adsabs/SciX_UAT_keywords huggingface dataset:
HAFFET: Hybrid Analytic Flux FittEr for Transients

The progenitors for many types of supernovae (SNe) are still unknown, and an approach to diagnose their physical origins is to investigate the light-curve brightness and shape of a large set of SNe. However, it is often difficult to compare and contrast the existing sample studies due to differences in their approaches and assumptions, for example, in how to eliminate host galaxy extinction, and this might lead to systematic errors when comparing the results. We therefore introduce the Hybrid Analytic Flux FittEr for Transients (HAFFET), a Python-based software package that can be applied to download photometric and spectroscopic data for transients from open online sources, derive bolometric light curves, and fit them to semianalytical models for estimation of their physical parameters. In a companion study, we have investigated a large collection of SNe Ib and Ic observed with the Zwicky Transient Facility (ZTF) with HAFFET, and here we detail the methodology and the software package to encourage more users. As large-scale surveys such as ZTF and LSST continue to discover increasing numbers of transients, tools such as HAFFET will be critical for enabling rapid comparison of models against data in statistically consistent, comparable, and reproducible ways. Additionally, HAFFET is created with a graphical user interface mode, which we hope will boost the efficiency and make the usage much easier (https://github.com/saberyoung/HAFFET).

Keywords: astronomy software; astronomy data modeling; supernovae; open source software
Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies

While tidal disruption events (TDEs) have long been heralded as laboratories for the study of quiescent black holes, the small number of known TDEs and uncertainties in their emission mechanism have hindered progress toward this promise. Here we present 17 new TDEs that have been detected recently by the Zwicky Transient Facility along with Swift UV and X-ray follow-up observations. Our homogeneous analysis of the optical/UV light curves, including 22 previously known TDEs from the literature, reveals a clean separation of light-curve properties with spectroscopic class. The TDEs with Bowen fluorescence features in their optical spectra have smaller blackbody radii, lower optical luminosities, and higher disruption rates compared to the rest of the sample. The small subset of TDEs that show only helium emission lines in their spectra have the longest rise times, the highest luminosities, and the lowest rates. A high detection rate of Bowen lines in TDEs with small photometric radii could be explained by the high density that is required for this fluorescence mechanism. The stellar debris can provide a source for this dense material. Diffusion of photons through this debris may explain why the rise and fade timescale of the TDEs in our sample are not correlated. We also report, for the first time, the detection of soft X-ray flares from a TDE on ∼day timescales. Based on the fact that the X-ray flares peak at a luminosity similar to the optical/UV blackbody luminosity, we attribute them to brief glimpses through a reprocessing layer that otherwise obscures the inner accretion flow.

Keywords: astrophysical black holes; tidal disruption; galaxy nuclei
Three-dimensional Interaction between a Planet and an Isothermal Gaseous Disk. III. Locally Isothermal Cases

We performed linear calculations to determine the Type I planetary migration rate for 3D locally isothermal disks with radial temperature gradients. For 3D disks with radial temperature gradients, the linear wave equation has a divergent term of the third pole, which makes corotation a nonremoval singularity. We suppressed the divergence with the Landau prescription to obtain the wave solutions. Despite the singularity at corotation, we derived a definite torque on the planet because the divergent term amplifies the waves only in the neighborhood of corotation and has little effect on the planetary torque. Consequently, we derived the formulas for the total, Lindblad, and corotation torques for locally isothermal disks. The resulting torque term due to the disk temperature gradient agrees well with the results of previous 3D hydrodynamical simulations for locally isothermal disks. Our linear calculation also provides the 3D horseshoe torque, which is close to the results of previous 3D hydrodynamical simulations.

Keywords: planet formation; protoplanetary disks
Metallicity-PAH Relation of MIR-selected Star-forming Galaxies in AKARI North Ecliptic Pole-wide Survey

We investigate the variation in the mid-infrared spectral energy distributions of 373 low-redshift (z < 0.4) star-forming galaxies, which reflects a variety of polycyclic aromatic hydrocarbon (PAH) emission features. The relative strength of PAH emission is parameterized as q PAH, which is defined as the mass fraction of PAH particles in the total dust mass. With the aid of continuous mid-infrared photometric data points covering 7-24 μm and far-infrared flux densities, q PAH values are derived through spectral energy distribution fitting. The correlation between q PAH and other physical properties of galaxies, i.e., gas-phase metallicity ( $12+\mathrm{log}({\rm{O}}/{\rm{H}})$ ), stellar mass, and specific star-formation rate (sSFR) are explored. As in previous studies, q PAH values of galaxies with high metallicity are found to be higher than those with low metallicity. The strength of PAH emission is also positively correlated with the stellar mass and negatively correlated with the sSFR. The correlation between q PAH and each parameter still exists even after the other two parameters are fixed. In addition to the PAH strength, the application of metallicity-dependent gas-to-dust mass ratio appears to work well to estimate gas mass that matches the observed relationship between molecular gas and physical parameters. The result obtained will be used to calibrate the observed PAH luminosity-total infrared luminosity relation, based on the variation of MIR-FIR SED, which is used in the estimation of hidden star formation.

Keywords: galaxy evolution; infrared galaxies; polycyclic aromatic hydrocarbons; spectral energy distribution; galaxy properties
Combinations of Standard Pings and Standard Candles: An Effective and Hubble Constant-free Probe of Dark Energy Evolution

On the basis of the theoretical predication that a small fraction of fast radio bursts (FRBs) might be associated with gravitational waves (GWs), Wei et al. proposed FRB/GW association systems, i.e., the joint measurement of dispersion measures (DM) of FRBs and luminosity distances DL of GWs (the combination DM · DL), as an effective complementary cosmic probe, which has the advantage of being independent of the Hubble constant H0. However, it is still unclear what the progenitor of FRBs is and whether a GW signal should be associated with them. In this paper, we propose that, with the fundamental assumption that luminosity distance is a monotonously increasing function of redshift, this DM · DL method could be further extended to the combination of DM measurements of localized FRBs and independent DL measurements of type Ia supernovae (SNe Ia) at similar redshifts. In practice, this extended combination, i.e., DM · DL as a function of redshift from independent DM and DL measurements, may be more applicable. In addition, we investigated the constraining power of this extended combination on dark energy evolution. It was obtained that, in the frame of the Chevalier-Polarski-Linder parameterization, the power of constraints on the dark energy equation of state from only ∼500 DM · DL combinations is even stronger than the one from the currently available 1048 Pantheon SNe Ia. More interestingly, we also found that, compared with the popular luminosity distance-redshift relation alone, the combination DM · DL, as a function of redshift, is more effective in constraining the parameter characterizing the evolution of dark energy. This benefit, along with rapid progress in the upcoming FRB observations, can be of great importance for studying the nature of dark energy.

Keywords: radio bursts; type ia supernovae; cosmological parameters
Implicit Biases in Transit Models Using Stellar Pseudo Density

The transit technique is responsible for the majority of exoplanet discoveries to date. Characterizing these planets involves careful modeling of their transit profiles. A common technique involves expressing the transit duration using a density-like parameter, $\tilde{\rho }$ , often called the "circular density." Most notably, the Kepler project-the largest analysis of transit light curves to date-adopted a linear prior on $\tilde{\rho }$ . Here, we show that such a prior biases measurements of impact parameter, b, due to the nonlinear relationship between $\tilde{\rho }$ and transit duration. This bias slightly favors low values (b ≲ 0.3) and strongly disfavors high values (b ≳ 0.7) unless the transit signal-to-noise ratio is sufficient to provide an independent constraint on b, a criterion that is not satisfied for the majority of Kepler planets. Planet-to-star radius ratio, r, is also biased due to r - b covariance. Consequently, the median Kepler DR25 target suffers a 1.6% systematic underestimate of r. We present a techniques for correcting these biases and for avoiding them in the first place.

Keywords: exoplanets; bayesian statistics; astronomy data modeling; light curves; transit photometry
Formation and Eruption of Hot Channels during an M6.5 Class Solar Flare

We investigate the formation and eruption of hot channels associated with the M6.5 class flare (SOL 2015-06-22T18:23) that occurred in NOAA AR 12371 on 2015 June 22. Two flare precursors are observed before the flare's main phase. Observations in 94 and 131 Å by SDO/AIA revealed the early morphology of the first hot channel as a group of hot loops, termed the seed hot channel. A few seed hot channels are formed above the polarity inversion line (PIL) and the formation is associated with the parallel motion of the footpoint brightenings along the PIL, which proceeds into the early stage of the flare main phase. During this process, seed hot channels build up and rise slowly, accelerating at the peak of the second precursor. They merge during the process of acceleration, forming a larger hot channel, which then forms an inverted-γ-shape kinking structure. Before the flare peak, the second kinking hot channel with negative crossing appears near the first kinking hot channel that erupted. The eruption of these two hot channels produces two peaks on the main flare's GOES light curve. The propagation of the footpoint brightenings along the PIL indicates that the first kinking hot channel may be formed due to zipper reconnection. The occurrence of merging between seed hot channels observed by AIA is supported by the extrapolated nonlinear force-free field models. The observed writhing motion of the first kinking hot channel may be driven by the Lorentz force.

Keywords: solar x-ray flares; solar magnetic reconnection; solar extreme ultraviolet emission
Nonlinear Evolution of Streaming Instabilities in Accreting Protoplanetary Disks

The streaming instability (SI) is one of the most promising candidates for triggering planetesimal formation by producing dense dust clumps that undergo gravitational collapse. Understanding how the SI operates in realistic protoplanetary disks (PPDs) is therefore crucial to assess the efficiency of planetesimal formation. Modern models of PPDs show that large-scale magnetic torques or winds can drive laminar gas accretion near the disk midplane. In a previous study, we identified a new linear dust-gas instability, the azimuthal drift SI (AdSI), applicable to such accreting disks and is powered by the relative azimuthal motion between dust and gas that results from the gas being torqued. In this work, we present the first nonlinear simulations of the AdSI. We show that it can destabilize an accreting, dusty disk even in the absence of a global radial pressure gradient, which is unlike the classic SI. We find the AdSI drives turbulence and the formation of vertically extended dust filaments that undergo merging. In dust-rich disks, merged AdSI filaments reach maximum dust-to-gas ratios exceeding 100. Moreover, we find that even in dust-poor disks the AdSI can increase local dust densities by 2 orders of magnitude. We discuss the possible role of the AdSI in planetesimal formation, especially in regions of an accreting PPD with vanishing radial pressure gradients.

Keywords: astrophysical fluid dynamics; planet formation; hydrodynamics; protoplanetary disks; hydrodynamical simulations
Solar Wind Turbulence Around Mars: Relation between the Energy Cascade Rate and the Proton Cyclotron Waves Activity

The first estimation of the incompressible energy cascade rate at magnetohydrodynamic (MHD) scales in the plasma upstream of the Martian bow shock is obtained, making use of magnetic field and plasma observations provided by Mars Atmosphere and Volatile EvolutioN (MAVEN) over 600 orbits. In particular, the energy cascade rate is computed for events with and without proton cyclotron wave (PCW) activity, for time intervals when MAVEN was in the solar wind with no magnetic connection to the bow shock. It is shown that the nonlinear cascade of energy at the MHD scales is slightly amplified when PCWs are present in the plasma, around the Martian perihelion. In addition, the analysis of the normalized cross helicity and residual energy for the turbulent fluctuations shows the presence of Alfvénic and non-Alfvénic fluctuations in a magnetic dominant regime for the majority of the cases.

Keywords: interplanetary turbulence; solar wind; plasma physics
Study of the Prompt Emission of Short Gamma-Ray Bursts Using a Multicolor Blackbody: A Clue to the Viewing Angle

The prompt emission of short gamma-ray bursts (sGRBs) with known redshifts is analyzed using the model of a multicolor blackbody, which is interpreted as the emission from a nondissipative photosphere taking into account a power-law jet structure and the viewing geometry of the jet. We find nearly 69% and 26% of the sample is consistent with a multicolor blackbody and a pure blackbody model, respectively. Using this interpretation, we infer that nearly 57% (18%) of the sGRBs in our sample are observed within (or along the edge of) the jet core. The sGRB jets are deduced to possess a narrow core with a median θc ~ 3°. This suggests the rate of sGRBs that would be viewed within the jet core to be 1.8-26 Gpc-3 yr-1. The power-law index of the decreasing Lorentz factor profile of the jet structure is deduced to be 1.3-2.2. The intrinsic luminosity is found to range between 1048-1053 erg s-1. The average values of the Lorentz factor and nozzle radius of the sGRB jets are inferred to be 210 (85) and 107.7 (109.6) cm for the cases when the photosphere forms in the coasting (accelerating) phase, respectively. The viability of the inferred values of the different parameters of the GRB outflow and viewing geometry within this physical interpretation enhances the prospect of the photospheric emission model explaining the observed GRB spectrum.

Keywords: gamma-ray bursts; burst astrophysics; gamma-ray transient sources
Six Outbursts of Comet 46P/Wirtanen

Cometary activity is a manifestation of sublimation-driven processes at the surface of nuclei. However, cometary outbursts may arise from other processes that are not necessarily driven by volatiles. In order to fully understand nuclear surfaces and their evolution, we must identify the causes of cometary outbursts. In that context, we present a study of mini-outbursts of comet 46P/Wirtanen. Six events are found in our long-term lightcurve of the comet around its perihelion passage in 2018. The apparent strengths range from -0.2 to -1.6 mag in a 5″ radius aperture and correspond to dust masses between ~104 and 106 kg, but with large uncertainties due to the unknown grain size distributions. However, the nominal mass estimates are on the same order of magnitude as the mini-outbursts at comet 9P/Tempel 1 and 67P/Churyumov-Gerasimenko, events that were notably lacking at comet 103P/Hartley 2. We compare the frequency of outbursts at the four comets, and suggest that the surface of 46P has large-scale (~10-100 m) roughness that is intermediate to that of 67P and 103P, if not similar to the latter. The strength of the outbursts appear to be correlated with time since the last event, but a physical interpretation with respect to solar insolation is lacking. We also examine Hubble Space Telescope images taken about two days following a near-perihelion outburst. No evidence for macroscopic ejecta was found in the image, with a limiting radius of about 2 m.

Keywords: comets; short period comets; broad band photometry; coma dust
Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability

We study the optical flux and polarization variability of the binary black hole blazar OJ 287 using quasi-simultaneous observations from 2015 to 2023 carried out using telescopes in the USA, Japan, Russia, Crimea, and Bulgaria. This is one of the most extensive quasi-simultaneous optical flux and polarization variability studies of OJ 287. OJ 287 showed large amplitude, ~3.0 mag flux variability, large changes of ~37% in degree of polarization, and a large swing of ~215° in the angle of the electric vector of polarization. During the period of observation, several flares in flux were detected. Those flares are correlated with a rapid increase in the degree of polarization and swings in electric vector of polarization angle. A peculiar behavior of anticorrelation between flux and polarization degree, accompanied by a nearly constant polarization angle, was detected from JD 2,458,156 to JD 2,458,292. We briefly discuss some explanations for the flux and polarization variations observed in OJ 287.

Keywords: blazars; active galactic nuclei; bl lacertae objects; jets; optical astronomy
Extreme Nature of Four Blue-excess Dust-obscured Galaxies Revealed by Optical Spectroscopy

We report optical spectroscopic observations of four blue-excess dust-obscured galaxies (BluDOGs) identified by the Subaru Hyper Suprime-Cam. BluDOGs are a subclass of dust-obscured galaxies (DOGs; defined with the extremely red color (i - [22])AB ≥ 7.0; Toba et al., showing a significant flux excess in the optical g and r bands over the power-law fits to the fluxes at the longer wavelengths. Noboriguchi et al. have suggested that BluDOGs may correspond to the blowing-out phase involved in a gas-rich major-merger scenario. However, the detailed properties of BluDOGs are not understood because of the lack of spectroscopic information. In this work, we carry out deep optical spectroscopic observations of four BluDOGs using Subaru/FOCAS and VLT/FORS2. The obtained spectra show broad emission lines with extremely large equivalent widths, and a blue wing in the C IV line profile. The redshifts are between 2.2 and 3.3. The averaged rest-frame equivalent widths of the C IV lines are 160 ± 33 Å, ~7 times higher than the average of a typical type 1 quasar. The FWHMs of their velocity profiles are between 1990 and 4470 km s-1, and their asymmetric parameters are 0.05 and 0.25. Such strong C IV lines significantly affect the broadband magnitudes, which are partly the origin of the blue excess seen in the spectral energy distribution of BluDOGs. Their estimated supermassive black hole masses are 1.1 × 108 < M BH/M ⊙ <5.5 × 108. The inferred Eddington ratios of the BluDOGs are higher than 1 (1.1 < λ Edd < 3.8), suggesting that the BluDOGs are in a rapidly evolving phase of supermassive black holes.

Keywords: active galaxies; infrared galaxies; galaxy evolution; quasars; spectroscopy
JWST/NIRCam Probes Young Star Clusters in the Reionization Era Sunrise Arc

Star cluster formation in the early universe and its contribution to reionization remains largely unconstrained to date. Here we present JWST/NIRCam imaging of the most highly magnified galaxy known at z ~ 6, the Sunrise arc. We identify six young massive star clusters (YMCs) with measured radii spanning from ~20 down to ~1 pc (corrected for lensing magnification), estimated stellar masses of ~106-7 M ⊙, and ages of 1-30 Myr based on SED fitting to photometry measured in eight filters extending to rest frame 7000 Å. The resulting stellar mass surface densities are higher than 1000 M ⊙ pc-2 (up to a few 105 M ⊙ pc-2), and their inferred dynamical ages qualify the majority of these systems as gravitationally bound stellar clusters. The star cluster ages map the progression of star formation along the arc, with two evolved systems (≳10 Myr old) followed by very young clusters. The youngest stellar clusters (<5 Myr) show evidence of prominent Hβ+[O III] emission based on photometry with equivalent widths larger than >1000 Å rest frame and are hosted in a 200 pc sized star-forming complex. Such a region dominates the ionizing photon production with a high efficiency $\mathrm{log}({\xi }_{\mathrm{ion}}[\mathrm{Hz}\,{\mathrm{erg}}^{-1}])\sim 25.7$ . A significant fraction of the recently formed stellar mass of the galaxy (10%-30%) occurred in these YMCs. We speculate that such sources of ionizing radiation boost the ionizing photon production efficiency, which eventually carves ionized channels that might favor the escape of Lyman continuum radiation. The survival of some of the clusters would make them the progenitors of massive and relatively metal-poor globular clusters in the local universe.

Keywords: high-redshift galaxies; young star clusters; reionization; globular star clusters
The Mega-MUSCLES Spectral Energy Distribution of TRAPPIST-1

We present a 5 Å-100 μm spectral energy distribution (SED) of the ultracool dwarf star TRAPPIST-1, obtained as part of the Mega-MUSCLES Treasury Survey. The SED combines ultraviolet and blue-optical spectroscopy obtained with the Hubble Space Telescope, X-ray spectroscopy obtained with XMM-Newton, and models of the stellar photosphere, chromosphere, transition region, and corona. A new differential emission measure model of the unobserved extreme-ultraviolet spectrum is provided, improving on the Lyα-EUV relations often used to estimate the 100-911 Å flux from low-mass stars. We describe the observations and models used, as well as the recipe for combining them into an SED. We also provide a semiempirical, noise-free model of the stellar ultraviolet spectrum based on our observations for use in atmospheric modeling of the TRAPPIST-1 planets.

Keywords: m dwarf stars; exoplanet astronomy; exoplanet atmospheres; ultraviolet astronomy; x-ray astronomy; spectral energy distribution; spectroscopy; stellar atmospheres
Signs of Emissions of Alkali Metals Na I, Li I, and K I During First Minutes After DART Probe Crash on Dimorphos

We present the results of the analysis of spectral observations taken a few minutes before, at the time, and in the first minutes after the impact of the DART probe on the asteroid Dimorphos. Our analysis showed signs of Na I, Li I, and K I alkali metal emissions appearing at the time of the impact and for several minutes after it.

Keywords: near-earth objects; asteroids; spectroscopy