adsabs/SciX_UAT_keywords huggingface dataset:
SN 2010kd: Photometric and Spectroscopic Analysis of a Slow-decaying Superluminous Supernova

This paper presents data and analysis of SN 2010kd, a low-redshift (z = 0.101) H-deficient superluminous supernova (SLSN), based on ultraviolet/optical photometry and optical spectroscopy spanning between -28 and +194 days relative to B-band maximum light. The B-band light-curve comparison of SN 2010kd with a subset of well-studied SLSNe I at comparable redshifts indicates that it is a slow-decaying PTF12dam-like SLSN. Analytical light-curve modeling using the Minim code suggests that the bolometric light curve of SN 2010kd favors circumstellar matter interaction for the powering mechanism. SYNAPPS modeling of the early-phase spectra does not identify broad H or He lines, whereas the photospheric-phase spectra are dominated by O I, O II, C II, C IV, and Si II, in particular the presence of both low- and high-velocity components of O II and Si II lines. The nebular-phase spectra of SN 2010kd are dominated by O I and Ca II emission lines similar to those seen in other SLSNe I. The line velocities in SN 2010kd exhibit flatter evolution curves similar to SN 2015bn but with comparatively higher values. SN 2010kd shows a higher single-zone local thermodynamic equilibrium temperature in comparison to PTF12dam and SN 2015bn, and it has an upper O I ejected mass limit of ∼10 M⊙. The host of SN 2010kd is a dwarf galaxy with a high star formation rate (∼0.18 ± 0.04 M⊙ yr-1) and extreme emission lines.

Keywords: supernovae; core-collapse supernovae; photometry; spectroscopy
Structure of the Plasma near the Heliospheric Current Sheet as Seen by WISPR/Parker Solar Probe from inside the Streamer Belt

Parker Solar Probe (PSP) crossed the heliospheric current sheet (HCS) near the perihelion on encounters E8 and E11, enabling the Wide-field Imager for Solar Probe (WISPR) to image the streamer belt plasma in high resolution while flying through it. With perihelia of 16 R ⊙ and 13 R ⊙ for E8 and E11, respectively, WISPR images enable investigation of the structure of density encasing the HCS at much higher resolution than reported previously. As PSP flies closer to the Sun, fine-scale structures are resolved within the coronal rays of the streamer belt. Near the HCS, WISPR observes a fan of rays of various sizes and brightnesses, indicating large density variations in the HCS plasma sheet transverse to the radial direction. Near the perihelion, when PSP's speed exceeds the solar corotation speed, some rays exhibit large changes in apparent latitude as the HCS is encountered, and rays pass over and under the spacecraft. The multiple viewpoints provided during the HCS crossing enable us to extract the coordinates of a few rays in a heliocentric frame. The rays were found to lie near the HCS from a PFSS model. We compare their locations to the location of the streamers as seen in synoptic maps from the Large Angle and Spectrometric Coronagraph, and find that the rays generally fall within the bright streamer bands seen in these maps, which confirms that they are features of the streamer belt plasma. We speculate that the density variations in the helmet streamer plasma result from continuous interchange reconnection along the coronal hole boundaries.

Keywords: solar coronal streamers; solar k corona
Hubble Space Telescope UV and Hα Measurements of the Accretion Excess Emission from the Young Giant Planet PDS 70 b

Recent discoveries of young exoplanets within their natal disks offer exciting opportunities to study ongoing planet formation. In particular, a planet's mass accretion rate can be constrained by observing the accretion-induced excess emission. So far, planetary accretion is only probed by the Hα line, which is then converted to a total accretion luminosity using correlations derived for stars. However, the majority of the accretion luminosity is expected to emerge from hydrogen continuum emission, and is best measured in the ultraviolet (UV). In this paper, we present HST/WFC3/UVIS F336W (UV) and F656N (Hα) high-contrast imaging observations of PDS 70. Applying a suite of novel observational techniques, we detect the planet PDS 70 b with signal-to-noise ratios of 5.3 and 7.8 in the F336W and F656N bands, respectively. This is the first time that an exoplanet has been directly imaged in the UV. Our observed Hα flux of PDS 70 b is higher by $3.5\sigma $ than the most recent published result. However, the light curve retrieved from our observations does not support greater than 30% variability in the planet's Hα emission in six epochs over a five month timescale. We estimate a mass accretion rate of $1.4\pm 0.2\times {10}^{-8}{M}_{\mathrm{Jup}}\,{\mathrm{yr}}^{-1}$ . Hα accounts for 36% of the total accretion luminosity. Such a high proportion of energy released in line emission suggests efficient production of Hα emission in planetary accretion, and motivates using the Hα band for searches of accreting planets. These results demonstrate HST/WFC3/UVIS's excellent high-contrast imaging performance and highlight its potential for planet formation studies.

Keywords: exoplanet astronomy; exoplanet formation; planet formation; accretion; extrasolar gaseous giant planets
The Behavior of HgMn Stars in the Far-UV -6: κ Cnc

The analysis of eighteen high resolution SWP spectra of the HgMn star HD 78316 (κ Cnc) recorded by the International Ultraviolet Explorer reveals that the far-ultraviolet flux of this star remained constant over the various observations with IUE. The TESS lightcurve of HD 78316 reveals a double-wave structure with a rotational period of about 6.25 days. The absence of far-ultraviolet variability and the reproducibility of the brightness in the V band during most IUE observations do not support the presence of large chemical gradients over the surface of κ Cnc at the time of the IUE observations.

Keywords: chemically peculiar stars
The Impact of Cosmic Variance on Inferences of Global Neutral Fraction Derived from Lyα Luminosity Functions during Reionization

We investigate the impact of field-to-field variation, deriving from cosmic variance, in measured Lyα emitter (LAE) luminosity functions (LFs) and this variation's impact on inferences of the neutral fraction of the intergalactic medium (IGM) during reionization. We post-process a z = 7 IGM simulation to populate the dark matter halos with LAEs. These LAEs have realistic UV magnitudes, Lyα fluxes, and Lyα line profiles. We calculate the attenuation of Lyα emission in universes with varying IGM neutral fraction, ${\bar{x}}_{{\rm{H}}\,{\rm\small{I}}}$ . In a ${\bar{x}}_{{\rm{H}}\,{\rm\small{I}}}$ = 0.3 simulation, we perform 100 realizations of a mock 2 deg2 survey with a redshift window Δz = 0.5 and flux limit f Lyα > 1 × 10-17 erg s-1 cm-2; such a survey is typical in depth and volume of the largest LAE surveys conducted today. For each realization, we compute the LAE LF and use it to recover the input ${\bar{x}}_{{\rm{H}}\,{\rm\small{I}}}$ . Comparing the inferred values of ${\bar{x}}_{{\rm{H}}\,{\rm\small{I}}}$ across the ensemble of the surveys, we find that cosmic variance, deriving from large-scale structure and variation in the neutral gas along the sightline, imposes a floor in the uncertainty of ${\rm{\Delta }}{\bar{x}}_{{\rm{H}}\,{\rm\small{I}}}\sim 0.2$ when ${\bar{x}}_{{\rm{H}}\,{\rm\small{I}}}$ = 0.3. We explore mitigation strategies to decrease this uncertainty, such as increasing the volume, decreasing the flux limit, or probing the volume with many independent fields. Increasing the area and/or depth of the survey does not mitigate the uncertainty, but composing a survey with many independent fields is effective. This finding highlights the best strategy for LAE surveys aiming at constraining the ${\bar{x}}_{{\rm{H}}\,{\rm\small{I}}}$ of the universe during reionization.

Keywords: reionization; lyman-alpha galaxies; intergalactic medium; high-redshift galaxies; early universe
A Measurement of the CMB E-mode Angular Power Spectrum at Subdegree Scales from 670 Square Degrees of POLARBEAR Data

We report a measurement of the E-mode polarization power spectrum of the cosmic microwave background (CMB) using 150 GHz data taken from 2014 July to 2016 December with the POLARBEAR experiment. We reach an effective polarization map noise level of $32\,\mu {\rm{K}}$ - $\mathrm{arcmin}$ across an observation area of 670 square degrees. We measure the EE power spectrum over the angular multipole range $500\leqslant {\ell }\lt 3000$ , tracing the third to seventh acoustic peaks with high sensitivity. The statistical uncertainty on E-mode bandpowers is ∼2.3 $\mu {{\rm{K}}}^{2}$ at ${\ell }\sim 1000$ , with a systematic uncertainty of 0.5 $\mu {{\rm{K}}}^{2}$ . The data are consistent with the standard ΛCDM cosmological model with a probability-to-exceed of 0.38. We combine recent CMB E-mode measurements and make inferences about cosmological parameters in ΛCDM as well as in extensions to ΛCDM. Adding the ground-based CMB polarization measurements to the Planck data set reduces the uncertainty on the Hubble constant by a factor of 1.2 to ${H}_{0}=67\mathrm{.}20\pm 0\mathrm{.}57\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ . When allowing the number of relativistic species ( ${N}_{\mathrm{eff}}$ ) to vary, we find ${N}_{\mathrm{eff}}=2\mathrm{.}94\pm 0\mathrm{.}16$ , which is in good agreement with the standard value of 3.046. Instead allowing the primordial helium abundance ( ${Y}_{\mathrm{He}}$ ) to vary, the data favor ${Y}_{\mathrm{He}}=0\mathrm{.}248\pm 0\mathrm{.}012$ . This is very close to the expectation of 0.2467 from big bang nucleosynthesis. When varying both ${Y}_{\mathrm{He}}$ and ${N}_{\mathrm{eff}}$ , we find ${N}_{\mathrm{eff}}=2\mathrm{.}70\pm 0\mathrm{.}26$ and ${Y}_{\mathrm{He}}=0\mathrm{.}262\pm 0\mathrm{.}015$ .

Keywords: cosmic microwave background radiation
Laboratory Study of the Cameron Bands and UV Doublet in the Middle Ultraviolet 180-300 nm by Electron Impact upon CO2 with Application to Mars

We have observed electron impact fluorescence from CO2 to excite the Cameron bands (CBs), CO (a 3Π → X 1Σ+; 180-280 nm), the first-negative group (1NG) bands, CO+ (B 2Σ+ → X 2Σ+; 180-320 nm), the fourth-positive group (4PG) bands, CO (A 1Π → X 1Σ+; 111-280 nm), and the UV doublet, CO2 + ( $\tilde{B}{\ }^{2}{{\rm{\Sigma }}}_{u}^{+}\to \tilde{X}{\ }^{2}{{\rm{\Pi }}}_{g};$ 288.3 and 289.6 nm) in the ultraviolet (UV). This wavelength range matches the spectral region of past and present spacecraft equipped to observe UV dayglow and aurora emissions from the thermospheres (100-300 km) of Mars and Venus. Our large vacuum system apparatus is able to measure the emission cross sections of the strongest optically forbidden UV transitions found in planetary spectra. Based on our cross-sectional measurements, previous CB emission cross-sectional errors exceed a factor of 3. The UV doublet lifetime is perturbed through $\tilde{B}{\ }^{2}{{\rm{\Sigma }}}_{u}^{+}-\tilde{A}{\ }^{2}{{\rm{\Pi }}}_{u}$ spin-orbit coupling. Forward modeling codes of the Mars dayglow have not been accurate in the mid-UV due to systematic errors in these two emission cross sections. We furnish absolute emission cross sections for several band systems over electron energies 20-100 eV for CO2. We present a CB lifetime, which together with emission cross sections, furnish a set of fundamental physical constants for electron transport codes such as AURIC (Atmospheric Ultraviolet Radiance Integrated Code). AURIC and Trans-Mars are used in the analysis of UV spectra from the Martian dayglow and aurora.

Keywords: carbon dioxide; mars; molecular physics; radiative processes; molecular spectroscopy; experimental techniques; collisional processes
Bright z ∼ 9 Galaxies in Parallel: The Bright End of the Rest-frame UV Luminosity Function from HST Parallel Programs

The abundance of bright galaxies at z > 8 can provide key constraints on models of galaxy formation and evolution, as the predicted abundance varies greatly when different physical prescriptions for gas cooling and star formation are implemented. We present the results of a search for bright z ∼ 9–10 galaxies selected from pure parallel Hubble Space Telescope (HST) imaging programs. We include 132 fields observed as part of the Brightest of Reionizing Galaxies survey, the Hubble Infrared Pure Parallel Imaging Extragalactic Survey, and the WFC3 Infrared Spectroscopic Parallel survey. These observations cover a total of 620 arcmin2, about 70% of which is also covered with Spitzer Space Telescope infrared imaging. We identify 13 candidate galaxies in the range 8.3 < z < 11 with 24.5 < m H < 26.5 (‑22.9 < M UV < ‑21.2), 11 of which constitute new discoveries. This sample capitalizes on the uncorrelated nature of pure parallel observations to overcome cosmic variance and leverages a full multiwavelength selection process to minimize contamination without sacrificing completeness. We perform detailed completeness and contamination analyses, and present measurements of the bright end of the UV luminosity function using a pseudobinning technique. We find a number density consistent with results from Finkelstein et al. and other searches in HST parallel fields. These bright candidates likely reside in overdensities, potentially representing some of the earliest sites of cosmic reionization. These new candidates are excellent targets for follow up with JWST, and four of them will be observed with the NIRSpec prism in Cycle 1.

Keywords: high-redshift galaxies; galaxy evolution; luminosity function
How Jupiters Save or Destroy Inner Neptunes around Evolved Stars

In about 6 Gyr our Sun will evolve into a red giant and finally end its life as a white dwarf. This stellar metamorphosis will occur to virtually all known host stars of exoplanetary systems and is therefore crucial for their final fate. It is clear that the innermost planets will be engulfed and evaporated during the giant phase and that planets located farther out will survive. However, the destiny of planets in-between, at ∼1 and 10 au, has not yet been investigated with a multiplanet tidal treatment. We here combine for the first time multiplanet interactions, stellar evolution, and tidal effects in an N-body code to study the evolution of a Neptune-Jupiter planetary system. We report that the fate of the Neptune-mass planet, located closer to the star than the Jupiter-mass planet, can be very different from the fate of a single Neptune. The simultaneous effects of gravitational interactions, mass loss, and tides can drive the planetary system toward mean motion resonances. Crossing these resonances affects particularly the eccentricity of the Neptune and thereby also its fate, which can be engulfment, collision with the Jupiter-mass planet, ejection from the system, or survival at a larger separation.

Keywords: exoplanet dynamics; exoplanet evolution; evolved stars; tides
Limits on Polarized Dust Spectral Index Variations for CMB Foreground Analysis

Using Planck polarization data, we search for and constrain spatial variations of the polarized dust foreground for cosmic microwave background (CMB) observations, specifically in its spectral index, βd. Failure to account for such variations will cause errors in the foreground cleaning that propagate into errors on cosmological parameter recovery from the cleaned CMB map. It is unclear how robust prior studies of the Planck data that constrained βd variations are due to challenges with noise modeling, residual systematics, and priors. To clarify constraints on βd and its variation, we employ two pixel space analyses of the polarized dust foreground at >3°7 scales on ≈60% of the sky at high Galactic latitudes. A template fitting method, which measures βd over three regions of ≈20% of the sky, does not find significant deviations from a uniform βd = 1.55, consistent with prior Planck determinations. An additional analysis in these regions, based on multifrequency fits to a dust and CMB model per pixel, puts limits on ${\sigma }_{{\beta }_{d}}$ , the Gaussian spatial variation in βd. The data support ${\sigma }_{{\beta }_{d}}$ up to 0.45 at the highest latitudes, 0.30 at midlatitudes, and 0.15 at low latitudes. We also demonstrate that care must be taken when interpreting the current Planck constraints, βd maps, and noise simulations. Due to residual systematics and low dust signal-to-noise ratios at high latitudes, forecasts for ongoing and future missions should include the possibility of large values of ${\sigma }_{{\beta }_{d}}$ as estimated in this paper, based on current polarization data.

Keywords: cosmic microwave background radiation
The Lyman Alpha Reference Sample. X. Predicting Lyα Output from Star-forming Galaxies Using Multivariate Regression

Understanding the production and escape of Lyα radiation from star-forming galaxies is a long-standing problem in astrophysics. The ability to predict the Lyα luminosity of galaxies would open up new ways of exploring the epoch of reionization (EOR) and estimating Lyα emission from galaxies in cosmological simulations where radiative transfer calculations cannot be done. We apply multivariate regression methods to the Lyman Alpha Reference Sample data set to obtain a relation between the galaxy properties and the emitted Lyα. The derived relation predicts the Lyα luminosity of our galaxy sample to good accuracy, regardless of whether we consider only direct observables (rms dispersion around the relation of ∼0.19 dex) or derived physical quantities (rms ∼ 0.27 dex). We confirm the predictive ability on a separate sample of compact star-forming galaxies and find that the prediction works well, but that aperture effects on measured Lyα luminosity may be important, depending on the redshift of the galaxy. We apply statistical feature selection techniques to determine an order of importance of the variables in our data set, enabling future observations to be optimized for predictive ability. When using physical variables, we are able to determine that the most important predictive parameters are, in order, star formation rate, dust extinction, compactness, and the gas covering fraction. We discuss the application of our results in terms of studying the EOR and intensity mapping experiments.

Keywords: starburst galaxies; lyman-alpha galaxies; multivariate analysis
The Importance of Star Formation Intensity in Lyα Escape from Green Pea Galaxies and Lyman Break Galaxy Analogs

We have studied ultraviolet images of 40 Green Pea galaxies and 15 local Lyman Break Galaxy Analogs to understand the relation between Lyα photon escape and central UV photometric properties. We measured star-formation intensity (SFI; star formation rate per unit area) from the central 250 pc region ( ${S}_{250\mathrm{pc}}$ ) using Cosmic Origins Spectrograph near-ultraviolet images from the Hubble Space Telescope. The measured ${S}_{250\mathrm{pc}}$ of our sample Green Peas ranges from 2.3-46 M⊙ yr-1 kpc-2, with a geometric mean of 15 M⊙ yr-1 kpc-2 and a standard deviation of 0.266 dex, forming a relatively narrow distribution. The Lyman Break Galaxy Analogs show a similarly narrow distribution of ${S}_{250\mathrm{pc}}$ (0.271 dex), though with a larger mean of 28 M⊙ yr-1 kpc-2. We show that while the Lyα equivalent width (EW(Lyα)) and the Lyα escape fraction ( ${f}_{\mathrm{esc}}^{\mathrm{Ly}\alpha }$ ) are not significantly correlated with the central SFI ( ${S}_{250\mathrm{pc}}$ ), both are positively correlated with the ratio of surface brightness to galaxy stellar mass (S250 pc/Mstar), with correlation coefficients (p-values) of 0.702 (1 × 10-8) and 0.529 (5 × 10-4) with EW(Lyα) and ${f}_{\mathrm{esc}}^{\mathrm{Ly}\alpha }$ , respectively. These correlations suggest a scenario where intense central star formation can drive a galactic wind in galaxies with relatively shallow gravitational potential wells, thus clearing channels for the escape of Lyα photons.

Keywords: compact galaxies; starburst galaxies; galaxy formation; galaxy evolution; galaxy structure; star formation; reionization
Spectral Survey of a Hot Core with an Eruptive Accretion in S255IR NIRS3 (SHEA): The Discovery of Class I and II Millimeter Methanol Maser Transitions

We report the detection of the millimeter CH3OH masers including a new detection of class I (110,11-101,10A) and class II (61,5-52,4E) maser transitions toward the high-mass protostar S255IR NIRS3 in postburst phase. The CH3OH emissions were detected as a mixture of maser and thermal characteristics. We examine the detected transitions using an excitation diagram and local thermodynamic equilibrium model spectra and compare the observed properties with those of thermal lines. Class II CH3OH maser transitions showed distinctive intensity and velocity distributions from those of thermal transitions. Bright, distinct emission components in addition to the fragmented and arc-shaped emissions are only detected in class I CH3OH maser transitions toward southern and western directions from the protostellar position, implying the presence of the slow outflow shocks.

Keywords: protostars; star formation; massive stars; astrophysical masers
A Diverse Population of z 2 ULIRGs Revealed by JWST Imaging

Four ultraluminous infrared galaxies (ULIRGs) observed with JWST/NIRcam in the Cosmos Evolution Early Release Science program offer an unbiased preview of the z ~ 2 ULIRG population. The objects were originally selected at 24 μm and have strong polycyclic aromatic hydrocarbon emission features observed with Spitzer/Infrared Spectrometer. The four objects have similar stellar masses of ~1011 M ⊙ but otherwise are quite diverse. One is an isolated disk galaxy, but it has an active nucleus as shown by X-ray observations and by a bright point-source nucleus. Two others are merging pairs with mass ratios of 6-7:1. One has active nuclei in both components, while the other has only one active nucleus: the one in the less-massive neighbor, not the ULIRG. The fourth object is clumpy and irregular and is probably a merger, but there is no sign of an active nucleus. The intrinsic spectral energy distributions for the four active galactic nuclei in these systems are typical of type-2 QSOs. This study is consistent with the idea that even if internal processes can produce large luminosities at z ~ 2, galaxy merging may still be necessary for the most luminous objects. The diversity of these four initial examples suggests that large samples will be needed to understand the z ~ 2 ULIRG population.

Keywords: infrared galaxies; high-redshift galaxies; ultraluminous infrared galaxies; active galactic nuclei; spectral energy distribution
Revealing Gravitational Collapse in the Serpens G3-G6 Molecular Cloud Using Velocity Gradients

The relative role of turbulence, magnetic fields, and self-gravity in star formation is a subject of intensive debate. We present IRAM 30 m telescope observations of the 13CO (1-0) emission in the Serpens G3-G6 molecular cloud and apply to the data a set of statistical methods. These include the probability density functions of column density and the velocity gradients technique. We combine our data with the Planck 353 GHz polarized dust emission observations and Hershel H2 column density. We suggest that the Serpens G3-G6 south clump is undergoing a gravitational collapse. Our analysis reveals that the gravitational collapse happens at volume density n ≥ 103 cm-3. We estimate the plane-of-the-sky magnetic field strength to be approximately 120 μG using the traditional Davis-Chandrasekhar-Fermi method and 100 μG using a new technique proposed in Lazarian et al (2020). We find that the Serpens G3-G6 south clump's total magnetic field energy significantly surpasses kinetic energy and gravitational energy. We conclude that the gravitational collapse could be successfully triggered in a supersonic and sub-Alfvénic cloud.

Keywords: interstellar medium; interstellar magnetic fields; interstellar dynamics