adsabs/SciX_UAT_keywords huggingface dataset:
Early Insights for Atmospheric Retrievals of Exoplanets Using JWST Transit Spectroscopy

We have entered the era of the James Webb Space Telescope (JWST). We use the first JWST transmission spectrum of the hot Saturn-mass exoplanet, WASP-39 b, obtained with the NIRSpec instrument in the 3-5 μm range to investigate (a) what atmospheric constraints are possible with JWST-quality data in this spectral range, (b) requirements for atmospheric models used in retrievals, (c) effect of differences between data reduction pipelines on retrieved atmospheric properties, and (d) complementarity between JWST data in the 3-5 μm range and Hubble Space Telescope (HST) observations at shorter wavelengths. JWST spectra in the 3-5 μm range provide a promising avenue for chemical detections while encompassing a window in cloud opacity for several prominent aerosols. We confirm recent inferences of CO2, SO2, H2O, and CO in WASP-39 b; report tentative evidence for H2S; and retrieve elemental abundances consistent with Saturn's metallicity. We retrieve molecular abundances with ~0.3-0.6 dex precision with this relatively limited spectral range. When considering the 3-5 μm data alone, reported differences in spectra with different reduction pipelines can affect abundance estimates by up to ~1 dex and the detectability of less prominent species. Complementing with data at shorter wavelengths, e.g., with other JWST instruments or HST WFC3 (~0.8-1.7 μm), can significantly improve the accuracy and precision of the abundance estimates. The high data quality enables constraints on aerosol properties, including their composition, modal size, and extent, motivating their consideration in retrievals. Our results highlight the promise of JWST exoplanet spectroscopy, while underscoring the importance of robust data reduction and atmospheric retrieval approaches in the JWST era.

Keywords: exoplanet atmospheres; james webb space telescope; transmission spectroscopy; infrared spectroscopy; radiative transfer
JWST's First Glimpse of a z > 2 Forming Cluster Reveals a Top-heavy Stellar Mass Function

Clusters and their progenitors (protoclusters) at z ∼ 2 ‑ 4, the peak epoch of star formation, are ideal laboratories to study the formation process of both the clusters themselves and their member galaxies. However, a complete census of their member galaxies has been challenging due to observational difficulties. Here we present new JWST/NIRCam observations targeting the distant cluster CLJ1001 at z = 2.51 from the COSMOS-Web program, which, in combination with previous narrowband imaging targeting Hα emitters and deep millimeter surveys of CO emitters, provide a complete view of massive galaxy assembly in CLJ1001. In particular, JWST reveals a population of massive, extremely red cluster members in the long-wavelength bands that were invisible in previous Hubble Space Telescope (HST)/F160W imaging (HST-dark members). Based on this highly complete spectroscopic sample of member galaxies, we show that the spatial distribution of galaxies in CLJ1001 exhibits a strong central concentration, with the central galaxy density already resembling that of low-z clusters. Moreover, we reveal a "top-heavy" stellar mass function for the star-forming galaxies (SFGs), with an overabundance of massive SFGs piled up in the cluster core. These features strongly suggest that CLJ1001 is caught in a rapid transition, with many of its massive SFGs likely soon becoming quiescent. In the context of cluster formation, these findings suggest that the earliest clusters form from the inside out and top to bottom, with the massive galaxies in the core assembling first, followed by the less massive ones in the outskirts.

Keywords: galaxies; protoclusters; high-redshift galaxy clusters
Systematic Phase Curve Study of Known Transiting Systems from Year One of the TESS Mission

We present a systematic phase curve analysis of known transiting systems observed by the Transiting Exoplanet Survey Satellite (TESS) during year one of the primary mission. Using theoretical predictions for the amplitude of the planetary longitudinal atmospheric brightness modulation, stellar ellipsoidal distortion and Doppler boosting, as well as brightness considerations to select targets with likely detectable signals, we applied a uniform data processing and light-curve modeling framework to fit the full-orbit phase curves of 22 transiting systems with planet-mass or brown dwarf companions, including previously published systems. Statistically significant secondary eclipse depths and/or atmospheric brightness modulation amplitudes were measured for HIP 65A, WASP-18, WASP-19, WASP-72, WASP-100, WASP-111, WASP-121, and WASP-122/KELT-14. For WASP-100b, we found marginal evidence that the brightest region of the atmosphere is shifted eastward away from the substellar point. We detected significant ellipsoidal distortion signals in the light curves of HIP 65A, TOI-503, WASP-18, and WASP-30, with HIP 65A, TOI-503 and WASP-18 also exhibiting Doppler boosting. The measured amplitudes of these signals agree with the predictions of theoretical models. Combining the optical secondary eclipse depths with previously published Spitzer 3.6 and 4.5 μm measurements, we derived dayside brightness temperatures and visible-light geometric albedos for a subset of the analyzed systems. We also calculated updated transit ephemerides combining the transit timings from the TESS light curves with previous literature values.

Keywords: exoplanet astronomy; exoplanet atmospheres
Linear and Circular Polarimetry of the Optically Bright Relativistic Tidal Disruption Event AT 2022cmc

Tidal disruption events (TDEs) occur when a star orbiting a massive black hole is sufficiently close to being tidally ripped apart by the black hole. AT 2022cmc is the first relativistic TDE that was observed (and discovered) as an optically bright and fast transient, showing signatures of nonthermal radiation induced by a jet that is oriented toward the Earth. In this work, we present optical linear and circular polarization measurements, observed with the Very Large Telescope/FORS2 in the R band (which corresponds to the blue/UV part of the spectrum in the rest frame), ~7.2 and ~12.2 rest-frame days after the first detection, respectively, when the light curve of the transient had settled in a bright blue plateau. Both linear and circular polarizations are consistent with zero, p lin = 0.14% ± 0.73%, and p cir = -0.30% ± 0.53%. This is the highest signal-to-noise ratio linear polarization measurement obtained for a relativistic TDE and the first circular polarimetry for such a transient. The nondetection of the linear and circular polarizations is consistent with the scenario of AT 2022cmc being a TDE where the thermal component (disk+outflows) is viewed pole-on, assuming an axially symmetric geometry. The presence and effect of a jet and/or external shocks are, however, difficult to disentangle.

Keywords: tidal disruption; polarimetry; high energy astrophysics; relativistic jets
The Remnant and Origin of the Historical Supernova 1181 AD

The guest star of AD 1181 is the only historical supernova of the past millennium that is without a definite counterpart. The previously proposed association with supernova remnant G130.7+3.1 (3C 58) is in strong doubt because of the inferred age of this remnant. Here we report a new identification of SN 1181 with our codiscovery of the hottest known Wolf-Rayet star of the oxygen sequence (IRAS 00500+6713 or 2MASS J00531123+6730023, here named by us as "Parker's star") and its surrounding nebula Pa 30. Our spectroscopy of the nebula shows a fast shock with extreme velocities of ≈1100 km s-1. The derived expansion age of the nebula implies an explosive event ≈1000 yr ago that agrees with the 1181 event. The on-sky location also fits the historical Chinese and Japanese reports of SN 1181 to within 3°5. Pa 30 and Parker's star have previously been proposed to be the result of a double-degenerate merger, leading to a rare Type Iax supernova. The likely historical magnitude and the distance suggest the event was subluminous for normal supernova. This agrees with the proposed Type Iax association that would also be only the second of its kind in the Galaxy. Taken together, the age, location, event magnitude, and duration elevate Pa 30 to prime position as the counterpart of SN 1181. This source is the only Type Iax supernova where detailed studies of the remnant star and nebula are possible. It provides strong observational support for the double-degenerate merger scenario for Type Iax supernovae.

Keywords: supernovae; supernova remnants; wolf-rayet stars
The AGORA High-resolution Galaxy Simulations Comparison Project. III. Cosmological Zoom-in Simulation of a Milky Way-mass Halo

We present a suite of high-resolution cosmological zoom-in simulations to z = 4 of a 1012 M⊙ halo at z = 0, obtained using seven contemporary astrophysical simulation codes (ART-I, ENZO, RAMSES, CHANGA, GADGET-3, GEAR, and GIZMO) widely used in the numerical galaxy formation community. The physics prescriptions for gas cooling and heating and star formation are the same as the ones used in our previous Assembling Galaxies of Resolved Anatomy (AGORA) disk comparison but now account for the effects of cosmological processes such as the expansion of the universe, intergalactic gas inflow, and the cosmic ultraviolet background radiation emitted by massive stars and quasars. In this work, we introduce the most careful comparison yet of galaxy formation simulations run by different code groups, together with a series of four calibration steps each of which is designed to reduce the number of tunable simulation parameters adopted in the final run. In the first two steps, we methodically calibrate the gas physics, such as cooling and heating, in simulations without star formation. In the third step, we seek agreement on the total stellar mass produced with the common star formation prescription used in the AGORA disk comparison, in stellar-feedback-free simulations. In the last calibration step, we activate stellar feedback, where each code group is asked to set the feedback prescription to as close to the most widely used one in its code community as possible, while aiming for convergence in the stellar mass at z = 4 to the values predicted by semiempirical models. After all the participating code groups successfully complete the calibration steps, we achieve a suite of cosmological simulations with similar mass assembly histories down to z = 4. With numerical accuracy that resolves the internal structure of a target halo (≲100 physical pc at z = 4), we find that the codes overall agree well with one another, e.g., in gas and stellar properties, but also show differences, e.g., in circumgalactic medium (CGM) properties. We argue that, if adequately tested in accordance with our proposed calibration steps and common parameters, high-resolution cosmological zoom-in simulations can have robust and reproducible results. New code groups are invited to join and enrich this comparison by generating equivalent models or to test the code's compatibility on their own, by adopting the common initial conditions, the common easy-to-implement physics package, and the proposed calibration steps. Further analyses of the zoom-in simulations presented here will be presented in forthcoming reports from the AGORA Collaboration, including studies of the CGM, simulations by additional codes, and results at lower redshift.

Keywords: galaxy formation; astronomical simulations; hydrodynamical simulations; stellar feedback
TOI-503: The First Known Brown-dwarf Am-star Binary from the TESS Mission

We report the discovery of an intermediate-mass transiting brown dwarf (BD), TOI-503b, from the TESS mission. TOI-503b is the first BD discovered by TESS, and it has circular orbit around a metallic-line A-type star with a period of P = 3.6772 ± 0.0001 days. The light curve from TESS indicates that TOI-503b transits its host star in a grazing manner, which limits the precision with which we measure the BD's radius ( ${R}_{b}={1.34}_{-0.15}^{+0.26}{R}_{{\rm{J}}} ). We obtained high-resolution spectroscopic observations with the FIES, Ondřejov, PARAS, Tautenburg, and TRES spectrographs, and measured the mass of TOI-503b to be Mb = 53.7 ± 1.2 ${M}_{{\rm{J}}} . The host star has a mass of M⋆ = 1.80 ± 0.06 M⊙, a radius of R⋆ = 1.70 ± 0.05R⊙, an effective temperature of Teff = 7650 ± 160 K, and a relatively high metallicity of 0.61 ± 0.07 dex. We used stellar isochrones to derive the age of the system to be ∼180 Myr, which places its age between that of RIK 72b (a ∼10 Myr old BD in the Upper Scorpius stellar association) and AD 3116b (a ∼600 Myr old BD in the Praesepe cluster). Given the difficulty in measuring the tidal interactions between BDs and their host stars, we cannot precisely say whether this BD formed in situ or has had its orbit circularized by its host star over the relatively short age of the system. Instead, we offer an examination of plausible values for the tidal quality factor for the star and BD. TOI-503b joins a growing number of known short-period, intermediate-mass BDs orbiting main-sequence stars, and is the second such BD known to transit an A star, after HATS-70b. With the growth in the population in this regime, the driest region in the BD desert ( $35\mbox{--}55{M}_{{\rm{J}}}\sin i ) is reforesting.

Keywords: brown dwarfs; stellar ages; am stars; spectroscopy; transit photometry; radial velocity; stellar rotation; stellar astronomy
Cross Correlation between the Thermal Sunyaev-Zel'dovich Effect and Projected Galaxy Density Field

We present a joint analysis of the power spectra of the Planck Compton y parameter map and the projected galaxy density field using the Wide Field Infrared Survey Explorer (WISE) all-sky survey. We detect the statistical correlation between WISE and Planck data (gy) with a significance of 21.8σ. We also measure the autocorrelation spectrum for the thermal Sunyaev-Zel'dovich (tSZ) (yy) and the galaxy density field maps (gg) with a significance of 150σ and 88σ, respectively. We then construct a halo model and use the measured correlations ${C}_{{\ell }}^{\mathrm{gg}}$ , ${C}_{{\ell }}^{{yy}}$ , and ${C}_{{\ell }}^{{\rm{g}}y}$ to constrain the tSZ mass bias $B\equiv {M}_{500}/{M}_{500}^{\mathrm{tSZ}}$ . We also fit for the galaxy bias, which is included with explicit redshift and multipole dependencies as ${b}_{{\rm{g}}}{(z,{\ell })={b}_{{\rm{g}}}^{0}(1+z)}^{\alpha }{({\ell }/{{\ell }}_{0})}^{\beta }$ , with ℓ 0 = 117. We obtain the constraints to be B = 1.50 ± 0.07(stat) ± 0.34(sys), i.e., 1 - b H = 0.67 ± 0.03(stat) ± 0.16(sys) (68% confidence level) for the hydrostatic mass bias, and ${b}_{{\rm{g}}}^{0}={1.28}_{-0.04}^{+0.03}(\mathrm{stat})\pm 0.11(\mathrm{sys})$ , with $\alpha ={0.20}_{-0.07}^{+0.11}(\mathrm{stat})\pm 0.10(\mathrm{sys})$ and β = 0.45 ±0.01(stat) ± 0.02(sys) for the galaxy bias. Incoming data sets from future CMB and galaxy surveys (e.g., Rubin Observatory) will allow probing the large-scale gas distribution in more detail.

Keywords: sunyaev-zeldovich effect; infrared galaxies
Modeling Star Formation Histories of Post Starburst Galaxies with BAGPIPES

Post-starburst galaxies provide insights into quenching mechanisms. While these galaxies show signs of quiescence, obtaining accurate star formation rates (SFRs) is difficult. This research uses BAGPIPES, a Bayesian spectrum-fitting code, to obtain model spectra of 13 galaxies. From these models, we calculate SFRs over 10 and 100 Myr durations. We compare these SFRs to published Hα and total infrared (TIR) SFRs to examine biases in these measurements. We find that the BAGPIPES-inferred 10, 100 Myr SFRs are comparable with Hα and TIR traced SFRs, respectively, with longer-duration tracers showing systematically higher SFRs.

Keywords: post-starburst galaxies; galaxies; galaxy evolution; galaxy quenching
Direct Observation of a Large-scale CME Flux Rope Event Arising from an Unwinding Coronal Jet

Coronal mass ejections (CMEs) and coronal jets are two types of common solar eruptive phenomena, which often independently happen at different spatial scales. In this work, we present a stereoscopic observation of a large-scale CME flux rope arising from an unwinding blowout jet in a multipolar complex magnetic system. Based on a multiband observational analysis, we find that this whole event starts with a small filament whose eruption occurs at a coronal geyser site after a series of homologous jets. Aided by magnetic field extrapolations, it reveals that the coronal geyser site forms above an elongate opposite-polarity interface, where the emergence-driven photospheric flux cancellation and repetitive reconnection are responsible for those preceding recurrent jets and also contribute to the ultimate filament destabilization. By interacting with overlying fields, the erupting filament breaks one of its legs, and results in an unwinding blowout jet. Our estimation suggests that around 1.4-2.0 turns of twist release in its jet spire. This prominent twist transport in the jet spire rapidly creates a newborn larger-scale flux rope from the jet base to a remote site. Soon after its formation, this large-scale flux rope erupts toward the outer coronae causing an Earth-directed CME. In its source region, two sets of distinct postflare loops form in succession, indicating this eruption involves two stages of flare magnetic reconnection. This work not only reveals a real magnetic coupling process between different eruptive activities but provides a new hint for understanding for the creation of large-scale CME flux ropes during the solar eruption.

Keywords: solar activity; solar coronal mass ejections; solar magnetic reconnection; solar filament eruptions
Radiative Reconnection-powered TeV Flares from the Black Hole Magnetosphere in M87

Active galactic nuclei in general, and the supermassive black hole in M87 in particular, show bright and rapid gamma-ray flares up to energies of 100 GeV and above. For M87, the flares show multiwavelength components, and the variability timescale is comparable to the dynamical time of the event horizon, suggesting that the emission may come from a compact region near the nucleus. However, the emission mechanism for these flares is not well understood. Recent high-resolution general-relativistic magnetohydrodynamic simulations show the occurrence of episodic magnetic reconnection events that can power flares near the black hole event horizon. In this work, we analyze the radiative properties of the reconnecting current layer under the extreme plasma conditions applicable to the black hole in M87 from first principles. We show that abundant pair production is expected in the vicinity of the reconnection layer, to the extent that the produced secondary pair plasma dominates the reconnection dynamics. Using analytic estimates backed by two-dimensional particle-in-cell simulations, we demonstrate that in the presence of strong synchrotron cooling, reconnection can produce a hard power-law distribution of pair plasma imprinted in the outgoing synchrotron (up to a few tens of MeV) and the inverse-Compton signal (up to TeV). We produce synthetic radiation spectra from our simulations, which can be directly compared with the results of future multiwavelength observations of M87* flares.

Keywords: black hole physics; plasma astrophysics; special relativity; gamma-rays; active galactic nuclei; plasma physics; radiative processes
Photometric and Spectroscopic Analysis of Eclipsing Binary NSVS 11868841

We present new photometric and spectroscopic data on the low-mass, eclipsing binary star NSVS 11868841. Light and velocity data are analyzed and modeled. Resulting best-fit models indicate a change in the orbital period. Our 2019 October observation of secondary eclipse occurs 0.01042 days prior to that predicted by the latest published ephemeris when assuming a circular orbit. Our spectroscopic data from 2009 and 2019 yield a consistent systemic velocity of -9.78 ± 1.3 km s-1 and a mass ratio of 0.928 ± 0.016, both of which are significantly different than previous studies. Orbital period changes have not been indicated in earlier works either.

Keywords: eclipsing binary stars; variable stars; binary stars; photometry; spectroscopy; low mass stars; eclipsing binary minima timing method; variable star period change
Remote Sensing of Coronal Forces during a Solar Prominence Eruption

We present a new methodology-the Keplerian Optical Dynamics Analysis (KODA)-for quantifying the dynamics of erupting magnetic structures in the solar corona. The technique involves adaptive spatiotemporal tracking of propagating intensity gradients and their characterization in terms of time-evolving Keplerian areas swept out by the position vectors of moving plasma blobs. Whereas gravity induces purely ballistic motions consistent with Kepler's second law, noncentral forces such as the Lorentz force introduce nonzero torques resulting in more complex motions. KODA algorithms enable direct evaluation of the line-of-sight component of the net torque density from the image-plane projection of the areal acceleration. The method is applied to the prominence eruption of 2011 June 7, observed by the Solar Dynamics Observatory's Atmospheric Imaging Assembly. Results obtained include quantitative estimates of the magnetic forces, field intensities, and blob masses and energies across a vast region impacted by the postreconnection redistribution of the prominence material. The magnetic pressure and energy are strongly dominant during the early, rising phase of the eruption, while the dynamic pressure and kinetic energy become significant contributors during the subsequent falling phases. Measured intensive properties of the prominence blobs are consistent with those of typical active-region prominences; measured extensive properties are compared with those of the whole pre-eruption prominence and the post-eruption coronal mass ejection of 2011 June 7, all derived by other investigators and techniques. We show that KODA provides valuable information on spatially and temporally dependent characteristics of coronal eruptions that is not readily available via alternative means, thereby shedding new light on the environment and evolution of these solar events.

Keywords: solar prominences; remote sensing; solar magnetic reconnection; solar filament eruptions; solar magnetic fields; solar active region filaments; solar active region magnetic fields