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We present the first data release of the Far-Infrared Polarimetric Large Area CMZ Exploration (FIREPLACE) survey. The survey was taken using the 214 μm band of the HAWC+ instrument with the SOFIA telescope (19.″6 resolution; 0.7 pc). In this first data release we present dust polarization observations covering a ∼0.°5 region of the Galactic center’s central molecular zone (CMZ), approximately centered on the Sgr B2 complex. We detect ∼25,000 Nyquist-sampled polarization pseudovectors, after applying the standard SOFIA cuts for minimum signal-to-noise ratios in fractional polarization and total intensity of three and 200, respectively. Analysis of the magnetic field orientation suggests a bimodal distribution in the field direction. This bimodal distribution shows enhancements in the distribution of field directions for orientations parallel and perpendicular to the Galactic plane, which are suggestive of a CMZ magnetic field configuration with polodial and torodial components. Furthermore, a detailed analysis of individual clouds included in our survey (i.e., Sgr B2, Sgr B2-NW, Sgr B2-Halo, Sgr B1, and Cloud E/F) shows they have fractional polarization values of 1%–10% at 214 μm, with most of the emission having values <5%. A few of these clouds (i.e., Sgr B2 and Cloud E/F) show relatively low fractional polarization values toward their cores and higher fractional polarization values toward their less dense peripheries. We also observe higher fractional polarization toward compact H ii regions, which could indicate an enhancement in the grain alignment in the dust surrounding these sources.

We study the evolution of the FU Ori object V960 Mon since its outburst, using available multiwavelength photometric time series over 8 yr, complemented by several epochs of moderate-dispersion spectrophotometry. We find that the source fading can be well-described by a decrease in the temperature of the inner disk, which results from a combination of decreasing accretion rate and increasing inner disk radius. We model the system with a disk atmosphere model that produces the observed variations in multiband photometry (this paper) and high-resolution spectral lines (a companion paper).

The subluminous red nova (SLRN) Zwicky Transient Facility (ZTF) SLRN-2020 is the most compelling direct detection of a planet being consumed by its host star, a scenario known as a planetary engulfment event. We present JWST spectroscopy of ZTF SLRN-2020 taken +830 days after its optical emission peak using the NIRSpec fixed-slit 3–5 μm high-resolution grating and the MIRI 5–12 μm low-resolution spectrometer. NIRSpec reveals the 12CO fundamental band (ν = 1–0) in emission at ∼4.7 μm, Brackett-α emission, and the potential detection of PH3 in emission at ∼4.3 μm. The JWST spectra are consistent with the claim that ZTF SLRN-2020 arose from a planetary engulfment event. We utilize DUSTY to model the late-time ∼1–12 μm spectral energy distribution (SED) of ZTF SLRN-2020, where the best-fit parameters indicate the presence of warm, 720−50+80 K, circumstellar dust with a total dust mass of Log MdM⊙=−10.61−0.16+0.08 M⊙. We also fit a DUSTY model to archival photometry taken +320 days after the peak that suggested the presence of a cooler, Td=280−20+450 K, and more massive, Log MdM⊙=−5.89−3.21+0.29 , circumstellar dust component. Assuming the cool component originates from the ZTF SLRN-2020 ejecta, we interpret the warm component as fallback from the ejecta. From the late-time SED model, we measure a luminosity of L*=0.29−0.06+0.03 L⊙ for the remnant host star, which is consistent with a ∼0.7 M⊙ K-type star that should not yet have evolved off the main sequence. If ZTF SLRN-2020 was not triggered by stellar evolution, we suggest that the planetary engulfment was due to orbital decay from tidal interactions between the planet and the host star.

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 μ m 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. Active galactic nuclei are surrounded by a dusty and molecular disk that fuels supermassive black holes and connects them to their host galaxies. Here, the authors show with JWST interferometric observations that most of the dust in the Circinus galaxies lies in a compact disk, while only a tiny fraction traces hot outflowing material.

We present the detection of a magnetized dust ring (M0.8–0.2) in the central molecular zone (CMZ) of the Galactic center. The results presented in this paper utilize the first data release of the Far-Infrared Polarimetric Large Area CMZ Emission (FIREPLACE) survey (i.e., Paper I of this series). The FIREPLACE survey is a 214 μm polarimetric survey of the Galactic center using the SOFIA/HAWC+ telescope. The M0.8–0.2 ring is a region of gas and dust that has a circular morphology with a central depression. The dust polarization in the M0.8–0.2 ring implies a curved magnetic field that traces the ring-like structure of the cloud. We posit an interpretation in which an expanding shell compresses and concentrates the ambient gas and magnetic field. We argue that this compression results in strengthening of the magnetic field, as we infer from the observations toward the interior of the ring.

Binaries that host a carbon-rich Wolf–Rayet (WC) star and an OB-type companion can be copious dust producers. Yet the properties of dust, particularly the grain size distribution, in these systems remain uncertain. We present Band 6 observations of WR 112 by the Atacama Large Millimeter/submillimeter Array telescope (ALMA), which are the first millimeter observations of a WC binary system capable of resolving its dust emission. By combining ALMA observations with James Webb Space Telescope images, we were able to analyze the spatially resolved spectral energy distribution (SED) of WR 112. We found that the SEDs are consistent with emissions from hydrogen-poor amorphous carbon grains. Notably, our results also suggest that the majority of grains in the system have radii below one micrometer, and the extended dust structures are dominated by nanometer-sized grains. Among four parameterizations of the grain radius distribution that we tested, a bimodal distribution, with abundant nanometer-sized grains and a secondary population of 0.1 μm grains, best reproduces the observed SED. This bimodal distribution helps to reconcile the previously conflicting grain size estimates reported for WR 112 and for other WC systems. We hypothesize that dust destruction mechanisms such as radiative torque disruption and radiative-driven sublimation are responsible for driving the system to the bimodal grain size distribution.

The James Webb Space Telescope (JWST) has opened up a new window to study highly reddened explosive transients. We present results from late-time JWST follow-up spectroscopic observations with NIRSpec and MIRI-LRS of the intermediate-luminosity red transient (ILRT) AT 2019abn. ILRTs represent a mysterious class of transients that exhibit peak luminosities between those of classical novae and supernovae and that are known to be highly dust obscured. Similar to the prototypical examples of this class of objects, NGC 300 2008-OT and SN 2008S, AT 2019abn has an extremely red and dusty progenitor detected only in pre-explosion Spitzer/IRAC imaging at 3.6 and 4.5 μm and not in deep optical or near-infrared Hubble Space Telescope images. We find that late-time observations of AT 2019abn from NEOWISE and JWST are consistent with the late-time evolution of SN 2008S. In part because they are so obscured by dust, it is unknown what produces an ILRT, with hypotheses including high-mass stellar merger events, nonterminal stellar outbursts, and terminal supernova explosions through electron capture in super-AGB (SAGB) stars. Our JWST observations show strong mid-IR class C polycyclic aromatic hydrocarbon features at 6.3 and 8.25 μm typical of carbon-rich post-AGB sources. These features suggest that the dust around AT 2019abn is composed of carbonaceous grains, which are not typically observed around red supergiants. However, depending on the strength and temperature of hot bottom burning, SAGB stars may be expected to exhibit a carbon-rich chemistry. Thus, our JWST observations are consistent with AT 2019abn having an SAGB progenitor and exploding as an electron-capture supernova.

Wolf-Rayet (WR) 140 is the archetypal periodic dust-forming colliding-wind binary that hosts a carbon-rich WR (WC) star and an O-star companion with an orbital period of 7.93 yr and an orbital eccentricity of 0.9. Throughout the past few decades, multiple dust-formation episodes from WR 140 have been observed that are linked to the binary orbit and occur near the time of periastron passage. Given its predictable dust-formation episodes, WR 140 presents an ideal astrophysical laboratory to investigate the formation and evolution of dust in the hostile environment around a massive binary system. In this paper, we present near- and mid-infrared (IR) spectroscopic and imaging observations of WR 140 with Subaru/SCExAO+CHARIS, Keck/NIRC2+PyWFS, and Subaru/Cooled Mid-Infrared Camera and Spectrograph taken between 2020 June and September that resolve the circumstellar dust emission linked to its most recent dust-formation episode in 2016 December. Our spectral energy distribution analysis of WR 140's resolved circumstellar dust emission reveals the presence of a hot (T d ∼ 1000 K) near-IR dust component that is co-spatial with the previously known and cooler (T d ∼ 500 K) mid-IR dust component composed of 300–500 Å sized dust grains. We attribute the hot near-IR dust emission to the presence of nano-sized (nanodust) grains and suggest they were formed from grain–grain collisions or the rotational disruption of the larger grain size population by radiative torques in the strong radiation field from the central binary. Lastly, we speculate on the astrophysical implications of nanodust formation around colliding-wind WC binaries, which may present an early source of carbonaceous nanodust in the interstellar medium.

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.

The central regions of the Milky Way constitute a unique laboratory for a wide swath of astrophysical studies; consequently, the inner ∼400 pc have been the target of numerous large surveys at all accessible wavelengths. In this paper, we present a catalog of sources at 25 and 37 μm located within all of the regions observed with the SOFIA/FORCAST instrument in the inner ∼200 pc of the Galaxy. The majority of the observations were obtained as part of the SOFIA Cycle 7 Galactic Center Legacy program survey, which was designed to complement the Spitzer/MIPS 24 μm catalog in regions saturated in the MIPS observations. Due to the wide variety of source types captured by our observations at 25 and 37 μm, we do not limit the FORCAST source catalog to unresolved point sources, or treat all sources as if they are pointlike sources. The catalog includes all detectable sources in the regions, resulting in a catalog of 950 sources, including point sources, compact sources, and extended sources. We also provide the user with metrics to discriminate between the source types.