In this study, we conduct extensive high-pressure experiments to investigate phase stability in the cobalt-nitrogen system. Through a combination of synthesis in a laser-heated diamond anvil cell, first-principles calculations, Raman spectroscopy, and single-crystal X-ray diffraction, we establish the stability fields of known high-pressure phases, hexagonal NiAs-type CoN, and marcasite-type CoN2 within the pressure range of 50-90 GPa. We synthesize and characterize previously unknown nitrides, Co3N2, Pnma-CoN and two polynitrides, CoN3 and CoN5, within the pressure range of 90-120 GPa. Both polynitrides exhibit novel types of polymeric nitrogen chains and networks. CoN3 feature branched-type nitrogen trimers (N3) and CoN5 show pi-bonded nitrogen chain. As the nitrogen content in the cobalt nitride increases, the CoN6 polyhedral frameworks transit from face-sharing (in CoN) to edge-sharing (in CoN2 and CoN3), and finally to isolated (in CoN5). Our study provides insights into the intricate interplay between structure evolution, bonding arrangements, and high-pressure synthesis in polynitrides, expanding the knowledge for the development of advanced energy materials

Nitrogen represents an archetypal example of material exhibiting a pressure -driven transformation from molecular to polymeric state. Detailed investigations of such transformations are challenging because of a large kinetic barrier between molecular and polymeric structures, making the transformation largely dependent on kinetic stimuli. In the case of nitrogen, additional complications occur due to the rich polymorphism in the vicinity of the transition. Here, we report the observation of both molecular (theta) and black phosphorus (bp) polymeric phases, crystallized upon temperature quenching of fluid nitrogen to room temperature at 97-114 GPa. Synchrotron single -crystal x-ray diffraction, Raman spectroscopy, and first -principles theoretical calculations have been used for diagnostics of the phases and determination of their structure and stability. The structure of theta - N2 is determined as tetragonal, space group P42212-one of the phases previously predicted theoretically above 9.5 GPa but never recognized experimentally. Molecular theta - N2 is the most stable among molecular phases bordering the stability field of polymeric phases, partially settling a previously noted discrepancy between theory and experiment concerning the thermodynamic stability limit of molecular phases.

We present NIRCam and NIRISS modules for DOLPHOT, a widely used crowded-field stellar photometry package. We describe details of the modules including pixel masking, astrometric alignment, star finding, photometry, catalog creation, and artificial star tests. We tested these modules using NIRCam and NIRISS images of M92 (a Milky Way globular cluster), Draco II (an ultrafaint dwarf galaxy), and Wolf-Lundmark-Mellote (a star-forming dwarf galaxy). DOLPHOT's photometry is highly precise, and the color-magnitude diagrams are deeper and have better definition than anticipated during original program design in 2017. The primary systematic uncertainties in DOLPHOT's photometry arise from mismatches in the model and observed point-spread functions (PSFs) and aperture corrections, each contributing less than or similar to 0.01 mag to the photometric error budget. Version 1.2 of WebbPSF models, which include charge diffusion and interpixel capacitance effects, significantly reduced PSF-related uncertainties. We also observed minor (less than or similar to 0.05 mag) chip-to-chip variations in NIRCam's zero-points, which will be addressed by the JWST flux calibration program. Globular cluster observations are crucial for photometric calibration. Temporal variations in the photometry are generally less than or similar to 0.01 mag, although rare large misalignment events can introduce errors up to 0.08 mag. We provide recommended DOLPHOT parameters, guidelines for photometric reduction, and advice for improved observing strategies. Our Early Release Science DOLPHOT data products are available on MAST, complemented by comprehensive online documentation and tutorials for using DOLPHOT with JWST imaging data.

We introduce the Sloan Digital Sky Survey (SDSS)/ Apache Point Observatory Galactic Evolution Experiment (APOGEE) value-added catalogue of Galactic globular cluster (GC) stars. The catalogue is the result of a critical search of the APOGEE Data Release 17 (DR17) catalogue for candidate members of all known Galactic GCs. Candidate members are assigned to various GCs on the basis of position in the sky, proper motion, and radial velocity. The catalogue contains a total of 7737 entries for 6422 unique stars associated with 72 Galactic GCs. Full APOGEE DR17 information is provided, including radial velocities and abundances for up to 20 elements. Membership probabilities estimated on the basis of precision radial velocities are made available. Comparisons with chemical compositions derived from the GALactic Archaeology with HERMES (GALAH) survey, as well as optical values from the literature, show good agreement. This catalogue represents a significant increase in the public data base of GC star chemical compositions and kinematics, providing a massive homogeneous data set that will enable a variety of studies. The catalogue in fits format is available for public download from the SDSS-IV DR17 value-added catalogue website.

Photomorphogenesis is a light-dependent plant growth and development program. As the core regulator of photomorphogenesis, ELONGATED HYPOCOTYL 5 (HY5) is affected by dynamic changes in its transcriptional activity and protein stability; however, little is known about the mediators of these processes. Here, we identified PHOTOREGULATORY PROTEIN KINASE 1 (PPK1), which interacts with and phosphorylates HY5 in Arabidopsis, as one such mediator. The phosphorylation of HY5 by PPK1 is essential to establish high-affinity binding with B-BOX PROTEIN 24 (BBX24) and CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), which inhibit the transcriptional activity and promote the degradation of HY5, respectively. As such, PPKs regulate not only the binding of HY5 to its target genes under light conditions but also HY5 degradation when plants are transferred from light to dark. Our data identify a PPK-mediated phospho-code on HY5 that integrates the molecular mechanisms underlying the regulation of HY5 to precisely control plant photomorphogenesis.

We present new JWST NIRSpec integral field spectroscopy (IFS) data for the luminous infrared galaxy NGC 7469, a nearby (70.6 Mpc) active galaxy with a Seyfert 1.5 nucleus that drives a highly ionized gas outflow and a prominent nuclear star-forming ring. Using the superb sensitivity and high spatial resolution of the JWST instrument NIRSpec IFS, we investigate the role of the Seyfert nucleus in the excitation and dynamics of the circumnuclear gas. Our analysis focuses on the [Fe ii], H2, and hydrogen recombination lines that trace the radiation/shocked-excited molecular and ionized interstellar medium around the active galactic nucleus (AGN). We investigate gas excitation through H2/Br gamma and [Fe ii]/Pa beta emission line ratios and find that photoionization by the AGN dominates within the central 300 pc of the galaxy except in a small region that shows signatures of shock-heated gas; these shock-heated regions are likely associated with a compact radio jet. In addition, the velocity field and velocity dispersion maps reveal complex gas kinematics. Rotation is the dominant feature, but we also identify noncircular motions consistent with gas inflows as traced by the velocity residuals and the spiral pattern in the Pa alpha velocity dispersion map. The inflow is 2 orders of magnitude higher than the AGN accretion rate. The compact nuclear radio jet has enough power to drive the highly ionized outflow. This scenario suggests that the inflow and outflow are in a self-regulating feeding-feedback process, with a contribution from the radio jet helping to drive the outflow.

The Large Magellanic Cloud (LMC) is the Milky Way ' s most massive satellite galaxy, which only recently (similar to 2 billion years ago) fell into our Galaxy. As stellar atmospheres preserve the composition of their natal cloud, the LMC ' s recent infall makes its most ancient, metal-deficient (' low-metallicity ') stars unique windows into early star formation and nucleosynthesis in a formerly distant region of the high-redshift universe. Here we present the elemental abundances of ten stars in the LMC with iron-to-hydrogen ratios ranging from similar to 1/300th to similar to 1/12,000th that of the Sun. Our most metal-deficient star is markedly more metal-deficient than any in the LMC with available detailed chemical abundance patterns and was probably enriched by a single extragalactic ' first-star ' supernova. This star lacks appreciable carbon enhancement, as does our overall sample, unlike the lowest-metallicity stars in the Milky Way. This and other abundance differences affirm that the extragalactic early LMC experienced diverging enrichment processes compared to the early Milky Way. Early element production, driven by the earliest stars, thus, appears to proceed in an environment-dependent manner.

Milky Way globular clusters (GCs) display chemical enrichment in a phenomenon called multiple stellar populations (MSPs). While the enrichment mechanism is not fully understood, there is a correlation between a cluster's mass and the fraction of enriched stars found therein. However, present-day GC masses are often smaller than their masses at the time of formation due to dynamical mass-loss. In this work, we explore the relationship between mass and MSPs using the stellar stream 300S. We present the chemical abundances of eight red giant branch member stars in 300S with high-resolution spectroscopy from Magellan/MIKE. We identify one enriched star characteristic of MSPs and no detectable metallicity dispersion, confirming that the progenitor of 300S was a GC. The fraction of enriched stars (12.5 per cent) observed in our 300S stars is less than the 50 per cent of stars found enriched in Milky Way GCs of comparable present-day mass (similar to 10(4.5 )M(circle dot)). We calculate the mass of 300S's progenitor and compare it to the initial masses of intact GCs, finding that 300S aligns well with the trend between the system mass at formation and enrichment. 300S's progenitor may straddle the critical mass threshold for the formation of MSPs and can therefore serve as a benchmark for the stellar enrichment process. Additionally, we identify a CH star, with high abundances of s-process elements, probably accreted from a binary companion. The rarity of such binaries in intact GCs may imply stellar streams permit the survival of binaries that would otherwise be disrupted.