Montserrat Villar Martin, Antonio Cabrera Lavers, Andrew Humphrey, Marckelson Silva, Cristina Ramos Almeida, Javier Piqueras, Bjorn Emonts. 2018. A 100 kpc nebula associated with the ‘Teacup’ fading quasar. Monthly Notices of the Royal Astronomical Society 474, 2, 2302-2312 DOI: 10.1093/mnras/stx2911
We report the discovery of an similar to 100 kpc ionized nebula associated with the radio-quiet type 2 quasar (QSO2) nicknamed the ‘Teacup’ (z = 0.085). The giant nebula is among the largest known around active galaxies at any z. We propose that it is part of the circumgalactic medium (CGM) of the QSO2 host, which has been populated with tidal debris by galactic interactions. This rich gaseous medium has been rendered visible due to the illumination by the powerful active nucleus (AGN). Subsolar abundances (similar to 0.5 Z circle dot) are tentatively favoured by AGN photoionization models. We also report the detection of coronal emission (Fe+6) from the NE bubble, at similar to 9 kpc from the AGN. The detection of coronal lines at such large distances from the AGN and the [N II]lambda 6583/H alpha, [S II]lambda lambda 6716,6731/H alpha, [O I]lambda 6300/H alpha optical emission-line ratios of the giant nebula are consistent with the fading quasar scenario proposed by Gagne et al. The fading rate appears to have been faster in the last similar to 46 000 yr. Deep wide field integral field spectroscopy of giant nebulae around powerful AGN such as the ‘Teacup’s’ with instruments such as MUSE on VLT opens up a way to detect and study the elusive material from the CGM around massive active galaxies thanks to the illumination by the luminous AGN.