While collisional accumulation is nearly universally accepted as the formation mechanism of rock and ice worlds, the situation regarding gas giant planet formation is more nuanced. Gas accretion by solid cores formed by collisional accumulation is the generally favored mechanism, but observations increasingly suggest that gas disk gravitational instability might explain the formation of at least the massive or wide-orbit gas giant exoplanets. This paper continues a series aimed at refining three-dimensional (3D) hydrodynamical models of disk instabilities, where the handling of the gas thermodynamics is a crucial factor. Boss (2017, 2021) used the beta cooling approximation to calculate 3D models of disks with initial masses of 0.091 M-circle dot extending from 4 to 20 au around 1 M-circle dot protostars. Here we employ 3D flux-limited diffusion (FLD) approximation models of the same disks, in order to provide a superior treatment of disk gas thermodynamics. The new models have quadrupled spatial resolution compared to previous 3D FLD models, in both the radial and azimuthal spherical coordinates, resulting in the highest spatial resolution 3D FLD models to date. The new models continue to support the hypothesis that such disks can form self-gravitating, dense clumps capable of contracting to form gas giant protoplanets, and suggest that the FLD models yield similar numbers of clumps as beta cooling models with beta similar to 1 to similar to 10, including the critical value of beta = 3 for fragmentation proposed by Gammie.

Cook et al. found that iron meteorites have an initial abundance ratio of the short-lived isotope Fe-60 to the stable isotope Fe-56 of Fe-60/Fe-56 similar to (6.4 +/- 2.0) x 10(-7). This appears to require the injection of live Fe-60 from a Type II supernova (SN II) into the presolar molecular cloud core, as the observed ratio is over a factor of 10 times higher than would be expected to be found in the ambient interstellar medium (ISM) as a result of galactic chemical evolution. The supernova triggering and injection scenario offers a ready explanation for an elevated initial Fe-60 level, and in addition provides a physical mechanism for explaining the noncarbonaceous-carbonaceous (NC-CC) dichotomy of meteorites. The NC-CC scenario hypothesizes the solar nebula first accreted material that was enriched in supernova-derived nuclides, and then later accreted material depleted in supernova-derived nuclides. While the NC-CC dichotomy refers to stable nuclides, not short-lived isotopes like Fe-60, the SN II triggering hypothesis provides an explanation for the otherwise unexplained change in nuclides being accreted by the solar nebula. Three-dimensional hydrodynamical models of SN II shock-triggered collapse show that after triggering collapse of the presolar cloud core, the shock front sweeps away the local ISM while accelerating the resulting protostar/disk to a speed of several kilometers per second, sufficient for the protostar/disk system to encounter within similar to 1 Myr the more distant regions of a giant molecular cloud complex that might be expected to have a depleted inventory of supernova-derived nuclides.

II Zw 23 (UGC 3179) is a luminous (M-B similar to -21) nearby compact narrow emission line starburst galaxy with blue optical colors and strong emission lines. We present a photometric and morphological study of II Zw 23 and its interacting companion, KPG103a, using data obtained with the WIYN 3.5m telescope in combination with a WFPC2 image from the Hubble Space Telescope archives. II Zw 23 has a highly disturbed outer structure with long trails of debris that may be contributing material toward the production of tidal dwarfs. Its central regions appear disky, a structure that is consistent with the overall rotation pattern observed in the Ha velocity field measured from Densepak observations obtained with WIYN. We find additional evidence for interaction in this system, including the discovery of a new tidal loop extending from an associated dwarf galaxy, which appears to be in the process of disrupting along its orbit. We also present Ha equivalent widths and discuss the relative star formation rates across this interacting system.

Quasars are the most luminous non-transient objects known and as a result they enable studies of the Universe at the earliest cosmic epochs. Despite extensive efforts, however, the quasar ULAS J1120 + 0641 at redshift z = 7.09 has remained the only one known at z > 7 for more than half a decade(1). Here we report observations of the quasar ULAS J134208.10 + 092838.61 (hereafter J1342 + 0928) at redshift z = 7.54. This quasar has a bolometric luminosity of 4 x 10(13) times the luminosity of the Sun and a black-hole mass of 8 x 10(8) solar masses. The existence of this supermassive black hole when the Universe was only 690 million years old-just five per cent of its current age-reinforces models of early black-hole growth that allow black holes with initial masses of more than about 10(4) solar masses(2,3) or episodic hyper-Eddington accretion(4,5). We see strong evidence of absorption of the spectrum of the quasar redwards of the Lyman alpha emission line (the Gunn-Peterson damping wing), as would be expected if a significant amount (more than 10 per cent) of the hydrogen in the intergalactic medium surrounding J1342 + 0928 is neutral. We derive such a significant fraction of neutral hydrogen, although the exact fraction depends on the modelling. However, even in our most conservative analysis we find a fraction of more than 0.33 (0.11) at 68 per cent (95 per cent) probability, indicating that we are probing well within the reionization epoch of the Universe.

We present results of a deep spectroscopic survey quantifying the statistics of the escape of ionizing radiation from star -forming galaxies at z similar to 3. We measure the ratio of ionizing to non-ionizing UV flux density f(900)/f(1500)obs, where f(900) is the mean flux density evaluated over the range [880, 910] angstrom. We quantify the emergent ratio of ionizing to non-ionizing UV flux density by analyzing high signal-to-noise ratio composite spectra formed from subsamples with common observed properties and numbers sufficient to reduce the statistical uncertainty in the modeled IGM+CGM correction to obtain precise values of < f(900)/f(1500)>(out), including a full-sample average < f(900)/f(1500)>(out) 0.057 +/- 0.006. We show that < f(900)/f(1500)>(out) increases., monotonically with W lambda(Ly alpha), inducing an inverse correlation with UV luminosity as a by-product. We fit the composite spectra using stellar spectral synthesis together with models of the ISM in which a fraction f(c) of the stellar continuum is covered by gas with column density NH (I). We show that the composite spectra simultaneously constrain the intrinsic properties of the stars (L90041500)int along with f(c), N-H (I), E (B - V), and f(esc,abs), the absolute escape fraction of ionizing photons. We find a sample-averaged f(esc,abs) 0.09 +/- 0.01, with subsamples falling along a linear relation < f(esc),(abs)> similar or equal to 0.75[W-lambda(Ly alpha)/110 angstrom]. Using the far-UV luminosity function, the distribution function n(W(Lya)), and the relationship between WA(Ly alpha) and < f(900)/f(1500)>(out), we estimate the total ionizing emissivity of z similar to 3 star forming galaxies with M-uv <= -19.5, which exceeds the contribution of quasi-stellar objects by a factor of similar to 3, and accounts for similar to 50% of the total is an element of(Lyc) at z similar to 3 estimated using indirect methods.

We present Keck/OSIRIS laser guide-star assisted adaptive optics (LGSAO) integral-field spectroscopy of [O III].5007 nebular emission from 12 galaxies hosting optically faint (R = 20-25; nu L-nu similar to 10(44) - 10(46) erg s(-1)) active galactic nuclei (AGNs) at redshift z similar to 2-3. In combination with deep Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) rest-frame optical imaging, Keck/MOSFIRE rest-optical spectroscopy, and Keck/KCWI rest-UV integral-field spectroscopy, we demonstrate that both the continuum and emission-line structures of these sources exhibit a wide range of morphologies, from compact, isolated point sources to double-AGN merging systems with extensive similar to 50 kpc tidal tails. One of the 12 galaxies previously known to exhibit a proximate damped Lya system coincident in redshift with the galaxy shows evidence for both an extended [O III] narrow-line emission region and spatially offset Lya emission (with morphologically distinct blueshifted and redshifted components) indicative of large-scale gas flows photoionized by the central AGN. We do not find widespread evidence of star formation in the host galaxies surrounding these AGNs; the [O III] velocity dispersions tend to be high (sigma = 100-500 km s(-1)), the continuum morphologies are much more compact than a mass-matched star-forming comparison sample, and the diagnostic nebular emission-line ratios are dominated by an AGN-like ionizing spectrum. The sample is most consistent with a population of AGNs that radiate at approximately their Eddington limit and photoionize extended [O III] nebulae whose characteristic sizes scale approximately as the square root of the AGN luminosity.

This Letter reports the discovery of spatially extended line-emitting nebula, reaching to approximate to 100 physical kpc (pkpc) from a damped Ly alpha absorber (DLA) at z(DLA) = 0.313 along the sightline toward quasi-stellar object (QSO) PKS 1127-145 (z(Q)(SO) = 1.188). This DLA was known to be associated with a galaxy group of dynamical mass M-group similar to 3 x 10(12) M-circle dot, but its physical origin remained ambiguous. New wide-field integral field observations revealed a giant nebula detected in [O II], H beta, [O III], H alpha, and [N II] emission, with the line-emitting gas following closely the motions of group galaxies. One of the denser streams passes directly in front of the QSO with kinematics that are consistent with the absorption profiles recorded in the QSO echelle spectra. The emission morphology, kinematics, and line ratios of the nebula suggest that shocks and turbulent mixing layers, produced as a result of stripped gaseous streams moving at supersonic speed across the ambient hot medium, contribute significantly to the ionization of the gas. While the DLA may not be associated with any specific detected member of the group, both the kinematic and dust properties are consistent with the DLA originating in streams of gas stripped from sub-L-* group members at less than or similar to 25 pkpc from the QSO sightline. This study demonstrates that gas stripping in low-mass galaxy groups is effective in releasing metal-enriched gas from star-forming regions, producing absorption systems in QSO spectra, and that combining absorption and emission-line observations provides an exciting new opportunity for studying gas and galaxy co-evolution.

We present results from the Keck Baryonic Structure Survey (KBSS) including the first detailed measurements of the column densities, kinematics, and internal energy of metal-bearing gas within the virial radius (35?100 physical kpc) of eight ?L* galaxies at z?2. From our full sample of 130 metal-bearing absorbers, we infer that halo gas is kinematically complex when viewed in singly, doubly, and triply ionized species. Broad O vi and C iv absorbers are detected at velocities similar to the lower-ionization gas but with a very different kinematic structure, indicating that the circumgalactic medium (CGM) is multiphase. There is a high covering fraction of metal-bearing gas within 100 kpc, including highly ionized gas such as O vi; however, observations of a single galaxy probed by a lensed background QSO suggest the size of metal-bearing clouds is small (vi-bearing gas). The mass in metals found within the halo is substantial, equivalent to ?25% of the metal mass within the interstellar medium. The gas kinematics unambiguously show that 70% of galaxies with detected metal absorption have some unbound metal-enriched gas, suggesting galactic winds may commonly eject gas from halos at z?2. When modeled assuming that ions with different ionization potentials can originate within a single gaseous structure, significant thermal broadening is detected in CGM absorbers that dominates the internal energy of the gas. Some 40% of the detected gas has temperatures in the range 10(4.5?5.5) K where cooling times are short, suggesting the CGM is dynamic, with constant heating or cooling to produce this short-lived thermal phase.

We present initial results from the Cosmic Ultraviolet Baryon Survey (CUBS). CUBS is designed to map diffuse baryonic structures at redshift z less than or similar to 1 using absorption-line spectroscopy of 15 UV-bright QSOs with matching deep galaxy survey data. CUBS QSOs are selected based on their NUV brightness to avoid biases against the presence of intervening Lyman limit systems (LLSs) at z(abs) < 1. We report five new LLSs of log N(H I)/cm(-2) greater than or similar to 17.2 over a total redshift survey path-length of Delta z(LL) = 9.3, and a number density of n(z) = 0.43(-0.18)(+0.26) . Considering all absorbers with log N(H I)/cm(-2) > 16.5 leads to n(z) = 1.08(-0.25)(+0.31) at z(abs) < 1. All LLSs exhibit a multicomponent structure and associated metal transitions from multiple ionization states such as C II, CIII, MgII, Si II, Si III, and OVI absorption. Differential chemical enrichment levels as well as ionization states are directly observed across individual components in three LLSs. We present deep galaxy survey data obtained using the VLT-MUSE integral field spectrograph and the Magellan Telescopes, reaching sensitivities necessary for detecting galaxies fainter than 0.1L(*) at d less than or similar to 300 physical kpc (pkpc) in all five fields. A diverse range of galaxy properties is seen around these LLSs, from a low-mass dwarf galaxy pair, a co-rotating gaseous halo/disc, a star-forming galaxy, a massive quiescent galaxy, to a galaxy group. The closest galaxies have projected distances ranging from d = 15 to 72 pkpc and intrinsic luminosities from approximate to 0.01L(*) to approximate to 3L(*). Our study shows that LLSs originate in a variety of galaxy environments and trace gaseous structures with a broad range of metallicities.

We present new measurements of the spatial distribution and kinematics of neutral hydrogen in the circumgalactic and intergalactic medium surrounding star-forming galaxies at z similar to 2. Using the spectra of similar or equal to 3000 galaxies with redshifts < z > = 2.3 +/- 0.4 from the Keck Baryonic Structure Survey, we assemble a sample of more than 200 000 distinct foreground-background pairs with projected angular separations of 3-500 arcsec and spectroscopic redshifts, with < z(fg)> = 2.23 and < z(bg)> = 2.57 (foreground, background redshifts, respectively.) The ensemble of sightlines and foreground galaxies is used to construct a 2D map of the mean excess HI Ly alpha optical depth relative to the intergalactic mean as a function of projected galactocentric distance (20 less than or similar to D-tran/pkpc less than or similar to 4000) and line-of-sight velocity. We obtain accurate galaxy systemic redshifts, providing significant information on the line-of-sight kinematics of HI gas as a function of projected distance D-tran. We compare the map with cosmological zoom-in simulation, finding qualitative agreement between them. A simple two-component (accretion, outflow) analytical model generally reproduces the observed line-of-sight kinematics and projected spatial distribution of HI. The best-fitting model suggests that galaxy-scale outflows with initial velocity v(out) similar or equal to 600 km s(-1) dominate the kinematics of circumgalactic HI out to D-tran similar or equal to 50 kpc, while HI at D-tran greater than or similar to 100 kpc is dominated by infall with characteristic v(in) less than or similar to circular velocity. Over the impact parameter range 80 less than or similar to D-tran/pkpc less than or similar to 200, the HI line-of-sight velocity range reaches a minimum, with a corresponding flattening in the rest-frame Ly alpha equivalent width. These observations can be naturally explained as the transition between outflow-dominated and accretion-dominated flows. Beyond D-tran similar or equal to 300 pkpc (similar to 1 cMpc), the line-of-sight kinematics are dominated by Hubble expansion.