Supernova driven winds are often invoked to remove chemically enriched gasfrom dwarf galaxies to match their low observed metallicities. In such shallowpotential wells, outflows may produce massive amounts of enriched halo gas(circum-galactic medium or CGM) and pollute the intergalactic medium (IGM).Here, we present a survey of the CGM and IGM around $18$ star-forming fielddwarfs with stellar masses of $\log\,M_*/M_\odot\approx8-9$ at $z\approx0.2$.Eight of these have CGM probed by quasar absorption spectra at projecteddistances, $d$, less than the host virial radius, $R_{\rm h}$. Ten are probedin the surrounding IGM at $d/R_{\rm h}=1-3$. The absorption measurementsinclude neutral hydrogen, the dominant silicon ions for diffuse cool gas($T\sim10^4$ K; Si II, Si III, and Si IV), moderately ionized carbon (C IV),and highly ionized oxygen (O VI). Metal absorption from the CGM of the dwarfsis less common and $\approx4\times$ weaker compared to massive star-forminggalaxies though O VI absorption is still common. None of the dwarfs probed at$d/R_{\rm h}=1-3$ have definitive metal-line detections. Combining theavailable silicon ions, we estimate that the cool CGM of the dwarfs accountsfor only $2-6\%$ of the expected silicon budget from the yields of supernovaeassociated with past star-formation. The highly ionized O VI accounts for$\approx8\%$ of the oxygen budget. As O VI traces an ion with expectedequilibrium ion fractions of $\lesssim 0.2$, the highly ionized CGM mayrepresent a significant metal reservoir even for dwarfs not expected tomaintain gravitationally shock heated hot halos.

We study radial profiles in H$\alpha$ equivalent width and specific starformation rate (sSFR) derived from spatially-resolved SDSS-IV MaNGAspectroscopy to gain insight on the physical mechanisms that suppress starformation and determine a galaxy's location in the SFR-$\rm M_\star$ diagram.Even within the star-forming blue cloud, the typical sSFR profile depends onstellar mass. Flat radial profiles are observed for $\rm log(M_\star/M_\odot )< 10.5$, while star-forming galaxies of higher mass show a significant decreasein sSFR in the central regions, a likely consequence of both larger bulges andan inside-out growth history. Our primary focus is the green valley where, atall masses, we find sSFR profiles that are suppressed with respect to normalstar-forming galaxies at all galactocentric distances out to 2 effective radii.The responsible quenching mechanism therefore appears to affect the entiregalaxy, not simply an expanding central region. However, those galaxies inwhich central star formation has shut down (classified spectroscopically ascentral low-ionisation emission-line regions, or cLIERs) show an even strongersuppression in sSFR across the whole disc. These systems are also moresuppressed than green valley galaxies with residual, central star-formation. Infact, compared to structural parameters like $\Sigma_1$ (the mass surfacedensity within 1 kpc), central quiescence is a stronger predictor of ongoingsSFR suppression at fixed $\rm M_\star$. The green valley hosts both quiescentbulges and strongly suppressed star forming discs, supporting a scenario inwhich a slow quenching process affects the entire galaxy, and not just thecentral regions.

We study the spatially-resolved star formation rates of 1494 galaxies in theSDSSIV-MaNGA Survey. Star formation rates are calculated using a two-stepprocess, exploiting H$_\alpha$ in star-forming regions and $D_n4000$ in zonesidentified as AGN/LI(N)ER or lineless according to the BPT diagram. Thisenables a complete view of how radial profiles of specific star formation ratedepend on stellar mass, galaxy structure and environment, providing valuableclues about the nature of both secular and environmental quenching processes.We report on the existence of `Centrally Suppressed' galaxies, which have lowerSSFR in their cores compared to their disks. The profiles of centrallysuppressed and unsuppressed galaxies are distributed in a bimodal way, withvery few galaxies having intermediate profile shapes. Galaxies with largestellar masses and central velocity dispersions are much more likely to becentrally-suppressed than low-mass galaxies, a result linked to theirmorphology and the presence of AGN/LI(N)ER like emission. Centrally suppressedgalaxies also display lower star formation at all radii compared tounsuppressed galaxies. Independent of galaxy type, galaxies identified assatellites in larger dark matter halos have noticeably lower SSFR at outerradii compared to central galaxies. This uniform suppression could be a signalof the stripping of hot gas reservoirs through a process like strangulation. Wefind that satellites are not more likely to be suppressed in their cores thancentrals, indicating that core suppression is an entirely secular process. Wefind no secondary correlation between the local environment density and theprofiles of star formation rate surface density.