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Given the limited availability of direct evidence (pre-explosion observations) for supernova (SN) progenitors, the location of supernovae (SNe) within their host galaxies can be used to set limits on one of their most fundamental characteristics, their initial progenitor mass. We present our constraints on SN progenitors derived by comparing the radial distributions of 80 SNe in the SINGG and SUNGG surveys to the R-band, Halpha, and UV light distributions of the 55 host galaxies. The strong correlation of Type Ia SNe with R-band light is consistent with models containing only low mass progenitors, reflecting earlier findings. When we limit the analysis of Type II SNe to apertures containing 90 per cent of the total flux, the radial distribution of these SNe best traces far ultraviolet (FUV) emission, consistent with recent direct detections indicating Type II SNe have moderately massive red supergiant progenitors. Stripped Envelope (SE) SNe have the strongest correlation with Halpha fluxes, indicative of very massive progenitors (M* > 20 M_solar). This result contradicts a small, but growing, number of direct detections of SE SN progenitors indicating they are moderately massive binary systems. Our result is consistent, however, with a recent population analysis suggesting binary SE SN progenitor masses are regularly underestimated. SE SNe are centralised with respect to Type II SNe and there are no SE SNe recorded beyond half the maximum disc radius in the optical and one third the disc radius in the ultraviolet. The absence of SE SNe beyond these distances is consistent with reduced massive star formation efficiencies in the outskirts of the host galaxies., Comment: 17 pages

For the first time both H$\alpha$ and far-ultraviolet (FUV) observations from an HI-selected sample are used to determine the dust-corrected star formation rate density (SFRD: $\dot{\rho}$) in the local Universe. Applying the two star formation rate indicators on 294 local galaxies we determine log($\dot{\rho}$$ _{H\alpha}) = -1.68~^{+0.13}_{-0.05}$ [M$_{\odot} $ yr$^{-1} $ Mpc$^{-3}]$ and log($\dot{\rho}_{FUV}$) $ = -1.71~^{+0.12}_{-0.13}$ [M$_\odot $ yr$^{-1} $ Mpc$^{-3}]$. These values are derived from scaling H$\alpha$ and FUV observations to the HI mass function. Galaxies were selected to uniformly sample the full HI mass (M$_{HI}$) range of the HI Parkes All-Sky Survey (M$_{HI} \sim10^{7}$ to $\sim10^{10.7}$ M$_{\odot}$). The approach leads to relatively larger sampling of dwarf galaxies compared to optically-selected surveys. The low HI mass, low luminosity and low surface brightness galaxy populations have, on average, lower H$\alpha$/FUV flux ratios than the remaining galaxy populations, consistent with the earlier results of Meurer. The near-identical H$\alpha$- and FUV-derived SFRD values arise with the low H$\alpha$/FUV flux ratios of some galaxies being offset by enhanced H$\alpha$ from the brightest and high mass galaxy populations. Our findings confirm the necessity to fully sample the HI mass range for a complete census of local star formation to include lower stellar mass galaxies which dominate the local Universe., Comment: 17 pages, 7 figures

HI-Selected galaxies obey a linear relationship between their maximum detected radius Rmax and rotational velocity. This result covers measurements in the optical, ultraviolet, and HI emission in galaxies spanning a factor of 30 in size and velocity, from small dwarf irregulars to the largest spirals. Hence, galaxies behave as clocks, rotating once a Gyr at the very outskirts of their discs. Observations of a large optically-selected sample are consistent, implying this relationship is generic to disc galaxies in the low redshift Universe. A linear RV relationship is expected from simple models of galaxy formation and evolution. The total mass within Rmax has collapsed by a factor of 37 compared to the present mean density of the Universe. Adopting standard assumptions we find a mean halo spin parameter lambda in the range 0.020 to 0.035. The dispersion in lambda, 0.16 dex, is smaller than expected from simulations. This may be due to the biases in our selection of disc galaxies rather than all halos. The estimated mass densities of stars and atomic gas at Rmax are similar (~0.5 Msun/pc^2) indicating outer discs are highly evolved. The gas consumption and stellar population build time-scales are hundreds of Gyr, hence star formation is not driving the current evolution of outer discs. The estimated ratio between Rmax and disc scale length is consistent with long-standing predictions from monolithic collapse models. Hence, it remains unclear whether disc extent results from continual accretion, a rapid initial collapse, secular evolution or a combination thereof., Comment: 14 pages, 7 figures, 3 in colour. Published in MNRAS. This v2 corrects wrong journal in the references section (all instances of "Astrophysics and Space Sciences" should have been ApJ). The Posti+2017 has also been updated. An erratum has been submitted to MNRAS