A 25 $\rm deg^2$ region, including the M81 complex (M81, M82, NGC 3077), NGC2976 and IC2574, was mapped during ~3000 hours with the DRAO synthesistelescope. With a physical resolution of ~1 kpc, these observations allow us toprobe a large region down to column density levels of ~$\rm 1\times10^{18}\,cm^{-2}$ over 16 $\rm km\, s^{-1}$, mapping the extent of the HI arm connectingthe system and NGC 2976, and resolving the HI clouds adjacent to the arm. Theobservations also reveal a few clouds located between the system and IC 2574,probably tidally stripped from a past interaction between the two systems.Given the regular velocity distribution in the HI envelope of the system, weattempt and derive an idealised large-scale rotation curve of the system. Weobserve a flat trend for the rotation velocity of the overall system from 20kpc out to 80 kpc, well beyond the outskirts of the M81 disk, although withasymmetries like a wiggle at the vicinity of M82. This supports the assumptionthat intergalactic gas and galaxies in the system participate to a large-scaleordered rotation motion which is dominated by M81. Also, our HI analysis of thegroup further supports the hypothesis that the galaxies forming the systemmoved closer from afar, in agreement with numerical simulations.

We present high angular resolution (0.3" or 37 pc) Atacama LargeMillimeter/sub-millimeter Array (ALMA) observations of the CO(2-1) lineemission from a central disc in the early-type galaxy NGC 524. This disc isshown to be dynamically relaxed, exhibiting ordered rotation about a compact1.3mm continuum source, which we identify as emission from an activesupermassive black hole (SMBH). There is a hole at the centre of the discslightly larger than the SMBH sphere of influence. An azimuthal distortion ofthe observed velocity field is found to be due to either a position angle warpor radial gas flow over the inner 2.5". By forward-modelling the observations,we obtain an estimate of the SMBH mass of$4.0^{+3.5}_{-2.0}\times10^8\,\mathrm{M_\odot}$, where the uncertainties are atthe $3\sigma$ level. The uncertainties are dominated by the poorly constrainedinclination and the stellar mass-to-light ratio of this galaxy, and ourmeasurement is consistent with the established correlation between SMBH massand stellar velocity dispersion. Our result is roughly half that of theprevious stellar dynamical measurement, but is consistent within theuncertainties of both. We also present and apply a new tool for modellingcomplex molecular gas distributions.

Recent simulations predict that the presence of stellar bulge suppress theefficiency of star formation in early-type galaxies, and this `morphologicalquenching' scenario is supported by many observations. In this study, wediscuss the net effect of galaxy morphologies on the star formation efficiency(SFE) during the phase of galaxy transition, on the basis of our CO($J=1-0$)observations of 28 local `green-valley' galaxies with the Nobeyama 45m RadioTelescope. We observed 13 `disk-dominated' and 15 `bulge-dominated'green-valley galaxies at fixed stellar mass ($M_*$) and star formation rate(SFR), supplemented by 1 disk- and 6 bulge-dominated galaxies satisfying thesame criteria from the xCOLD~GASS survey. By using a total of 35 green-valleygalaxies, we reveal that the distributions of molecular gas mass, molecular gasfraction, and SFE of green-valley galaxies do not change with theirmorphologies, suggesting little impact of galaxy morphologies on their SFE, andinterestingly this result is also valid for normal star-forming galaxies on theSF main-sequence selected from the xCOLD~GASS galaxies. On the other hand, wefind that $\sim$20 % of bulge-dominated green-valley galaxies do not showsignificant CO emission line, showing high SFEs for their M$_*$ and SFR. Thesemolecular gas deficient sources identified only in the bulge-dominatedgreen-valley galaxies may represent an important population during thequenching phase under the influence of stellar bulge, but our results suggestthat the presence of stellar bulge does not decrease the efficiency of on-goingstar formation, in contrast to the prediction of the morphological quenchingscenario.