A key processing step in ground-based astronomy involves combining multiple noisy and blurry exposures to produce an image of the night sky with an improved signal-to-noise ratio. Typically, this is achieved via image coaddition, and can be undertaken such that the resulting night sky image has enhanced spatial resolution. Yet, this task remains a formidable challenge despite decades of advancements. In this paper, we introduce ImageMM: a new framework based on the majorization–minimization (MM) algorithm for joint multi-frame astronomical image restoration and super-resolution. ImageMM uses multiple registered astronomical exposures to produce a nonparametric latent image of the night sky, prior to the atmosphere’s impact on the observed exposures. Our framework also features a novel variational approach to compute refined point-spread functions of arbitrary resolution for the restoration and super-resolution procedure. Our algorithms, implemented in TensorFlow, leverage graphics processing unit acceleration to produce latent images in near real time, even when processing high-resolution exposures. We tested ImageMM on Hyper Suprime-Cam (HSC) exposures, which are a precursor of the upcoming imaging data from the Rubin Observatory. The results are encouraging: ImageMM produces sharp latent images, in which spatial features of bright sources are revealed in unprecedented detail (e.g., showing the structure of spiral galaxies), and where faint sources that are usually indistinguishable from the noisy sky background also become discernible, thus pushing the detection limits. Moreover, aperture photometry performed on the HSC pipeline coadd and ImageMM’s latent images yielded consistent source detection and flux measurements, thereby demonstrating ImageMM’s suitability for cutting-edge photometric studies with state-of-the-art astronomical imaging data.

We analyze high angular and velocity resolution H i line data of two LITTLE THINGS blue compact dwarfs (BCDs): Haro 29 and Haro 36. Both of these BCDs are disturbed morphologically and kinematically. Haro 29's H i data reveal a kinematic major axis that is offset from the optical major axis, and a disturbed outer H i component, indicating that Haro 29 may have had a past interaction. Position–velocity diagrams of Haro 36 indicate that it has two kinematically separate components at its center and a likely tidal tail in front of the galaxy. We find that Haro 36 most likely had an interaction in the past, is currently interacting with an unknown companion, or is a merger remnant.

This paper presents VARnet, a capable signal-processing model for rapid astronomical time series analysis. VARnet leverages wavelet decomposition, a novel method of Fourier feature extraction via the finite-embedding Fourier transform, and deep learning to detect faint signals in light curves, utilizing the strengths of modern GPUs to achieve submillisecond single-source run time. We apply VARnet to the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) single-exposure database, which holds nearly 200 billion apparitions over 10.5 yr of infrared sources on the entire sky. This paper devises a pipeline in order to extract variable candidates from the NEOWISE data, serving as a proof of concept for both the efficacy of VARnet and methods for an upcoming variability survey over the entirety of the NEOWISE data set. We implement models and simulations to synthesize unique light curves to train VARnet. In this case, the model achieves an F1 score of 0.91 over a four-class classification scheme on a validation set of real variable sources present in the infrared. With ∼2000 points per light curve on a GPU with 22 GB of VRAM, VARnet produces a per-source processing time of <53 μs. We confirm that our VARnet is sensitive and precise to both known and previously undiscovered variable sources. These methods prove promising for a complete future survey of variability with the Wide-field Infrared Survey Explorer, and effectively showcase the power of the VARnet model architecture.

Megaconstellations of thousands to tens of thousands of artificial satellites (satcons) are rapidly being developed and launched. These satcons will have negative consequences for observational astronomy research, and are poised to drastically interfere with naked-eye stargazing worldwide should mitigation efforts be unsuccessful. Here we provide predictions for the optical brightnesses and on-sky distributions of several satcons, including Starlink, OneWeb, Kuiper, and StarNet/GW, for a total of 65,000 satellites on their filed or predicted orbits. We develop a simple model of satellite reflectivity, which is calibrated using published Starlink observations. We use this model to estimate the visible magnitudes and on-sky distributions for these satellites as seen from different places on Earth, in different seasons, and different times of night. For latitudes near 50° north and south, satcon satellites make up a few percent of all visible point sources all night long near the summer solstice, as well as near sunrise and sunset on the equinoxes. Altering the satellites’ altitudes only changes the specific impacts of the problem. Without drastic reduction of the reflectivities, or significantly fewer total satellites in orbit, satcons will greatly change the night sky worldwide.

The optical impact of Starlink is of great concern and the Gen1 network is well studied. However, understanding of the planned second-generation (Gen2) constellation containing almost 30,000 satellites with two thirds in very low Earth orbit (VLEO) below 450 km is developing. This work models Gen2 orbital parameters and considers line-of-sight visibility and spacecraft illumination in relation to terrestrial latitude and investigates changes through the day/night transition period. At peak latitudes there will be over 1200 satellites illuminated above the naked-eye horizon that persist long into the local winter night. At higher latitudes in summer spacecraft may then remain illuminated during darkness hours without interruption. For optical astronomy around 90% will be below the observational horizon, still leaving up to 120 in the field of view. Of those illuminated at nightfall, traditional LEO satellites dominate and persist for longer. This is demonstrated at latitudes representing major observatories where VLEO satellites are fully eclipsed 30 minutes after astronomical dusk, but higher layers continue to restrict observations. Broader literature suggests that at nightfall the lower spacecraft may be brighter if larger, but will be out of focus and rapidly transit detectors before quickly eclipsing and so the impact may be further reduced. This work develops understanding of the Starlink Gen2 network and suggests that operators deploying satellites further below the recommend 600 km altitude limit will continue to reduce the impacts on terrestrial optical astronomy; however, that benefit must be considered against the wider environmental impacts throughout the lifecycle to make informed decisions on sustainability metrics.

Recent analyses have shown that distant orbits within the scattered disk population of the Kuiper Belt exhibit an unexpected clustering in their respective arguments of perihelion. While several hypotheses have been put forward to explain this alignment, to date, a theoretical model that can successfully account for the observations remains elusive. In this work we show that the orbits of distant Kuiper Belt objects (KBOs) cluster not only in argument of perihelion, but also in physical space. We demonstrate that the perihelion positions and orbital planes of the objects are tightly confined and that such a clustering has only a probability of 0.007% to be due to chance, thus requiring a dynamical origin. We find that the observed orbital alignment can be maintained by a distant eccentric planet with mass ≳10 m_⊕ whose orbit lies in approximately the same plane as those of the distant KBOs, but whose perihelion is 180° away from the perihelia of the minor bodies. In addition to accounting for the observed orbital alignment, the existence of such a planet naturally explains the presence of high-perihelion Sedna-like objects, as well as the known collection of high semimajor axis objects with inclinations between 60° and 150° whose origin was previously unclear. Continued analysis of both distant and highly inclined outer solar system objects provides the opportunity for testing our hypothesis as well as further constraining the orbital elements and mass of the distant planet.

The planetary and lunar ephemerides called DE440 and DE441 have been generated by fitting numerically integrated orbits to ground-based and space-based observations. Compared to the previous general-purpose ephemerides DE430, seven years of new data have been added to compute DE440 and DE441, with improved dynamical models and data calibration. The orbit of Jupiter has improved substantially by fitting to the Juno radio range and Very Long Baseline Array (VLBA) data of the Juno spacecraft. The orbit of Saturn has been improved by radio range and VLBA data of the Cassini spacecraft, with improved estimation of the spacecraft orbit. The orbit of Pluto has been improved from use of stellar occultation data reduced against the Gaia star catalog. The ephemerides DE440 and DE441 are fit to the same data set, but DE441 assumes no damping between the lunar liquid core and the solid mantle, which avoids a divergence when integrated backward in time. Therefore, DE441 is less accurate than DE440 for the current century, but covers a much longer duration of years −13,200 to +17,191, compared to DE440 covering years 1550–2650.

Spot-crossing transits offer a unique opportunity to probe spot properties such as temperature, size, and surface distribution. TOI-3884 is a rare system in which spot-crossing features are persistently observed during every transit. This is due to its unusual configuration: a nearly polar-orbit super-Neptune transits a pole-on mid-M dwarf, repeatedly crossing a polar spot. However, previous studies have reported discrepant values in key system parameters, such as stellar inclination and obliquity. To address this, we conducted multiband, multiepoch transit observations of TOI-3884 b using the MuSCAT instrument series, along with photometric monitoring with the Las Cumbres Observatory 1 m telescopes/Sinistro. We detected time-dependent variations in the spot-crossing signals, indicating that the spot is not exactly on the pole. From the monitoring data, we measured a stellar rotation period of $11.04{3}_{-0.053}^{+0.054}$ days with a modulation amplitude of ∼5% in the r band, consistent with the time variability in the spot-crossing features. Our analysis reconciles previous discrepancies and improves the constraints on the parameters of the system geometry (${i}_{\star }=139.{9}_{-2.0}^{+1.2}$ deg and $\lambda =41.{0}_{-9.0}^{+3.7}$ deg) and those of the spot properties (spot radius of $0.42{5}_{-0.011}^{+0.018}\,{R}_{\star }$ and a spot–photosphere temperature difference of $20{0}_{-9}^{+11}$ K). These results provide a critical context for interpreting upcoming transmission spectroscopy of TOI-3884 b, as well as yielding new insights into the magnetic activity and spin–orbit geometry of M dwarfs.

In this brief communication we provide the rationale for and the outcome of the International Astronomical Union (IAU) resolution vote at the XXIXth General Assembly in Honolulu, Hawaii, in 2015, on recommended nominal conversion constants for selected solar and planetary properties. The problem addressed by the resolution is a lack of established conversion constants between solar and planetary values and SI units: a missing standard has caused a proliferation of solar values (e.g., solar radius, solar irradiance, solar luminosity, solar effective temperature, and solar mass parameter) in the literature, with cited solar values typically based on best estimates at the time of paper writing. As precision of observations increases, a set of consistent values becomes increasingly important. To address this, an IAU Working Group on Nominal Units for Stellar and Planetary Astronomy formed in 2011, uniting experts from the solar, stellar, planetary, exoplanetary, and fundamental astronomy, as well as from general standards fields to converge on optimal values for nominal conversion constants. The effort resulted in the IAU 2015 Resolution B3, passed at the IAU General Assembly by a large majority. The resolution recommends the use of nominal solar and planetary values, which are by definition exact and are expressed in SI units. These nominal values should be understood as conversion factors only, not as the true solar/planetary properties or current best estimates. Authors and journal editors are urged to join in using the standard values set forth by this resolution in future work and publications to help minimize further confusion.

The Astropy Project supports and fosters the development of open-source and openly developed Python packages that provide commonly needed functionality to the astronomical community. A key element of the Astropy Project is the core package astropy, which serves as the foundation for more specialized projects and packages. In this article, we provide an overview of the organization of the Astropy project and summarize key features in the core package, as of the recent major release, version 2.0. We then describe the project infrastructure designed to facilitate and support development for a broader ecosystem of interoperable packages. We conclude with a future outlook of planned new features and directions for the broader Astropy Project.

The radius inflation is predominantly observed in short-period, low-mass stellar systems, while being rarely detected in long-period binaries. Using Transiting Exoplanet Survey Satellite photometric and Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectroscopic survey data, we conducted a detailed photometric and spectroscopic analysis of six long-period (P > 7 days) detached eclipsing binaries: TIC 17303250, TIC 196817076, TIC 219488423, TIC 252991035, TIC 344753509, and TIC 72696540. Our results indicate that the first five systems are composed of low-mass stars (M ≤ 0.8M_⊙), while TIC 72696540 is likely composed of subgiant stars with M₁ = 1.267 ± 0.011M_⊙, R₁ = 2.365 ± 0.043R_⊙, and M₂ = 1.281 ± 0.011M_⊙, R₂ = 2.517 ± 0.035R_⊙. Their large radii are solely due to their evolutionary stage. Apart from TIC 72696540, none of the components of these systems displays a clear Li Iλ6708 line. Under the assumption of binary rotational synchronization, the rotational velocities of these low-mass stars are found to be less than 8 km s⁻¹, which is the upper limit related to the LAMOST-MRS resolution. Notably, however, significant radius inflation is evident in the systems TIC 17303250, TIC 344753509, and TIC 252991035. Their radii exceed the predictions of the 12 Gyr isochrones. A positive correlation between radius inflation and metallicity is evident in four of the five low-mass stars, with TIC 196817076 being the sole exception. These results suggest that metallicity may play a significant role in causing radius inflation.

The Gaia BP/RP spectra provide an excellent opportunity to search for extremely metal-poor (EMP; [M/H] ≤ –3.0) stars. In this study, we assess the potential of our Gaia BP/RP-based candidate catalog, vetting newly identified EMP candidates with higher-resolution follow-up observations. The candidates are selected based on the metallicity derived from BP/RP spectra and the goodness of fit. Fifteen candidates were observed with the Intermediate Dispersion Spectrograph (IDS) on the Isaac Newton Telescope to validate the sample. We analyzed the data with 1D local thermodynamic equilibrium models and assessed the reliability of the [C/Fe] estimates. Three well-studied metal-poor stars are included as a sanity check. For most targets, the metallicities estimated from IDS data agree well with those derived from BP/RP spectra. Five of these stars are EMP stars (four of them are newly identified), including two with [M/H] ≤ –3.5, one of which is a carbon-enhanced metal-poor star. Reliable [C/Fe] estimates are obtained for eight stars. The efficiency in detecting EMP candidates (as eight candidates with [M/H] ≤ –3.0 yielding five EMP stars) is estimated to be $6{3}_{-24}^{+19} \%$ at a 68% confidence level, which is comparable to or higher than that of the Pristine-Gaia synthetic metallicity catalogue (38%), highlighting the potential of our method.

We have developed a software pipeline, AutoWISP, for extracting high-precision photometry from citizen scientists’ observations made with consumer-grade color digital cameras (digital single-lens reflex, or DSLR, cameras), based on our previously developed tool, AstroWISP. The new pipeline is designed to convert these observations, including color images, into high-precision light curves of stars. We outline the individual steps of the pipeline and present a case study using a Sony-α 7R II DSLR camera, demonstrating subpercent photometric precision, and highlighting the benefits of three-color photometry of stars. Project PANOPTES will adopt this photometric pipeline and, we hope, be used by citizen scientists worldwide. Our aim is for AutoWISP to pave the way for potentially transformative contributions from citizen scientists with access to observing equipment.

On 2017 September 20, we observed GJ 4334, an M5V dwarf rotating with a period of 23.5 days, simultaneously with both the Space Telescope Imaging Spectrograph aboard Hubble (1160–1710 Å) and the Dual Imaging Spectrograph mounted on the 3.5 m telescope at Apache Point Observatory (3750–5050; 5800–6950 Å) as part of a larger survey of intermediately active M dwarfs. GJ 4334 flared during the observation, starting with a rise in the flux of optical chromospheric emission lines, followed by the rapid rise and decay of multiple far-ultraviolet emission lines formed in the transition region, followed by the slow decay of the optical lines. We find significant broadening and asymmetries in the optical emission lines that are potentially from bulk plasma motion, a postflare elevated flux in both the optical and far-ultraviolet, and trends in the rise and decay timescales of the Balmer series such that higher-order lines rise earlier and decay faster than lower-order lines. The equivalent durations of the flare in individual lines range from 800 to 3 × 10⁴ s, mapping to flare energies of 1 × 10²⁸–3 × 10²⁹ erg for each line. To contextualize GJ 4334’s flare behavior, we measure and compare its optical flare frequency distribution with TESS to EV Lacertae, a similar mass but faster rotating M dwarf, and find that GJ 4334 has an excess of large flares relative to the power law established by the majority of its smaller flares. This data set is a rare opportunity to characterize flares near a critical transition in stellar magnetic activity.

Superfast rotators (SFRs; P < 2.2 hr) are of great importance in asteroid studies; yet, many reported detections suffer from aliasing caused by an insufficient observation cadence. We present dense CCD photometry for 15 SFR candidates (14 after excluding 11219 Benbohn, whose published period already exceeds the spin barrier) observed from 2023 August 11 to 2024 August 11 with the 1.5 m Sierra Nevada and 1.4 m Astronomical Station of Vidojevica telescopes. Our data set comprises approximately 2400 calibrated data points, with per-measurement formal errors of 0.02–0.04 mag and total on-target coverage of 2–13 hr per object. We have reliably determined periods for nine targets. In terms of spin rate, we have confirmed four SFRs with periods of 1.06–1.84 hr and peak-to-peak amplitudes of 0.054–0.685 mag. Three candidates remain ambiguous, while the rest are reclassified, showing the best solutions with periods greater than 2.5 hr. Extrapolating from our confirmation rate (4/14) to the 3.9% occurrence rate found in the Light Curve Database yields a central SFR fraction of 1.1%, with a 1σ lower bound of 0.6% among kilometer-scale asteroids.

The radius inflation is predominantly observed in short-period, low-mass stellar systems, while being rarely detected in long-period binaries. Using Transiting Exoplanet Survey Satellite photometric and Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectroscopic survey data, we conducted a detailed photometric and spectroscopic analysis of six long-period (P > 7 days) detached eclipsing binaries: TIC 17303250, TIC 196817076, TIC 219488423, TIC 252991035, TIC 344753509, and TIC 72696540. Our results indicate that the first five systems are composed of low-mass stars (M ≤ 0.8M_⊙), while TIC 72696540 is likely composed of subgiant stars with M₁ = 1.267 ± 0.011M_⊙, R₁ = 2.365 ± 0.043R_⊙, and M₂ = 1.281 ± 0.011M_⊙, R₂ = 2.517 ± 0.035R_⊙. Their large radii are solely due to their evolutionary stage. Apart from TIC 72696540, none of the components of these systems displays a clear Li Iλ6708 line. Under the assumption of binary rotational synchronization, the rotational velocities of these low-mass stars are found to be less than 8 km s⁻¹, which is the upper limit related to the LAMOST-MRS resolution. Notably, however, significant radius inflation is evident in the systems TIC 17303250, TIC 344753509, and TIC 252991035. Their radii exceed the predictions of the 12 Gyr isochrones. A positive correlation between radius inflation and metallicity is evident in four of the five low-mass stars, with TIC 196817076 being the sole exception. These results suggest that metallicity may play a significant role in causing radius inflation.

The Gaia BP/RP spectra provide an excellent opportunity to search for extremely metal-poor (EMP; [M/H] ≤ –3.0) stars. In this study, we assess the potential of our Gaia BP/RP-based candidate catalog, vetting newly identified EMP candidates with higher-resolution follow-up observations. The candidates are selected based on the metallicity derived from BP/RP spectra and the goodness of fit. Fifteen candidates were observed with the Intermediate Dispersion Spectrograph (IDS) on the Isaac Newton Telescope to validate the sample. We analyzed the data with 1D local thermodynamic equilibrium models and assessed the reliability of the [C/Fe] estimates. Three well-studied metal-poor stars are included as a sanity check. For most targets, the metallicities estimated from IDS data agree well with those derived from BP/RP spectra. Five of these stars are EMP stars (four of them are newly identified), including two with [M/H] ≤ –3.5, one of which is a carbon-enhanced metal-poor star. Reliable [C/Fe] estimates are obtained for eight stars. The efficiency in detecting EMP candidates (as eight candidates with [M/H] ≤ –3.0 yielding five EMP stars) is estimated to be $6{3}_{-24}^{+19} \%$ at a 68% confidence level, which is comparable to or higher than that of the Pristine-Gaia synthetic metallicity catalogue (38%), highlighting the potential of our method.

We have developed a software pipeline, AutoWISP, for extracting high-precision photometry from citizen scientists’ observations made with consumer-grade color digital cameras (digital single-lens reflex, or DSLR, cameras), based on our previously developed tool, AstroWISP. The new pipeline is designed to convert these observations, including color images, into high-precision light curves of stars. We outline the individual steps of the pipeline and present a case study using a Sony-α 7R II DSLR camera, demonstrating subpercent photometric precision, and highlighting the benefits of three-color photometry of stars. Project PANOPTES will adopt this photometric pipeline and, we hope, be used by citizen scientists worldwide. Our aim is for AutoWISP to pave the way for potentially transformative contributions from citizen scientists with access to observing equipment.

On 2017 September 20, we observed GJ 4334, an M5V dwarf rotating with a period of 23.5 days, simultaneously with both the Space Telescope Imaging Spectrograph aboard Hubble (1160–1710 Å) and the Dual Imaging Spectrograph mounted on the 3.5 m telescope at Apache Point Observatory (3750–5050; 5800–6950 Å) as part of a larger survey of intermediately active M dwarfs. GJ 4334 flared during the observation, starting with a rise in the flux of optical chromospheric emission lines, followed by the rapid rise and decay of multiple far-ultraviolet emission lines formed in the transition region, followed by the slow decay of the optical lines. We find significant broadening and asymmetries in the optical emission lines that are potentially from bulk plasma motion, a postflare elevated flux in both the optical and far-ultraviolet, and trends in the rise and decay timescales of the Balmer series such that higher-order lines rise earlier and decay faster than lower-order lines. The equivalent durations of the flare in individual lines range from 800 to 3 × 10⁴ s, mapping to flare energies of 1 × 10²⁸–3 × 10²⁹ erg for each line. To contextualize GJ 4334’s flare behavior, we measure and compare its optical flare frequency distribution with TESS to EV Lacertae, a similar mass but faster rotating M dwarf, and find that GJ 4334 has an excess of large flares relative to the power law established by the majority of its smaller flares. This data set is a rare opportunity to characterize flares near a critical transition in stellar magnetic activity.

Superfast rotators (SFRs; P < 2.2 hr) are of great importance in asteroid studies; yet, many reported detections suffer from aliasing caused by an insufficient observation cadence. We present dense CCD photometry for 15 SFR candidates (14 after excluding 11219 Benbohn, whose published period already exceeds the spin barrier) observed from 2023 August 11 to 2024 August 11 with the 1.5 m Sierra Nevada and 1.4 m Astronomical Station of Vidojevica telescopes. Our data set comprises approximately 2400 calibrated data points, with per-measurement formal errors of 0.02–0.04 mag and total on-target coverage of 2–13 hr per object. We have reliably determined periods for nine targets. In terms of spin rate, we have confirmed four SFRs with periods of 1.06–1.84 hr and peak-to-peak amplitudes of 0.054–0.685 mag. Three candidates remain ambiguous, while the rest are reclassified, showing the best solutions with periods greater than 2.5 hr. Extrapolating from our confirmation rate (4/14) to the 3.9% occurrence rate found in the Light Curve Database yields a central SFR fraction of 1.1%, with a 1σ lower bound of 0.6% among kilometer-scale asteroids.

Photoevaporative models predict that the lower edge of the Neptune desert is sculpted by atmospheric mass loss. However, the stellar high-energy fluxes that power hydrodynamic escape and set predicted mass loss rates can be uncertain by multiple orders of magnitude. These uncertainties can be bypassed by studying mass loss for planets within the same system, as they have effectively undergone scaled versions of the same irradiation history. The TOI-4010 system is an ideal test case for mass loss models, as it contains three Neptune-sized planets with planet b located in the “Neptune desert,” planet c in the “Neptune ridge,” and planet d in the “Neptune savanna.” Using Keck/NIRSPEC, we measured the metastable helium transit depths of all three planets in order to search for evidence of atmospheric escape. We place upper bounds on the excess helium absorption of 1.23%, 0.81%, and 0.87% at 95% confidence for TOI-4010 b, c, and d respectively. We fit our transmission spectra with Parker wind models and find that this corresponds to 95th-percentile upper limits of 10^10.17 g s⁻¹, 10^10.53 g s⁻¹, and 10^10.50 g s⁻¹ on the mass loss rates of TOI-4010 b, c, and d respectively. Our non-detections are inconsistent with expectations from one-dimensional hydrodynamic models for solar composition atmospheres. We consider potential reductions in signal from a decreased host star extreme ultra-violet and X-ray luminosity, planetary magnetic fields, enhanced atmospheric metallicities, and fractionation, and explore the implications of our measurements for the past evaporation histories of all three planets.

We present a foundational, scalable algorithm architecture for processing data from aperture synthesis radio telescopes. The analysis leading to the architecture is rooted in the theory of aperture synthesis, signal processing, and numerical optimization, keeping it scalable for variations in computing load, algorithmic complexity, and accommodate the continuing evolution of algorithms. It also adheres to scientific software design principles and use of modern performance engineering techniques providing a stable foundation for long-term scalability, performance, and development cost. We first show that algorithms for both calibration and imaging share a common mathematical foundation and can be expressed as numerical optimization problems. We then decompose the resulting mathematical framework into fundamental conceptual architectural components, and assemble calibration and imaging algorithms from these foundational components. For a physical architectural view, we used a library of algorithms implemented in the LibRA software for the various architectural components, and used the Kokkos framework in the compute-intensive components for performance portable implementation. This was deployed on hardware ranging from desktop-class computers to multiple supercomputer class high-performance computing and high-throughput computing (HTC) platforms with a variety of CPU and GPU architectures, and job schedulers (HTCondor and Slurm). As a test, we imaged archival data from the Very Large Array telescope in the A-array configuration for the Hubble Ultra Deep Field. Using over 100 GPUs, we achieve a processing rate of ∼2 TB hr⁻¹ to make one of the deepest images in the 2–4 GHz band with an rms noise of ∼1 μJy beam⁻¹.

Phosphorus-enhanced (P-rich; [P/Fe] ≳ +0.8) giants have been found among mildly metal-poor field stars, but in only one star in a globular cluster (GC), M4 (NGC 6121). Also, in a sample of bulge spheroid stars, some of them showed a moderate P enhancement in the range +0.5 < [P/Fe] < +1.0. In this paper we derive the P abundance of moderately metal-poor ([Fe/H] ≳ −1) GC stars, aiming to check if the phenomenon could be related to the unusual multiple stellar populations found in most GCs. Here we present the detection of moderately P-enhanced stars among two out of seven bulge GCs (Tonantzintla 1 and NGC 6316), with metallicities similar to those of the bulge-field P-rich stars. Using H-band high-resolution (R ∼ 22,500) spectra from the APOGEE-2 survey, we present the first high-resolution abundance analysis of [P/Fe] from the P I 16482.932 Å line in a sample of selected bulge GCs. We find that all P-rich stars tend to also be N-rich, which hints at the origin of P-rich stars as second-generation stars in GCs. However no other correlations of P and other elements are found, which are usually indicators of second-generation stars. Further studies with larger samples and comparisons with field stars will be needed before any firm conclusions are drawn.

A key processing step in ground-based astronomy involves combining multiple noisy and blurry exposures to produce an image of the night sky with an improved signal-to-noise ratio. Typically, this is achieved via image coaddition, and can be undertaken such that the resulting night sky image has enhanced spatial resolution. Yet, this task remains a formidable challenge despite decades of advancements. In this paper, we introduce ImageMM: a new framework based on the majorization–minimization (MM) algorithm for joint multi-frame astronomical image restoration and super-resolution. ImageMM uses multiple registered astronomical exposures to produce a nonparametric latent image of the night sky, prior to the atmosphere’s impact on the observed exposures. Our framework also features a novel variational approach to compute refined point-spread functions of arbitrary resolution for the restoration and super-resolution procedure. Our algorithms, implemented in TensorFlow, leverage graphics processing unit acceleration to produce latent images in near real time, even when processing high-resolution exposures. We tested ImageMM on Hyper Suprime-Cam (HSC) exposures, which are a precursor of the upcoming imaging data from the Rubin Observatory. The results are encouraging: ImageMM produces sharp latent images, in which spatial features of bright sources are revealed in unprecedented detail (e.g., showing the structure of spiral galaxies), and where faint sources that are usually indistinguishable from the noisy sky background also become discernible, thus pushing the detection limits. Moreover, aperture photometry performed on the HSC pipeline coadd and ImageMM’s latent images yielded consistent source detection and flux measurements, thereby demonstrating ImageMM’s suitability for cutting-edge photometric studies with state-of-the-art astronomical imaging data.

We present JWST/MIRI observations of the debris disk surrounding the nearby solar analog Eridani obtained as part of the Archetypal Debris Disk Guaranteed Time Observation program. Multiwavelength images from 15, 18, 21, and 25.5 μm show a smooth dust distribution with no evidence of sculpting by massive planets outside of 5 au. Maps of the color temperature and opacity constrain the dust properties, while radiative transfer modeling of a warm dust component traces the interaction between the debris disk and Eridani b (∼3.5 au). Dynamical and collisional modeling further shows that the disk morphology is dominated by dust produced in the outer planetesimal belt (∼70 au) moving inward via stellar wind drag. We confirm the presence of a disk interior to the Eri b orbit first detected from mid-IR interferometry. Drag-dominated inner disk regions have also been observed around Vega and Fomalhaut, hinting at the diversity of asteroid belt analogs.

We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 ≤ z ≤ 0.62. The luminosity distances of these objects are determined by methods that employ relations between SN Ia luminosity and light curve shape. Combined with previous data from our High-z Supernova Search Team and recent results by Riess et al., this expanded set of 16 high-redshift supernovae and a set of 34 nearby supernovae are used to place constraints on the following cosmological parameters: the Hubble constant (H₀), the mass density (Ω_M), the cosmological constant (i.e., the vacuum energy density, Ω_Λ), the deceleration parameter (q₀), and the dynamical age of the universe (t₀). The distances of the high-redshift SNe Ia are, on average, 10%–15% farther than expected in a low mass density (Ω_M = 0.2) universe without a cosmological constant. Different light curve fitting methods, SN Ia subsamples, and prior constraints unanimously favor eternally expanding models with positive cosmological constant (i.e., Ω_Λ > 0) and a current acceleration of the expansion (i.e., q₀ < 0). With no prior constraint on mass density other than Ω_M ≥ 0, the spectroscopically confirmed SNe Ia are statistically consistent with q₀ < 0 at the 2.8 σ and 3.9 σ confidence levels, and with Ω_Λ > 0 at the 3.0 σ and 4.0 σ confidence levels, for two different fitting methods, respectively. Fixing a "minimal" mass density, Ω_M = 0.2, results in the weakest detection, Ω_Λ > 0 at the 3.0 σ confidence level from one of the two methods. For a flat universe prior (Ω_M + Ω_Λ = 1), the spectroscopically confirmed SNe Ia require Ω_Λ > 0 at 7 σ and 9 σ formal statistical significance for the two different fitting methods. A universe closed by ordinary matter (i.e., Ω_M = 1) is formally ruled out at the 7 σ to 8 σ confidence level for the two different fitting methods. We estimate the dynamical age of the universe to be 14.2 ± 1.7 Gyr including systematic uncertainties in the current Cepheid distance scale. We estimate the likely effect of several sources of systematic error, including progenitor and metallicity evolution, extinction, sample selection bias, local perturbations in the expansion rate, gravitational lensing, and sample contamination. Presently, none of these effects appear to reconcile the data with Ω_Λ = 0 and q₀ ≥ 0.

Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imaging data covering 99.998% of the celestial sphere in the near-infrared J (1.25 μm), H (1.65 μm), and K_s (2.16 μm) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona, and Cerro Tololo, Chile. The 7.8 s of integration time accumulated for each point on the sky and strict quality control yielded a 10 σ point-source detection level of better than 15.8, 15.1, and 14.3 mag at the J, H, and K_s bands, respectively, for virtually the entire sky. Bright source extractions have 1 σ photometric uncertainty of <0.03 mag and astrometric accuracy of order 100 mas. Calibration offsets between any two points in the sky are <0.02 mag. The 2MASS All-Sky Data Release includes 4.1 million compressed FITS images covering the entire sky, 471 million source extractions in a Point Source Catalog, and 1.6 million objects identified as extended in an Extended Source Catalog.

The Sloan Digital Sky Survey (SDSS) will provide the data to support detailed investigations of the distribution of luminous and nonluminous matter in the universe: a photometrically and astrometrically calibrated digital imaging survey of π sr above about Galactic latitude 30° in five broad optical bands to a depth of g′ ∼ 23 mag, and a spectroscopic survey of the approximately 10⁶ brightest galaxies and 10⁵ brightest quasars found in the photometric object catalog produced by the imaging survey. This paper summarizes the observational parameters and data products of the SDSS and serves as an introduction to extensive technical on-line documentation.

Multi-epoch radial velocity measurements of stars can be used to identify stellar, substellar, and planetary-mass companions. Even a small number of observation epochs can be informative about companions, though there can be multiple qualitatively different orbital solutions that fit the data. We have custom-built a Monte Carlo sampler (The Joker) that delivers reliable (and often highly multimodal) posterior samplings for companion orbital parameters given sparse radial velocity data. Here we use The Joker to perform a search for companions to 96,231 red giant stars observed in the APOGEE survey (DR14) with ≥3 spectroscopic epochs. We select stars with probable companions by making a cut on our posterior belief about the amplitude of the variation in stellar radial velocity induced by the orbit. We provide (1) a catalog of 320 companions for which the stellar companion’s properties can be confidently determined, (2) a catalog of 4898 stars that likely have companions, but would require more observations to uniquely determine the orbital properties, and (3) posterior samplings for the full orbital parameters for all stars in the parent sample. We show the characteristics of systems with confidently determined companion properties and highlight interesting systems with candidate compact object companions.

The all sky surveys done by the Palomar Observatory Schmidt, the European Southern Observatory Schmidt, and the United Kingdom Schmidt, the InfraRed Astronomical Satellite, and the Two Micron All Sky Survey have proven to be extremely useful tools for astronomy with value that lasts for decades. The Wide-field Infrared Survey Explorer (WISE) is mapping the whole sky following its launch on 2009 December 14. WISE began surveying the sky on 2010 January 14 and completed its first full coverage of the sky on July 17. The survey will continue to cover the sky a second time until the cryogen is exhausted (anticipated in 2010 November). WISE is achieving 5σ point source sensitivities better than 0.08, 0.11, 1, and 6 mJy in unconfused regions on the ecliptic in bands centered at wavelengths of 3.4, 4.6, 12, and 22 μm. Sensitivity improves toward the ecliptic poles due to denser coverage and lower zodiacal background. The angular resolution is 61, 64, 65, and 120 at 3.4, 4.6, 12, and 22 μm, and the astrometric precision for high signal-to-noise sources is better than 015.

We construct dynamical models for a sample of 36 nearby galaxies with Hubble Space Telescope (HST) photometry and ground-based kinematics. The models assume that each galaxy is axisymmetric, with a two-integral distribution function, arbitrary inclination angle, a position-independent stellar mass-to-light ratio Υ, and a central massive dark object (MDO) of arbitrary mass M_•. They provide acceptable fits to 32 of the galaxies for some value of M_• and Υ; the four galaxies that cannot be fitted have kinematically decoupled cores. The mass-to-light ratios inferred for the 32 well-fitted galaxies are consistent with the fundamental-plane correlation Υ ∝ L^0.2, where L is galaxy luminosity. In all but six galaxies the models require at the 95% confidence level an MDO of mass M_• ∼ 0.006M_bulge ≡ 0.006ΥL. Five of the six galaxies consistent with M_• = 0 are also consistent with this correlation. The other (NGC 7332) has a much stronger upper limit on M_•. We predict the second-moment profiles that should be observed at HST resolution for the 32 galaxies that our models describe well.

We consider various parameterizations for the probability distribution describing the correlation of the masses of these MDOs with other galaxy properties. One of the best models can be summarized thus: a fraction f ≃ 0.97 of early-type galaxies have MDOs, whose masses are well described by a Gaussian distribution in log (M_•/M_bulge) of mean -2.28 and standard deviation ∼0.51. There is also marginal evidence that M_• is distributed differently for "core" and "power law" galaxies, with core galaxies having a somewhat steeper dependence on M_bulge.

We have compiled a new and complete catalog of the main properties of the 1509 pulsars for which published information currently exists. The catalog includes all spin-powered pulsars, as well as anomalous X-ray pulsars and soft gamma-ray repeaters showing coherent pulsed emission, but excludes accretion-powered systems. References are given for all data listed. We have also developed a new World Wide Web interface for accessing and displaying either tabular or plotted data with the option of selecting pulsars to be displayed via logical conditions on parameter expressions. The Web interface has an "expert" mode giving access to a wider range of parameters and allowing the use of custom databases. For users with locally installed software and database on Unix or Linux systems, the catalog may be accessed from a command-line interface. C-language functions to access specified parameters are also available. The catalog is updated from time to time to include new information.

We present a two-dimensional fitting algorithm (GALFIT) designed to extract structural components from galaxy images, with emphasis on closely modeling light profiles of spatially well-resolved, nearby galaxies observed with the Hubble Space Telescope. Our algorithm improves on previous techniques in two areas: by being able to simultaneously fit a galaxy with an arbitrary number of components and with optimization in computation speed, suited for working on large galaxy images. We use two-dimensional models such as the "Nuker" law, the Sérsic (de Vaucouleurs) profile, an exponential disk, and Gaussian or Moffat functions. The azimuthal shapes are generalized ellipses that can fit disky and boxy components. Some potential applications of our program include: standard modeling of global galaxy profiles; extracting bars, stellar disks, double nuclei, and compact nuclear sources; and measuring absolute dust extinction or surface brightness fluctuations after removing the galaxy model. When examined in detail, we find that even simple looking galaxies generally require at least three components to be modeled accurately, rather than the one or two components more often employed. Many galaxies with complex isophotes, ellipticity changes, and position angle twists can be modeled accurately in two dimensions. We illustrate this by way of 11 case studies, which include regular and barred spiral galaxies, highly disky lenticular galaxies, and elliptical galaxies displaying various levels of complexities. A useful extension of this algorithm is to accurately extract nuclear point sources in galaxies. We compare two-dimensional and one-dimensional extraction techniques on simulated images of galaxies having nuclear slopes with different degrees of cuspiness, and we then illustrate the application of the program to several examples of nearby galaxies with weak nuclei.

The Sloan Digital Sky Survey (SDSS) is an imaging and spectroscopic survey that will eventually cover approximately one-quarter of the celestial sphere and collect spectra of ≈10⁶ galaxies, 100,000 quasars, 30,000 stars, and 30,000 serendipity targets. In 2001 June, the SDSS released to the general astronomical community its early data release, roughly 462 deg² of imaging data including almost 14 million detected objects and 54,008 follow-up spectra. The imaging data were collected in drift-scan mode in five bandpasses (u, g, r, i, and z); our 95% completeness limits for stars are 22.0, 22.2, 22.2, 21.3, and 20.5, respectively. The photometric calibration is reproducible to 5%, 3%, 3%, 3%, and 5%, respectively. The spectra are flux- and wavelength-calibrated, with 4096 pixels from 3800 to 9200 Å at R ≈ 1800. We present the means by which these data are distributed to the astronomical community, descriptions of the hardware used to obtain the data, the software used for processing the data, the measured quantities for each observed object, and an overview of the properties of this data set.

We describe the design, construction, and performance of the Sloan Digital Sky Survey telescope located at Apache Point Observatory. The telescope is a modified two-corrector Ritchey-Chrétien design with a 2.5 m, f/2.25 primary, a 1.08 m secondary, a Gascoigne astigmatism corrector, and one of a pair of interchangeable highly aspheric correctors near the focal plane, one for imaging and the other for spectroscopy. The final focal ratio is f/5. The telescope is instrumented by a wide-area, multiband CCD camera and a pair of fiber-fed double spectrographs. Novel features of the telescope include the following: (1) A 3° diameter (0.65 m) focal plane that has excellent image quality and small geometric distortions over a wide wavelength range (3000-10,600 Å) in the imaging mode, and good image quality combined with very small lateral and longitudinal color errors in the spectroscopic mode. The unusual requirement of very low distortion is set by the demands of time-delay-and-integrate (TDI) imaging. (2) Very high precision motion to support open-loop TDI observations. (3) A unique wind baffle/enclosure construction to maximize image quality and minimize construction costs. The telescope had first light in 1998 May and began regular survey operations in 2000.