Community Science and Data Center

The dusty and molecular torus is an elusive structure surrounding supermassive black holes, yet its importance is unequivocal for understanding feedback and accretion mechanisms. The torus and accretion disk feed the inspiraling gas onto the active nucleus, launching outflows that fundamentally connect the active nucleus's activity to the host galaxy. In this work, we utilize the aperture-masking interferometric mode onboard the JWST to achieve a resolution of 0.08" at 4.3 μm and bring out the fainter features in the central 10 pc of the Circinus galaxy. We show that most of the dust mass is located along the equatorial axis in the form of a 5×3 pc disk feeding the active nucleus. Only <1% of the dust emission arises from an arc structure composed of hot dust entrained in a molecular and ionized outflow, while the extended emission is associated with dust heated by the active galaxy at large scales.

Abstract We present an efficient estimator for higher-order galaxy clustering using small groups of nearby galaxies, or multiplets. Using the Luminous Red Galaxy (LRG) sample from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2, we identify galaxy multiplets as discrete objects and measure their cross-correlations with the general galaxy field. Our results show that the multiplets exhibit stronger clustering bias as they trace more massive dark matter halos than individual galaxies. When comparing the observed clustering statistics with the mock catalogs generated from the N-body simulation AbacusSummit, we find that the mocks underpredict multiplet clustering despite reproducing the galaxy two-point auto-correlation reasonably well. This discrepancy indicates that the standard Halo Occupation Distribution (HOD) model is insufficient to describe the properties of galaxy multiplets, revealing the greater constraining power of this higher-order statistic on galaxy-halo connection and the possibility that multiplets are specific to additional assembly bias. We demonstrate that incorporating secondary biases into the HOD model improves agreement with the observed multiplet statistics, specifically by allowing galaxies to preferentially occupy halos in denser environments. Our results highlight the potential of utilizing multiplet clustering, beyond traditional two-point correlation measurements, to break degeneracies in models describing the galaxy-dark matter connection.

ABSTRACT In preparation for the first cosmological measurements from the full shape of the Lyman-$\alpha$ (Ly $\alpha$) forest from Dark Energy Spectroscopic Instrument (DESI), we must carefully model all relevant systematics that might bias our analysis. It has been shown that random quasar redshift errors produce a smoothing effect on the mean quasar continuum in the Ly $\alpha$ forest region. This, in turn, gives rise to spurious features in the Ly $\alpha$ autocorrelation and its cross-correlation with quasars. Using synthetic data sets based on the DESI survey, we confirm that the impact on baryon acoustic oscillation measurements is small, but that a bias is introduced to parameters which depend on the full shape of our correlations. We combine a model of this contamination in the cross-correlation with a new model we introduce here for the autocorrelation. These are parametrized by three parameters, which, when included in a joint fit to both correlation functions, successfully eliminate any impact of redshift errors on our full-shape constraints. We also present a strategy for removing this contamination from real data, by removing $\sim$0.3 per cent of correlating pairs.

Abstract Much of the carbonaceous dust observed in the early Universe may originate from colliding wind binaries (CWBs) hosting hot, luminous Wolf–Rayet (W-R) stars. Downstream of the shock between the stellar winds there exists a suitable environment for dust grain formation, and the orbital motions of the stars wrap this dust into richly structured spiral geometries. The Apep system is the most extreme W-R CWB in our Milky Way: two W-R stars produce a complex spiral dust nebula, whose slow expansion has been linked to a gamma-ray burst progenitor. It has been unclear whether the O-type supergiant 0 . ″ 7 distant from the W-R + W-R binary is physically associated with the system, and whether it affects the dusty nebula. Multiepoch Very Large Telescope/VISIR and JWST/MIRI observations show that this northern companion star routinely carves a cavity in the dust nebula—the first time such an effect has been observed in a CWB—which unambiguously associates the O star as a bound component to the Apep system. These observations are used together with a new geometric model to infer the cavity geometry and the orbit of the W-R + W-R binary, yielding the first strong constraints on wind and orbital parameters. We confirm an orbital period of over 190 yr for the inner binary—nearly an order of magnitude longer than the next longest-period dust-producing W-R CWB. This, together with the confirmed classification as a hierarchical triple, cements Apep as a singular astrophysical laboratory for studying colliding winds and the terminal life stages of the most massive star systems.

Abstract Open clusters are one of the best astrophysical laboratories we have available for stellar astrophysics studies. This work presents metallicities and individual abundances for 14 M dwarfs and six G dwarfs from two well-known open clusters: Hyades and Coma Berenices. Our analysis is based on near-infrared (1.51–1.69 μ m), high-resolution ( R ∼ 22,500) spectra obtained from the Sloan Digital Sky Survey (SDSS) IV/APOGEE Survey. Using one-dimensional, plane-parallel MARCS model atmospheres, the APOGEE line list, and the Turbospectrum radiative transfer code in local thermodynamic equilibrium, we derived spectroscopic stellar parameters for the M dwarfs, along with abundances of 13 elements (C, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, and Fe) for both M and G dwarfs. We find a high degree of chemical homogeneity within each cluster when comparing abundances derived from M and G dwarfs: δ [M/H] (M dwarfs–G dwarfs) of 0.01 ± 0.04, and 0.02 ± 0.03 for the Hyades and Coma Berenices, respectively. The overall cluster metallicities derived from M dwarfs (Hyades: 0.16 ± 0.03 and Coma Berenices: 0.02 ± 0.06) are consistent with previous literature determinations. Finally, we demonstrate the value of M dwarfs as key tracers in Galactic archeology, emphasizing their potential for studying Galactic metallicity gradients and chemical evolution.

Abstract A quadruply lensed source, J125856.3–031944, has been discovered using the DELVE survey and Wide-field Infrared Survey Explorer W1–W2 colors. Follow-up direct imaging carried out with the Magellan Baade 6.5 m telescope is analyzed, as is spectroscopy from the 2.5 m Nordic Optical Telescope. The lensed image configuration is kite-like, with the major axis of the lensing galaxy along the symmetry axis of the kite, and with the faintest image at its tail. Redward of 6000 Å, the tail image is strongly blended with the lensing galaxy. The Sloan g direct imaging carried out with Magellan permits deblending. As the lensed image configuration is nearly circular, simple models give high predicted magnifications for all four images. The source’s narrow emission lines at redshift z = 2.225 and low intrinsic luminosity qualify it as a type 2 active galactic nucleus. The Magellan image shows a substantial residual that suggests a second lensing galaxy.

Abstract Colliding winds in massive binaries generate X-ray-bright shocks, synchrotron radio emission, and sometimes even dusty “pinwheel” spirals. We report the first X-ray detections of the dusty WC+O binary system WR 112 from Chandra and Swift, alongside 27 yr of Very Large Array/Australia Telescope Compact Array radio monitoring and new diffraction-limited Keck images. Because we view the nearly circular orbit almost edge-on, the colliding-wind zone alternates between heavy Wolf–Rayet wind self-absorption and near-transparent O-star wind foreground each 20 yr orbit, producing phase-locked radio and X-ray variability. This scenario leads to a prediction that the radio spectral index is flatter from a larger nonthermal contribution around the radio intensity maximum, which indeed was observed. Existing models that assume a single dust-expansion speed fail to reproduce the combined infrared (IR) geometry and radio light curve. Instead, we require an accelerating postshock flow that climbs from near-stationary to ∼1350 km s−1 in about one orbital cycle, naturally matching the IR spiral from 5″ down to within 0 . ″ 1, while also fitting the phase of the radio brightening. These kinematic constraints supply critical boundary conditions for future hydrodynamic simulations, which can link hot-plasma cooling, nonthermal radio emission, X-ray spectra, and dust formation in a self-consistent framework. WR 112 thus joins WR 140, WR 104, and WR 70-16 (Apep) as a benchmark system for testing colliding-wind physics under an increasingly diverse range of orbital architectures and physical conditions.

To provide quality patient care, health professionals must be able to effectively communicate interpersonally and in team environments. While a lack of communication and conflict negotiation skills certainly can create obstacles to patient care, the organizational structures in which health professionals do their work also can obstruct communication or make it more difficult. Structurational divergence theory helps identify and explain the negative communication cycles that result when individuals must fulfill obligations from multiple competing systems, each with its own social rules. The structure of health care delivery systems also can result in structurational divergence, as health care workers must often navigate the space between their clinician priorities of improved patient health and the corporate priorities of greater efficiency and profit. This divergence creates tension for the clinician that can lead to burnout and moral injury, especially when the clinician feels forced to act outside the patient's best interests. Individual efforts to address moral injury are less likely to be successful than collective group action. However, medical education can take steps to prepare students with the knowledge and tools necessary to navigate competing role demands, systemic obstacles, and ethical dilemmas to ensure quality patient care.

The Vera C. Rubin Observatory is a new NSF/DOE-funded facility on Cerro Pachón, Chile. It houses the 8.4m Simonyi Survey Telescope and the 3.2 Gigapixel LSSTCam camera. The Observatory is in the final stages of commissioning, expected to enter operations by the end of 2025. Once operational, Rubin will execute the Legacy Survey of Space and Time (LSST). Enabled by its 9.6 square degree field of view and a cadence covering the sky every 3-4 days to ~24.5 mag, the LSST dataset will dramatically advance numerous area of astronomy, including our understanding of the Solar System by delivering the largest catalog of small bodies to date.This talk will present the first public Solar System-related results from Rubin's early commissioning efforts. We will discuss the discovery yields, measured performance of the observatory, early comparison to predictions, and talk through the expectations for further data during commissioning's Science Validation surveys. With a steady stream of public solar system discoveries expected to start in late commissioning, small bodies are likely to be one of the first areas of highly impactful early science. We hope this talk will help prepare the Solar System community for those imminent opportunities, and illustrate the transformational capabilities that Rubin is about to bring.

Abstract We present a new data reduction technique for unchopped spectroscopic data developed for the Far-Infrared Field Integral Line Spectrometer instrument on-board the Stratospheric Observatory for Infrared Astronomy (SOFIA) to reduce spectral artifacts caused by large nod offsets. These large offsets are required to quantify the background without astronomical signal when large regions in the sky are mapped, e.g., in the Large Magellanic Cloud where reference beam offsets up to 1° can be needed. The technique uses the precipitable water vapor overburden derived from re-analyses from the European Centre for Medium-Range Weather Forecasts to determine the fraction of flux measured in each spatial and spectral pixel contributed by the atmospheric background. With that it is then possible to scale the reference measurement in the off beam to the sky elevation of the on source measurement. These large maps on SOFIA typically use the “on-the-fly” observing mode. The mode is highly efficient, but each point in the final map is integrated with multiple scans. Therefore artifacts from background subtraction do not only generate point by point offsets but can also degenerate the signal to noise ratio in each of the spectra since the sky background is often not spectrally flat.