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We present an Integral Field Unit survey of 73 galaxy clusters and groups with the VIsible Multi Object Spectrograph on the Very Large Telescope. We exploit the data to determine the H α gas dynamics on kpc scales to study the feedback processes occurring within the dense cluster cores. We determine the kinematic state of the ionized gas and show that the majority of systems (~2/3) have relatively ordered velocity fields on kpc scales that are similar to the kinematics of rotating discs and are decoupled from the stellar kinematics of the brightest cluster galaxy. The majority of the H α flux (>50 per cent) is typically associated with these ordered kinematics and most systems show relatively simple morphologies suggesting they have not been disturbed by a recent merger or interaction. Approximately 20 per cent of the sample (13/73) have disturbed morphologies which can typically be attributed to active galactic nuclei activity disrupting the gas. Only one system shows any evidence of an interaction with another cluster member. A spectral analysis of the gas suggests that the ionization of the gas within cluster cores is dominated by non-stellar processes, possibly originating from the intracluster medium itself. [ABSTRACT FROM AUTHOR]

ABSTRACT We present adaptive optics-assisted K-band integral field spectroscopy of the central cluster galaxy in 2A 0335+096 ( z= 0.0349). The H2 v=1-0 S(1) emission is concentrated in two peaks within 600 pc of the nucleus and fainter but kinematically active emission extends towards the nucleus. The H2 is in a rotating structure which aligns with, and appears to have been accreted from, a stream of Hα emission extending over 14 kpc towards a companion galaxy. The projected rotation axis aligns with the 5 GHz radio lobes. This H2 traces the known 1.2 × 109 M⊙ CO-emitting reservoir; limits on the Brγ emission confirm that the H2 emission is not excited by star formation, which occurs at a rate of less than 1 M⊙ yr−1 in this gas. If its accretion on to the black hole can be regulated whilst star formation remains suppressed, the reservoir could last for at least 1 Gyr; the simultaneous accretion of just ∼5 per cent of the gas could drive a series of active galactic nucleus (AGN) outbursts which offset X-ray cooling in the cluster core for the full ∼1 Gyr. Alternatively, if the regulation is ineffective and the bulk of the H2 accretes within a few orbital periods (25-100 Myr), the resulting 1062 erg outburst would be among the most powerful cluster AGN outbursts known. In either case, these observations further support cold feedback scenarios for AGN heating. [ABSTRACT FROM AUTHOR]

We present VLT-SINFONI K-band integral field spectroscopy of the central galaxies in the cool core clusters A1664, A2204 and PKS 0745−191, to probe the spatio-kinematic properties of the Paα and ro-vibrational H2 line emission. In A1664, the two emission-line velocity systems seen in our previous Hα spectroscopy appear in both Paα and H2 emission, with notable morphological differences. The recession velocity of the red component of Paα increases linearly with decreasing radius, particularly along an 8 kpc filament aligned with the major axis of the underlying galaxy and the cluster X-ray emission. These kinematics are modelled as gravitational free-fall as gas cools rapidly out of the hot phase. In A2204, the gas shows three or four filaments reaching radii of 10 kpc, three of which lie towards ‘ghost bubbles’ seen in X-ray imaging by Sanders et al. For PKS 0745−191, we confirm the twin-arm morphology in the narrow-band images of Donahue et al.; the Paα kinematics suggest rotational motion about an axis aligned with the kiloparsec-scale radio jet; on nucleus, we find an underlying broad Paα component [full width at half-maximum (FWHM) ] and a secondary H2 velocity system redshifted by . The S(3)/Paα ratio is the highest in the most isolated and extended regions where it matches the levels in the NGC 1275 filaments as modelled by Ferland et al. Regions with much lower ratios highlight active star formation and are often kinematically quiescent (FWHM ). Our findings suggest that the three clusters may be captured in different stages of the ‘cold feedback’ cycle of Pizzolato & Soker, with A1664 in a short-lived phase of extreme cooling and star formation prior to an active galactic nucleus (AGN) heating event; PKS 0745−191 in an outburst state with the AGN accreting from a cool gas disc, and A2204 in a later phase in which cool gas is dragged out of the galaxy by the buoyant rise of old radio bubbles. [ABSTRACT FROM AUTHOR]