Sazuna/UAT_keywords huggingface dataset:
CMB-S4: Foreground-cleaning Pipeline Comparison for Measuring Primordial Gravitational Waves. We compare multiple foreground-cleaning pipelines for estimating the tensor-to-scalar ratio, r, using simulated maps of the planned CMB-S4 experiment within the context of the South Pole Deep Patch. To evaluate robustness, we analyze bias and uncertainty on r across various foreground suites using map-based simulations. The foreground-cleaning methods include: a parametric maximum likelihood approach applied to auto- and cross-power spectra between frequency maps; a map-based parametric maximum-likelihood method; and a harmonic-space internal linear combination using frequency maps. We summarize the conceptual basis of each method to highlight their similarities and differences. To better probe the impact of foreground residuals, we implement an iterative internal delensing step, leveraging a map-based pipeline to generate a lensing B-mode template from the large aperture telescope frequency maps. Our results show that the performance of the three approaches is comparable for simple and intermediate-complexity foregrounds, with σ(r) ranging from 3─5 ×10−4. However, biases at the 1σ─2σ level appear when analyzing more complex forms of foreground emission. By extending the baseline pipelines to marginalize over foreground residuals, we demonstrate that contamination can be reduced to within statistical uncertainties, albeit with a pipeline-dependent impact on σ(r), which translates to a detection significance between 2σ and 4σ for an input value of r = 0.003. These findings suggest varying levels of maturity among the tested pipelines, with the auto- and cross-spectra-based approach demonstrating the best stability and overall performance. Moreover, given the extremely low noise levels, mutual validation of independent foreground-cleaning pipelines is essential to ensure the robustness of any potential detection.

Keywords: Cosmology, Cosmic microwave background radiation, Astronomy data analysis, Cosmic inflation, Gravitational waves
The Evolution of Half-mass Radii and Color Gradients for Young and Old Quiescent Galaxies at 0.5 &lt; z &lt; 3 with JWST/PRIMER. We present a study of the size growth of the red sequence between 0.5 &lt; z &lt; 3, tracing the evolution of quiescent galaxies in both effective half-light and half-mass radii using multiwavelength JWST/NIRCam imaging provided by the PRIMER survey. Half-light radii are measured from imaging in six different filters for 502 quiescent galaxies with log(M*/M⊙) &gt; 10, whereas half-mass radii are derived from the F444W profiles together with the F277W − F444W color─M*/L relation. We investigate the dependence of the ratio re,mass/re,light on redshift, stellar mass, and the wavelength used to measure re,light, also separating the sample into younger and older quiescent galaxies. Our data demonstrate that rest-frame infrared sizes accurately trace mass-weighted sizes, while sizes measured at rest-frame optical wavelengths (0.5─0.7 μm) are 0.1─0.2 dex larger, with only minor variations in redshift. We find that the average size of young quiescent galaxies agrees with that of old quiescent galaxies at intermediate masses, 10 &lt; log(M*/M⊙) &lt; 11, within their respective uncertainties in all observed-frame half-light, rest-frame half-light, and half-mass─radius measurements. At face value, our results point to a combination of progenitor bias and minor mergers driving the size growth of intermediate-mass quiescent galaxies at 0.5 &lt; z &lt; 3.

Keywords: Galaxy formation, Galaxy structure, Galaxy evolution
The Galaxy─Active Galactic Nucleus Scaling Relations over 13 Billion Years in SHARK v2.0. I. Supermassive Black Hole Masses. The presence of strong correlations between supermassive black hole (SMBH) masses and galaxy properties like stellar mass have been well established for the local Universe, but how these scaling relations evolve with cosmic time is yet to be settled in both observations and theoretical models. Recent works have also highlighted the role of galaxy morphology on the scatter of the SMBH─galaxy mass scaling relations, while the impact of other galaxy properties remains poorly studied, like the role of galaxy environment. We use the state-of-the-art SHARK v2.0 semianalytic model to explore the evolution of these galaxy─SMBH scaling relations to expand the available predictions from theoretical models to contrast with existing and upcoming observations. We find the relations between SMBH masses and both total and bulge stellar masses predicted by SHARK v2.0 to be in good overall agreement with observational measurements across a wide range of redshifts and stellar masses. These scaling relations show a significant evolution as a function of cosmic time in SHARK v2.0, with SMBH masses ∼1 dex lower at z = 0 compared to z = 9 at fixed stellar mass and the scatter increasing by a factor of ∼2─5 toward low redshift. Both relations show a strong dependence with galaxy morphology and the main source for SMBH growth (gas accretion or mergers), with weaker trends with star formation rate, galaxy size, and environment. We find that galaxy morphology alone explains most of the scatter around both scaling relations, with other galaxy properties tying to the SMBH scaling relations through their correlations with morphology.

Keywords: Supermassive black holes, Galaxy formation, Galaxy environments, Scaling relations, Astronomical simulations
Constraints on Emission Models by Broadband Observations of Soft Gamma-Ray Pulsar PSR B1509─58. Soft γ-ray pulsars featuring broad single peaks exhibit different observational properties compared to ordinary double-peaked high-energy pulsars. These two types of pulsars are considered to be the result of different viewing angles. Therefore, the radiation characteristics of soft γ-ray pulsars play a crucial role in testing radiation models. However, the weak fluxes of the broad single-peak pulsars in the high-energy range have limited in-depth research on them in the past. In this work, the profile and spectral analysis of PSR B1509─58 from keV to GeV energies are performed using new observations from NICER, Insight-HXMT, and Fermi GBM-NaI/LAT. We find that the pulse profile narrows as the energy increases, and the FWHM can be fitted with FWHM = (0.35 ± 0.02) · (E/1 keV)−0.053 ± 0.009. The phase-averaged spectrum fitted by a modified super exponential cutoff power law model reveals that the energy corresponding to the maximum luminosity  Emax  is 2.1 ± 1 MeV. Furthermore, we fit the pulse profiles across different energy bands using a geometric annular gap model. Within the framework of this model, the observed narrowing of the pulse profile and the rapid softening of the phase-averaged spectrum can be interpreted as a result of the radiation angle moving away from the magnetic axis with increasing energy. The observational and modeling results support the existence of an annular gap acceleration region located inside the null-charge surface, suggesting that higher-energy radiation originates from areas closer to the surface of the neutron star.

Keywords: High energy astrophysics, Pulsars
The Slow Brightening of WNTR23bzdiq/WTP19aalzlk: Possible Onset of Common Envelope Evolution in an Asymptotic Giant Branch Star?. We present WNTR23bzdiq/WTP19aalzlk, a slow eruption of an early-asymptotic giant branch (AGB) star in M31 identified by the Wide-field Infrared Transient Explorer near-infrared (NIR) and the NEOWISE mid-infrared (MIR) surveyors. This source brightened gradually over 7 yr: a 0.5 mag optical rise (2018─2021), a 1 mag optical outburst lasting ∼1000 days (2021─2023), and another 1 mag optical rebrightening in 2024. This was accompanied by a steady MIR brightening of 1 mag over 10 yr in NEOWISE data. Archival optical data show only erratic, small-amplitude (&lt;0.3 mag) brightness variations from 2003 to 2015, revealing a progenitor star with Teff ≍ 3500 K and L ≍ 1.6 × 104 L⊙—consistent with a 7 ± 2 M⊙ star in its early-AGB phase. During the eruption, the luminosity rose to ≍5 × 104 L⊙with slow photospheric expansion (≍5 km s−1) and constant temperatures (≍3600 K) inferred from the spectral energy distribution. Optical and NIR spectra of the eruption resemble late M-type stars, with a mixed-temperature behavior—transitioning from M1 in the optical to M7/M8 in the NIR. These properties of WNTR23bzdiq resemble those of stellar merger transients, particularly the giant star merger OGLE-2002-BLG-360, but on longer timescales. As such, WNTR23bzdiq potentially marks the onset of common envelope evolution (CEE) in a binary with an AGB primary, and is possibly a member of the emerging population of infrared transients from CEE in giant stars. Continued multiwavelength monitoring, particularly MIR observations with JWST to quantify dust production, will shed further light on WNTR23bzdiq.

Keywords: Close binary stars, Transient sources, Infrared astronomy, Asymptotic giant branch stars, Common envelope evolution
First Data Release of the Merian Survey: A Wide-field Imaging Survey of Dwarf Galaxies at z ∼ 0.06─0.10. We present an overview of the Merian Survey and its forthcoming first data release (DR1), an optical imaging survey optimized for studying bright-star-forming dwarf galaxies. Merian uses two medium-band filters (N708 and N540, centered at 708 and 540 nm), custom-built for the Dark Energy Camera (DECam) on the Blanco telescope. Merian covers ∼750 deg2 of equatorial fields, overlapping with the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) wide, deep, and ultra-deep fields. Combined with the HSC-SSP imaging data (grizy), Merian DECam medium-band imaging allows for photometric redshift measurements via detection of Hα and [O III] line emission flux excess in the N708 and N540 filters, respectively, at 0.06 &lt; z &lt; 0.10. We present the survey design, observations taken to date, data reduction using the Legacy Survey of Space and Time Science Pipelines, aperture-matched photometry for accurate galaxy colors, and the contents of DR1. The key science goals of Merian include probing the dark matter halos of dwarf galaxies out to their virial radii using high signal-to-noise weak lensing profile measurements, decoupling the effects of baryonic processes from dark matter, and understanding the role of black holes in dwarf galaxy evolution. This rich data set will also offer unique opportunities for studying extremely metal-poor galaxies via their strong [O III] emission and Hα lines, as well as [O II] emitters at z ∼ 0.4, and Lyα emitters at z ∼ 3.3 and z ∼ 4.8. Merian showcases the power of utilizing narrow and medium-band filters alongside broad-band filters for sky imaging, demonstrating their synergistic capacity to unveil astrophysical insights across diverse astrophysical phenomena.

Keywords: Observational astronomy, Surveys, Dwarf galaxies, Redshift surveys, Galaxy photometry, Dark matter
A Multiwavelength Study of ELAN Environments (AMUSE<SUP>2</SUP>): The Impact of Dense Environment on Massive Dusty Star-forming Galaxies at Cosmic Noon. To understand how massive galaxies are influenced by their surroundings, we present new Atacama Large Millimeter/submillimeter Array and Northern Extended Millimeter Array observations as part of A Multiwavelength Study of Enormous Lyα Nebula (ELAN) Environments (AMUSE2). These observations target submillimeter sources discovered in single-dish surveys around nine quasars hosting Lyα nebulae at z = 2 ∼3, including two enormous Lyα nebulae. Through detection of mid-J CO lines, we confirm physical associations of 15 SMGs, which are located outside the expected virial radii of the central dark-matter halos hosting the quasars. We find  73−21+29%  of SMGs have line profiles better described by double-Gaussian models, with a median peak-to-peak separation of 350 ± 25 km s−1, suggesting rotating disks or interacting pairs. Modified blackbody fits of the far-infrared photometry yield a median β of 2.0 ± 0.2 and Tdust of 34 ± 3 K. Overall, SMGs outside quasar halos share similar physical properties with those in the field, but combining data from other studies reveals depleted gas fractions within quasar halos. This suggests that dense environments significantly impact massive star-forming galaxies only within halo scales at cosmic noon. Additionally, spatial analyses of 15 SMGs indicate they trace large-scale structures, possibly filamentary or elongated pancake-like, with a scale height of 2─5 cMpc. Our measured distributions and densities of star formation rates align with models, although likely represent lower limits.

Keywords: Observational astronomy, Molecular gas, Galaxy formation, Interstellar dust, Large-scale structure of the universe, Quasars, Galaxy environments, Protoclusters, Galaxy evolution, Interstellar medium, Submillimeter astronomy
Open Cluster Study Using Gaia. I. Membership and Cluster Properties. Star clusters are interesting laboratories to study star formation, single and binary stellar evolution, and stellar dynamics. We have used the exquisite data from Gaia's Data Release 3 (DR3) to study 21 relatively rich and nearby open clusters with member numbers (Ncl) &gt; 500. We have developed a nonparametric method to identify cluster members. Our method works well for clusters located in both sparse and crowded environments and hence can be applied to a wide variety of star clusters. Since the member classification scheme does not make any assumptions on the expected distributions of potential cluster members, our method can identify members associated with clusters that are oddly shaped or have complex internal spatial or kinematic structures. In addition, since the membership determination does not depend on the proximity to any well-defined sequences on the color─magnitude diagram, this method easily identifies straggler members. Furthermore, for each of these clusters, we estimate essential cluster properties including age, metallicity, distance, and reddening using detailed Markov Chain Monte Carlo parameter estimation. We report the full posteriors for these important cluster properties for all clusters in our study.

Keywords: Open star clusters, Astrometry, Star clusters
Degenerate Neutron Capture Rates in the Threshold of Neutron Star─Black Hole Mergers. We first show that the rate of energy generation due to neutron capture rates can be important in neutron star─black hole mergers (NS─BH mergers) by considering neutron degeneracy. Neutrons during NS─BH mergers exist in a highly degenerate state, yet prior studies have typically assumed Maxwell─Boltzmann statistics for neutron capture rates. To resolve this discrepancy, we present a modified Saha equation for nuclear statistical equilibrium that accounts for neutron degeneracy and incorporates the newly computed degenerate neutron capture rates (B. Knight et al.) into the WinNet nuclear reaction network. This correction significantly alters initial nuclear abundances, r-process nucleosynthesis pathways, and energy generation. Our results reveal that degenerate neutron capture induces cooling of the ejecta (reaching up to ∼1055 erg s−1), followed by enhanced late-time heating driven by neutron captures (up to 1054 erg s−1), beta decay, and neutron emissions. Strikingly, the influence of neutron degeneracy persists for nearly 1 s, suggesting potentially detectable observational signatures. These modifications can have implications for the light curves, possibly shaping their early-time luminosity and thermal evolution or even short gamma-ray bursts, which are believed to be associated with mergers. Nevertheless, our findings do not have a significant impact on the final abundances or the total energy.

Keywords: Nuclear astrophysics, High energy astrophysics
Pulsed Gamma-Ray Emission of PSR J0447+2447. PSR J0447+2447 is an isolated millisecond pulsar with a period of ∼2.9953 ms discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). By jointly analyzing data from FAST and the Fermi Large Area Telescope, we derived a phase-connected timing solution of this pulsar, which enabled us to detect γ-ray pulsations from PSR J0447+2447 with a weighted H-test value of 132.5, corresponding to a detection significance of ∼10.1σ. The luminosity of the pulsar in the 0.1─100 GeV range is Lγ = (3.79 ± 0.61 ± 1.5)×1032 erg s−1 assuming the pulsar is at a distance of ∼1.0 kpc, corresponding to a γ-ray energy efficiency of (4.52 ± 1.17 ± 2.02)%.

Keywords: Radio pulsars, Gamma-rays, Millisecond pulsars
Fermi-LAT Detected Gamma-Ray Emission Likely Associated with SNR Kes 78. We have analyzed the GeV gamma-ray emission in the region of the supernova remnant (SNR) Kes 78 using ∼16.7 yr of Fermi-LAT observations and found that the catalog sources 4FGL J1852.4+0037e and 4FGL J1851.8−0007c are better represented as two extended sources modeled as 2Ext. One of them, designated as E2, is located at R.A. = 282 .° 86, decl. = −0 .° 11 with the 68% containment radius R68 = 0 .° 31, and is detected with a significance of 15.2σ in the 0.2─500 GeV energy range. The gamma-ray emission of source E2 is well described by a log-parabola (LogP) spectral model with spectral index Γ = 1.2 and curvature β = 0.3. The fitting with electron─proton number ratio Kep = 0.01 indicates that the GeV emission of source E2 is dominated by hadronic emission. Given the dense molecular environment surrounding the middle-aged SNR Kes 78, the hadronic scenario provides a natural explanation for the observed GeV emission. The extended source E2 can also be replaced with two point sources. One of them, designated as PTS1, is coincident with the newly discovered pulsar (PSR) J1852−0002g within the 68% positional uncertainty circle, indicating a possible gamma-ray contribution from this PSR. The gamma-ray spectrum of source PTS1 can be well described by a LogP spectral shape. The synchro-curvature radiation model provides a satisfactory spectral fit for source PTS1, suggesting that some of the GeV emission from the Kes 78 region might possibly originate from the magnetosphere of PSR J1852−0002g.

Keywords: Supernova remnants, Gamma-rays, High energy astrophysics, Pulsars
Cosmology Constraints from Type Ia Supernova Simulations of the Nancy Grace Roman Space Telescope Strategy Recommended by the High-Latitude Time Domain Survey Definition Committee. Within the next few years, the upcoming Nancy Grace Roman Space Telescope will be gathering data for the High-Latitude Time Domain Survey (HLTDS) that will be used to significantly improve the Type Ia supernova measurement of the dark energy equation of state parameters w0 and wa. Here we generate a catalog-level simulation of the in-guide strategy recommended by the HLTDS definition committee, and determine dark energy parameter constraints using a detailed analysis that includes light curve fitting, photometric redshifts and classification, BEAMS formalism, systematic uncertainties, and cosmology fitting. After analysis and selection requirements, the sample includes ∼10,000 Roman SNe Ia that we combine with ∼4400 events from LSST. The resulting dark energy figure of merit is well above the NASA mission requirement of 326, with the caveat that SN Ia model training systematics have not been included.

Keywords: Cosmology, Type Ia supernovae
The Significant Contribution of Supersoft X-Ray Sources to Nebular He II Line Emission. Nebular spectral lines provide insight into the properties of the interstellar medium and the ionizing radiation within galaxies. The presence of high-energy ionization lines such as He II indicates the existence of ionizing photons with energies exceeding the second ionization energy of helium (54 eV). There is an enigma surrounding the origin of these lines observed in star-forming galaxies because stellar ionization cannot account for such high energy emission. This paper proposes that supersoft X-ray sources (SSSs) may produce the He II ionization lines in star-forming galaxies. We model the spectra of SSSs using blackbody radiation and add them to the young stellar population spectra to represent the overall spectra of galaxies. Using a photoionization model, we predict the resulting He II λ4686 and Hβ line fluxes and inspect the contribution of SSSs to the elevation of the He II λ4686 /Hβ ratio in star-forming galaxies, both at low and high redshifts. We find that incorporating a blackbody with temperatures between kT = 10─100 eV can boost the He II λ4686 /Hβ line ratio to the levels observed in local galaxies by SDSS and in early galaxies by NIRSpec. This blackbody temperature range aligns with the observed temperatures of SSSs. The number of SSSs in spiral galaxies listed in Chandra catalogs, and our estimates of the total population, confirms that SSSs are promising candidates for the source of the He II ionization.

Keywords: X-ray astronomy, Galaxy spectroscopy, High-redshift galaxies, Emission line galaxies
An Accurate Modeling of Nano-hertz Gravitational Wave Signal from Eccentric Supermassive Binary Black Holes: An Essential Step Toward a Robust Discovery. The stochastic gravitational wave background (SGWB) in the nanohertz (nHz) regime, detectable by pulsar timing arrays (PTAs), provides a promising probe of the cosmic population of supermassive black hole binaries (SMBHBs). These binaries are expected to retain significant eccentricity throughout their evolution. We present a new technique to model the nHz SGWB by incorporating eccentricity into a multiscale adaptive simulation framework. Using the time-domain eccentric waveform model ESIGMAHM, we generate realistic GW signals from astrophysical populations of SMBHBs. Unlike circular binaries, eccentric systems emit across multiple frequencies, introducing spectral correlations between frequency bins. These correlations provide a novel observational signature of the eccentricity distribution of the SMBHB population. In this work, we adopt simplified power-law models for the eccentricity distribution. While this does not capture the full complexity of galactic environments, it effectively highlights the key features of GW emission from eccentric binaries and their imprint on the SGWB. Our approach advances nHz GW signal modeling by incorporating eccentricity at small scales, enabling more realistic predictions and offering a new avenue for probing SMBHB astrophysics with future PTA observations.

Keywords: Cosmology, Supermassive black holes, Gravitational waves
Mapping the Spatial Distribution of Fast Radio Bursts within their Host Galaxies. We present deep optical and near-infrared observations of the host galaxies of 34 fast radio bursts (FRBs) detected by the Commensal Real-time ASKAP Fast Transient (or CRAFT) survey on the Australian SKA Pathfinder (ASKAP) to compare the locations of FRBs relative to their host light distributions. Incorporating three additional FRBs from the literature, for a total of four repeating and 33 apparently nonrepeating FRBs, we determine their projected galactocentric offsets and find a median of  4.2−2.5+5.7  kpc ( 1.0−0.6+1.5re ). We model their host surface-brightness profiles and develop synthetic spatial distributions of their globular clusters (GCs) based on host properties. We calculate the likelihood the observed location of each FRB is consistent with the smooth light of its host galaxy, residual (primarily spiral) substructure, or GC distributions. The majority of FRBs favor locations within the disks of their galaxies, while only 11% ± 5% favor a GC origin, primarily those with galactocentric offsets ≳3re. At z &lt; 0.15, where spiral structure is apparent in 86% of our sample of FRB hosts, we find ≍20%─46% of FRBs favor an association with spiral arms. Assuming FRBs derive from magnetars, our results support multiple formation channels, with the majority of progenitors associated with massive stars and a minority formed through dynamical channels. However, the moderate fraction of FRBs associated with spiral structure indicates that high star formation efficiency of the youngest and most massive stars is not a predominant driver in the production of FRB progenitors.

Keywords: Globular star clusters, Magnetars, Galaxies, Radio transient sources