Sazuna/UAT_keywords huggingface dataset:
On the Possible Mechanisms of the SEP Event and Electron Enhancement over the SEP Decay Phase on 2023 August 5. We carry out this study on the solar energetic particle (SEP) event that occurred on 2023 August 5 over the ascending phase of the current solar cycle 25. It is found that the SEP event might have been initiated by the M1.6 flare, while the SEP peak was caused by the coronal shock manifested in DH-type II radio burst over the propagation phase of a halo coronal mass ejection (CME; ∼1000 km s‑1), thus creating a mixed SEP event. There were two enhancements of the electron fluxes lying over the SEP rise and decay phase. It is surprising that, despite a stronger flare (X1.6) and a faster halo CME (∼1647 km s‑1), there was no SEP enhancement during the second enhancement of the electron fluxes. In order to investigate this, we make an additional effort to analyze the X1.6 flare based on the availability of the temporal, spectral, and spatial evolution of the electromagnetic radiation components. It is observed that the CME shock was aligned with the flare eruption direction and was close to the western limb (W77°), and thus the radially moving CME shock missed the Earth. In another development, it is observed that the electron impulsive phase lies over the type III radio bursts, indicating that the electrons might have escaped directly during the eruption. The radio flux and radio dynamic spectra of a higher frequency lie over the rise phase of the soft X-ray derivative, indicating that a large number of electrons travelled through magnetic fields.

Keywords: Solar energetic particles, Solar flares, Stellar coronal mass ejections
Cosmic Censorship in Sgr A* and M87*: Observationally Excluding Naked Singularities. The imaging of Sagittarius A* (Sgr A*) and the supermassive black hole at the center of Messier 87 (M87*) by the Event Horizon Telescope constrains the location and nature of emission from these objects. Coupled with flux limits from the near-infrared through the ultraviolet, the attendant size constraints provide strong evidence for the absence of an accretion-powered photosphere, and therefore for the existence of an event horizon about an astrophysical black hole. Here, we demonstrate that a broad class of naked singularities exhibit inner turning points for time-like geodesics, and therefore may generically be excluded, regardless of the nature and unknown physical impact of the singularity itself, subject to the single weak assumption that its nongravitational impact is localized to its immediate vicinity. While we restrict our attention to static, spherically symmetric spacetimes, we are nevertheless able to exclude or constrain a large number of commonly invoked naked singularity spacetimes in this way.

Keywords: Naked singularities, Galactic center, High energy astrophysics, Gravitation, Strong gravitational lensing, Active galaxies, Radio continuum emission
UNCOVER: A NIRSpec Census of Lensed Galaxies at z = 8.50–13.08 Probing a High-AGN Fraction and Ionized Bubbles in the Shadow. We present JWST NIRSpec prism spectroscopy of lensed galaxies at z ≳ 9 found behind the massive galaxy cluster Abell 2744 in the UNCOVER Cycle 1 Treasury Program. We confirm the redshift via emission lines and/or the Lyα break for 10 galaxies at z = 8.50–13.08 down to M  V  = ‑17.3. We achieve a 100% confirmation rate for z &gt; 9 candidates reported in H. Atek et al. Using six sources with multiple line detections, we find that offsets in redshift estimates between the lines and the Lyα break alone can be ±0.2, raising caution in designing future follow-up spectroscopy for the break-only sources with the Atacama Large Millimeter/submillimeter Array. With spec-z-confirmed sources in UNCOVER and the literature, we derive lower limits on the rest-frame ultraviolet (UV) luminosity function (LF) at z ≃ 9–12 and find that these lower limits agree with recent photometric measurements. We identify at least two unambiguous and several possible active galactic nucleus (AGN) systems based on X-ray, broad Hβ, high ionization lines, and excess in the UV LF. This requires the AGN LFs at z ≃ 9–10 to be comparable or even higher than the X-ray AGN LF estimated at z ∼ 6 and suggests a plausible cause of the high abundance of z &gt; 9 galaxies claimed in the recent photometric measurements is AGNs. One UV-luminous source is confirmed at the same redshift as a broad-line AGN at z = 8.50 with a physical separation of 380 kpc in the source plane. These two sources show emission blueward of Lyα, indicating a giant ionized bubble enclosing them with a radius of 7.69 ± 0.18 pMpc. Our results imply that AGNs have a nonnegligible contribution to cosmic reionization.

Keywords: Luminosity function, Early universe, Active galactic nuclei, Reionization, High-redshift galaxies
Molecular Gas Mass Measurements of an Active, Starburst Galaxy at z ≍ 2.6 Using ALMA Observations of the [C I], CO, and Dust Emission. We present new Atacama Large Millimeter/submillimeter Array (ALMA) observations of a starburst galaxy at cosmic noon hosting a radio-loud active galactic nucleus: PKS 0529-549 at z = 2.57. To investigate the conditions of its cold interstellar medium, we use ALMA observations that spatially resolve the [C I] fine-structure lines, [C I] (2─1) and [C I] (1─0), CO rotational lines, CO (7─6) and CO (4─3), and the rest-frame continuum emission at 461 and 809 GHz. The four emission lines display different morphologies, suggesting spatial variation in the gas excitation conditions. The radio jets have just broken out of the molecular gas but not through the more extended ionized gas halo. The [C I] (2─1) emission is more extended (≍8 kpc × 5 kpc) than detected in previous shallower ALMA observations. The [C I] luminosity ratio implies an excitation temperature of 44 ± 16 K, similar to the dust temperature. Using the [C I] lines, CO (4─3), and 227 GHz dust continuum, we infer the mass of molecular gas M mol using three independent approaches and typical assumptions in the literature. All approaches point to a massive molecular gas reservoir of about 1011 M ☉, but the exact values differ by up to a factor of 4. Deep observations are critical in correctly characterizing the distribution of cold gas in high-redshift galaxies, and highlight the need to improve systematic uncertainties in inferring accurate molecular gas masses.

Keywords: AGN host galaxies, Starburst galaxies, Molecular gas, Galaxy properties, Galaxy jets, Radio galaxies, Galaxy evolution
The Milky Way's Rowdy Neighbors: The Effects of the Large Magellanic Cloud and Sagittarius Dwarf on the Milky Way Disk. The Milky Way (MW) is a barred spiral galaxy shaped by tidal interactions with its satellites. The Large Magellanic Cloud (LMC) and the Sagittarius dwarf galaxy (Sgr) are the dominant influences at the present day. This paper presents a suite of four 109 particle N-body simulations, illustrating the response of the stellar disk of the MW to the close approach of the LMC and the merger of Sgr into the MW. The suite is intended to provide a resource for others to study the complex interactions between the MW and its satellites independently and together, in comparison to an isolated disk control simulation. The high temporal and mass resolution allows for a quantitative Fourier decomposition of the stellar kinematics, disentangling the individual influence of each satellite on the MW. In our preliminary analysis, we find that the influences from the LMC and Sgr on the disk of the MW appear distinct, additive, and separable within our tailored simulations. Notably, the corrugations induced by Sgr reproduce the large radial velocity wave seen in the data. Overall, our findings emphasise the need to include both satellites when modeling the present-day state of the MW structure and kinematics.

Keywords: Milky Way dynamics, Large Magellanic Cloud, Galaxy disks, Milky Way Galaxy physics, Milky Way disk, N-body simulations, Milky Way evolution, Sagittarius dwarf spheroidal galaxy, Milky Way Galaxy, Astronomical simulations, Galactic bar
A Precursor to Solar Prominence Eruptions: Detection and Analysis of EUV Prominence Oscillations. The eruption of prominences can have a significant influence on the solar–terrestrial environment. However, accurately predicting these eruptions remains a challenge. We apply automated detection methods for extreme ultraviolet (EUV) prominences observed by the twin spacecraft from the Solar Terrestrial Relations Observatory (STEREO) mission and the Solar Dynamics Observatory near Earth. We study an event, during 2011 March, when each STEREO spacecraft is in quadrature with respect to the Earth. For two time ranges, we obtain longitudinal height profiles as a function of time. We also track the corresponding EUV filaments across the solar disk, which reveal the emergence of ultra-long-period oscillations in the EUV filament channels. Our analysis shows a correlation between the prominence's increasing height and the oscillation periods, suggesting a potential link to the subsequent eruption observed by the STEREO spacecraft off-limb. These findings offer new insights into prominence dynamics and may pave the way for improved eruption prediction.

Keywords: Solar prominences, Quiescent solar prominence, Solar physics, Solar filaments, Solar filament eruptions, Solar oscillations
SN2023fyq: A Type Ibn Supernova with Long-standing Precursor Activity Due to Binary Interaction. We present photometric and spectroscopic observations of SN 2023fyq, a Type Ibn supernova (SN) in the nearby galaxy NGC 4388 (D ≃ 18 Mpc). In addition, we trace the 3 yr long precursor emission at the position of SN 2023fyq using data from DLT40, ATLAS, Zwicky Transient Facility, ASAS-SN, Swift, and amateur astronomer Koichi Itagaki. The double-peaked postexplosion light curve reaches a luminosity of ∼1043 erg s−1. The strong intermediate-width He lines observed in the nebular spectrum imply the interaction is still active at late phases. We found that the precursor activity in SN 2023fyq is best explained by the mass transfer in a binary system involving a low-mass He star and a compact companion. An equatorial disk is likely formed in this process (∼0.6M ⊙), and the interaction of SN ejecta with this disk powers the second peak of the SN. The early SN light curve reveals the presence of dense extended material (∼0.3M ⊙) at ∼3000R ⊙ ejected weeks before the SN explosion, likely due to final-stage core silicon burning or runaway mass transfer resulting from binary orbital shrinking, leading to rapid-rising precursor emission within ∼30 days prior to explosion. The final explosion could be triggered either by the core collapse of the He star or by the merger of the He star with a compact object. SN 2023fyq, along with SN 2018gjx and SN 2015G, forms a unique class of Type Ibn SNe, which originate in binary systems and are likely to exhibit detectable long-lasting pre-explosion outbursts with magnitudes ranging from −10 to −13.

Keywords: Circumstellar matter, Core-collapse supernovae, Stellar mass loss
A Search Using GEO600 for Gravitational Waves Coincident with Fast Radio Bursts from SGR 1935+2154. The magnetar SGR 1935+2154 is the only known Galactic source of fast radio bursts (FRBs). FRBs from SGR 1935+2154 were first detected by the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB and the Survey for Transient Astronomical Radio Emission 2 in 2020 April, after the conclusion of the LIGO, Virgo, and KAGRA Collaborations' O3 observing run. Here, we analyze four periods of gravitational wave (GW) data from the GEO600 detector coincident with four periods of FRB activity detected by CHIME/FRB, as well as X-ray glitches and X-ray bursts detected by NICER and NuSTAR close to the time of one of the FRBs. We do not detect any significant GW emission from any of the events. Instead, using a short-duration GW search (for bursts ≤1 s) we derive 50% (90%) upper limits of 1048 (1049) erg for GWs at 300 Hz and 1049 (1050) erg at 2 kHz, and constrain the GW-to-radio energy ratio to ≤1014−1016. We also derive upper limits from a long-duration search for bursts with durations between 1 and 10 s. These represent the strictest upper limits on concurrent GW emission from FRBs.

Keywords: Gravitational wave sources, Soft gamma-ray repeaters, Gravitational waves, X-ray sources, Magnetars, Radio transient sources
The Redshift of GRB 190829A/SN 2019oyw: A Case Study of GRB-SN Evolution. The nearby long gamma-ray burst (GRB) 190829A was observed using the Hubble Space Telescope/Wide Field Camera 3/infrared grisms about four weeks to 500 days after the burst. We find the spectral features of its associated supernova, SN 2019oyw, are redshifted by several thousand km s−1 compared to the redshift of the large spiral galaxy on which it is superposed. This velocity offset is seen in several features but most clearly in Ca II near-infrared triplet λλ8498, 8542, 8662 (CaIR3). We also analyze Very Large Telescope/FOcal Reducer and low dispersion Spectrograph and X-shooter spectra of the supernova (SN) and find strong evolution with time of its P-Cygni features of CaIR3 from the blue to the red. However, comparison with a large sample of Type Ic-BL and Ic SNe shows no other object with the CaIR3 line as red as that of SN 2019oyw were it at the z = 0.0785 redshift of the disk galaxy. This implies that SN 2019oyw is either a highly unusual SN or is moving rapidly with respect to its apparent host. Indeed, using CaIR3 we find the redshift of SN 2019oyw is 0.0944 ≤ z ≤ 0.1156. The GRB-SN is superposed on a particularly dusty region of the massive spiral galaxy; therefore, while we see no sign of a small host galaxy behind the spiral, it could be obscured. Our work provides a surprising result on the origins of GRB 190829A, as well as insights into the time evolution of GRB-SNe spectra and a method for directly determining the redshift of a GRB-SN using the evolution of strong spectral features such as CaIR3.

Keywords: Gamma-ray bursts, Core-collapse supernovae, Spectroscopy
Enhanced Peak and Extended Cooling of the Extreme-ultraviolet Late Phase in a Confined Solar Flare. We present observations and analysis of an X1.8 noneruptive solar flare on 2012 October 23, which is characterized by an extremely large late-phase peak seen in the warm coronal extreme-ultraviolet (EUV) emissions (∼3 MK), with the peak intensity over 1.4 times that of the main flare peak. The flare is driven by a failed eruption of a magnetic flux rope, whose strong squeeze force acting on the overlying magnetic structures gives rise to an intense early heating of the late-phase loops. Based on differential emission measure analysis, it is found that the late-phase loops experience a "longer-than-expected" cooling, without the presence of any obvious additional heating, while their volume emission measure maintains a plateau for a long time before turning into an evident decay. Without the need for an additional heating, we propose that the special thermodynamic evolution of the late-phase loops revealed in this flare might arise from loop cross-sectional expansions with height, which are evidenced by both direct measurements from EUV images and by magnetic field extrapolation. By blocking the losses of both heat flux and mass from the corona, such an upward cross-sectional expansion not only elongates the loop-cooling time, but also more effectively sustains the loop density, therefore leading to a later-than-expected occurrence of the warm coronal late phase in combination with a sufficiently high late-phase peak. We further verify such a scenario by analytically solving the cooling process of a late-phase loop characterized by a variable cross section.

Keywords: Hydrodynamics, Solar flares, Solar corona, Solar extreme ultraviolet emission
Mapping the Inner 0.1 pc of a Supermassive Black Hole Environment with the Tidal Disruption Event and Extreme Coronal-line Emitter AT 2022upj. Extreme coronal-line emitters (ECLEs) are objects showing transient high-ionization lines in the centers of galaxies. They have been attributed to echoes of high-energy flares of ionizing radiation, such as those produced by tidal disruption events (TDEs), but have only recently been observed within hundreds of days after an optical transient was detected. AT 2022upj is a nuclear UV–optical flare at z = 0.054, with spectra showing [Fe x] λ6375 and [Fe XIV] λ5303 during the optical peak, the earliest presence of extreme coronal lines during an ongoing transient. AT 2022upj is also the second ever ECLE (and the first with a concurrent flare) to show broad He II λ4686 emission, a key signature of optical/UV TDEs. We also detect X-ray emission during the optical transient phase, which may be related to the source of ionizing photons for the extreme coronal lines. Finally, we analyze the spectroscopic evolution of each emission line and find that [Fe x] and [Fe XIV] weaken within 400 days of the optical peak, while [Fe VII] λ5720, [Fe VII] λ6087, and [O III] λλ4959,5007 emerge over the same period. The velocities of the iron lines indicate circumnuclear gas within 0.1 pc of the central supermassive black hole (SMBH), while a dust echo inferred from NEOWISE data indicates that circumnuclear dust lies a minimum of 0.4 pc away, providing evidence of stratified material around an SMBH. AT 2022upj is thus the first confirmed ECLE–TDE with clear signatures of both classes and with spectroscopic evolution on a ∼year-long timescale. This event helps unveil the impacts of highly energetic flares such as TDEs on the complex environments around SMBHs.

Keywords: High energy astrophysics, Tidal disruption, Galaxy accretion
Development of Torus and Kink Instabilities in Eruptive Prominences. Several filament eruptions with pronounced writhing of the axis of the structure are analyzed. Initially, smooth arches of eruptive filaments are transformed into large-scale helical structures with at least one complete turn due to the development of kink instability. However, the initiation of the eruptions seems to be caused not by the kink instability but by catastrophic loss of equilibrium or torus instability. Calculations of the decay index of the coronal potential magnetic field indicate that the studied filaments began to rise rapidly at heights where the decay index was close to unity, the threshold for the catastrophic loss of equilibrium of straight flux ropes. Although it is often assumed that the kink instability precedes the subsequent torus instability leading to a full eruption, these examples testify to the possibility of the reverse order of the eruption development.

Keywords: Solar activity, Solar magnetic fields, Solar filaments, Solar prominences
Electron Cyclotron Maser with Moderately Relativistic Electrons. Electron cyclotron maser (ECM) emission is an important coherent emission mechanism for the direct amplification of electromagnetic waves by nonthermal electrons in a magnetized plasma. This paper will report on our recent study on ECM emission by fast electron beams with moderately relativistic energy. The results show that, similar to the spontaneous emission by the magnetic cyclotron motion of energetic electrons in a magnetic field, the coherent emission also exhibits the characteristic of a gradual transition from harmonic emission to continuous emission as the energy of the energetic electrons increases from subrelativistic to relativistic. The effects of the characteristic beam electrons energy (Ec) and the plasma-to-cyclotron frequency ratio (ωpe/ωce) on the growth rate, the peak-value frequency, and the spectral width are discussed further. These results are helpful for us to understand phenomena associated with astrophysical radio bursts.

Keywords: Solar radio emission, Radio bursts, Non-thermal radiation sources, Plasma astrophysics
The Decline and Fall of ROME. V. A Preliminary Search for Star-disrupted Planet Interactions and Coronal Activity at 5 GHz among White Dwarfs within 25 pc. The recent discovery of planetesimals orbiting white dwarfs has renewed interest in the final chapters of the evolution of planetary systems. Although observational and theoretical studies have examined the dynamical evolution of these systems, studies of their magnetic star–planet interactions, as powered by unipolar induction, have thus far only been assessed theoretically. This fifth paper of the Radio Observations of Magnetized Exoplanets series presents the results of a targeted minisurvey of nine white dwarfs within 25 pc without known stellar mass companions in search of radio emissions generated by magnetic interactions between white dwarfs and their planetary remnants. This ∼5 GHz Arecibo radio telescope survey achieved mJy-level sensitivity over &lt;1 s integration times. Although no exoplanet-induced stellar radio flares were detected, this is the first survey to search for magnetic star–planet interactions between white dwarfs and planetary companions, cores, or disrupted planetesimals. It is also the most extensive and sensitive radio survey for intrinsic coronal emissions from apparently isolated white dwarfs. The study of radio emissions from white dwarf systems may present a new means to detect and measure DC and DQ magnetic fields, search for white dwarf coronae, characterize the density and spatial distribution of white dwarf magnetospheric plasma, characterize the dynamical and electrical properties of planetary cores, and offer new constraints on the modeling of double-degenerate merger events.

Keywords: Planetary system evolution, Magnetospheric radio emissions, Exoplanets, DQ stars, White dwarf stars, Stellar activity, Stellar coronae, Non-thermal radiation sources, Planetesimals, Star-planet interactions, DC stars, Magnetic fields
Expanding the Ultracompacts: Gravitational-wave-driven Mass Transfer in the Shortest-period Binaries with Accretion Disks. We report the discovery of three ultracompact binary white dwarf systems hosting accretion disks, with orbital periods of 7.95, 8.68, and 13.15 minutes. This significantly augments the population of mass-transferring binaries at the shortest periods, and provides the first evidence that accretors in ultracompacts can be dense enough to host accretion disks even below 10 minutes (where previously only direct-impact accretors were known). In the two shortest-period systems, we measured changes in the orbital periods driven by the combined effect of gravitational-wave emission and mass transfer. We find   is negative in one case, and positive in the other. This is only the second system measured with a positive  , and it is the most compact binary known that has survived a period minimum. Using these systems as examples, we show how the measurement of   is a powerful tool in constraining the physical properties of binaries, e.g., the mass and mass─radius relation of the donor stars. We find that the chirp masses of ultracompact binaries at these periods seem to cluster around  , perhaps suggesting a common origin for these systems or a selection bias in electromagnetic discoveries. Our new systems are among the highest-amplitude known gravitational-wave sources in the millihertz regime, providing an exquisite opportunity for multimessenger study with future space-based observatories such as LISA and TianQin. We discuss how such systems provide fascinating laboratories to study the unique regime where the accretion process is mediated by gravitational waves.

Keywords: Stellar accretion disks, White dwarf stars, Compact binary stars, Gravitational wave sources