Complex AGN feedback in the Teacup galaxy A powerful ionised galactic outflow, jet-ISM interaction, and evidence forAGN-triggered star formation in a giant bubble

Context. The z similar to 0.1 type-2 QSO J1430+1339, known as the "Teacup", is a complex galaxy showing a loop of ionised gas similar to 10 kpc in diameter, co-spatial radio bubbles, a compact (similar to 1 kpc) jet, and outflow activity. Its closeness offers the opportunity to study in detail the intricate interplay between the central supermassive black hole (SMBH) and the material in and around the galaxy, both the interstellar medium (ISM) and circumgalactic medium (CGM). Aims. We characterise the spatially resolved properties and effects of the galactic ionised gas outflow and compare them with those of the radio jet and with theoretical predictions to infer its acceleration mechanism. Methods. We used VLT/MUSE optical integral field spectroscopic observations to obtain flux, kinematic, and excitation maps of the extended (up to similar to 100 kpc) ionised gas and to characterise the properties of stellar populations. We built radial profiles of the outflow properties as a function of distance from the active nucleus, from kiloparsec up to tens of kiloparsec scales, at similar to 1 kpc resolution. Results. We detect a velocity dispersion enhancement (greater than or similar to 300 km s(-1)) elongated over several kiloparsecs perpendicular to the radio jet, the active galactic nucleus (AGN) ionisation lobes, and the fast outflow, similar to what is found in other galaxies hosting compact, low-power jets, indicating that the jet strongly perturbs the host ISM during its passage. We observe a decreasing trend with distance from the nucleus for the outflow properties (mass outflow rate, kinetic rate, momentum rate). The mass outflow rate drops from around 100 M-circle dot yr(-1) in the inner 1-2 kpc to less than or similar to 0.1 M-circle dot yr(-1) at 30 kpc. The mass outflow rate of the ionised outflow is significantly higher (similar to 1-8 times) than the molecular one, in contrast with what is often quoted in AGN. Based on energetic and morphological arguments, the driver of the multi-phase outflow is likely a combination of AGN radiation and the jet, or AGN radiation pressure on dust alone. The outflow mass-loading factor is similar to 5-10 and the molecular gas depletion time due to the multi-phase outflow is less than or similar to 10(8) yr, indicating that the outflow can significantly affect the star formation and the gas reservoir in the galaxy. However, the fraction of the ionised outflow that is able to escape the dark matter halo potential is likely negligible. We detect blue-coloured continuum emission co-spatial with the ionised gas loop. Here, stellar populations are younger (less than or similar to 100-150 Myr) than in the rest of the galaxy (similar to 0.5-1 Gyr). This constitutes possible evidence for star formation triggered at the edge of the bubble due to the compressing action of the jet and outflow ("positive feedback"), as predicted by theory. All in all, the Teacup constitutes a rich system in which AGN feedback from outflows and jets, in both its negative and positive flavours, co-exist.