Paper: Quasar-driven outflows do not cause rapid in-situ quenching of star formation

Jan Scholtz, former PhD student of Chris Harrison, has published his paper re-assessing the insitu impact of ionised outflows (driven by three z~2.5 quasars) on the star formation in their host galaxies. The paper has been accepted by MNRAS and is available on the arXiv:2106.05277.

The paper uses spatially-resolved measurements of the dust distribution (using sub-mm interferometric data from ALMA) and the ionised gas properties (using integral field spectroscopic data from SINFONI). The three quasars under investigation were of particular interest due to previous claims (using only SINFONI data) of strong evidence that the star formation was suppressed at the location of the galaxy-wide ionised outflows. However, the new evidence from ALMA suggests that dusty-star formation is still ongoing at the locations of the outflows, in at least two of these targets. Nonetheless, compared to regular star-forming galaxies at the same redshift, and with the same mass, their star formation rates appear to be low. This might mean the impact by the quasar driven outflows on the host galaxy, is not a rapid shut down of star formation, but star formation could be suppressed on longer timescales by the cumulative effect of quasar episodes during the growth of these massive black holes. This all adds to helping solve the mystery of how quasars change the life of galaxies!