We conduct a survey of low surface brightness (LSB) satellite galaxies aroundthe Local Volume massive spirals using long exposures with small amateurtelescopes. We identified 27 low and very low surface brightness objects aroundthe galaxies NGC,672, 891, 1156, 2683, 3344, 4258, 4618, 4631, and 5457situated within 10 Mpc from us, and found nothing new around NGC,2903, 3239,4214, and 5585. Assuming that the dwarf candidates are the satellites of theneighboring luminous galaxies, their absolute magnitudes are in the range of-8.6 > M_B > -13.3, their effective diameters are 0.4-4.7 kpc, and the averagesurface brightness is 26.1 mag/sq arcsec. The mean linear projected separationof the satellite candidates from the host galaxies is 73 kpc. Our spectroscopicobservations of two LSB dwarfs with the Russian 6-meter telescope confirm theirphysical connection to the host galaxies NGC,891 and NGC,2683.

We use a set of high-resolution N-body simulations of the Galactic disk tostudy its interactions with the population of satellites predictedcosmologically. One simulation illustrates that multiple passages of massivesatellites with different velocities through the disk generate a wobble, havingthe appearance of rings in face-on projections of the stellar disk. They alsoproduce flares in the disk outer parts and gradually heat the disk throughbending waves. A different numerical experiment shows that an individualsatellite as massive as the Sagittarius dwarf galaxy passing through the diskwill drive coupled horizontal and vertical oscillations of stars in underdenseregions, with small significant associated heating. This experiment shows thatvertical excursions of stars in these low-density regions can exceed 1 kpc inthe Solar neighborhood, resembling the coherent vertical oscillations recentlydetected locally. They can also induce non-zero vertical streaming motions aslarge as 10-20 km s$^{-1}$, consistent with recent observations in the Galacticdisk. This phenomenon appears as a local ring, with modest associated diskheating.

We present a statistical analysis of the environments of 11 supernovae (SNe)which occurred in 6 nearby galaxies (z $\lesssim$ 0.016). All galaxies wereobserved with MUSE, the high spatial resolution integral field spectrographmounted to the 8m VLT UT4. These data enable us to map the full spatial extentof host galaxies up to $\sim$3 effective radii. In this way, not only can onecharacterise the specific host environment of each SN, one can compare theirproperties with stellar populations within the full range of other environmentswithin the host. We present a method that consists of selecting all HII regionsfound within host galaxies from 2D extinction-corrected H$\alpha$ emissionmaps. These regions are then characterised in terms of their H$\alpha$equivalent widths, star formation rates, and oxygen abundances. Identifying HIIregions spatially coincident with SN explosion sites, we are thus able todetermine where within the distributions of host galaxy e.g. metallicities andages each SN is found, thus providing new constraints on SN progenitorproperties. This initial pilot study using MUSE opens the way for a revolutionin SN environment studies where we are now able to study multiple environmentSN progenitor dependencies using a single instrument and single pointing.

We have obtained high-spatial-resolution spectrophotometric data on severalnearby spiral galaxies with the Southern African Large Telescope (SALT)Fabry-P\'erot interferometer on the Robert Stobie Spectrograph (RSS) as a partof the RSS Imaging spectroscopy Nearby Galaxy Survey (RINGS). We havesuccessfully reduced two tracks of Fabry-P\'erot data for the galaxy NGC 2280to produce a velocity field of the H-alpha line of excited hydrogen. We havemodeled these data with the DiskFit modeling software and found these models tobe in excellent agreement both with previous measurements in the literature andwith our lower-resolution HI velocity field of the same galaxy. Despite thisgood agreement, small regions exist where the difference between the H-alphaand HI velocities is larger than would be expected from typical dispersions. Weinvestigate these regions of high velocity difference and offer possibleexplanations for their existence.

We present a study of spatial variations in the metallicity of old red giantbranch stars in the Andromeda galaxy. Photometric metallicity estimates arederived by interpolating isochrones for over seven million stars in thePanchromatic Hubble Andromeda Treasury (PHAT) survey. This is the firstsystematic study of stellar metallicities over the inner 20 kpc of Andromeda'sgalactic disk. We see a clear metallicity gradient of $-0.020\pm0.004$ dex/kpcfrom $\sim4-20$ kpc assuming a constant RGB age. This metallicity gradient isderived after correcting for the effects of photometric bias and completenessand dust extinction and is quite insensitive to these effects. The unknown agegradient in M31's disk creates the dominant systematic uncertainty in ourderived metallicity gradient. However, spectroscopic analyses of galaxiessimilar to M31 show that they typically have small age gradients that make thissystematic error comparable to the 1$\sigma$ error on our metallicity gradientmeasurement. In addition to the metallicity gradient, we observe an asymmetriclocal enhancement in metallicity at radii of 3-6 kpc that appears to beassociated with Andromeda's elongated bar. This same region also appears tohave an enhanced stellar density and velocity dispersion.

We perform a systematic Bayesian analysis of rotation vs. dispersion support($v_{\rm rot} / \sigma$) in $40$ dwarf galaxies throughout the Local Volume(LV) over a stellar mass range $10^{3.5} M_{\rm \odot} < M_{\star} < 10^8M_{\rm \odot}$. We find that the stars in $\sim 80\%$ of the LV dwarf galaxiesstudied -- both satellites and isolated systems -- are dispersion-supported. Inparticular, we show that $6/10$ *isolated* dwarfs in our sample have $v_{\rmrot} / \sigma < 1.0$. All have $v_{\rm rot} / \sigma \lesssim 2.0$. Theseresults challenge the traditional view that the stars in gas-rich dwarfirregulars (dIrrs) are distributed in cold, rotationally-supported stellardisks, while gas-poor dwarf spheroidals (dSphs) are kinematically distinct inhaving dispersion-supported stars. We see no clear trend between $v_{\rm rot} /\sigma$ and distance to the closest $\rm L_{\star}$ galaxy, nor between $v_{\rmrot} / \sigma$ and $M_{\star}$ within our mass range. We apply the sameBayesian analysis to four FIRE hydrodynamic zoom-in simulations of isolateddwarf galaxies ($10^9 M_{\odot} < M_{\rm vir} < 10^{10} M_{\rm \odot}$) andshow that the simulated *isolated* dIrr galaxies have stellar ellipticities andstellar $v_{\rm rot} / \sigma$ ratios that are consistent with the observedpopulation of dIrrs *and* dSphs without the need to subject these dwarfs to anyexternal perturbations or tidal forces. We posit that most dwarf galaxies formas puffy, dispersion-dominated systems, rather than cold, angularmomentum-supported disks. If this is the case, then transforming a dIrr into adSph may require little more than removing its gas.