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Abstract We report on a flare-driven coronal rain event observed along postflare loops during the decay phase of an X1.6-class solar flare. Although high-resolution studies of flare-driven coronal rain have been conducted, imaging spectroscopic studies are rare due to observational difficulties. Our observation taken with the Fast Imaging Solar Spectrograph, installed at the 1.6 m Goode Solar Telescope of the Big Bear Solar Observatory, provided unprecedented high-resolution spectroscopic imaging data of coronal rain in the Hαand Caii854.2 nm lines. We identify two locations along postflare loops with rain displaying distinctly different thermal properties, different Doppler velocities, and different patterns of acceleration and deceleration. We also observed intense brightening at one footpoint of coronal rain, where the spectroscopic analysis reveals an energy conversion process resulting in significant localized chromospheric heating. We thoroughly investigate the footpoint brightening Doppler velocities and compare their spectral line profiles to typical flare-ribbon line profiles. We estimate the spatial scale of the fine structure of the coronal rain and the footpoint brightening. Our results provide important insights into the dynamic and thermal properties of flare-driven coronal rain and the related chromospheric response, which will help validate the flare-driven modeling of coronal rain. 

Context.The elemental abundance in the solar corona differs from that in the photosphere, with low first ionization potential (FIP) elements showing enhanced abundances, a phenomenon known as the FIP effect. This effect is considered to be driven by ponderomotive forces associated with magnetohydrodynamic (MHD) waves, particularly incompressible transverse waves. Aims.We aim to investigate the relationship between coronal abundance fractionation and transverse MHD waves in the chromosphere. We focus on analyzing the spatial correlation between the FIP fractionation and these waves, while exploring wave properties to validate the ponderomotive-force-driven fractionation model. Methods.We analyzed the Hαdata from the Fast Imaging Solar Spectrograph of the Goode Solar Telescope to detect chromospheric transverse MHD waves, and Si X(low FIP) and S X(high FIP) spectra from the EUV Imaging Spectrometer on board Hinode to determine the relative abundance in an active region. By extrapolating linear-force-free magnetic fields with Solar Dynamics Observatory/Helioseismic and Magnetic Imager magnetograms, we examine the connection between chromospheric waves and coronal composition. Around 400 wave packets were identified, and their properties, including the period, velocity amplitude, propagation speed, and propagation direction, were studied. Results.These chromospheric transverse MHD waves, mostly incompressible or weakly compressible, are found near loop footpoints, particularly in the sunspot penumbra and superpenumbral fibrils. The highly fractionated coronal region is associated with areas where these waves were detected within closed magnetic fields. Our examination of the statistics of wave properties revealed that downward-propagating low-frequency waves are particularly prominent, comprising about 43% of the detected waves. Conclusions.The correlation between abundance fractionation and transverse MHD waves, along with wave properties, supports the hypothesis that FIP fractionation occurs due to the ponderomotive force from transverse MHD waves in the chromosphere. Additionally, the observed characteristics of these chromospheric waves provide valuable observational constraints for understanding the FIP fractionation process. 

Abstract Lyαemitters (LAEs) are star-forming galaxies that efficiently probe the spatial distribution of galaxies in the high-redshift Universe. The spatial clustering of LAEs reflects the properties of their individual host dark matter halos, allowing us to study the evolution of the galaxy–halo connection. We analyze the clustering of 5233, 5220, and 3706 LAEs atz= 2.4, 3.1, and 4.5, respectively, in the 9 deg²COSMOS field from the One-hundred-deg²DECam Imaging in Narrowbands survey. After correcting for redshift-space distortions, LAE contamination rates, and the integral constraint, the observed angular correlation functions imply linear galaxy bias factors ofb= $1.72_{-0.27}^{+0.26},2.01_{-0.29}^{+0.26},$and $2.95_{-0.46}^{+0.40}$forz= 2.4, 3.1, and 4.5, respectively. The median dark matter halo masses inferred from these measurements are $\log (M_h/M_{\odot })$= $11.44_{-0.28}^{+0.30},11.13_{-0.26}^{+0.26},\mathrm{and}10.85_{-0.24}^{+0.24}$for the three samples, respectively. The analysis also reveals that LAEs occupy roughly 3%–7% of the halos whose clustering strength matches that of the LAEs. 

Context.We identified and analysed massive quiescent galaxies (MQGs) atz ≈ 3.1 within the 2 deg²COSMOS field and explored the effect of the galaxy environment on quenching processes. By examining the variation in the quenched fraction and physical properties of these galaxies in different environmental contexts, including local densities, protoclusters, and cosmic filaments, we investigated the connection between environmental factors and galaxy quenching at cosmic noon. Aims.We selected MQGs atz ≈ 3.1 using deep photometric data from the COSMOS2020 catalogue combined with narrow-band-selected Lyman-αemitters (LAEs) from the One-hundred-square-degree DECam Imaging in Narrowbands (ODIN) survey. We performed a spectral energy distribution fitting using the code BAGPIPES to derive the star formation histories and quenching timescales. We constructed Voronoi-tessellation density maps using LAEs, and we independently selected galaxies photometrically to characterize the galaxy environments. Methods.We identified 24 MQGs atz ≈ 3.1, each of which has a stellar mass higher than 10^10.6 M_⊙. These MQGs share remarkably uniform star-formation histories, with intense starburst phases followed by rapid quenching within short timescales (≤400 Myr). The consistency of these quenching timescales suggests a universal and highly efficient quenching mechanism in this epoch. We found no significant correlation between environmental density (either local or large scale) and galaxy quenching parameters such as the quenching duration, the quenched fraction, or the timing. MQGs show no preferential distribution with respect to protoclusters or filaments compared to massive star-forming galaxies. Some MQGs reside close to gas-rich filaments, but show no evidence of rejuvenated star formation. This implies gas-heating mechanisms and not gas exhaustion. These results indicate that the quenching processes atz ≈ 3.1 likely depend little on the immediate galaxy environment. Results.Our findings suggest that environmental processes alone, such as galaxy mergers, interactions, or gas stripping, cannot fully explain the galaxy quenching atz ≈ 3.1. Internal mechanisms such as feedback from AGN, stellar feedback, virial shock heating, or morphological quenching instead play an important role in quenching. Future spectroscopic observations must confirm the quiescent nature and precise redshifts of these galaxies. Observational studies of gas dynamics, gas temperature, and ionisation conditions within and around MQGs will also clarify the physical mechanisms driving galaxy quenching during this critical epoch of galaxy evolution. 

Abstract The Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT) offers multi-object spectroscopy over an 8′ field-of-view at resolutions up toR ∼ 3000. Reduction is typically conducted usingRSSMOSPipeline, which performs basic data calibrations, sky subtraction, and wavelength calibration. However, flux calibration of SALT-RSS using spectrophotometric standard star observations is difficult due to variable primary mirror illumination. We describe a novel approach where stars with Sloan Digital Sky Survey spectra are included as alignment stars on RSS slitmasks and then used to perform a rough flux calibration of the resulting data. RSS offers multiple settings that can be pieced together to cover the entire optical range, utilizing grating angle dithers to fill chip gaps. We introduce a nonlinear reprojection routine that defines an exponential wavelength array spanning 3500–9500 Å with gradually decreasing resolution and then reprojects several individual settings into a single 2D spectrum for each object. Our flux calibration and nonlinear reprojection routines are released as part of the Calibration And Reprojection for RSS Pipeline (CARRSSPipeline), that enables the extraction of full-optical-coverage, flux-calibrated, medium-resolution one-dimensional spectra. 

Context.Submillimeter galaxies (SMGs) constitute a key population of bright star-forming galaxies at high-redshift. These galaxies challenge galaxy formation models, particularly regarding the reproduction of their observed number counts and redshift distributions. Furthermore, although SMGs contribute significantly to the cosmic star formation rate density (SFRD), their precise role remains uncertain. Upcoming surveys, such as the Ultra Deep Survey with the TolTEC camera, are expected to offer valuable insights into SMG properties and their broader impact in the Universe. Aims.Robust modeling of SMGs in a cosmological representative volume is necessary to investigate their nature in preparation for next-generation submillimeter surveys. Here, we test different parametric models for SMGs in large-volume hydrodynamical simulations, assess their contribution to the SFRD, and build expectations for future submillimeter surveys. Methods.We implement and test parametric relations derived from radiative transfer calculations across three cosmological simulation suites: EAGLE, IllustrisTNG, and FLAMINGO. We place particular emphasis on the FLAMINGO simulations due to their large volume and robust statistical sampling of SMGs. Based on the model that best reproduces observational number counts, we forecast submillimeter fluxes within the simulations, analyze the properties of SMGs, and evaluate their evolution over cosmic time. Results.Our results show that the FLAMINGO simulation reproduces the observed redshift distribution and source number counts of SMGs without requiring a top-heavy initial mass function. On the other hand, the EAGLE and IllustrisTNG simulations show a deficit of bright SMGs. We find that SMGs with S₈₅₀ > 1 mJy contribute up to ∼27% of the cosmic SFRD atz ∼ 2.6 in the FLAMINGO simulation, which is consistent with recent observations. Flux density functions reveal a rise in SMG abundance fromz = 6 toz = 2.5 that is followed by a sharp decline in the number of brighter SMGs fromz = 2.5 toz = 0. Leveraging the SMG population in FLAMINGO, we forecast that the TolTEC UDS will detect ∼80 000 sources over 0.8 deg²at 1.1 mm (at the 4σdetection limit), capturing about 50% of the cosmic SFRD atz ∼ 2.5. 

Aims.We investigate the physical properties and redshift evolution of simulated galaxies residing in unvirialized cosmic structures (i.e., protoclusters) at cosmic noon, to understand the influence of the environment on galaxy formation. This work is intended to build clear expectations for the ongoing ODIN (One-hundred-deg²DECam Imaging in Narrowbands) survey, which is mapping large-scale structures atz= 2.4,3.1, and 4.5 using Lyα-emitting galaxies (LAEs) as tracers. Methods.From the IllustrisTNG simulations, we define subregions centered on the most massive clusters ranked by total stellar mass atz= 0 and study the properties of galaxies within, including those of LAEs. To model the LAE population, we take a semi-analytical approach that assigns Lyαluminosity and equivalent width based on the UV luminosities to galaxies in a probabilistic manner. We investigate stellar mass, star formation rate (SFR), major merger events, and specific star formation rate of the population of star-forming galaxies and LAEs in the field- and protocluster environment and trace their evolution across cosmic time betweenz= 0−4. Results.We find that the overall shape of the UV luminosity function in simulated protocluster environments is characterized by a substantially shallower faint-end slope and a large excess on the bright end, signaling different formation histories for galaxies therein. The difference is milder for the Lyαluminosity function. While protocluster galaxies follow the same SFR-M_★scaling relation as average field galaxies, a larger fraction appears to have experienced major mergers in the last 200 Myr and as a result shows enhanced star formation at a ≈60% level, leading to a flatter distribution in both SFR and M_★relative to galaxies in the average field. We find that protocluster galaxies, including LAEs, begin to quench much earlier (z∼0.8−1.6) than field galaxies (z∼0.5−0.9); our result is in qualitative agreement with recent observational results and highlights the importance of large-scale environment on the overall formation history of galaxies. 

Abstract The One-hundred-deg²DECam Imaging in Narrowbands (ODIN) survey is carrying out a systematic search for protoclusters during Cosmic Noon, using Lyα-emitting galaxies (LAEs) as tracers. Once completed, ODIN aims to identify hundreds of protoclusters at redshifts of 2.4, 3.1, and 4.5 across seven extragalactic fields, covering a total area of up to 91 deg². In this work, we report the high clustering strength of the ODIN protoclusters, determined via measurements of their cross-correlation with LAEs. Our sample consists of 150 protocluster candidates atz = 2.4 and 3.1, identified in two ODIN fields with a total area of 13.9 deg². Atz = 2.4 and 3.1, the inferred protocluster biases are $6.6_{-1.1}^{+1.3}$and $6.1_{-1.1}^{+1.3}$, corresponding to mean halo masses of $\log 〈M/M_{\odot }〉=13.53_{-0.24}^{+0.21}$and $12.96_{-0.33}^{+0.28}$, respectively. By the present day, these protoclusters are expected to evolve into virialized galaxy clusters with a mean mass of ∼10^14.5M_⊙. By comparing the observed number density of protoclusters to that of halos with the same measured clustering strength, we find that the completeness of our sample is of order unity. Finally, the similar descendant masses derived for our samples atz= 2.4 and 3.1, assuming that the halo number density remains constant, suggest that they represent similar structures observed at different cosmic epochs. As a consequence, any observed differences between the two samples can be understood as redshift evolution. The ODIN protocluster samples will thus provide valuable insights into the cosmic evolution of cluster galaxies. 

Abstract In this work, we test the frequent assumption that Lyα-emitting galaxies (LAEs) are experiencing their first major burst of star formation at the time of observation. To this end, we identify 74 LAEs from the ODIN Survey with rest-UV-through-NIR photometry from UVCANDELS. For each LAE, we perform nonparametric star formation history (SFH) reconstruction using the Dense Basis Gaussian-process-based method of spectral energy distribution fitting. We find that a strong majority (67%) of our LAE SFHs align with the frequently assumed archetype of a first major star formation burst, with at most modest star formation rates (SFRs) in the past. However, the rest of our LAE SFHs have significant amounts of star formation in the past, with 28% exhibiting earlier bursts of star formation, with the ongoing burst having the highest SFR (dominant bursts) and the final 5% having experienced their highest SFR in the past (nondominant bursts). Combining the SFHs indicating first and dominant bursts, ∼95% of LAEs are experiencing their largest burst yet: a formative burst. We also find that the fraction of total stellar mass created in the last 200 Myr is ∼1.3 times higher in LAEs than in mass-matched Lyman break galaxy (LBG) samples, and that a majority of LBGs are experiencing dominant bursts, reaffirming that LAEs differ from other star-forming galaxies. Overall, our results suggest that multiple evolutionary paths can produce galaxies with strong observed Lyαemission. 

Abstract Background and AimsA comprehensive standardized evaluation tool was needed to assess community awareness and preparedness when the pandemic hit the United States. This study aimed to develop and validate a new Coronavirus Awareness and Preparedness Scale (CAPS) through psychometric testing. MethodsThis study unfolded in two phases. Phase 1 (conducted in March and April 2020) focused on the development of the scale. Phase 2 (conducted in June and July 2020) measured the reliability and validity of the scale. Psychometric testing, including exploratory factor analysis and reliability testing, was performed with a convenience sample of 1237 faculty, staff, and students at a southern university in the United States. ResultsThe final CAPS model consists of four factors with 26 items: threat (seven items), confidence (11 items), individual precautions (three items), and public precautions (five items). The scale demonstrated satisfactory internal consistency (Cronbach'sα = 0.75). Strong and statistically significant item correlations were observed within the subscales through item analysis. ConclusionThe CAPS is a reliable and valid comprehensive evaluation instrument designed to gauge community awareness and preparedness during the early stages of the COVID‐19 pandemic. Its adaptability makes it suitable for measuring readiness and preparedness concerning any novel airborne disease or future airborne pandemic within a community.