Search

ZrO is a well-studied metal monoxide because of its astrophysical importance in characterizing S stars. The bands of the d 3Φ–a3Δ system (γ system) with v ′ ≤ 4 and v ″ ≤ 5 are rotationally analyzed using the PGOPHER program to provide spectroscopic constants. The high-resolution ZrO emission spectrum was recorded with a Fourier transform spectrometer using a high-temperature carbon furnace source. New ab initio calculations of the transition dipole moment were carried out in order to determine the vibronic band strengths. The spectroscopic constants, along with the band strengths, are used to calculate a line list for the γ system. This line list can be used to determine Zr abundances in S stars. We also correct the line strengths for the B 1Π– A 1Δ transition calculated in our previous work. [ABSTRACT FROM AUTHOR]

Accurate classification of transients obtained from spectroscopic data are important to understand their nature and discover new classes of astronomical objects. For supernovae (SNe), SNID, NGSF (a Python version of SUPERFIT), and DASH are widely used in the community. Each tool provides its own metric to help determine classification, such as rlap of SNID, chi2/dof of NGSF, and Probability of DASH. However, we do not know how accurate these tools are, and they have not been tested with a large homogeneous data set. Thus, in this work, we study the accuracy of these spectral classification tools using 4646 SEDMachine spectra, which have accurate classifications obtained from the Zwicky Transient Facility Bright Transient Survey (BTS). Comparing our classifications with those from BTS, we have tested the classification accuracy in various ways. We find that NGSF has the best performance (overall Accuracy 87.6% when samples are split into SNe Ia and Non-Ia types), while SNID and DASH have similar performance with overall Accuracy of 79.3% and 76.2%, respectively. Specifically for SNe Ia, SNID can accurately classify them when rlap > 15 without contamination from other types, such as Ibc, II, SLSN, and other objects that are not SNe (Purity > 98%). For other types, determining their classification is often uncertain. We conclude that it is difficult to obtain an accurate classification from these tools alone. This results in additional human visual inspection effort being required in order to confirm the classification. To reduce this human visual inspection and to support the classification process for future large-scale surveys, this work provides supporting information, such as the accuracy of each tool as a function of its metric. [ABSTRACT FROM AUTHOR]

We explore the influence of radio-mode feedback on the properties of the cool circumgalactic medium (CGM). To this end, we assemble a statistical sample of approximately 30,000 radio galaxies with background quasars by combining optical spectroscopic measurements of luminous red galaxies and quasars from the year 1 data set of the Dark Energy Spectroscopic Instrument and radio sources from the LOw-Frequency ARray Two-metre Sky Survey (LoTSS) DR2 catalog and the Very Large Array Sky Survey (VLASS) quick-look catalog. Galaxies with similar optical properties but with no radio counterparts in LoTSS and VLASS are selected as the control group. We measure the cool CGM properties of radio galaxies and their control samples traced by Mg ii absorption lines, including covering fraction, rest equivalent width, and gas kinematics. Our results show no significant difference in the properties of gas around radio galaxies and their control sample, indicating that the operating radio-mode feedback of massive galaxies does not produce detectable effects on the properties of the cool CGM. Finally, we show that the CGM of radio galaxies contains a nonnegligible amount of cool gas with approximately 1010 M ⊙. This abundance can place a stringent constraint on the radio-mode feedback models. [ABSTRACT FROM AUTHOR]

We have performed wide-field, ultra-low-surface-brightness H α emission-line mapping around NGC 1068 with the newly commissioned Circumgalactic H α Spectrograph. NGC 1068 is notable for its active galactic nucleus, which globally ionizes gas in the disk and halo. Line-emitting diffuse ionized gas is distributed throughout the galactic disk and large-scale ionized filaments are found well beyond the disk, aligned with the cone angle of the central jet. We report the discovery of a new ribbon of ionized gas around NGC 1068 beyond even the known outer filamentary structure, located 20 kpc from the galaxy. The H α surface brightness of this ribbon is on the order of the bright telluric lines, ranging from 4 to 16 R, with fainter regions on the order of the sky background continuum. Unlike previous extended emission, the ribbon is not as well aligned with the current axis of the central jet. It is not associated with any galactic structure or known tidal features in the halo of NGC 1068, though it may originate from a larger distribution of unmapped neutral atomic or molecular gas in the halo. The morphology of the ribbon emission in H α is correlated with extended UV emission around NGC 1068. H α -to-UV flux ratios in the ribbon are comparable to extended emission-line ratios in the halos of NGC 5128, NGC 253, and M82. The H α excess in the ribbon gas suggests ionization by slow shocks or a mixture of in situ star formation and photoionization and collisional ionization processes. [ABSTRACT FROM AUTHOR]

Gaia DR3 photometry and Blue Photometer (BP) and Red Photometer (RP) spectra have been widely used as reference in photometric calibrations. In this work, we check the spatial uniformity of Gaia DR3 photometry and BP/RP spectra by comparing the BP, RP, and G -band photometry with the synthetic ones from the BP/RP spectra. The discrepancies have a small dispersion of 1.07, 0.55, and 1.02 mmag for the BP, RP, and G bands, respectively. However, the discrepancies exhibit obvious spatial patterns, which are clearly associated with Gaia's scanning law. The patterns observed in the BP and G bands are similar, with discrepancies between photometry and spectra being more pronounced in these bands compared to the RP band. A further independent test with the Dark Energy Survey DR2 photometry reveals that the spatial patterns are more likely attributed to the Gaia DR3 BP/RP spectra, particularly in the BP band. On one hand, our results confirm the high spatial uniformity of Gaia data at the mmag level. On the other hand, our results suggest that the spatial uniformity of Gaia DR3 BP/RP spectra is not as good as that of Gaia DR3 photometry, and could be further improved in the future. [ABSTRACT FROM AUTHOR]

In the era of state-of-the-art space-borne telescopes, high-resolution ground-based observation has emerged as a crucial method for characterizing exoplanets, providing essential insights into their atmospheric compositions. In the optical and near-infrared regions, high-resolution spectroscopy has been powerful for hot Jupiters (HJs) and ultrahot Jupiters (UHJs) during their primary transits, as it can probe molecules with better sensitivity. Here, we focus on a comparative simulation study of WASP-76 b (UHJ) and WASP-77 A b (HJ) for different numbers of transits, utilizing three ground-based spectrographs, GIANO-B (Telescopio Nazionale Galileo), CARMENES (Centro Astronomico Hispano Alemán), and ANDES (European Extremely Large Telescope or E-ELT), with varying instrumental parameters, spectral coverages, and resolutions. We aim to evaluate the feasibility of using the upcoming ground-based E-ELT to probe molecules from planet atmospheres and to show how it surpasses other ground-based observatories in terms of detectability. With the 1D model petitCODE, we have self-consistently simulated the atmospheric pressure–temperature profiles, which are subsequently integrated into the 1D chemical kinetics model, VULCAN, to evolve the atmospheric chemistry. High-resolution spectra are obtained by performing line-by-line radiative transfer using petitRADTRANS. Finally, we use the resulting spectra to assess the detectability ( σ det ) of molecular bands, employing the ground-based noise simulator SPECTR. Utilizing cross-correlation spectroscopy, we have successfully demonstrated the robust consistency between our simulation study and real-time observations for both planets. ANDES excels overall in molecular detection, due to its enhanced instrumental architecture, reinforcing E-ELT's importance for studying exoplanet atmospheres. Additionally, our theoretical simulations predict the detection of CO, NH3, and H2S in the WASP-76 b atmosphere with σ det > 3. [ABSTRACT FROM AUTHOR]

SN H0pe is a triply imaged supernova (SN) at redshift z = 1.78 discovered using the James Webb Space Telescope. In order to classify the SN spectroscopically and measure the relative time delays of its three images (designated A, B, and C), we acquired NIRSpec follow-up spectroscopy spanning 0.6–5 μ m. From the high signal-to-noise spectra of the two bright images B and C, we first classify the SN, whose spectra most closely match those of SN 1994D and SN 2013dy, as a Type Ia SN. We identify prominent blueshifted absorption features corresponding to Si ii λ 6355 and Ca ii H λ 3970 and K λ 3935. We next measure the absolute phases of the three images from our spectra, which allow us to constrain their relative time delays. The absolute phases of the three images, determined by fitting the three spectra to Hsiao07 SN templates, are 6.5 − 1.8 + 2.4 days, 24.3 − 3.9 + 3.9 days, and 50.6 − 15.3 + 16.1 days for the brightest to faintest images. These correspond to relative time delays between Image A and Image B and between Image B and Image C of − 122.3 − 43.8 + 43.7 days and 49.3 − 14.7 + 12.2 days, respectively. The SALT3-NIR model yields phases and time delays consistent with these values. After unblinding, we additionally explored the effect of using Hsiao07 template spectra for simulations through 80 days instead of 60 days past maximum, and found a small (11.5 and 1.0 days, respectively) yet statistically insignificant (∼0.25 σ and ∼0.1 σ) effect on the inferred image delays. [ABSTRACT FROM AUTHOR]

We propose and discuss a new experimental approach to measure the centroid shift induced by gravitational microlensing in the images of lensed quasars (astrometric microlensing). Our strategy is based on taking the photocenter of a region in the quasar large enough as to be insensitive to microlensing as reference to measure the centroid displacement of the continuum. In this way, single-epoch measurements of astrometric microlensing can be performed. Using numerical simulations, we show that, indeed, the centroid shift monotonically decreases as the size of the emitting region increases, and only for relatively large regions, like the broad line region (BLR), does the centroid shift become negligible. This opens interesting possibilities to study the stratification of the different emitters in the accretion disk and the BLR. We estimate the amplitude of the centroid shifts for 79 gravitationally lensed images and study more thoroughly the special cases Q2237+030 A, RXJ1131-1231 A, PG1115+080 A2, and SDSS J1004+4112 A. We propose to use spectro-astrometry to simultaneously obtain the photocenters of the continuum and of different emission line regions since, with the precision of forthcoming instruments, astrometric microlensing by ∼1 M ⊙ mass microlenses may be detected in many quasar lensed images. When we consider more massive micro/millilenses, M ≳ 10 M ⊙, often proposed as the constituents of dark matter, the BLR becomes sensitive to microlensing and can no longer be used as a positional reference to measure centroid shifts. Differential microlensing between the images of a lensed quasar along several epochs should be used instead. [ABSTRACT FROM AUTHOR]

We present the second and final release of optical spectroscopy of Type Ia supernovae (SNe Ia) obtained during the first and second phases of the Carnegie Supernova Project (CSP-I and CSP-II). The newly released data consist of 148 spectra of 30 SNe Ia observed in the course of CSP-I and 234 spectra of 127 SNe Ia obtained during CSP-II. We also present 216 optical spectra of 46 historical SNe Ia, including 53 spectra of 30 SNe Ia observed by the Calán/Tololo Supernova Survey. We combine these observations with previously published CSP data and publicly available spectra to compile a large sample of measurements of spectroscopic parameters at maximum light, consisting of pseudo-equivalent widths and expansion velocities of selected features for 232 CSP and historical SNe Ia (including more than 1000 spectra). Finally, we review some of the strongest correlations between spectroscopic and photometric properties of SNe Ia. Specifically, we define two samples: one consisting of SNe Ia discovered by targeted searches (most of them CSP-I objects) and the other composed of SNe Ia discovered by untargeted searches, which includes most of the CSP-II objects. The analyzed correlations are similar for both samples. We find a larger incidence of SNe Ia belonging to the cool and broad-line Branch subtypes among the events discovered by targeted searches, shallow-silicon SNe Ia are present with similar frequencies in both samples, while core normal SNe Ia are more frequent in untargeted searches. [ABSTRACT FROM AUTHOR]

Cen A hosts the closest active galactic nucleus to the Milky Way, which makes it an ideal target for investigating the dynamical processes in the vicinity of accreting supermassive black holes. In this paper, we present 14 Chandra HETGS spectra of the nucleus of Cen A that were observed throughout 2022. We compared them with each other, and contrasted them against the two previous Chandra HETGS spectra from 2001. This enabled an investigation into the spectral changes occurring on timescales of months and 21 years. All Chandra spectra could be well fitted by an absorbed power law with a strong and narrow Fe K α line, a leaked power-law feature at low energies, and Si and S K α lines that could not be associated with the central engine. The flux of the continuum varied by a factor of 2.74 ± 0.05 over the course of the observations, whereas the Fe line only varied by 18.8% ± 8.8%. The photon index increased over 21 years, and the hydrogen column density varied significantly within a few months as well. The Fe K α line was found at a lower energy than expected from the Cen A redshift, amounting to an excess velocity of 326 − 94 + 84 km s − 1 relative to Cen A. We investigated warped accretion disks, bulk motion, and outflows as possible explanations of this shift. The spectra also featured ionized absorption lines from Fe xxv and Fe xxvi, describing a variable inflow. [ABSTRACT FROM AUTHOR]

We performed a rigorous reverberation-mapping analysis of the broad-line region (BLR) in a highly accreting (L / L Edd = 0.74–3.4) active galactic nucleus, Markarian 142 (Mrk 142), for the first time using concurrent observations of the inner accretion disk and the BLR to determine a time lag for the H β λ 4861 emission relative to the ultraviolet (UV) continuum variations. We used continuum data taken with the Niel Gehrels Swift Observatory in the UVW 2 band, and the Las Cumbres Observatory, Dan Zowada Memorial Observatory, and Liverpool Telescope in the g band, as part of the broader Mrk 142 multiwavelength monitoring campaign in 2019. We obtained new spectroscopic observations covering the H β broad emission line in the optical from the Gemini North Telescope and the Lijiang 2.4 m Telescope for a total of 102 epochs (over a period of 8 months) contemporaneous to the continuum data. Our primary result states a UV-to-H β time lag of 8.68 − 0.72 + 0.75 days in Mrk 142 obtained from light-curve analysis with a Python-based running optimal average algorithm. We placed our new measurements for Mrk 142 on the optical and UV radius–luminosity relations for NGC 5548 to understand the nature of the continuum driver. The positions of Mrk 142 on the scaling relations suggest that UV is closer to the "true" driving continuum than the optical. Furthermore, we obtain log (M • / M ⊙) = 6.32 ± 0.29 assuming UV as the primary driving continuum. [ABSTRACT FROM AUTHOR]

The observations from the Dark Energy Spectroscopic Instrument (DESI) will significantly increase the numbers of known extremely metal-poor stars by a factor of ∼10, improving the sample statistics to study the early chemical evolution of the Milky Way and the nature of the first stars. In this paper we report follow-up observations with high signal-to-noise ratio of nine metal-poor stars identified during the DESI commissioning with the Optical System for Imaging and Low-Resolution Integrated Spectroscopy (OSIRIS) instrument on the 10.4 m Gran Telescopio Canarias. The analysis of the data using a well-vetted methodology confirms the quality of the DESI spectra and the performance of the pipelines developed for the data reduction and analysis of DESI data. [ABSTRACT FROM AUTHOR]

The population of metastable levels is key to high-precision density diagnostics of astrophysical plasmas. In photoionized plasmas, density is used to infer the distance from the ionizing source, which is otherwise difficult to obtain. Perfecting models that compute these populations is thus crucial. The present paper presents a semianalytic hydrogenic approximation for assessing the relative importance of different processes in populating atomic levels. This approximation shows that in the presence of a radiation source, photoexcitations and collisional excitations are both important over a wide range of plasma temperatures and ionizing spectra, while radiative recombination is orders of magnitude weaker. The interesting case of Fe+21 with a collisional radiative model with photoexcitation demonstrates this effect. The population of the first excited metastable level in Fe+21 is sensitive to the electron number density in the critical range of n e = 1012–1015 cm−3; it was observed to be significantly populated in the X-ray spectrum of the 2005 outburst of the X-ray binary GRO J1655-40. The present model shows that photoexcitation is the predominant process indirectly populating the metastable level. For the photoionized plasma in the GRO J1655-40 outflow, the model indicates a measured value of n e = (2.6 ± 0.5) × 1013 cm−3, implying a distance from the source of r = (4.4 ± 0.4) × 1010 cm. Finally, we show how the computed critical density and distance of Fe+21 yield the correct ionization parameter of the ion, independent of ionization balance calculations. [ABSTRACT FROM AUTHOR]

We present optical, near-infrared, and radio observations of supernova (SN) SN IIb 2022crv. We show that it retained a very thin H envelope and transitioned from an SN IIb to an SN Ib; prominent H α seen in the pre-maximum phase diminishes toward the post-maximum phase, while He i lines show increasing strength. SYNAPPS modeling of the early spectra of SN 2022crv suggests that the absorption feature at 6200 Å is explained by a substantial contribution of H α together with Si ii, as is also supported by the velocity evolution of H α. The light-curve evolution is consistent with the canonical stripped-envelope SN subclass but among the slowest. The light curve lacks the initial cooling phase and shows a bright main peak (peak M V = −17.82 ± 0.17 mag), mostly driven by radioactive decay of 56Ni. The light-curve analysis suggests a thin outer H envelope (M env ∼ 0.05 M ⊙) and a compact progenitor (R env ∼ 3 R ⊙). An interaction-powered synchrotron self-absorption model can reproduce the radio light curves with a mean shock velocity of 0.1 c. The mass-loss rate is estimated to be in the range of (1.9−2.8) × 10−5 M ⊙ yr−1 for an assumed wind velocity of 1000 km s−1, which is on the high end in comparison with other compact SNe IIb/Ib. SN 2022crv fills a previously unoccupied parameter space of a very compact progenitor, representing a beautiful continuity between the compact and extended progenitor scenario of SNe IIb/Ib. [ABSTRACT FROM AUTHOR]

The chromospheric Ly α line of neutral hydrogen (1216 Å) is the most intense emission line in the solar spectrum, yet until recently observations of flare-related Ly α emission have been scarce. Here, we examine the relationship between nonthermal electrons accelerated during the impulsive phase of three M3 flares that were co-observed by RHESSI, GOES, and the Solar Dynamics Observatory, and the corresponding response of the chromosphere in Ly α. Despite having identical X-ray magnitudes, these flares showed significantly different Ly α responses. The peak Ly α enhancements above the quiescent background for these flares were 1.5%, 3.3%, and 6.4%. However, the predicted Ly α enhancements from FISM2 were consistently <2.5%. By comparing the properties of the nonthermal electrons derived from spectral analysis of hard X-ray observations, flares with a "harder" spectral index were found to produce a greater Ly α enhancement. The percentage of nonthermal energy radiated by the Ly α line during the impulsive phase was found to range from 2.0% to 7.9%. Comparatively, the radiative losses in He ii (304 Å) were found to range from 0.6% to 1.4% of the nonthermal energy while displaying enhancements above the background of 7.3% to 10.8%. FISM2 was also found to underestimate the level of He ii emission in two of the three flares. These results may have implications for space weather studies and for modeling the response of the terrestrial atmosphere to changes in the solar irradiance, and will guide the interpretation of flare-related Ly α observations that will become available during Solar Cycle 25. [ABSTRACT FROM AUTHOR]

Luminous quasars are powerful targets to investigate the role of feedback from supermassive black holes (BHs) in regulating the growth phases of BHs themselves and of their host galaxies, up to the highest redshifts. Here we investigate the cosmic evolution of the occurrence and kinematics of BH-driven outflows, as traced by broad absorption line (BAL) features, due to the C iv ionic transition. We exploit a sample of 1935 quasars at z = 2.1–6.6 with bolometric luminosity log(L bol/erg s−1) ≳ 46.5, drawn from the Sloan Digital Sky Survey and from the X-Shooter legacy survey of Quasars at the Reionization Epoch (XQR-30). We consider rest-frame optical bright quasars to minimize observational biases due to quasar selection criteria. We apply a homogeneous BAL-identification analysis, based on employing composite template spectra to estimate the quasar intrinsic emission. We find a BAL quasar fraction close to 20% at z ∼ 2–4, while it increases to almost 50% at z ∼ 6. The velocity and width of the BAL features also increase at z ≳ 4.5. We exclude the possibility that the redshift evolution of the BAL properties is due to differences in terms of quasar luminosity and accretion rate. These results suggest significant BH feedback occurring in the 1 Gyr old universe, likely affecting the growth of BHs and, possibly, of their host galaxies, as supported by models of early BH and galaxy evolution. [ABSTRACT FROM AUTHOR]

Young supernova remnant (SNR) shocks are believed to be the main sites of galactic cosmic-ray production, showing X-ray synchrotron-dominated spectra in the vicinity of their shock. While a faint thermal signature left by the shocked interstellar medium (ISM) should also be found in the spectra, proofs for such an emission in Tycho's SNR have been lacking. We perform an extended statistical analysis of the X-ray spectra of five regions behind the blast wave of Tycho's SNR using Chandra archival data. We use Bayesian inference to perform extended parameter space exploration and sample the posterior distributions of a variety of models of interest. According to Bayes factors, spectra of all five regions of analysis are best described by composite three-component models taking nonthermal emission, ejecta emission, and shocked ISM emission into account. The shocked ISM stands out the most in the northern limb of the SNR. We find for the shocked ISM a mean electron temperature kT e = 0.96 − 0.51 + 1.33 keV for all regions and a mean ionization timescale n e t = 2.55 − 1.22 + 0.5 × 10 9 cm−3 s resulting in a mean ambient density n e = 0.32 − 0.15 + 0.23 cm−3 around the remnant. We performed an extended analysis of the northern limb and show that the measured synchrotron cutoff energy is not well constrained in the presence of a shocked ISM component. Such results cannot currently be further investigated by analyzing emission lines in the 0.5–1 keV range, because of the low Chandra spectral resolution in this band. We show with simulated spectra that Athena X-ray Integral Field Unit future performances will be crucial to address this point. [ABSTRACT FROM AUTHOR]

In the context of a project aimed at characterizing the properties of the so-called Bulge Fossil Fragments (the fossil remnants of the bulge formation epoch), here we present the first determination of the metallicity distribution of Liller 1. For a sample of 64 individual member stars we used ESO-MUSE spectra to measure the equivalent width of the Ca II triplet and then derive the iron abundance. To test the validity of the adopted calibration in the metal-rich regime, the procedure was first applied to three reference bulge globular clusters (NGC 6569, NGC 6440, and NGC 6528). In all the three cases, we found single-component iron distributions, with abundance values fully in agreement with those reported in the literature. The application of the same methodology to Liller 1 yielded, instead, a clear bimodal iron distribution, with a subsolar component at [Fe/H] = −0.48 dex (σ = 0.22) and a supersolar component at [Fe/H] = +0.26 dex (σ = 0.17). The latter is found to be significantly more centrally concentrated than the metal-poor population, as expected in a self-enrichment scenario and in agreement with that found in another bulge system, Terzan 5. The obtained metallicity distribution is astonishingly similar to that predicted by the reconstructed star formation history of Liller 1, which is characterized by three main bursts and a low, but constant, activity of star formation over the entire lifetime. These findings provide further support to the possibility that, similar to Terzan 5, Liller 1 is also a Bulge Fossil Fragment. [ABSTRACT FROM AUTHOR]

Dust extinction is one of the fundamental measurements of dust grain sizes, compositions, and shapes. Most of the wavelength-dependent variations seen in Milky Way extinction are strongly correlated with the single parameter R (V) = A (V)/ E (B − V). Existing R (V)-dependent extinction relationships use a mixture of spectroscopic and photometry observations, and hence do not fully capture all the important dust features or continuum variations. Using four existing samples of spectroscopically measured dust extinction curves, we consistently measure the R (V)-dependent extinction relationship spectroscopically from the far-ultraviolet (FUV) to mid-infrared for the first time. Linear fits of A (λ)/ A (V) dependent on R (V) are done using a method that fully accounts for their significant and correlated uncertainties. These linear parameters are fit with analytic wavelength-dependent functions to determine the smooth R (V) (2.3–5.6) and wavelength (912 Å–32 μ m) dependent extinction relationship. This relationship shows that the FUV rise, 2175 Å bump, and the three broad optical features are dependent on R (V), but the 10 and 20 μ m features are not. Existing literature relationships show significant deviations compared to this relationship especially in the FUV and infrared (IR). Extinction curves that clearly deviate from this relationship illustrate that this relationship only describes the average behavior versus R (V). We find tentative evidence that the relationship may not be linear with R (V)−1 especially in the ultraviolet (UV). For the first time, this relationship provides measurements of dust extinction that spectroscopically resolve the continuum and features in the UV, optical, and IR as a function of R (V), enabling detailed studies of dust grain properties and full spectroscopic accounting for the effects of dust extinction on astrophysical objects. [ABSTRACT FROM AUTHOR]

The temperatures of the heavy ions (T i ) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of T i is usually challenging due to the nonthermal motion, instrumental limitations, and optically thin nature of the coronal emissions. We present the measurement of T i and its dependency on the ion charge-to-mass ratio (Z / A) at the polar coronal hole boundary, only assuming that heavy ions have the same nonthermal velocity. To improve the Z / A coverage and study the influence of the instrumental broadening, we used a coordinated observation from the EUV Imaging Spectrometer on board the Hinode satellite and the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on board the Solar and Heliospheric Observatory. We found that the T i of ions with Z / A less than 0.20 or greater than 0.33 are much higher than the local electron temperature. We ran the Alfvén Wave Solar Model-realtime to investigate the formation of optically thin emissions along the line of sight (LOS). The simulation suggested that plasma bulk motions along the LOS broaden the widths of hot emission lines in the coronal hole (e.g., Fe xii, Fe xiii). We discussed other factors that might affect the T i measurement, including the non-Gaussian wings in some bright SUMER lines, which can be fitted by a double-Gaussian or a κ distribution. Our study confirms the preferential heating of heavy ions in coronal holes and provides new constraints on coronal heating models. [ABSTRACT FROM AUTHOR]

The physical properties of transiting exoplanets are connected with the physical properties of their host stars. We present a homogeneous spectroscopic analysis based on the spectra of FGK-type stars observed with the Hydra spectrograph on the WIYN telescope. We derived the effective temperatures, surface gravities, and metallicities, for 81 stars observed by K2 and 33 by Kepler 1. We constructed an Fe i and ii line list that is adequate for the analysis of R ∼ 18,000 spectra covering 6050–6350 Å and adopted the spectroscopic technique based on equivalent-width measurements. The calculations were done in LTE using Kurucz model atmospheres and the qoyllur-quipu (q 2) package. We validated our methodology via an analysis of a benchmark solar twin and solar proxies, which are used as a solar reference. We estimated the effects that including Zeeman-sensitive Fe i lines have on the derived stellar parameters for young and possibly active stars in our sample and found them not to be significant. Stellar masses and radii were derived by combining the stellar parameters with Gaia EDR3 and V magnitudes and isochrones. The measured stellar radii have a 4.2% median internal precision, leading to a median internal uncertainty of 4.4% in the derived planetary radii. With our sample of 83 confirmed planets orbiting K2 host stars, the radius gap near R planet ∼ 1.9 R ⊕ is detected, in agreement with previous findings. Relations between the planetary radius, orbital period, and metallicity are explored and these also confirm previous findings for Kepler 1 systems. [ABSTRACT FROM AUTHOR]

The Near-Infrared Spectrograph (NIRSpec) is one of the four focal plane instruments on the James Webb Space Telescope. In this paper, we summarize the in-orbit performance of NIRSpec, as derived from data collected during its commissioning campaign and the first few months of nominal science operations. More specifically, we discuss the performance of some critical hardware components such as the two NIRSpec Hawaii-2RG detectors, wheel mechanisms, and the microshutter array. We also summarize the accuracy of the two target acquisition procedures used to accurately place science targets into the slit apertures, discuss the current status of the spectrophotometric and wavelength calibration of NIRSpec spectra, and provide the "as measured" sensitivity in all NIRSpec science modes. Finally, we point out a few important considerations for the preparation of NIRSpec science programs. [ABSTRACT FROM AUTHOR]

We present multiwavelength time-series spectroscopy of SN 2013aa and SN 2017cbv, two Type Ia supernovae (SNe Ia) on the outskirts of the same host galaxy, NGC 5643. This work utilizes new nebular-phase near-infrared (NIR) spectra obtained by the Carnegie Supernova Project-II, in addition to previously published optical and NIR spectra. Using nebular-phase [Fe ii ] lines in the optical and NIR, we examine the explosion kinematics and test the efficacy of several common emission-line-fitting techniques. The NIR [Fe ii ] 1.644 μ m line provides the most robust velocity measurements against variations due to the choice of the fit method and line blending. The resulting effects on velocity measurements due to choosing different fit methods, initial fit parameters, continuum and line profile functions, and fit region boundaries were also investigated. The NIR [Fe ii ] velocities yield the same radial shift direction as velocities measured using the optical [Fe ii ] λ 7155 line, but the sizes of the shifts are consistently and substantially lower, pointing to a potential issue in optical studies. The NIR [Fe ii ] 1.644 μ m emission profile shows a lack of significant asymmetry in both SNe, and the observed low velocities elevate the importance for correcting for any velocity contribution from the host galaxy's rotation. The low [Fe ii ] velocities measured in the NIR at nebular phases disfavor progenitor scenarios in close double-degenerate systems for both SN 2013aa and SN 2017cbv. The time evolution of the NIR [Fe ii ] 1.644 μ m line also indicates moderately high progenitor white dwarf central density and potentially high magnetic fields. [ABSTRACT FROM AUTHOR]

The aim of the Lunar Legacy Project is to map the distribution of water on the Moon's surface through the detection and characterization of the 6 μ m spectral band indicative of molecular water. Spectra were taken with the Faint Object infraRed Camera for the SOFIA Telescope instrument on the Stratospheric Observatory for Infrared Astronomy (SOFIA) between 2018 and 2022. This paper describes the processing steps necessary to reduce the raw data downloaded from the SOFIA archive to create flux-calibrated spectra. The reduction mostly requires the SOFIA Redux package which can be downloaded from the SOFIA website, and some steps in the process require scripts written by our team in Python. [ABSTRACT FROM AUTHOR]

AIM: To evaluate the role of bone marrow-derived stem cells in the treatment of advanced dry age-related macular degeneration (AMD) using multifocal electroretinogram (mf-ERG) and fundus autofluorescence imaging. METHODS: Thirty patients (60 eyes) with bilateral central geographic atrophy (GA) were recruited. Worse eye of each patient received autologous bone marrow-derived hematopoietic stem cells (BM-HSCs) (group 1) and the fellow eye with better visual acuity served as control (group 2). The effect of stem cell therapy was determined in terms of visual acuity, amplitude and implicit time in mf-ERG and size of GA on fundus autofluorescence imaging. These tests were performed at presentation and first, third and sixth month follow up. Adverse events (if any) were also monitored. RESULTS: At 6mo follow-up there was no statistically significant improvement in median logMAR best corrected visual acuity (BCVA) in either group. Mf-ERG revealed significant improvement in amplitude and implicit time in the intervention group. A significant decrease was also noted in greatest linear dimension (GLD) of GA in the eyes receiving stem cells [6.78±2.60 mm at baseline to 6.56±2.59 mm at 6mo (P=0.021)]. However, no such improvement was noted in the control group. CONCLUSION: Electrophysiological and anatomical improvement in the intervention group sheds light on the therapeutic role of BM-HSCs. Further studies are required to determine the stage of disease at which the maximal benefit can be achieved and to standardize the dose and frequency of stem cell injection.