Sazuna/UAT_keywords huggingface dataset:
Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H. The search for rocky planet atmospheres with JWST has focused on planets transiting M dwarfs. Such planets have favorable planet-to-star size ratios, enhancing the amplitude of atmospheric features. Since the expected signal strength of atmospheric features is similar to the single-transit performance of JWST, multiple observations are required to confirm any detection. Here, we present two transit observations of the rocky planet GJ 1132 b with JWST NIRSpec G395H, covering 2.8-5.2 μm. Previous Hubble Space Telescope WFC3 observations of GJ 1132 b were inconclusive, with evidence reported for either an atmosphere or a featureless spectrum based on analyses of the same data set. Our JWST data exhibit substantial differences between the two visits. One transit is consistent with either an H2O-dominated atmosphere containing ~1% CH4 and trace N2O ( ${\chi }_{\nu }^{2}=1.13$ ) or stellar contamination from unocculted starspots ( ${\chi }_{\nu }^{2}=1.36$ ). However, the second transit is consistent with a featureless spectrum. Neither visit is consistent with a previous report of HCN. Atmospheric variability is unlikely to explain the scale of the observed differences between the visits. Similarly, our out-of-transit stellar spectra show no evidence of changing stellar inhomogeneity between the two visits-observed 8 days apart, only 6.5% of the stellar rotation rate. We further find no evidence of differing instrumental systematic effects between visits. The most plausible explanation is an unlucky random noise draw leading to two significantly discrepant transmission spectra. Our results highlight the importance of multivisit repeatability with JWST prior to claiming atmospheric detections for these small, enigmatic planets.

Keywords: Extrasolar rocky planets, Exoplanet atmospheric composition , Starspots, Infrared spectroscopy, Exoplanet atmospheres, Super Earths, Planetary atmospheres, Transmission spectroscopy, Stellar atmospheres, Astronomy data reduction
SN 2023emq: A Flash-ionized Ibn Supernova with Possible C III Emission. SN 2023emq is a fast-evolving transient initially classified as a rare Type Icn supernova (SN), interacting with a H- and He-free circumstellar medium (CSM) around maximum light. Subsequent spectroscopy revealed the unambiguous emergence of narrow He lines, confidently placing SN 2023emq in the more common Type Ibn class. Photometrically, SN 2023emq has several uncommon properties regardless of its class, including its extreme initial decay (faster than &gt;90% of Type Ibn/Icn SNe) and sharp transition in the decline rate from 0.20 to 0.07 mag day-1 at +20 days. The bolometric light curve can be modeled as CSM interaction with 0.32M ☉ of ejecta and 0.12M ☉ of CSM, with 0.006M ☉ of nickel, as expected of fast, interacting SNe. Furthermore, broadband polarimetry at +8.7 days (P = 0.55% ± 0.30%) is consistent with spherical symmetry. A discovery of a transitional Type Icn/Ibn SN would be unprecedented and would give valuable insights into the nature of mass loss suffered by the progenitor just before death, but we favor an interpretation that SN 2023emq is a Type Ibn SN that exhibited flash-ionized features in the earliest spectrum, as the features are not an exact match with other Type Icn SNe to date. However, the feature at 5700 Å, in the region of C III and N II emission, is significantly stronger in SN 2023emq than in the few other flash-ionized Type Ibn SNe, and if it is related to C III, it possibly implies a continuum of properties between the two classes.

Keywords: Supernovae
The Large Magellanic Cloud's  30 kpc Bow Shock and Its Impact on the Circumgalactic Medium. The interaction between the supersonic motion of the Large Magellanic Cloud (LMC) and the circumgalactic medium (CGM) is expected to result in a bow shock that leads the LMC's gaseous disk. In this letter, we use hydrodynamic simulations of the LMC's recent infall to predict the extent of this shock and its effect on the Milky Way's (MW) CGM. The simulations clearly predict the existence of an asymmetric shock with a present-day standoff radius of ~6.7 kpc and a transverse diameter of ~30 kpc. Over the past 500 Myr, ~8% of the MW's CGM in the southern hemisphere should have interacted with the shock front. This interaction may have had the effect of smoothing over inhomogeneities and increasing mixing in the MW CGM. We find observational evidence of the existence of the bow shock in recent Hα maps of the LMC, providing a potential explanation for the envelope of ionized gas surrounding the LMC. Furthermore, the interaction of the bow shock with the MW CGM may also explain the observations of ionized gas surrounding the Magellanic Stream. Using recent orbital histories of MW satellites, we find that many satellites have likely interacted with the LMC shock. Additionally, the dwarf galaxy Ret2 is currently sitting inside the shock, which may impact the interpretation of the reported gamma-ray excess in Ret2. This work highlights how bow shocks associated with infalling satellites are an underexplored yet potentially very important dynamical mixing process in the circumgalactic and intracluster media.

Keywords: Hydrodynamical simulations, Large Magellanic Cloud, Circumgalactic medium
Ejecta Evolution Following a Planned Impact into an Asteroid: The First Five Weeks. The impact of the Double Asteroid Redirection Test spacecraft into Dimorphos, moon of the asteroid Didymos, changed Dimorphos's orbit substantially, largely from the ejection of material. We present results from 12 Earth-based facilities involved in a world-wide campaign to monitor the brightness and morphology of the ejecta in the first 35 days after impact. After an initial brightening of ~1.4 mag, we find consistent dimming rates of 0.11-0.12 mag day-1 in the first week, and 0.08-0.09 mag day-1 over the entire study period. The system returned to its pre-impact brightness 24.3-25.3 days after impact though the primary ejecta tail remained. The dimming paused briefly eight days after impact, near in time to the appearance of the second tail. This was likely due to a secondary release of material after re-impact of a boulder released in the initial impact, though movement of the primary ejecta through the aperture likely played a role.

Keywords: Impact phenomena, Near-Earth objects, Asteroids, Asteroid satellites
Auroras on Planets around Pulsars. The first extrasolar planets were discovered serendipitously, by finding the slight variation in otherwise highly regular timing of the pulses, caused by the planets orbiting a millisecond pulsar. In analogy with the solar system planets, we predict the existence of aurora on planets around millisecond pulsars. We perform the first magnetohydrodynamic simulations of magnetospheric pulsar-planet interaction and estimate the radio emission from such systems. We find that the radio emission from aurora on pulsar planets could be observable with the current instruments. We provide parameters for such a detection, which would be the first radio detection of an extrasolar planet. In addition to probing the atmosphere of planets in such extreme conditions, of great interest is also the prospect of the first direct probe into the pulsar wind.

Keywords: Magnetohydrodynamics, Pulsar planets, Aurorae
Similarity between Compact Extremely Red Objects Discovered with JWST in Cosmic Dawn and Blue-excess Dust-obscured Galaxies Known in Cosmic Noon. Spatially compact objects with extremely red color in the rest-frame optical to near-infrared (0.4-1 μm) and blue color in the rest-frame ultraviolet (UV; 0.2-0.4 μm) have been discovered at 5 &lt; z &lt; 9 using the James Webb Space Telescope (JWST). These extremely red objects (JWST-EROs) exhibit spectral energy distributions (SEDs) that are difficult to explain using a single component of either star-forming galaxies or quasars, leading to two-component models in which the blue UV and extremely red optical are explained using less-dusty and dusty spectra of galaxies or quasars, respectively. Here, we report the remarkable similarity in SEDs between JWST-EROs and blue-excess dust-obscured galaxies (BluDOGs) identified at 2 &lt; z &lt; 3. BluDOGs are a population of active galactic nuclei (AGNs) with black hole masses of ~108-9 M ⊙, which are 1 order of magnitude larger than those in some JWST-EROs. The Eddington ratios of BluDOGs are 1 or higher, whereas those of JWST-EROs are in the range of 0.1-1. Therefore, JWST-EROs are less massive, less active, and more common counterparts in higher-z of BluDOGs in cosmic noon. Conversely, JWST-EROs have a significantly higher fraction of those with blue excess than DOGs. We present the average UV spectra of BluDOGs as a comparison to JWST-EROs and discuss a coherent evolutionary scenario for dusty AGN populations.

Keywords: Active galactic nuclei, Galaxy evolution
Observing Planetesimal Formation under Streaming Instability in the Rings of HD 163296. We introduce a new technique to determine the gas turbulence and surface density in bright disk rings, under the assumption that dust growth is limited by turbulent fragmentation at the ring center. We benchmark this prescription in HD 163296, showing that our measurements are consistent with available turbulence upper limits and agree with independent estimates of the gas surface density within a factor of 2. We combine our results with literature measurements of the dust surface density and grain size to determine the dust-to-gas ratio and Stokes number in the 67 and 100 au rings. Our estimates suggest that particle clumping is taking place under the effect of streaming instability (SI) in the 100 au ring. Even though in the presence of external isotropic turbulence this process might be hindered, we provide evidence that turbulence is nonisotropic in both rings and likely originates from mechanisms (such as ambipolar diffusion) that could ease particle clumping under SI. Finally, we determine the mass accretion rate under the assumption that the disk is in steady state and turbulence regulates angular momentum transport. Our results are in tension with spectroscopic measurements and suggest that other mechanisms might be responsible for accretion, in qualitative agreement with the detection of a magnetocentrifugal wind in this system. Applying our method to larger samples can be used to statistically assess if SI is a viable mechanism to form planetesimals in bright rings.

Keywords: Gas-to-dust ratio, Dust continuum emission, Protoplanetary disks, CO line emission, Submillimeter astronomy, Planetary cores, Planet formation, Planetesimals
A Study of Two Periodogram Algorithms for Improving the Detection of Small Transiting Planets. The sensitivities of two periodograms are compared for weak signal planet detection in transit surveys: the widely used Box Least Squares (BLS) algorithm following light curve detrending and the Transit Comb Filter (TCF) algorithm following autoregressive ARIMA modeling. Small depth transits are injected into light curves with different simulated noise characteristics. Two measures of spectral peak significance are examined: the periodogram signal-to-noise ratio (S/N) and a false alarm probability (FAP) based on the generalized extreme value distribution. The relative performance of the BLS and TCF algorithms for small planet detection is examined for a range of light curve characteristics, including orbital period, transit duration, depth, number of transits, and type of noise. We find that the TCF periodogram applied to ARIMA fit residuals with the S/N detection metric is preferred when short-memory autocorrelation is present in the detrended light curve and even when the light curve noise had white Gaussian noise. BLS is more sensitive to small planets only under limited circumstances with the FAP metric. BLS periodogram characteristics are inferior when autocorrelated noise is present due to heteroscedastic noise and false period detection. Application of these methods to TESS light curves with known small exoplanets confirms our simulation results. The study ends with a decision tree that advises transit survey scientists on procedures to detect small planets most efficiently. The use of ARIMA detrending and TCF periodograms can significantly improve the sensitivity of any transit survey with regularly spaced cadence.

Keywords: Transits, Period search , Exoplanet detection methods, Transit photometry, Time series analysis
Are There Terrestrial Planets Lurking in the Outer Solar System?. Motivated by recent measurements of the free-floating-planet mass function at terrestrial masses, we consider the possibility that the solar system may have captured a terrestrial planet early in its history. We show that ~1.2 captured free-floating planets with mass strictly greater than that of Mars may exist in the outer solar system, with a median predicted distance of ~1400 au. If we consider a logarithmic bin centered on the mass of Mars, rather than a cutoff, we find that ~2.7 captured free-floating planets with mass comparable to Mars may exist in the outer solar system. We derive an expectation value of ~0.9 for the number of captured free-floating planets with mass comparable to that of Mars (~1.4 for mass comparable to that of Mercury) that are currently brighter than the 10 yr coadded point-source detection limits of the Vera C. Rubin Observatory's Legacy Survey of Space and Time. Blind shift-and-stack searches could potentially enable the detection of such a planet if it is currently in the Southern sky. The theoretical argument presented here does not rely on the existence of posited patterns in the orbital elements of small bodies in and beyond the Kuiper Belt, in contrast with other hypothetical outer-solar-system planets motivated in recent years.

Keywords: Free floating planets, Planetary dynamics
Star Formation and AGN Activity 500 Myr after the Big Bang: Insights from JWST. We consider the effect of including an active galactic nuclei (AGN) component when fitting spectral energy distributions of 109 spectroscopically confirmed z ≈ 3.5-12.5 galaxies with JWST. Remarkably, we find that the resulting cosmic star formation history is ≈0.4 dex lower at z ≳ 9.5 when an AGN component is included in the fitting. This alleviates previously reported excess star formation at z ≳ 9.5 compared to models based on typical baryon conversion efficiencies inside dark matter halos. We find that the individual stellar masses and star formation rates can be as much as ≈4 dex lower when fitting with an AGN component. These results highlight the importance of considering both stellar mass assembly and supermassive black hole growth when interpreting the light distributions of among the first galaxies to ever exist.

Keywords: Supermassive black holes, Active galactic nuclei, High-redshift galaxies, Quasars
Mid-infrared Outbursts in Nearby Galaxies: Nuclear Obscuration and Connections to Hidden Tidal Disruption Events and Changing-look Active Galactic Nuclei. We study the properties of galaxies hosting mid-infrared outbursts in the context of a catalog of 500,000 galaxies from the Sloan Digital Sky Survey. We find that nuclear obscuration, as inferred by the surrounding dust mass, does not correlate with host galaxy type, stellar properties (e.g., total mass and mean age), or with the extinction of the host galaxy as estimated by the Balmer decrement. This implies that nuclear obscuration may not be able to explain any overrepresentation of tidal disruption events in particular host galaxies. We identify a region in the galaxy catalog parameter space that contains all unobscured tidal disruption events but only harbors ≲11% of the mid-infrared outburst hosts. We find that mid-infrared outburst hosts appear more centrally concentrated and have higher galaxy Sérsic indices than galaxies hosting active galactic nuclei (AGNs) selected using the Baldwin-Phillips-Terlevich classification. We thus conclude that the majority of mid-infrared outbursts are not hidden tidal disruption events but are instead consistent with being obscured AGN that are highly variable, such as changing-look AGN.

Keywords: AGN host galaxies, Tidal disruption, Infrared sources, Galaxy nuclei
Relating Intermittency and Inverse Cascade to Stochastic Entropy in Solar Wind Turbulence. Turbulent energy transfer in nearly collisionless plasmas can be conceptualized as a scale-to-scale Langevin process. Hence, the statistics of magnetic field fluctuations can be embedded in the framework of stochastic process theory. In this work, we investigate the statistical properties of the pristine solar wind as observed by Parker Solar Probe by defining the cascade trajectories of magnetic field increments and by estimating the stochastic entropy variation along them. Through the stochastic entropy, we can identify two regimes where fluctuations exhibit contrasting statistical properties. In the inertial range, the entropy production is associated with an increase of the flatness indicating the occurrence of intermittency. Otherwise, trajectories associated with an entropy consumption exhibit global scale invariance. In the transition region toward ion scales, the phenomenology switches: entropy-consuming trajectories exhibit a sudden flatness increase, associated with the presence of small-scale intermittency, while entropy-producing trajectories display a nearly constant flatness. Results are interpreted in terms of physical processes consistent with an accumulation of energy at ion scales.

Keywords: Interplanetary turbulence, Space plasmas, Solar wind, Interplanetary physics
Constraints on the Alfvénicity of Switchbacks. Switchbacks (SBs) are localized structures in the solar wind containing deflections of the magnetic field direction relative to the background solar wind magnetic field. The amplitudes of the magnetic field deflection angles (θ) for different SBs vary from ~40° to ~160°-170°. Alignment of the perturbations of the magnetic field (Δ B ) and the bulk solar wind velocity (Δ V ) is observed inside SBs so that Δ V ~ Δ B when the background magnetic field is directed toward the Sun (if the background solar wind magnetic field direction is anti-sunward then Δ V ~ - Δ B , supporting anti-sunward propagation in the background solar wind frame). This causes spiky enhancements of the radial bulk velocity inside SBs. We have investigated the deviations of SB perturbations from Alfvénicity by evaluating the distribution of the parameter α, defined as the ratio of the parallel to Δ B component of Δ V to Δ V A = Δ B /4π n  i  m  i  inside SBs, i.e., α = V ∣∣/∣Δ V A∣ (α = ∣Δ V ∣/∣Δ V A∣ when Δ V ~ Δ B ), which quantifies the deviation of the perturbation from an Alfvénic one. Based on Parker Solar Probe (PSP) observations, we show that α inside SBs has systematically lower values than it has in the pristine solar wind: α inside SBs observed during PSP Encounter 1 were distributed in a range from ~0.2 to ~0.9. The upper limit on α is constrained by the requirement that the jump in velocity across the switchback boundary be less than the local Alfvén speed. This prevents the onset of shear flow instabilities. The consequence of this limitation is that the perturbation of the proton bulk velocity in SBs with θ &gt; π/3 cannot reach α = 1 (the Alfvénicity condition) and the highest possible α for an SB with θ = π is 0.5. These results have consequences for the interpretation of switchbacks as large amplitude Alfvén waves.

Keywords: Solar wind
Bridging Scales in Black Hole Accretion and Feedback: Magnetized Bondi Accretion in 3D GRMHD. Fueling and feedback couple supermassive black holes (SMBHs) to their host galaxies across many orders of magnitude in spatial and temporal scales, making this problem notoriously challenging to simulate. We use a multi-zone computational method based on the general relativistic magnetohydrodynamic (GRMHD) code KHARMA that allows us to span 7 orders of magnitude in spatial scale, to simulate accretion onto a non-spinning SMBH from an external medium with a Bondi radius of R B ≈ 2 × 105 GM •/c 2, where M • is the SMBH mass. For the classic idealized Bondi problem, spherical gas accretion without magnetic fields, our simulation results agree very well with the general relativistic analytic solution. Meanwhile, when the accreting gas is magnetized, the SMBH magnetosphere becomes saturated with a strong magnetic field. The density profile varies as ~r -1 rather than r -3/2 and the accretion rate $\dot{M}$ is consequently suppressed by over 2 orders of magnitude below the Bondi rate ${\dot{M}}_{{\rm{B}}}$ . We find continuous energy feedback from the accretion flow to the external medium at a level of $\sim {10}^{-2}\dot{M}{c}^{2}\sim 5\,\times \,{10}^{-5}{\dot{M}}_{{\rm{B}}}{c}^{2}$ . Energy transport across these widely disparate scales occurs via turbulent convection triggered by magnetic field reconnection near the SMBH. Thus, strong magnetic fields that accumulate on horizon scales transform the flow dynamics far from the SMBH and naturally explain observed extremely low accretion rates compared to the Bondi rate, as well as at least part of the energy feedback.

Keywords: Accretion, Supermassive black holes, Hydrodynamical simulations, Schwarzschild black holes, Bondi accretion, Active galactic nuclei
Stars Bisected by Relativistic Blades. We consider the dynamics of an equatorial explosion powered by a millisecond magnetar formed from the core collapse of a massive star. We study whether these outflows-generated by a priori magneto-centrifugally driven, relativistic magnetar winds-might be powerful enough to produce an ultrarelativistic blade ("lamina") that successfully carves its way through the dense stellar interior. We present high-resolution numerical special-relativistic hydrodynamic simulations of axisymmetric centrifugally driven explosions inside a star and follow the blast wave propagation just after breakout. We estimate the engine requirements to produce ultrarelativistic lamina jets and comment on the physicality of the parameters considered. We find that sufficiently collimated-half-opening angle θ  r  ≤ 0.°2-laminas successfully break out of a compact progenitor at ultrarelativistic velocities ( ${{\rm{\Gamma }}}_{\mathrm{core}}\gtrsim 30$ ) and extreme isotropic energies (E  k,iso ~ 5 × 1052 erg) within a few percent of the typical spin-down period for a millisecond magnetar. The various phases of these ultrathin outflows, such as collimation shocks, Kelvin-Helmholtz instabilities, and lifetime, are discussed, and we speculate on the observational signatures echoed by this outflow geometry.

Keywords: Magnetars, Relativistic jets, Relativistic fluid dynamics
Correlation between Supergranular Lane Widths and Sunspot Number; A Simple Way to Predict the Amplitude of Sunspot Cycle. The network structure seen in the solar images is the outline of supergranulation, which is the large-scale convection in the Sun with a size of about 30 Mm and a lifetime of 24 hr. We have obtained the supergranulation lane widths from the autocorrelation function of image windows from the Ca II K spectroheliograms. The images are obtained from the 100 yr Kodaikanal data, which contains information on more than nine solar cycles. The lane widths are known to show a positive correlation with the sunspot number. It is now found that the lane widths, obtained near the mid-latitudes during the sunspot cycle minima, are strongly correlated to the following sunspot number maxima. A straight-line fit adequately describes the variation. It is also found that the correlation is weak or insignificant at other times. The strong correlation of the two parameters thus provides a simple way to predict the maximum sunspot number about 4-5 yr in advance. The results are important in space weather predictions and solar irradiance variations.

Keywords: Solar cycle, Solar atmosphere