Cold Mode Gas Accretion on Two Galaxy Groups at z∼\sim2

We present Keck Cosmic Web Imager (KCWI) integral field spectroscopy (IFS) observations of rest-frame UV emission lines $\rm Ly\alpha$, C IV $\lambda \lambda$ 1548 \AA, 1550\AA and He II 1640 \AA observed in the circumgalactic medium (CGM) of two $z=2$ radio-loud quasar host galaxies. We detect extended emission on 80-90 kpc scale in $\rm Ly\alpha$ in both systems with C IV, and He II emission also detected out to 30-50 kpc. All emission lines show kinematics with a blue and redshifted gradient pattern consistent with velocities seen in massive dark matter halos and similar to kinematic patterns of inflowing gas seen in hydrodynamical simulations. Using the kinematics of both resolved $\rm Ly\alpha$ emission and absorption, we can confirm that both kinematic structures are associated with accretion. Combining the KCWI data with molecular gas observations with Atacama Large Millimeter/submillimeter Array (ALMA) and high spatial resolution of ionized gas with Keck OSIRIS, we find that both quasar host galaxies reside in proto-group environments at $z=2$. We estimate $1-6\times10^{10}$M$_\odot$ of warm-ionized gas within 30-50 kpc from the quasar that is likely accreting onto the galaxy group. We estimate inflow rates of 60-200 M$_\odot$yr$^{-1}$, within an order of magnitude of the outflow rates in these systems. In the 4C 09.17 system, we detect narrow gas streams associated with satellite galaxies, potentially reminiscent of ram-pressure stripping seen in local galaxy groups and clusters. We find that the quasar host galaxies reside in dynamically complex environments, with ongoing mergers, gas accretion, ISM stripping, and outflows likely playing an important role in shaping the assembly and evolution of massive galaxies at cosmic noon.Comment: 24 pages, 11 figures, 6 tabes. Accepted for publication in MNRA

Re-imagining the futures of geographical thought and praxis

The question of geography\u27s future has recurred throughout the history of geographical thought, and responses to it often presume a linear trajectory from the past and present to a possible future. Yet one of the major contributions that geographers have made to understanding spatio-temporality is reconceiving both space and time as plural, fluid, and co-constituted through multiple space–time trajectories simultaneously. Amidst the ongoing crises of the present, this article opens the current special issue with a call to pluralize geography\u27s futures by diversifying the voices speaking in the name of ‘geography’ and broadening the horizon of possibilities for the futures of geographical thought and praxis. We have assembled the contributions in this collection with the aim of raising important theoretical, methodological, and empirical questions about how geography\u27s past and present shape the conditions of possibility for its potential futures. In doing so, we seek to demonstrate how the worlding of geography\u27s futures is fundamentally a matter of transforming its disciplinary reproduction in the here-and-now

Oxygen Abundance Throughout the Dwarf Starburst Galaxy IC 10

Measurements of oxygen abundance throughout galaxies provide insight to the formation histories and ongoing processes. Here we present a study of the gas-phase oxygen abundance in the H ii regions and diffuse gas of the nearby starburst dwarf galaxy, IC 10. Using the Keck Cosmic Web Imager at W. M. Keck Observatory, we map the central region of IC 10 from 3500 to 5500 Å. The auroral [O III ] 4363 Å line is detected with a high signal-to-noise ratio in 12 of 46 H II regions observed, allowing for direct measurement of the oxygen abundance, yielding a median and standard deviation of $12+\mathrm{log}({\rm{O}}/{\rm{H}})=8.37\pm 0.25$ . We investigate trends between these directly measured oxygen abundances and other H II region properties, finding weak negative correlations with the radius, velocity dispersion, and luminosity. We also find weak negative correlations between the oxygen abundance and the derived quantities of turbulent pressure and ionized gas mass, and a moderate correlation with the derived dynamical mass. Strong line, R _23 abundance estimates are used in the remainder of the H II regions and on a resolved spaxel-by-spaxel basis. There is a large offset between the abundances measured with R _23 and the auroral line method. We find that the R _23 method is unable to capture the large range of abundances observed via the auroral line measurements. The extent of this variation in the measured abundances further indicates a poorly mixed interstellar medium in IC 10, which is not typical of dwarf galaxies and may be partly due to the ongoing starburst, accretion of pristine gas, or a late stage merger

Socially stratified epigenetic profiles are associated with cognitive functioning in children and adolescents

AbstractChildren’s cognitive functioning and educational performance are socially stratified. Social inequality, including classism and racism, may operate partly via epigenetic mechanisms that modulate neurocognitive development. Following preregistered analyses of data from 1,183 8-to 19-year-olds from the Texas Twin Project, we examined whether salivary DNA-methylation measures of inflammation (DNAm-CRP), cognitive functioning (Epigenetic-g), and pace of biological aging (DunedinPoAm) are socially stratified and associated with performance on tests of cognitive functions. We find that children growing up in more disadvantaged families and neighborhoods and children from marginalized racial/ethnic groups exhibit DNA-methylation profiles associated with higher chronic inflammation, lower cognitive functioning, and faster pace of biological aging. These salivary DNA-methylation profiles were associated with processing speed, general executive function, perceptual reasoning, verbal comprehension, reading, and math. Given that the DNA-methylation measures we examined were originally developed in adults, our results suggest that social inequalities may produce in children molecular signatures that, when observed in adults, are associated with chronic inflammation, advanced aging, and reduced cognitive function. Salivary DNA-methylation profiles might be useful as a surrogate endpoint in assessing the effectiveness of psychological and economic interventions that aim to reduce negative effects of childhood social inequality on lifespan development.Significance StatementChildren’s cognitive functioning differs by dimensions of social inequality, such as class and race. Epigenetic mechanisms that regulate gene expression might be critically involved in the biological embedding of environmental privilege and adversity. We find that children growing up in more disadvantaged families and neighborhoods and from marginalized racial/ethnic groups exhibit higher chronic inflammation, lower cognitive functioning, and a faster pace of biological aging, as indicated by novel salivary DNA-methylation measures. These DNA-methylation measures of higher inflammation, lower cognitive functioning, and a faster pace of biological aging were, in turn, associated with performance on multiple cognitive tests. DNA-methylation measures might be useful as a surrogate endpoint in evaluation of programs to address the childhood social determinants of lifelong cognitive disparities.</jats:sec