The formation of two stellar bars within a galaxy has proved challenging fornumerical studies. It is yet not clear whether the inner bar is born via a starformation process promoted by gas inflow along the outer bar, or whether it isdynamically assembled from instabilities in a small-scale stellar disc.Observational constraints to these scenarios are scarce. We present a thoroughstudy of the stellar content of two double-barred galaxies observed by the MUSETIMER project, NGC 1291 and NGC 5850, combined with a two-dimensionalmulti-component photometric decomposition performed on the 3.6{\mu}m imagesfrom S4G. Our analysis confirms the presence of {\sigma}-hollows appearing inthe stellar velocity dispersion distribution at the ends of the inner bars.Both galaxies host inner discs matching in size with the inner bars, suggestiveof a dynamical formation for the inner bars from small-scale discs. Theanalysis of the star formation histories for the structural components shapingthe galaxies provides constraints on the epoch of dynamical assembly of theinner bars, which took place >6.5 Gyr ago for NGC 1291 and >4.5 Gyr ago for NGC5850. This implies that inner bars are long-lived structures.

We present Hubble Space Telescope (HST) observations of the low surfacebrightness (SB) galaxy Coma P. This system was first discovered in the AreciboLegacy Fast ALFA HI survey and was cataloged as an (almost) dark galaxy becauseit did not exhibit any obvious optical counterpart in the available survey data(e.g., Sloan Digital Sky Survey). Subsequent WIYN pODI imaging revealed anultra-low SB stellar component located at the center of the HI detection. Weuse the HST images to produce a deep color-magnitude diagram (CMD) of theresolved stellar population present in Coma P. We clearly detect a red stellarsequence that we interpret to be a red giant branch, and use it to infer a tipof the red giant branch (TRGB) distance of 5.50$^{+0.28}_{-0.53}$ Mpc. The newdistance is substantially lower than earlier estimates and shows that Coma P isan extreme dwarf galaxy. Our derived stellar mass is only 4.3 $\times$ 10$^5$$M_\odot$, meaning that Coma P has an extreme HI-to-stellar mass ratio of 81.We present a detailed analysis of the galaxy environment within which Coma Presides. We hypothesize that Coma P formed within a local void and has spentmost of its lifetime in a low-density environment. Over time, the gravitationalattraction of the galaxies located in the void wall has moved it to the edge,where it had a recent "fly-by" interaction with M64. We investigate thepossibility that Coma P is at a farther distance and conclude that theavailable data are best fit by a distance of 5.5 Mpc.

As part of a large Hubble Space Telescope investigation aiming at reachingthe faintest stars in the Galactic globular cluster NGC 6752, an ACS/WFC fieldwas the subject of deep optical observations reaching magnitudes as faint asV~30. In this field we report the discovery of Bedin I a dwarf spheroidalgalaxy too faint and too close to the core of NGC 6752 for detection in earliersurveys. As it is of broad interest to complete the census of galaxies in thelocal Universe, in this Letter we provide the position of this new object alongwith preliminary assessments of its main param eters. Assuming the samereddening as for NGC 6752, we estimate a distance modulus of (m-M)_0 =29.70+/-0.13 from the observed red giant branch, i.e., 8.7 (+0.5 -0.7) Mpc, andsize of ~840x340pc, about 1/5 the size of the LMC. A comparison of the observedcolour-magnitude diagram with synthetic counterparts that account for thegalaxy distance modulus, reddening and photometric errors, suggests thepresence of an old (~13Gyr) and metal poor ([Fe/H]~-1.3) population. Thisobject is most likely a relatively isolated satellite dwarf spheroidal galaxyof the nearby great spiral NGC 6744, or potentially the most distant isolateddwarf spheroidal known with a secure distance.

We present observations of 50 pairs of redshift z ~ 0.2 star-forming galaxiesand background quasars. These sightlines probe the circumgalactic medium (CGM)out to half the virial radius, and we describe the circumgalactic gaskinematics relative to the reference frame defined by the galactic disks. Wedetect halo gas in MgII absorption, measure the equivalent-width-weightedDoppler shifts relative to each galaxy, and find that the CGM has a componentof angular momentum that is aligned with the galactic disk. No netcounter-rotation of the CGM is detected within 45 degrees of the major axis atany impact parameter. The velocity offset of the circumgalactic gas correlateswith the projected rotation speed in the disk plane out to disk radii ofroughly 70 kpc. We confirm previous claims that the MgII absorption becomesstronger near the galactic minor axis and show that the equivalent widthcorrelates with the velocity range of the absorption. We cannot directlymeasure the location of any absorber along the sightline, but we explore thehypothesis that individual velocity components can be associated with gasorbiting in the disk plane or flowing radially outward in a conical outflow. Weconclude that centrifugal forces partially support the low-ionization gas andgalactic outflows kinematically disturb the CGM producing excess absorption.Our results firmly rule out schema for the inner CGM that lack rotation andsuggest that angular momentum as well as galactic winds should be included inany viable model for the low-redshift CGM.

We constrain gas inflow speeds in several star-forming galaxies having colorgradients consistent with inside-out disk growth. Our method combines newmeasurements of disk orientation with previously described circumgalacticabsorption in background quasar spectra. Two quantities, a position angle andan axis ratio, describe the projected shape of each galactic disk on the sky,leaving an ambiguity about which side of the minor axis is tipped toward theobserver. This degeneracy regarding the 3D orientation of disks has compromisedprevious efforts to measure gas inflow speeds. We present HST and Keck/LGSAOimaging that resolves spiral structure in redshift $z\approx0.2$ galaxies. Wethen determine the sign of the disk inclination, under the assumption that thespiral arms trail the rotation. Using the measured rotation curve, we thenmodel the projection of both radial infall in the disk plane and circularorbits onto each quasar sightline. We compare the resulting line-of-sightvelocities to the observed velocity range of Mg II absorption in quasarspectra. We find maximum radial inflow speeds of 30-40 km s$^{-1}$ in twosightlines. We also rule out a velocity component from radial inflow in onesightline, suggesting that the structures feeding gas to these disks do nothave unity covering factor (even within 30$^{\circ}$ of the major axis and lowimpact parameters). We recommend appropriate selection criteria for buildinglarger samples of galaxy -- quasar pairs that produce orientations sensitive toconstraining inflow properties.

We use the MusE GAs FLOw and Wind (MEGAFLOW) survey to study the kinematicsof extended disk-like structures of cold gas around $z\approx1$ star-forminggalaxies. The combination of VLT/MUSE and VLT/UVES observations allows us toconnect the kinematics of the gas measured through MgII quasar absorptionspectroscopy to the kinematics and orientation of the associated galaxiesconstrained through integral field spectroscopy. Confirming previous results,we find that the galaxy-absorber pairs of the MEGAFLOW survey follow a strongbimodal distribution, consistent with a picture of MgII absorption beingpredominantly present in outflow cones and extended disk-like structures. Thisallows us to select a bona-fide sample of galaxy-absorber pairs probing thesedisks for impact parameters of 10-70 kpc. We test the hypothesis that thedisk-like gas is co-rotating with the galaxy disks, and find that for 7 out of9 pairs the absorption velocity shares the sign of the disk velocity,disfavouring random orbits. We further show that the data are roughlyconsistent with inflow velocities and angular momenta predicted by simulations,and that the corresponding mass accretion rates are sufficient to balance thestar formation rates.