1,3,5-Triaza­adamantan-7-amine

The title compound, C7H14N4, represents the first structurally characterized, isolated triaza­adamantane. In the crystal structure, weak inter­molecular N—H⋯N hydrogen bonds link the mol­ecules into columns about the crystallographic fourfold axis

A First Look at the Abundance Pattern -- O/H, C/O, Ne/O, and Fe/O -- in z>7z>7 Galaxies with JWST/NIRSpec

We analyze the rest-frame near-UV and optical nebular spectra of three z > 7 galaxies from the Early Release Observations taken with the Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST). These three high-z galaxies show the detection of several strong-emission nebular lines, including the temperature-sensitive [O III] $\lambda$4363 line, allowing us to directly determine the nebular conditions and gas-phase abundances for O/H, C/O, Ne/O, and Fe/O. We derive O/H abundances and ionization parameters that are generally consistent with other recent analyses. The lowest-mass galaxy has a large O/H uncertainty, which as a significant effect on anchoring the mass-metallicity relationship (i.e., slope) and tests of its redshift evolution. We also detect the C III] $\lambda$$\lambda$1907,1909 emission in a z > 8 galaxy from which we determine the most distant C/O abundance to date. This valuable detection provides the first test of C/O redshift evolution out to high-redshift. For neon, we use the high-ionization [Ne III] $\lambda$3869 line to measure the first Ne/O abundances at z>7, finding no evolution in this $\alpha$-element ratio. To investigate the Fe abundance, we explore the tentative detection of weak [Fe II] and [Fe III] lines in a z>8 galaxy, which would indicate a rapid build up of metals. Importantly, we demonstrate that properly flux-calibrated and higher S/N spectra are crucial to robustly determine the abundance pattern in z>7 galaxies with NIRSpec/JWST.Comment: Submitted to The Astrophysical Journal Letters. Comments welcom

The C. elegans ephrin EFN-4 functions non-cell autonomously with heparan sulfate proteoglycans to promote axon outgrowth and branching

The Eph receptors and their cognate ephrin ligands play key roles in many aspects of nervous system development. These interactions typically occur within an individual tissue type, serving either to guide axons to their terminal targets or to define boundaries between the rhombomeres of the hindbrain. We have identified a novel role for the Caenorhabditis elegans ephrin EFN-4 in promoting primary neurite outgrowth in AIY interneurons and D-class motor neurons. Rescue experiments reveal that EFN-4 functions non-cell autonomously in the epidermis to promote primary neurite outgrowth. We also find that EFN-4 plays a role in promoting ectopic axon branching in a C. elegans model of X-linked Kallmann syndrome. In this context, EFN-4 functions non-cell autonomously in the body wall muscle, and in parallel with HS biosynthesis genes and HSPG core proteins, which function cell autonomously in the AIY neurons. This is the first report of an epidermal ephrin providing a developmental cue to the nervous system

DUVET Survey: Mapping Outflows in the Metal-Poor Starburst Mrk 1486

We present a method to characterize star-formation driven outflows from edge-on galaxies and apply this method to the metal-poor starburst galaxy, Mrk 1486. Our method uses the distribution of emission line flux (from H$\beta$ and [OIII] 5007) to identify the location of the outflow and measure the extent above the disk, the opening angle, and the transverse kinematics. We show that this simple technique recovers a similar distribution of the outflow without requiring complex modelling of line-splitting or multi-Gaussian components, and is therefore applicable to lower spectral resolution data. In Mrk 1486 we observe an asymmetric outflow in both the location of the peak flux and total flux from each lobe. We estimate an opening angle of $17-37^{\circ}$ depending on the method and assumptions adopted. Within the minor axis outflows, we estimate a total mass outflow rate of $\sim2.5$ M$_{\odot}$ yr$^{-1}$, which corresponds to a mass loading factor of $\eta=0.7$. We observe a non-negligible amount of flux from ionized gas outflowing along the edge of the disk (perpendicular to the biconical components), with a mass outflow rate $\sim0.9$ M$_{\odot}$ yr$^{-1}$. Our results are intended to demonstrate a method that can be applied to high-throughput, low spectral resolution observations, such as narrow band filters or low spectral resolution IFS that may be more able to recover the faint emission from outflows.Comment: 12 Pages, 6 Figure

DUVET: Spatially Resolved Observations of Star Formation Regulation via Galactic Outflows in a Starbursting Disk Galaxy

We compare 500~pc scale, resolved observations of ionised and molecular gas for the $z\sim0.02$ starbursting disk galaxy IRAS08339+6517, using measurements from KCWI and NOEMA. We explore the relationship of the star formation driven ionised gas outflows with colocated galaxy properties. We find a roughly linear relationship between the outflow mass flux ($\dot{\Sigma}_{\rm out}$) and star formation rate surface density ($\Sigma_{\rm SFR}$), $\dot{\Sigma}_{\rm out}\propto\Sigma_{\rm SFR}^{1.06\pm0.10}$, and a strong correlation between $\dot{\Sigma}_{\rm out}$ and the gas depletion time, such that $\dot{\Sigma}_{\rm out} \propto t_{dep}^{-1.1\pm0.06}$. Moreover, we find these outflows are so-called ``breakout" outflows, according to the relationship between the gas fraction and disk kinematics. Assuming that ionised outflow mass scales with total outflow mass, our observations suggest that the regions of highest $\Sigma_{\rm SFR}$ in IRAS08 are removing more gas via the outflow than through the conversion of gas into stars. Our results are consistent with a picture in which the outflow limits the ability for a region of a disk to maintain short depletion times. Our results underline the need for resolved observations of outflows in more galaxies.Comment: 16 pages, 7 figures, Submitted to Ap

CLASSY III: The Properties of Starburst-Driven Warm Ionized Outflows

We report the results of analyses of galactic outflows in a sample of 45 low-redshift starburst galaxies in the COS Legacy Archive Spectroscopic SurveY (CLASSY), augmented by five additional similar starbursts with COS data. The outflows are traced by blueshifted absorption-lines of metals spanning a wide range of ionization potential. The high quality and broad spectral coverage of CLASSY data enable us to disentangle the absorption due to the static ISM from that due to outflows. We further use different line multiplets and doublets to determine the covering fraction, column density, and ionization state as a function of velocity for each outflow. We measure the outflow's mean velocity and velocity width, and find that both correlate in a highly significant way with the star-formation rate, galaxy mass, and circular velocity over ranges of four orders-of-magnitude for the first two properties. We also estimate outflow rates of metals, mass, momentum, and kinetic energy. We find that, at most, only about 20% of silicon created and ejected by supernovae in the starburst is carried in the warm phase we observe. The outflows' mass-loading factor increases steeply and inversely with both circular and outflow velocity (log-log slope $\sim$ -1.6), and reaches $\sim 10$ for dwarf galaxies. We find that the outflows typically carry about 10 to 100% of the momentum injected by massive stars and about 1 to 20% of the kinetic energy. We show that these results place interesting constraints on, and new insights into, models and simulations of galactic winds.Comment: 34 pages, 16 figures, 6 tables, submitted to Ap

Interpreting the Si II and C II line spectra from the COS Legacy Spectroscopic SurveY using a virtual galaxy from a high-resolution radiation-hydrodynamic simulation

Observations of low-ionization state (LIS) metal lines provide crucial insights into the interstellar medium of galaxies, yet, disentangling the physical processes responsible for the emerging line profiles is difficult. This work investigates how mock spectra generated using a single galaxy in a radiation-hydrodynamical simulation can help us interpret observations of a real galaxy. We create 22,500 C II and Si II spectra from the virtual galaxy at different times and through multiple lines of sight and compare them with the 45 observations of low-redshift star-forming galaxies from the COS Legacy Spectroscopic SurveY (CLASSY). We find that the mock profiles provide accurate replicates to the observations of 38 galaxies with a broad range of stellar masses ($10^6$ to $10^9$ $M_\odot$) and metallicities (0.02 to 0.55 $Z_\odot$). Additionally, we highlight that aperture losses explain the weakness of the fluorescent emission in several CLASSY spectra and must be accounted for when comparing simulations to observations. Overall, we show that the evolution of a single simulated galaxy can produce a large diversity of spectra whose properties are representative of galaxies of comparable or smaller masses. Building upon these results, we explore the origin of the continuum, residual flux, and fluorescent emission in the simulation. We find that these different spectral features all emerge from distinct regions in the galaxy's ISM, and their characteristics can vary as a function of the viewing angle. While these outcomes challenge simplified interpretations of down-the-barrel spectra, our results indicate that high-resolution simulations provide an optimal framework to interpret these observations.Comment: Accepted for publication in Ap