An extremely bright X-ray flare was detected from PDS 456 in September 2018. Based on observations, it showed a flux increase by a factor 4, including its time-scale doubling and a high level of flare energy, exceeding 1051erg. In addition, PDS 456 also displayed X-ray emission hardening following the flare. Radio images by very long baseline interferometry (VLBI) found PDS 456 has a complex nucleus described to be radio-emitting, an extended structure and a jet.
In 2019, observations by the Atacama Large Millimeter Array (ALMA) found PDS 456 to contain kiloparsec-scale molecular outflows. The molecular outflows are estimated to have a mass of 2.5 × 108M☉ while a value of 290 M☉ yr−1 was calculated for its outflow mass rate. Given its short depletion time, it is estimated the star-formation in PDS 456 would be quenched.
Additionally, disk wind from the accretion disk and signatures of highly ionized gas detected via X-ray broadband spectra of PDS 456, was also present. A supermassive black hole mass of 109.2±0.2 M☉ was estimated for the object.
↑Hamann, Fred; Chartas, George; Reeves, James; Nardini, Emanuele (2018-01-17), "Does the X-ray outflow quasar PDS 456 have a UV outflow at 0.3c?", Monthly Notices of the Royal Astronomical Society, 476: 943–953, arXiv:1801.04302, doi:10.1093/mnras/sty043
↑Nardini, E.; Reeves, J. N.; Gofford, J.; Harrison, F. A.; Risaliti, G.; Braito, V.; Costa, M. T.; Matzeu, G. A.; Walton, D. J. (2015-02-23), "Black hole feedback in the luminous quasar PDS 456", Science, 347 (6224): 860–863, arXiv:1502.06636, Bibcode:2015Sci...347..860N, doi:10.1126/science.1259202