations of Seyfert 1 galaxy ESO 141-G55, revealing significant variability in UV continuum and lines, with delays indicating the outer accretion disc as a potential origin.

Contribution

It provides detailed modeling of UV spectra and measures time delays between continuum and line variability, suggesting the outer accretion disc as the UV line emission site.

Findings

UV continuum and line fluxes vary significantly over 3 years.

Ionized UV lines show delays of 2.92 to 4.41 days relative to continuum.

Outer accretion disc at ~0.004c may produce UV lines.

Abstract

We present the results from a 3-year-long Ultraviolet monitoring campaign of the broad line Seyfert 1 galaxy ESO 141-G55 using International Ultraviolet Explorer (IUE). By modelling all individual, extinction-corrected UV spectra in 1150-1978 A and 1850-3348 A wavelength range, we have observed a significant variability in both UV continuum and line fluxes. Variabilities due to ionised UV lines like SiIV, CIV and HeII are delayed with respect to the UV continuum by 2.92$^{+0.54}_{-0.61}$, 4.41$^{+0.44}_{-0.54}$, 4.11$^{+0.35}_{-0.81}$ days, respectively. At a distance of $\sim$0.004c, an outer accretion disc can be a possible site for the origin of UV lines.