Feeding and feedback in dwarf galaxies (FeeD) I. Evidence of nuclear ultra-fast and galaxy-scale outflows in the dwarf galaxy Arp 151

Abstract

Feeding and feedback regulated by supermassive black holes play a central role in galaxy growth and evolution, yet these processes remain poorly understood in low-mass galaxies. In particular, the presence, properties, and role of nuclear ultra-fast outflows (UFOs) in low-mass galaxy systems are largely unexplored. We analyzed available NuSTAR X-ray observations of Arp 151 and find possible evidence (∼2σ confidence) of a fast outflow with a velocity of ∼0.18c from the central black hole. Furthermore, we have detected an optical galaxy-scale outflow in MaNGA integral field unit data. The estimated nuclear and galaxy-scale mass outflow rates are ∼0.015 M⊙/yr from NuSTAR and ∼0.43 M⊙/yr from MaNGA, respectively. Our estimates suggest that such outflows may significantly regulate the feedback process in the galaxy. A comparison of the kinetics of the UFO and the galaxy-scale outflow indicates that they are in the momentum-conserving phase. This tentative discovery implies that dwarf galaxies are also able to generate UFOs, which so far have been detected in massive galaxies. Thus, the active galactic nucleus feedback may also be important for the evolution of the dwarf galaxies.