Sazuna/UAT_keywords huggingface dataset:
Distribution of s-, r-, and p-process Nuclides in the Early Solar System Inferred from Sr Isotope Anomalies in Meteorites. Nucleosynthetic isotope anomalies in meteorites allow distinguishing between the noncarbonaceous (NC) and carbonaceous (CC) meteorite reservoirs and show that correlated isotope anomalies exist in both reservoirs. It is debated, however, whether these anomalies reflect thermal processing of presolar dust in the disk or are primordial heterogeneities inherited from the solar system's parental molecular cloud. Here, using new high-precision 84Sr isotope data, we show that NC meteorites, Mars, and the Earth and Moon are characterized by the same 84Sr isotopic composition. This 84Sr homogeneity of the inner solar system contrasts with the well-resolved and correlated isotope anomalies among NC meteorites observed for other elements, and most likely reflects correlated s- and (r, p)-process heterogeneities leading to 84Sr excesses and deficits of similar magnitude, which cancel each other out. For the same reason there is no clearly resolved 84Sr difference between NC and CC meteorites, because in some carbonaceous chondrites the characteristic 84Sr excess of the CC reservoir is counterbalanced by an 84Sr deficit resulting from s-process variations. Nevertheless, most carbonaceous chondrites exhibit 84Sr excesses, which reflect admixture of refractory inclusions and more pronounced s-process heterogeneities in these samples. Together, the correlated variation of s- and (r, p)-process nuclides revealed by the 84Sr data of this study refute an origin of these isotope anomalies solely by processing of presolar dust grains, but points to primordial mixing of isotopically distinct dust reservoirs as the dominant process producing the isotopic heterogeneity of the solar system.

Keywords: Cosmochemistry, Small Solar System bodies, Planetary system formation, Protoplanetary disks, Meteorites
V445 Puppis: Dustier than a Thousand Novae. V445 Puppis, the only known Galactic helium nova, is a unique test bed to verify supernova (SN) theories in the single-degenerate channel that involve a white dwarf (WD) accreting matter from a helium-rich donor. An estimate of the mass of the helium shell on the WD is crucial to deciding whether or not it will undergo an SN detonation. In this context, this study estimates the dust and ejecta masses in the 2000 November eruption of V445 Pup. Subsequent to its outburst, the star became cocooned in a dust envelope. An analysis of the spectral energy distribution (SED) of the dust using infrared data shows that V445 Pup produced at least 10-3 M ⊙ of dust, which is unprecedented for a classical or recurrent nova. The SED can be explained by a combination of a cold dust component at 105 ± 10 K, mass (1.9 ± 0.8) × 10-3 M ⊙, and a warm dust component at 255 ± 10 K, mass (2.2 ± 1.2) × 10-5 M ⊙. For a conservative choice of the gas-to-dust mass ratio in the range 10-100, the mass of the ejecta is 0.01-0.1 M ⊙. Such a high mass range raises the question: why did V445 Pup not detonate as a Type Ia SN as is predicted in certain double-detonation sub-Chandrasekhar supernovae formalisms? We reexamine the nature of V445 Pup and discuss its role as a potential SN progenitor.

Keywords: Explosive nucleosynthesis, Chemical abundances, Type Ia supernovae, Dust shells, Classical novae
Highly Depleted Alkali Metals in Jupiter's Deep Atmosphere. Water and ammonia vapors are known to be the major sources of spectral absorption at pressure levels observed by the microwave radiometer (MWR) on Juno. However, the brightness temperatures and limb darkening observed by the MWR at its longest-wavelength channel of 50 cm (600 MHz) in the first nine perijove passes indicate the existence of an additional source of opacity in the deep atmosphere of Jupiter (pressures beyond 100 bar). The absorption properties of ammonia and water vapor, and their relative abundances in Jupiter's atmosphere, do not provide sufficient opacity in the deep atmosphere to explain the 600 MHz channel observation. Here we show that free electrons due to the ionization of alkali metals, i.e., sodium and potassium, with subsolar metallicity, [M/H] (log-based 10 relative concentration to solar) in the range of [M/H] = -2 to [M/H] = -5, can provide the missing source of opacity in the deep atmosphere. If the alkali metals are not the source of additional opacity in the MWR data, then their metallicity at 1000 bars can only be even lower. This upper bound of -2 on the metallicity of the alkali metals contrasts with the other heavy elements-C, N, S, Ar, Kr, and Xe-that are all enriched relative to their solar abundances, having a metallicity of approximately +0.5.

Keywords: Extrasolar gaseous giant planets, Solar system, Chemical abundances, Jupiter
A Tight Correlation between Millimeter and X-Ray Emission in Accreting Massive Black Holes from &lt;100 mas Resolution ALMA Observations. Recent studies have proposed that the nuclear millimeter continuum emission observed in nearby active galactic nuclei (AGNs) could be created by the same population of electrons that gives rise to the X-ray emission that is ubiquitously observed in accreting black holes. We present the results of a dedicated high-spatial-resolution (~60-100 mas) Atacama Large Millimeter/submillimeter Array (ALMA) campaign on a volume-limited (&lt;50 Mpc) sample of 26 hard X-ray (&gt;10 keV) selected radio-quiet AGNs. We find an extremely high detection rate (25/26 or ${94}_{-6}^{+3} \% $ ), which shows that nuclear emission at millimeter wavelengths is nearly ubiquitous in accreting SMBHs. Our high-resolution observations show a tight correlation between the nuclear (1-23 pc) 100 GHz and the intrinsic X-ray emission (1σ scatter of 0.22 dex). The ratio between the 100 GHz continuum and the X-ray emission does not show any correlation with column density, black hole mass, Eddington ratio, or star formation rate, which suggests that the 100 GHz emission can be used as a proxy of SMBH accretion over a very broad range of these parameters. The strong correlation between 100 GHz and X-ray emission in radio-quiet AGNs could be used to estimate the column density based on the ratio between the observed 2-10 keV ( ${F}_{2\mbox{--}10\,\mathrm{keV}}^{\mathrm{obs}}$ ) and 100 GHz (F 100 GHz) fluxes. Specifically, a ratio $\mathrm{log}({F}_{2\mbox{--}10\,\mathrm{keV}}^{\mathrm{obs}}/{F}_{100\,\mathrm{GHz}})\leqslant 3.5$ strongly suggests that a source is heavily obscured ( $\mathrm{log}({N}_{{\rm{H}}}/{\mathrm{cm}}^{-2})\gtrsim 23.8$ ). Our work shows the potential of ALMA continuum observations to detect heavily obscured AGNs (up to an optical depth of one at 100 GHz, i.e., N H ≃ 1027 cm-2), and to identify binary SMBHs with separations &lt;100 pc, which cannot be probed by current X-ray facilities.

Keywords: Supermassive black holes, X-ray active galactic nuclei, Active galactic nuclei
Observations of Mini Coronal Dimmings Caused by Small-scale Eruptions in the Quiet Sun. Small-scale eruptions could play an important role in coronal heating, generation of solar energetic particles (SEPs), and mass source of the solar wind. However, they are poorly observed, and their characteristics, distributions, and origins remain unclear. Here a mini coronal dimming was captured by the recently launched Solar Orbiter spacecraft. The observations indicate that a minifilament eruption results in the dimming and takes away approximately (1.65 ± 0.54) × 1013 g of mass, which also exhibits similar features as the sources of SEP events. The released magnetic free energy is of the order of ~1027 erg. Our results suggest that weak constraining force makes the flux rope associated with the minifilament easily enter a torus-unstable domain. We discuss that weak magnetic constraints from low-altitude background fields may be a general condition for the quiet-Sun eruptions, which provide a possible mechanism for the transport of coronal material and energy from the lower to the middle or even higher corona.

Keywords: Quiet sun, Solar coronal transients, Solar filaments, Solar magnetic fields
A Luminous Red Supergiant and Dusty Long-period Variable Progenitor for SN 2023ixf. We analyze pre-explosion near- and mid-infrared (IR) imaging of the site of SN 2023ixf in the nearby spiral galaxy M101 and characterize the candidate progenitor star. The star displays compelling evidence of variability with a possible period of ≈1000 days and an amplitude of ∆m ≈ 0.6 mag in extensive monitoring with the Spitzer Space Telescope since 2004, likely indicative of radial pulsations. Variability consistent with this period is also seen in the near-IR J and K  s  bands between 2010 and 2023, up to just 10 days before the explosion. Beyond the periodic variability, we do not find evidence for any IR-bright pre-supernova outbursts in this time period. The IR brightness ( ${M}_{{K}_{s}}=-10.7$ mag) and color (J - K  s  = 1.6 mag) of the star suggest a luminous and dusty red supergiant. Modeling of the phase-averaged spectral energy distribution (SED) yields constraints on the stellar temperature ( ${T}_{\mathrm{eff}}={3500}_{-1400}^{+800}$ K) and luminosity ( $\mathrm{log}L/{L}_{\odot }=5.1\pm 0.2$ ). This places the candidate among the most luminous Type II supernova progenitors with direct imaging constraints, with the caveat that many of these rely only on optical measurements. Comparison with stellar evolution models gives an initial mass of M init = 17 ± 4 M ☉. We estimate the pre-supernova mass-loss rate of the star between 3 and 19 yr before explosion from the SED modeling at $\dot{M}\approx 3\times {10}^{-5}$ to 3 × 10-4 M ☉ yr-1 for an assumed wind velocity of v  w  = 10 km s-1, perhaps pointing to enhanced mass loss in a pulsation-driven wind.

Keywords: Evolved stars, Massive stars, Stellar mass loss, Circumstellar dust, Supernovae
Demonstrating Photon Ring Existence with Single-baseline Polarimetry. Images of supermassive black hole accretion flows contain features of both curved spacetime and plasma structure. Inferring properties of the spacetime from images requires modeling the plasma properties, and vice versa. The Event Horizon Telescope Collaboration has imaged near-horizon millimeter emission from both Messier 87* (M87*) and Sagittarius A* (Sgr A*) with very long baseline interferometry (VLBI) and has found a preference for magnetically arrested disk (MAD) accretion in each case. MAD accretion enables spacetime measurements through future observations of the photon ring, the image feature composed of near-orbiting photons. The ordered fields and relatively weak Faraday rotation of MADs yield rotationally symmetric polarization when viewed at modest inclination. In this letter, we utilize this symmetry along with parallel transport symmetries to construct a gain-robust interferometric quantity that detects the transition between the weakly lensed accretion flow image and the strongly lensed photon ring. We predict a shift in polarimetric phases on long baselines and demonstrate that the photon rings in M87* and Sgr A* can be unambiguously detected with sensitive, long-baseline measurements. For M87*, we find that photon ring detection in snapshot observations requires ~1 mJy sensitivity on &gt;15 Gλ baselines at 230 GHz and above, which could be achieved with space-VLBI or higher-frequency ground-based VLBI. For Sgr A*, we find that interstellar scattering inhibits photon ring detectability at 230 GHz, but ~10 mJy sensitivity on &gt;12 Gλ baselines at 345 GHz is sufficient and is accessible from the ground. For both sources, these sensitivity requirements may be relaxed by repeated observations and averaging.

Keywords: Gravitational lensing, Supermassive black holes, Very long baseline interferometry, Polarimetry
Collapsar Black Holes Are Likely Born Slowly Spinning. Collapsing stars constitute the main black hole (BH) formation channel, and are occasionally associated with the launch of relativistic jets that power γ-ray bursts (GRBs). Thus, collapsars offer an opportunity to infer the natal (before spin-up/down by accretion) BH spin directly from observations. We show that once the BH saturates with a large-scale magnetic flux, the jet power is dictated by the BH spin and mass accretion rate. Core-collapse simulations by Halevi et al. and GRB observations favor stellar density profiles that yield an accretion rate of $\dot{m}\approx {10}^{-2}\,{M}_{\odot }\,{{\rm{s}}}^{-1}$ , weakly dependent on time. This leaves the spin as the main factor that governs the jet power. By comparing the jet power to characteristic GRB luminosities, we find that the majority of BHs associated with jets are likely born slowly spinning with a dimensionless spin of a ≃ 0.2, or a ≃ 0.5 for wobbling jets, with the main uncertainty originating in the unknown γ-ray radiative efficiency. This result could be applied to the entire core-collapse BH population, unless an anticorrelation between the stellar magnetic field and angular momentum is present. In a companion paper, Jacquemin-Ide et al., we show that regardless of the natal spin, the extraction of BH rotational energy leads to spin-down to a ≲ 0.2, consistent with gravitational-wave observations. We verify our results by performing the first 3D general-relativistic magnetohydrodynamic simulations of collapsar jets with characteristic GRB energies, powered by slowly spinning BHs. We find that jets of typical GRB power struggle to escape from the star, providing the first numerical indication that many jets fail to generate a GRB.

Keywords: Black hole physics, Gamma-ray bursts, Core-collapse supernovae, Stellar mass black holes, Astrophysical black holes, Magnetohydrodynamical simulations
Evidence for Very Early Planetesimal Formation and <SUP>26</SUP>Al/<SUP>27</SUP>Al Heterogeneity in the Protoplanetary Disk. We present a U-corrected Pb-Pb age of 4566.19 ± 0.20 Ma (1.11 ± 0.26 Myr after t 0) for the moderately volatile element rich, andesitic meteorite Erg Chech 002 (EC002). Our Al-Mg isochron defines a 26Al/27Al initial ratio of (8.65 ± 0.09) × 10-6 that corresponds to a 26Al/27Al ratio of ${2.48}_{-0.56}^{+0.67}$ × 10-5 for the parent body precursor at the time of solar system formation. Whereas the published bulk chemistry and our high-precision Ca isotope measurement correspond to those for inner solar system materials, the 26Al/27Al ratio overlaps that for outer solar system CI chondrites. This indicates that the carriers and/or processes responsible for the nucleosynthetic isotope compositions for inner and outer disk materials are different than those controlling the heterogeneous distribution of 26Al. A low μ 26Mg* initial value of -6.1 ± 1.7 ppm infers a source region with a subchondritic Al/Mg ratio until 1.1 Myr after t 0 such that melt generation must have immediately preceded its crystallization. With 26Al as the main heating source, a modeled temperature-time path for a 100 km radius parent body with our inferred 26Al abundance suggests that accretion must have occurred before 0.5 Myr after t 0 to reach melting temperatures at appropriate depths within 1.1 Myr. This requires that the parent body formed very early within the protoplanetary disk, consistent with predictions of rapid formation of planetesimals by streaming instabilities within high-density dust filaments during the earliest phase of the protoplanetary disk. Finally, an absence of initial Pb in this otherwise moderately volatile-rich achondrite implies Pb was effectively sequestered to the Fe-Ni core.

Keywords: Cosmochronology, Cosmochemistry, Planet formation
A Black Hole Kicked at Birth: MAXI J1305-704. When a compact object is formed in a binary, any mass lost during core collapse will impart a kick on the binary's center of mass. Asymmetries in this mass loss or neutrino emission would impart an additional natal kick on the remnant black hole or neutron star, whether it was formed in a binary or in isolation. While it is well established that neutron stars receive natal kicks upon formation, it is unclear whether black holes do as well. Here, we consider the low-mass X-ray binary MAXI J1305-704, which has been reported to have a space velocity ≳200 km s-1. In addition to integrating its trajectory to infer its velocity upon formation of its black hole, we account for recent estimates of its period, black hole mass, mass ratio, and donor effective temperature from photometric and spectroscopic observations. We find that if MAXI J1305-704 formed via isolated binary evolution in the thick Galactic disk, then the supernova that formed its black hole imparted a natal kick of at least 70 km s-1 while ejecting less than ≃1 M ⊙ with 95% confidence assuming uninformative priors on mass loss and natal kick velocity.

Keywords: Low-mass x-ray binary stars, Supernovae, Astrophysical black holes
AT 2023clx: The Faintest and Closest Optical Tidal Disruption Event Discovered in Nearby Star-forming Galaxy NGC 3799. We report the discovery of a faint optical tidal disruption event (TDE) in the nearby star-forming galaxy NGC 3799. Identification of the TDE is based on its position at the galaxy nucleus, a light curve declining as t ‑5/3, a blue continuum with an almost constant blackbody temperature of ∼12,000 K, broad (≈15,000 km s‑1) Balmer lines, and characteristic He II 4686 Å emission. The light curve of AT 2023clx peaked at an absolute magnitude of ‑17.16 mag in the g band and a maximum blackbody bolometric luminosity of 4.56 × 1042 erg s‑1, making it the faintest TDE discovered to date. With a redshift of 0.01107 and a corresponding luminosity distance of 47.8 Mpc, it is also the closest optical TDE ever discovered to the best of our knowledge. Furthermore, our analysis of Swift/XRT observations of AT 2023clx yields a very tight 3σ upper limit of 9.53 × 1039 erg s‑1 in the range 0.3–10 keV. AT 2023clx, together with very few other faint TDEs such as AT 2020wey, prove that there are probably a large number of faint TDEs yet to be discovered at higher redshifts, which is consistent with the prediction of luminosity functions (LFs). The upcoming deeper optical time-domain surveys, such as the Legacy Survey of Space and Time and the Wide Field Survey Telescope, will discover more TDEs at even lower luminosities, allowing for a more precise constraint of the low end of the LF.

Keywords: Tidal disruption, Time domain astronomy
Thermal Effects in Binary Neutron Star Mergers. We study the impact of finite-temperature effects in numerical-relativity simulations of binary neutron star mergers with microphysical equations of state and neutrino transport in which we vary the effective nucleon masses in a controlled way. We find that, as the specific heat is increased, the merger remnants become colder and more compact due to the reduced thermal pressure support. Using a full Bayesian analysis, we demonstrate that this effect will be measurable in the postmerger gravitational wave signal with next-generation observatories at signal-to-noise ratios of 15.

Keywords: Neutron stars, Relativistic binary stars, Gravitational wave sources, Gravitational waves, Compact objects
The NANOGrav 15 yr Data Set: Constraints on Supermassive Black Hole Binaries from the Gravitational-wave Background. The NANOGrav 15 yr data set shows evidence for the presence of a low-frequency gravitational-wave background (GWB). While many physical processes can source such low-frequency gravitational waves, here we analyze the signal as coming from a population of supermassive black hole (SMBH) binaries distributed throughout the Universe. We show that astrophysically motivated models of SMBH binary populations are able to reproduce both the amplitude and shape of the observed low-frequency gravitational-wave spectrum. While multiple model variations are able to reproduce the GWB spectrum at our current measurement precision, our results highlight the importance of accurately modeling binary evolution for producing realistic GWB spectra. Additionally, while reasonable parameters are able to reproduce the 15 yr observations, the implied GWB amplitude necessitates either a large number of parameters to be at the edges of expected values or a small number of parameters to be notably different from standard expectations. While we are not yet able to definitively establish the origin of the inferred GWB signal, the consistency of the signal with astrophysical expectations offers a tantalizing prospect for confirming that SMBH binaries are able to form, reach subparsec separations, and eventually coalesce. As the significance grows over time, higher-order features of the GWB spectrum will definitively determine the nature of the GWB and allow for novel constraints on SMBH populations.

Keywords: Galaxy evolution, Supermassive black holes, Gravitational waves
The Vanishing of the Primary Emission Region in PKS 1510-089. In 2021 July, PKS 1510-089 exhibited a significant flux drop in the high-energy γ-ray (by a factor 10) and optical (by a factor 5) bands and remained in this low state throughout 2022. Similarly, the optical polarization in the source vanished, resulting in the optical spectrum being fully explained through the steady flux of the accretion disk and the broad-line region. Unlike the aforementioned bands, the very-high-energy γ-ray and X-ray fluxes did not exhibit a significant flux drop from year to year. This suggests that the steady-state very-high-energy γ-ray and X-ray fluxes originate from a different emission region than the vanished parts of the high-energy γ-ray and optical jet fluxes. The latter component has disappeared through either a swing of the jet away from the line of sight or a significant drop in the photon production efficiency of the jet close to the black hole. Either change could become visible in high-resolution radio images.

Keywords: Spectropolarimetry, Gamma-ray sources, Blazars, Relativistic jets, Flat-spectrum radio quasars, Non-thermal radiation sources
Photospheric Velocity Evolution of SN 2020bvc: Signature of r-process Nucleosynthesis from a Collapsar. Whether binary neutron star mergers are the only astrophysical site of rapid neutron-capture process (r-process) nucleosynthesis remains unknown. Collapsars associated with long gamma-ray bursts (GRBs) and hypernovae are promising candidates. Simulations have shown that outflows from collapsar accretion disks can produce enough r-process materials to explain the abundances in the universe. However, there is no observational evidence to confirm this result at present. SN 2020bvc is a broad-lined Type Ic (Ic-BL) supernova (SN) possibly associated with a low-luminosity GRB. Based on semi-analytic SN emission models with and without r-process materials, we perform a fitting to the multiband light curves and photospheric velocities of SN 2020bvc. We find that in a r-process-enriched model the mixing of r-process materials slows down the photospheric recession and therefore matches the velocity evolution better. The fitting results show that r-process materials with mass of ≈0.36 M ⊙ and opacity of ≈4 cm2 g-1 is needed to mix with about half of the SN ejecta. Our fitting results are weakly dependent on the nebular emission. Future statistical analysis of a sample of Type Ic-BL SNe helps us understand the contribution of collapsars to the r-process abundance.

Keywords: Type Ic supernovae, Explosive nucleosynthesis, Nucleosynthesis, Core-collapse supernovae, R-process