Sazuna/UAT_keywords huggingface dataset:
Projections of Earth's Technosphere: Strategies for Observing Technosignatures on Terrestrial Exoplanets. The search for technosignatures—remotely detectable evidence of extraterrestrial technology—draws upon examples from the recent history of Earth as well as projections of Earth's technosphere. Facilities like the Habitable Worlds Observatory (HWO) will significantly advance the feasibility of characterizing the atmospheres of habitable exoplanets at visible and near-infrared wavelengths, while other future mission concepts could extend this search to mid-infrared wavelengths. We draw upon a recently developed set of 10 self-consistent scenarios for future Earth technospheres as analogs for extraterrestrial technospheres, which we use to outline a stepwise technosignature search strategy, beginning with HWO and followed by other missions. We find that HWO could reveal elevated abundances of a CO2 + NO2 pair on planets with combustion and other large-scale industry, which could be observable in up to eight of the 10 scenarios. Follow-up radio observations could reveal narrowband directed transmissions, as occur in two of the scenarios. Further study involving direct detections at mid-infrared wavelengths with the Large Interferometer for Exoplanets could reveal spectral features from industry, such as the combinations of CO2 + CFC-11/12 in four scenarios and CO2 + CFC-11/12 + CF4 in one scenario; two of these also include the N2O + CH4 + NH3 triple from large-scale agriculture. Other mission concepts, such as a solar-gravitational-lens mission, could reveal large-scale surface features in two scenarios that would otherwise show no detectable technosignatures, while an interplanetary flyby or probe mission would be the most conclusive way to reveal the presence of technology on terrestrial exoplanets.

Keywords: Exoplanets, Technosignatures, Astrobiology, Search for extraterrestrial intelligence, Habitable planets
Capture into Apsidal Resonance and the Decimation of Planets around Inspiraling Binaries. Transiting circumbinary planets (CBPs) are conspicuously rare and entirely absent around stellar binaries with periods ≤7 days. Here we exploit a secular resonance to stimulate the orbit of a CBP into strong, disruptive interactions with the host binary. The process requires no tertiary companion and is triggered when the general relativistic precession of a tightening binary matches the Newtonian precession it induces in its companion planet. Adiabatic capture in this resonance sees the binary draining angular momentum from the CBP's orbit, which grows steadily in eccentricity until destabilization and eventual ejection or engulfment. We map this resonance in phase space and then investigate the dynamical outcomes of encounter in the course of tidally shrinking binaries. With the help of orbit-averaged simulations of a suite of systems, we find that, around tightening binaries, 8 out of 10 CBPs encounter and are captured in the resonance, 3 out of 4 are "destroyed," and survivors lurk on remote, low transit probability orbits. This suggests that the very process that forms tight binaries effectively clears the region where transiting CBPs could reside.

Keywords: Exoplanet dynamics, Star-planet interactions, Binary stars
The Plane Quasar Survey: An Ionized Extension of the Magellanic Stream on the Northern Side of the Galactic Plane. The Magellanic Stream (MS) is a vast gaseous structure in the Milky Way halo, containing most of its mass in ionized form and tracing the interaction between the Large and Small Magellanic Clouds and the Galaxy. Using Hubble Space Telescope/Cosmic Origin Spectrograph G160M spectra from the Plane Quasar Survey, we detect C IV absorbers likely associated with the MS, extending to the northern side of the Galactic plane, approximately 60∘ beyond its previously known ionized extent. These absorbers exhibit position and kinematic alignment and show consistent ionization trends with previously studied MS sight lines. The nondetection of low ions such as Al II and Si II, and the detection of C IV (and Si IV in some sight lines), indicates a highly ionized gas phase. The observed Si IV/C IV column density ratios suggest a gas temperature of T ∼ 105.3 K and favor collisional ionization over photoionization. We estimate the newly detected extension increases the previous ionized gas mass of the MS, and its coherent kinematics suggest that it was stripped within the past few hundred Myr and has not yet mixed with the Milky Way halo. The existence of highly ionized MS gas at a location above the Galactic plane may constrain the orbital direction of the Magellanic Clouds.

Keywords: Quasar absorption line spectroscopy, High-velocity clouds, Galaxy interactions, Ultraviolet astronomy, Magellanic Stream, Circumgalactic medium, Milky Way Galaxy
Understanding the Origin and Dynamical Evolution of the Unique Open Star Cluster Berkeley 20 Using FIRE Simulations. Open clusters (OCs) act as key probes that can be leveraged to constrain the formation and evolution of the Milky Way (MW)'s disk, as each has a unique chemical fingerprint and well-constrained age. Significant Galactic dynamic interactions can leave imprints on the orbital properties of OCs, allowing us to use the present-day properties of long-lived OCs to reconstruct the MW's dynamic history. To explore these changes, we identify OC analogs in FIRE-2 simulations of MW-mass galaxies. For this work, we focus on one particular FIRE-2 OC, which we identify as an analog to the old, subsolar, distant, and high-Galactic-latitude MW OC, Berkeley 20. Our simulated OC resides ∼6 kpc from the galactic center and ultimately reaches a height  ∣Zmax∣&gt;2  kpc from the galactic disk, similar to Berkeley 20. We trace the simulated cluster's orbital and environmental history, identifying key perturbative episodes, including (1) an interaction with a gas overdensity in a spiral arm that prompts an outward migration event and (2) a substantial interaction with a Sagittarius Dwarf Spheroidal Galaxy─mass satellite that causes significant orbital modification. Our simulated OC shows significant resilience to disruption during both its outward migration and the satellite-driven heating event that causes subsequent inward migration. Ultimately, we find these two key processes—migration and satellite heating—are essential to include when assessing OC orbital dynamics in the era of Gaia.

Keywords: Disk galaxies, Galaxy dynamics, Spiral arms, Open star clusters, Astronomical simulations
Unveiling Chemical Enrichment in the A2029 Core with XRISM, XMM-Newton, and Chandra. We present new measurements of the chemical abundance pattern in the core of the nearby galaxy cluster Abell 2029 (A2029), based on XRISM observations with Resolve (37 ks) and Xtend (500 ks), combined with archival data from XMM-Newton (European Photon Imaging Camera (EPIC), Reflection Grating Spectrometer (RGS)) and Chandra. Fe abundances derived from Resolve, Xtend, and EPIC are broadly consistent, while RGS gives systematically lower values. Because the XRISM gate valve remained closed during these observations, Resolve spectral fitting is restricted to the 2─10 keV band, providing reliable constraints only for elements with strong lines in this band (S, Ar, Ca, Fe, Ni). Abundances of the α-elements are therefore derived using complementary observations from Xtend, EPIC, RGS, and Chandra. We construct an average X/Fe pattern in the cluster core by using Resolve exclusively for S/Fe, Ar/Fe, Ca/Fe, and Ni/Fe and RGS + Xtend for O/Fe. The Ne/Fe ratio is averaged from Xtend, EPIC, RGS, and Chandra measurements; Mg/Fe, from EPIC and Chandra measurements; and Si/Fe, from Xtend, EPIC, and Chandra. Comparison with the supernova yield models indicates that the observed abundance pattern in the A2029 core is best reproduced by a combination of core-collapsed yields from low-metallicity progenitors (Zinit = 0.001) and a sub-Chandrasekhar-mass, double-degenerate Type Ia model. Additionally, we find an excess in Ca abundance in the core of A2029 that cannot be reproduced by the standard supernova yield models.

Keywords: Galaxy clusters
Pan-STARRS Follow-up of the Gravitational-wave Event S250818k and the Light Curve of SN2025ulz. Kilonovae are the scientifically rich—but observationally elusive—optical transient phenomena associated with compact binary mergers. Only a handful of events have been discovered to date, all through multiwavelength (gamma-ray) and multimessenger (gravitational-wave) signals. Given their scarcity, it is important to maximise the discovery possibility of new kilonova events. To this end, we present our follow-up observations of the gravitational-wave signal S250818k—a plausible binary neutron star merger at a distance of 237 ± 62 Mpc. Pan-STARRS tiled 286 and 318 deg2 (32% and 34% of the 90% sky localisation region) within 3 and 7 days of the GW signal, respectively. ATLAS covered 65% of the sky map within 3 days, but with lower sensitivity. These observations uncovered 47 new transients; however, none were deemed to be linked to S250818k. We undertook an expansive follow-up campaign of AT2025ulz, the purported counterpart to S250818k. The griz-band light curve, combined with our redshift measurement (z = 0.0849 ± 0.0003), all indicate that SN2025ulz is a type IIb supernova and thus not the counterpart to S250818k. We rule out the presence of an AT2017gfo-like kilonova within ≍27% of the distance posterior sampled by our Pan-STARRS pointings (≍9.1% across the total 90% 3D sky localisation). We demonstrate that early observations are optimal for probing the distance posterior of the 3D gravitational-wave sky map, and that SN2025ulz was a plausible kilonova candidate for ≲5 days, before ultimately being ruled out.

Keywords: Neutron stars, Gravitational waves, Sky surveys, Supernovae
Multimessengers from the Radioactive Decay of r-process Nuclei. The radioactive β-decay of nuclei synthesized in the rapid neutron capture process (r-process) releases a variety of particles, including electrons, γ-rays, neutrinos, and neutrons. These particles provide a rich set of multimessenger signals that carry information about the astrophysical environments where neutron-rich nucleosynthesis occurs. In this work, we calculate from first principles the emission spectra resulting from the β-decay of r-process nuclei. Our approach incorporates detailed nuclear structure and decay data to model the energy distributions of each particle species. We couple the spectra with a nuclear reaction network simulation to obtain the temporal evolution of these distributions. We find that the emission distributions vary significantly in time and are nonthermal, with substantial average energies. We investigate these nuclear signals as a direct probe of heavy element formation and show that they are complementary observables to kilonova.

Keywords: Gamma-ray bursts, Nucleosynthesis, R-process, Nuclear astrophysics, Compact objects, Compact nebulae
Numerical Nonadiabatic Tidal Calculations with GYRE-tides: The WASP-12 Test Case. We revisit the tidal evolution of the WASP-12 system using direct numerical calculations with the GYRE-tides code. WASP-12b is a hot Jupiter on a 1.1 day orbit around a slightly evolved F-type star. Its observed orbital decay rate,  ∣Ṗorb/Porb∣≍3.2Myr−1 , provides a strong constraint on stellar tidal dissipation. We confirm that linear tides with radiative damping and convective damping, as currently implemented, are not sufficient to reproduce the observed inspiral timescale. Nevertheless, our calculations, based on fully nonadiabatic forced oscillations in MESA stellar models with convective envelopes, yield dissipation rates that are consistent with previous semianalytic and adiabatic estimates, confirming the robustness of our numerical framework. As the only open-source, actively maintained tool that calculates the full nonadiabatic, mode resolved linear tidal response of the star, GYRE-tides provides a benchmark calculation for WASP-12 and future applications. Our results validate GYRE-tides as a tool for analyzing combined radiative and convective damping, and indicate that the observed decay rate requires tidal dissipation operating in or near the fully damped regime, which may be achieved through nonlinear damping. These contributions could also be evaluated by computing the wave luminosity at the radiative─convective boundary using our tool. GYRE-tides offers an open-source framework for computing tidal dissipation in short-period exoplanet systems, including the many systems expected to show orbital decay in upcoming Roman surveys.

Keywords: Hot Jupiters, Exoplanets, Astronomy software, Tidal interaction, Stellar astronomy, Tides, Stellar oscillations, Stellar evolution
Revealing an Oscillating and Contracting Compact Corona near the Event Horizon of the Supermassive Black Hole in 1ES 1927+654. Dynamic processes in the accretion flow near black holes produce X-ray flux variability, sometimes quasiperiodic. Determining its physical origin is key to mapping the accretion geometry but remains unresolved. We perform a novel phase-resolved analysis on a newly discovered quasiperiodic oscillation (QPO) in the active galactic nucleus 1ES 1927+654. For the first time in a supermassive black hole (SMBH), we detect a unique "U"-shaped QPO lag─energy spectrum and observe coronal spectral variability over the QPO phase. We find that the QPO is adequately explained by plasma resonant oscillations within a corona. The modeling of the QPO spectral properties reveals that the corona is contracting and confined to regions of only a few gravitational radii near the SMBH, consistent with theoretical predictions for a decreasing QPO period of near 10 minutes. These results present the first observational evidence for an oscillating and contracting compact corona around an SMBH.

Keywords: X-ray active galactic nuclei, Active galactic nuclei, Galaxy accretion disks
Quasar Negative Feedback to Surrounding Galaxies Probed with Lyα Emitters and Continuum-selected Galaxies. We report on the statistical analysis of quasar photoevaporation at z ∼ 2.2 by comparing the density of surrounding Lyα emitters (LAEs) and continuum-selected galaxies, based on the imaging data of the Hyper Suprime-Cam (HSC) Subaru Strategic Program and the CFHT Large Area U-band Deep Survey. We select 18 quasars from the Sloan Digital Sky Survey in the HSC Deep/UltraDeep fields, normalize the LAE/continuum-selected galaxy distribution around each quasar with the quasar proximity size, stack them, and then measure the average densities of the galaxies. As a result, we find that the density of LAEs is ≳5σ lower than that of continuum-selected galaxies within the quasar proximity region. Within the quasar proximity region, we find that the LAEs with high Lyα equivalent widths (EWs) are less dense than those with low EWs at the 3σ level and that LAEs with EW of ≳150 Å (rest-frame) are predominantly scarce. Finally, we find that both LAEs and continuum-selected galaxies have smaller densities when they are closer to quasars. We argue that the photoevaporation effect is more effective for smaller dark matter halos predominantly hosting LAEs, but that it may also affect larger halos.

Keywords: Galaxy formation, Galaxy evolution, Quasars
Handy Relation between Binary Black Hole Merger Times and Host Galaxy Properties. Over the past 15 yr, the evidence has clearly demonstrated that massive black hole (MBH) binary merger timescales depend strongly on the structural and kinematic properties of their host galaxy. Stellar density, gas content, shape, and kinematics all play a role, combining in nonlinear ways to affect the evolution of the binary. The binary properties themselves—such as the eccentricity, mass ratio, and orbital plane—all matter as well. This makes it nontrivial to estimate accurate cosmological MBH binary merger rates or to generate merger-rate ranges that reflect the distribution of galaxy hosts and orbits. We seek to accurately model the few-body stellar scattering phase, as this is the least well understood part of the journey from black holes in separate galaxies to a merged black hole. Using an extensive set of high-resolution, gas-free, direct N-body simulations, in which the shape, structure, and kinematics of each galaxy host are directly informed by observations, we map out MBH binary merger timescales over a range of galaxy hosts and MBH binary orbits. This yields a convenient set of scaling relations to determine MBH binary merger timescales—and the range of merger timescales—as functions of basic observables. Such scaling relations can be readily employed as a subgrid model in cosmological or semianalytic studies—for example, to model event rates for LISA or pulsar timing.

Keywords: Gravitational wave astronomy, Galaxy dynamics, Astrophysical black holes
Shadow-induced Warps in Protoplanetary Disks. Shadows are commonly observed in protoplanetary disks in near-infrared (NIR) and (sub)millimeter images, often cast by misaligned inner disks or other obscuring material. While recent studies show that shadows can alter disk dynamics, only the case symmetric across the midplane (e.g., from a polar-aligned inner disk) has been studied. Here we study shadows cast by an inner disk with a 30° mutual inclination using 3D radiation─hydrodynamical simulations. Given the same shadow shape and amplitude, the 30° inclined shadow leads to a much stronger accretion compared with the polar case, reaching α ∼ 1, because the disk is squeezed twice in one azimuth, leading to shocks and strong radial flows near the midplane. The outer disk develops a warp: the inner disk region tilts toward alignment with the shadow, while the outer, exponentially tapered disk tilts and twists in a different direction, inclined ∼ 32° relative to the inner region. Locally isothermal simulations with a prescribed temperature structure reproduce the effect, confirming that it is thermally driven. Fourier─Hermite analysis shows that it is the m = 1, n = 1 temperature perturbation that drives the warp by launching bending waves, with the tilting response of the disk approximately proportional to the modal amplitude. This mode always exists unless the shadow is coplanar or polar. Given a fixed temperature contrast, the m = 1, n = 1 mode peaks at an ∼15° mutual inclination, but still contributes substantially across 3°─30°. Shadows cause disk warps—they are not only a consequence of them. We discuss testable predictions for current and future Atacama Large Millimeter/submillimeter Array and NIR observations.

Keywords: Accretion, Hydrodynamics, Radiative transfer, Protoplanetary disks, Astrophysical fluid dynamics, Planet formation
Very Large Telescope Observations of Interstellar Comet 3I/ATLAS. II. From Quiescence to Glow: Dramatic Rise of Ni I Emission and Incipient CN Outgassing at Large Heliocentric Distances. We report Very Large Telescope spectroscopy of the interstellar comet 3I/Asteroid Terrestrial-impact Last Alert System (C/2025 N1), from rh ≃ 4.4 to 2.85 au, using X-Shooter (300─550 nm, R ≃ 3000) and the Ultraviolet and Visual Echelle Spectrograph (optical, R ≃ 35─80 k). The coma is dust-dominated, with a fairly constant red optical continuum slope (∼21%─22%/1000 Å). We report the detection of CN emission and also detect numerous Ni I lines, while Fe I remains undetected, potentially implying efficiently released gas-phase Ni. At rh ≃ 3.14 au, we derive 3σ limits of Q(OH) &lt; 1.48 × 1026 s−1 but find no indications for [O I], C2, C3, or NH2. From our latest X-Shooter measurements, conducted on 2025 August 21 (rh = 2.85 au), we measure production rates of  logQ(CN)=24.81±0.01  molecules s−1 and  logQ (Ni) = 23.30 ± 0.07 atoms s−1 and characterize their evolution as the comet approaches perihelion. We observe a steep heliocentric distance scaling for the production rates  Q(Ni)∝rh−7.7±1.0  and  Q(CN)∝rh−6.7±0.2 , and we predict an Ni─CO(2) correlation if the Ni I emission is driven by the carbonyl formation channel. Energetic considerations of activation barriers show that this behavior is inconsistent with the direct sublimation of canonical metal/sulfide phases and instead favors low-activation-energy release from dust—e.g., photon-stimulated desorption or mild thermolysis of metalated organics or Ni-rich nanophases, possibly including Ni─carbonyl-like complexes. These hypotheses will be testable with future coordinated ground-based and space-based monitoring, as 3I becomes more active during its continued passage through the solar system. *Based on observations collected at the European Southern Observatory under ESO programmes 115.29F3 and 115.27ZL.

Keywords: Comet surfaces, Comet origins
Multispacecraft Measurements of the Evolving Geometry of the Solar Alfvén Surface over Half a Solar Cycle. The geometry of a star's Alfvén surface determines stellar angular momentum loss, separates a causally distinct "corona" and stellar wind, and potentially affects exoplanetary habitability. The solar Alfvén surface is the only such structure that is directly measurable and, since 2021, has been routinely measured in situ by NASA's Parker Solar Probe (Parker). We use these unique measurements in concert with Solar Orbiter and L1 in situ data spanning the first half of solar cycle 25 in time and from 0.045 to 1 au in heliocentric distance to develop a radial scaling technique to estimate the morphology of the Alfvén surface from measurements of the solar wind speed and local Alfvén speed. We show that accounting for solar wind acceleration and mass flux is necessary to achieve reasonable agreement between the scaled location of the Alfvén surface and the locations of direct crossings measured by Parker. We produce continuous 2D equatorial cuts of the Alfvén surface over half a solar cycle (ascending phase and maximum). Parker's earliest crossings clipped outward extrusions, many of which are likely transient-related, while more recently, Parker has unambiguously sampled deep sub-Alfvénic flows. We analyze the average altitude, departure from spherical symmetry, and surface roughness, finding that all are positively correlated to solar activity. For the current modest solar cycle, the height varies up to 30%, which corresponds to a near doubling in angular momentum loss per unit mass loss.

Keywords: Stellar winds, Solar wind, Solar corona
High-resolution Imaging of the Magnetic Reconfiguration of the Corona from inside the Corona by WISPR on Parker Solar Probe. During the 22nd perihelion of Parker Solar Probe at 9.86 solar radii on 2024 December 24, the WISPR telescope captured a detailed sequence of events marking the return of open magnetic flux back to the Sun via the heliospheric current sheet (HCS) reconfiguration. In this Letter, we present a preliminary analysis and interpretation of three intriguing events: inflow swarms, HCS rearrangement, and in/out pair generation. Although all three have been reported from past 1 au coronagraphic observations, the WISPR images reveal new insights into the nature of the reconnection driving these events. We propose that inflowing "tadpoles" around a streamer boundary are likely due to interchange reconnection, but that similarly looking tadpoles forming higher up are the result of tearing-mode instabilities in the HCS. We also capture, for the first time in detail, the role of pinch-off reconnection in the creation of in/out pairs. Although based on only 24 hr of WISPR observations, these results showcase the remarkable power of local imaging and highlight the exciting scientific opportunities from Parker Solar Probe's future coronal flybys.

Keywords: Active solar corona, Solar magnetic fields, Solar magnetic reconnection