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We present spatially resolved Echelle spectroscopy of an intervening Mg  ii –Fe  ii –Mg  i absorption-line system detected at z abs = 0.73379 towards the giant gravitational arc PSZ1 G311.65–18.48. The absorbing gas is associated with an inclined disc-like star-forming galaxy, whose major axis is aligned with the two arc-segments reported here. We probe in absorption the galaxy's extended disc continuously, at ≈3 kpc sampling, from its inner region out to 15× the optical radius. We detect strong (⁠|$W_0^{2796}\gt 0.3$| Å) coherent absorption along 13 independent positions at impact parameters D  = 0–29 kpc on one side of the galaxy, and no absorption at D  = 28–57 kpc on the opposite side (all de-lensed distances at z abs). We show that (1) the gas distribution is anisotropic; (2) |$W_0^{2796}$|⁠ , |$W_0^{2600}$|⁠ , |$W_0^{2852}$|⁠ , and the ratio |$W_0^{2600}\!/W_0^{2796}$|⁠ , all anticorrelate with D ; (3) the |$W_0^{2796}$| – D relation is not cuspy and exhibits significantly less scatter than the quasar-absorber statistics; (4) the absorbing gas is co-rotating with the galaxy out to D ≲ 20 kpc, resembling a 'flat' rotation curve, but at D ≳ 20 kpc velocities decline below the expectations from a 3D disc-model extrapolated from the nebular [O  ii ] emission. These signatures constitute unambiguous evidence for rotating extra-planar diffuse gas, possibly also undergoing enriched accretion at its edge. Arguably, we are witnessing some of the long-sought processes of the baryon cycle in a single distant galaxy expected to be representative of such phenomena. [ABSTRACT FROM AUTHOR]

Galactic outflows regulate the amount of gas galaxies convert into stars. However, it is difficult to measure the mass outflows remove because they span a large range of temperatures and phases. Here, we study the rest-frame ultraviolet spectrum of a lensed galaxy at ɀ ~ 2.9 with prominent interstellar absorption lines from OI, tracing neutral gas, up to OVI, tracing transitional phase gas. The OVI profile mimics weak low-ionization profiles at low velocities, and strong saturated profiles at high velocities. These trends indicate that OVI gas is co-spatial with the low-ionization gas. Further, at velocities blueward of -200 km s-1 the column density of the low-ionization outflow rapidly drops while the OVI column density rises, suggesting that OVI is created as the low-ionization gas is destroyed. Photoionization models do not reproduce the observed OVI, but adequately match the low-ionization gas, indicating that the phases have different formation mechanisms. Photoionized outflows are more massive than OVI outflows for most of the observed velocities, although the OVI mass outflow rate exceeds the photoionized outflow at velocities above the galaxy's escape velocity. Therefore, most gas capable of escaping the galaxy is in a hot outflow phase. We suggest that the OVI absorption is a temporary by-product of conduction transferring mass from the photoionized phase to an unobserved hot wind, and discuss how this mass-loading impacts the observed circum-galactic medium. [ABSTRACT FROM AUTHOR]

ABSTRACT We present Hubble Space Telescope/Wide Field Camera 3 narrow-band imaging of the Hα emission in a sample of eight gravitationally lensed galaxies at z = 1-1.5. The magnification caused by the foreground clusters enables us to obtain a median source plane spatial resolution of 360 pc, as well as providing magnifications in flux ranging from ∼10× to ∼50×. This enables us to identify resolved star-forming H ii regions at this epoch and therefore study their Hα luminosity distributions for comparisons with equivalent samples at z ∼ 2 and in the local Universe. We find evolution in the both luminosity and surface brightness of H ii regions with redshift. The distribution of clump properties can be quantified with an H ii region luminosity function, which can be fit by a power law with an exponential break at some cut-off, and we find that the cut-off evolves with redshift. We therefore conclude that 'clumpy' galaxies are seen at high redshift because of the evolution of the cut-off mass; the galaxies themselves follow similar scaling relations to those at z = 0, but their H ii regions are larger and brighter and thus appear as clumps which dominate the morphology of the galaxy. A simple theoretical argument based on gas collapsing on scales of the Jeans mass in a marginally unstable disc shows that the clumpy morphologies of high- z galaxies are driven by the competing effects of higher gas fractions causing perturbations on larger scales, partially compensated by higher epicyclic frequencies which stabilize the disc. [ABSTRACT FROM AUTHOR]

We describe two peculiar galaxies falling into the massive galaxy clusters Abell 1689 and Abell 2667 , respectively. Hubble Space Telescope ( HST) images show extraordinary trails composed of bright blue knots and stellar streams associated with each of these systems. Combining optical, near- and mid-infrared and radio observations we prove that while both galaxies show similar extended trails of star-forming knots, their recent star formation histories are different. One is experiencing a strong burst of star formation, appearing as a rare example of a luminous infrared cluster galaxy. In comparison, the other has recently ceased its star formation activity. Our model suggests that the morphologies and star formation in these galaxies have been influenced by the combined action of tidal interaction (likely with the cluster potential) and of ram pressure with the intracluster medium (ICM). These results can be used to gain more insights to the origin of S0s, dwarf and ultracompact dwarf (UCD) cluster galaxies. [ABSTRACT FROM AUTHOR]