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2026

1. Boone, K., Ferguson, P., Tabbutt, M., Bechtol, K., Cheng, T., Drlica-Wagner, A., Martinez-Vazquez, C., Mutlu-Pakdil, B., Abbott, T., Aguena, M., Alves, O., Andrade-Oliveira, F., Bacon, D., Bocquet, S., Brooks, D., Camilleri, R., Carnero Rosell, A., da Costa, L., da Silva Pereira, M., Davis, T., De Vicente, J., Desai, S., Doel, P., Everett, S., Flaugher, B., Frieman, J., Garcia-Bellido, J., Gruen, D., Gutierrez, G., Hinton, S., Hollowood, D., Honscheid, K., James, D., Kuehn, K., Marshall, J., Mena-Fernandez, J., Menanteau, F., Miquel, R., Myles, J., Ogando, R., Plazas Malagon, A., Porredon, A., Rodriguez-Monroy, M., Sanchez, E., Sanchez Cid, D., Sevilla-Noarbe, I., Smith, M., Suchyta, E., Swanson, M., Vikram, V., Weaverdyck, N., DES Collaboration, 2026, ApJ, 1001, 208, Robust Measurement of Stellar Streams around the Milky Way: Correcting Spatially Variable Observational Selection Effects in Optical Imaging Surveys
   Abstract

   Observations of density variations in stellar streams are a promising probe of low-mass dark matter substructure in the Milky Way. However, survey systematics such as variations in seeing and sky brightness can also induce artificial fluctuations in the observed densities of known stellar streams. These variations arise because survey conditions affect both object detection and stargalaxy misclassification rates. To mitigate these effects, we use Balrog synthetic source injections in the Dark Energy Survey (DES) Y3 data to calculate detection rate variations and classification rates as functions of survey properties. We show that these rates are nearly separable with respect to survey properties and can be estimated with sufficient statistics from the synthetic catalogs. Applying these corrections reduces the standard deviation of relative detection rates across the DES footprint by a factor of 5, and our corrections significantly change the inferred linear density of the Phoenix stream when including faint objects. Additionally, for artificial streams with DES-like survey properties we are able to recover density power spectra with reduced bias. We also find that uncorrected power-spectrum results for Legacy Survey of Space and Time (LSST)-like data can be around 5 times more biased, highlighting the need for such corrections in future ground-based surveys.

2. Popovic, B., Shah, P., Kenworthy, W., Kessler, R., Davis, T., Goobar, A., Scolnic, D., Vincenzi, M., Wiseman, P., Chen, R., Charleton, E., Acevedo, M., Armstrong, P., Boyd, B., Brout, D., Camilleri, R., Frieman, J., Galbany, L., Grayling, M., Kelsey, L., Rose, B., Sanchez, B., Lee, J., Moller, A., Smith, M., Sullivan, M., Shiamtanis, N., Alarcon, A., Allam, S., Andrade-Oliveira, F., Avila, S., Bacon, D., Blazek, J., Bocquet, S., Brooks, D., Burke, D., Carnero Rosell, A., Carretero, J., Cawthon, R., da Costa, L., da Silva Pereira, M., Diehl, H., Dodelson, S., Doel, P., Everett, S., Frohmaier, C., Garcia-Bellido, J., Gruen, D., Gutierrez, G., Herner, K., Hinton, S., Hollowood, D., Honscheid, K., Huterer, D., James, D., Jeffrey, N., Kuehn, K., Lahav, O., Lee, S., Lidman, C., Marshall, J., Mena-Fernandez, J., Menanteau, F., Miquel, R., Muir, J., Myles, J., Ogando, R., Paterno, M., Plazas Malagon, A., Porredon, A., Prat, J., Nichol, R., Romer, A., Roodman, A., Sanchez, E., Sanchez Cid, D., Sevilla-Noarbe, I., Suchyta, E., Swanson, M., To, C., Tucker, D., Walker, A., Weaverdyck, N., Aguena, M., 2026, MNRAS, The Dark Energy Survey Supernova Program: A Reanalysis Of Cosmology Results And Evidence For Evolving Dark Energy With An Updated Type Ia Supernova Calibration
   Abstract

   We present improved cosmological constraints from a re-analysis of the Dark Energy Survey (DES) 5-year sample of Type Ia supernovae (DES-SN5YR). This re-analysis includes an improved photometric cross-calibration, recent white dwarf observations to cross-calibrate between DES and low redshift surveys, retraining the SALT3 light curve model and fixing a numerical approximation in the host galaxy colour law. Our fully recalibrated sample, which we call DES-Dovekie, comprises ~1600 likely Type Ia SNe from DES and ~200 low-redshift SNe from other surveys. With DES-Dovekie, we obtain _m = 0.330 0.015 in Flat CDM which changes _m by -0.022 compared to DES-SN5YR. Combining DES-Dovekie with CMB data from Planck, ACT and SPT and the DESI DR2 measurements in a Flat w₀w_aCDM cosmology, we find w₀ = -0.803 0.054, w_a = -0.72 0.21. Our results hold a significance of 3.2, reduced from 4.2 for DES-SN5YR, to reject the null hypothesis that the data are compatible with the cosmological constant. This significance is equivalent to a Bayesian model preference odds of approximately 5:1 in favour of the Flat w₀w_aCDM model. Using generally accepted thresholds for model preference, our updated data exhibits only a weak preference for evolving dark energy.

3. Thieberger, C., Hanley, J., Tan, S., Grundy, W., Steckloff, J., Lindberg, G., Engle, A., Tegler, S., 2026, PSJ, 7, 81, The Effects of Propane on NitrogenHydrocarbon Mixtures Relevant to Titan's Lakes and Seas
   Abstract

   Titan is the only extraterrestrial environment known to support bodies of standing liquid on its surface. The bulk constituents of these lakes and seas are liquid methane, ethane, and dissolved nitrogen from the atmosphere. However, trace species produced from photochemistry are also expected to be found in these liquid bodies. Propane is one of the most common among these trace species, but its effects on the Titan ternary system are poorly understood. In an effort to study these environments and map out their extremes, we present our experimental work done in the Astrophysical Materials Lab at Northern Arizona University. We studied the effects of propane on liquid binary mixtures of methanenitrogen and ethanenitrogen. This work presents the results of these experiments run at 90 and 85 K at pressures up to 3 bars, which correspond to depths of up to 200 m in Titan lakes. We observed a second liquid emerging at 90 K in liquidliquidvapor (LLV) equilibrium in methane-based mixtures at pressures >2.5 bars. At 85 K, these mixtures would split into LLV at much lower pressures given a sufficient propane molar fraction. In ethane-based mixtures, we observed a second liquid emerging at a consistent pressure of 2.3 bars at 85 K, but in liquidliquid equilibrium, regardless of the relative propane abundance. We also observed chemoclines, bubbles, and ice formation in several of our experiments. These observed phase changes under Titan conditions demonstrate that there could be compositional stratification of surface liquids, nitrogen droplets precipitating out of liquid hydrocarbon mixtures, or even ice formation under certain conditions.

4. Gimar, C., Raut, U., Grundy, W., Teolis, B., Kammer, J., 2026, A&A, 708, L6, Thermal clustering of solid ethane with potential relevance to Charon's Mordor region
   Abstract

   The methane condensed in Charon's winter hemisphere undergoes photolysis by interplanetary medium Lyman- photons, which yields solid ethane as the dominant photoproduct. With the onset of spring, the photolyzed surface experiences increased surface temperatures and solar wind exposure, conditions that promote further structural and chemical modification. We report laboratory measurements that show solid ethane undergoes a marked spectral reddening when thermally processed at Charon's subsolar maximum temperature of 60 K. The reddening follows an Arrhenius temperature dependence, proceeding on hour timescales at 60 K but requiring on the order of 100 years at 45 K. This behavior is consistent with thermally driven diffusion and aggregation of ethane molecules into nanoclusters that preferentially scatter shorter wavelengths. On Charon, simultaneous solar wind radiolysis may convert ethane nanoclusters into higher-order nonvolatile organic nanoclusters that can plausibly account for the observed reddish polar hue of the object.

5. Cocke, B., Massey, P., Morrell, N., Penny, L., Neugent, K., Eldridge, J., Szymanski, M., Udalski, A., Marin, L., 2026, ApJ, 1001, 116, An Orbit for a Massive WolfRayet Binary in the LMC: An Example of Binary Evolution
   Abstract

   WolfRayet (WR) stars are helium-burning, evolved massive stars which have had most of their hydrogen-rich outer layers removed, either through stellar winds and/or binary stripping. Here, we report on LMC 173-1, a WN3+O binary located in the Large Magellanic Cloud (LMC). Using spectra obtained from the Magellan and Gemini-S telescopes, we have derived system parameters for this intriguing binary. The WR star's mass is only 43% that of its companion, and we argue that this requires binary evolution rather than mass loss by stellar winds alone, given the metallicity of the LMC. The stars are close enough to each other with their 3.52 days period that the O star is actually orbiting within the wind of the WR star, as is the case for other well-known WR+O systems, such as V444 Cyg. As a result, high precision OGLE photometry reveals a WR atmospheric eclipse, as well as a 78 millimag ellipsoidal modulation, due primarily to the tidal distortion of the O star. Modeling the light curve allows us to estimate the orbital inclination. Derivation of stellar parameters suggests neither component is filling its Roche-lobe surface today. The O star is spinning much faster than synchronous rotation. Using BPASS v2.2 binary models, we discuss the probable evolutionary history of the system. The WR progenitor likely underwent Case A Roche-lobe overflow (RLOF) before leaving the main sequence. As it lost its H-rich envelope, it became a WN-type WR. The resulting system is a binary with similar luminosities but very different radii, representing a post-RLOF phase. *This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. It also utilizes observations from the International Gemini Observatory, a program of NSF NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the U.S. National Science Foundation (NSF) on behalf of the Gemini Observatory partnership: the NSF (United States), National Research Council (Canada), Agencia Nacional de Investigacion y Desarrollo (Chile), Ministerio de Ciencia, Tecnologiia e Innovacion (Argentina), Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea).

6. Yang, Y., Lewis, G., Li, T., Martell, S., Erkal, D., Ji, A., Koposov, S., Zucker, D., Pace, A., Cullinane, L., Da Costa, G., Kuehn, K., Limberg, G., Medina, G., 2026, MNRAS, 547, stag488, Epicyclic density variations in the Indus stellar stream
   Abstract

   Longitudinal density fluctuations observed in stellar streams can result from gravitational interactions with massive perturbers in the Milky Way, such as dark matter subhaloes. Analysing these density variations provides a powerful probe of properties (motion, mass, size, etc.) of the perturbing objects. However, caution is needed because density variations may arise naturally from internal dynamics of streams, namely epicycles. In this work, we focus on the Indus stellar stream, a remnant of an ancient dwarf satellite of the Galaxy. An Indus stream spanning $\sim 90^{\circ }$ is revealed in the southern Galactic sky using a comprehensive matched-filter analysis utilizing data from the Gaia mission. A spatial density model is fitted to the filtered map to quantitatively characterize the morphology, which demonstrates episodic density peaks and gaps in the stream. Through N-body simulations, we show that there are strong epicyclic motions of stars happening during tidal disruptions. The present-day longitudinal densities from simulations are comparable to the measurement from data, with similar numbers and locations of peaks and gaps, suggesting that the observed density should mainly be caused by epicycles. We also find that a cuspy dark matter halo for the Indus dwarf is likely to produce milder stellar epicyclic peaks compared to a cored halo, which results in steeper peaks. This arises from different instantaneous mass-loss due to distinct central mass distributions of haloes, where a cored halo usually leads to severer tidal stripping. The observed density exhibits moderate peak sharpness, implying that Indus may have originally possessed a cuspy halo.

7. Thomsen, A., Bucko, J., Kacprzak, T., Ajani, V., Fluri, J., Refregier, A., Anbajagane, D., Castander, F., Ferte, A., Gatti, M., Jeffrey, N., Alarcon, A., Amon, A., Bechtol, K., Becker, M., Bernstein, G., Campos, A., Carnero Rosell, A., Chang, C., Chen, R., Choi, A., Crocce, M., Davis, C., DeRose, J., Dodelson, S., Doux, C., Eckert, K., Elvin-Poole, J., Everett, S., Fosalba, P., Gruen, D., Harrison, I., Herner, K., Huff, E., Jarvis, M., Kuropatkin, N., Leget, P., MacCrann, N., McCullough, J., Myles, J., Navarro-Alsina, A., Pandey, S., Porredon, A., Prat, J., Raveri, M., Rodriguez-Monroy, M., Rollins, R., Roodman, A., Rykoff, E., Sanchez, C., Secco, L., Sheldon, E., Shin, T., Troxel, M., Tutusaus, I., Varga, T., Weaverdyck, N., Wechsler, R., Yanny, B., Yin, B., Zhang, Y., Zuntz, J., Aguena, M., Allam, S., Andrade-Oliveira, F., Bacon, D., Blazek, J., Brooks, D., Camilleri, R., Carretero, J., Cawthon, R., da Costa, L., da Silva Pereira, M., Davis, T., De Vicente, J., Desai, S., Doel, P., Garcia-Bellido, J., Gutierrez, G., Hinton, S., Hollowood, D., Honscheid, K., James, D., Kuehn, K., Lahav, O., Lee, S., Marshall, J., Mena-Fernandez, J., Menanteau, F., Miquel, R., Muir, J., Ogando, R., Plazas Malagon, A., Sanchez, E., Sanchez Cid, D., Sevilla-Noarbe, I., Smith, M., Suchyta, E., Swanson, M., Thomas, D., To, C., Tucker, D., DES Collaboration, 2026, PhRvD, 113, 083501, Dark Energy Survey Year 3 results: Simulation-based wCDM inference from weak lensing and galaxy clustering maps with deep learning: Analysis design
   Abstract

   Data-driven approaches using deep learning are emerging as powerful techniques to extract non-Gaussian information from cosmological large-scale structure. This work presents the first simulation-based inference (SBI) pipeline that combines weak lensing and galaxy clustering maps in a realistic Dark Energy Survey Year 3 (DES Y3) configuration and serves as preparation for a forthcoming analysis of the survey data. We develop a scalable forward model based on the COSMOGRIDV1 suite of N-body simulations to generate over one million self-consistent mock realizations of DES Y3 at the map level. Leveraging this large dataset, we train deep graph convolutional neural networks on the full survey footprint in spherical geometry to learn low-dimensional features that approximately maximize mutual information with target parameters. These learned compressions enable neural density estimation of the implicit likelihood via normalizing flows in a ten-dimensional parameter space spanning cosmological wCDM, intrinsic alignment, and linear galaxy bias parameters, while marginalizing over baryonic, photometric redshift, and shear bias nuisances. To ensure robustness, we extensively validate our inference pipeline using synthetic observations derived from both systematic contaminations in our forward model and independent BUZZARD galaxy catalogs. Our forecasts yield significant improvements in cosmological parameter constraints, achieving 23 higher figures of merit in the m-S8 plane relative to our implementation of baseline two-point statistics and effectively breaking parameter degeneracies through probe combination. These results demonstrate the potential of SBI analyses powered by deep learning for upcoming stage-IV wide-field imaging surveys.

8. Proudfoot, B., Grundy, W., Ragozzine, D., 2026, ApJL, 1001, L4, Trans-Neptunian Binary Mutual Events in the 2020s and 2030s
   Abstract

   Mutual events of trans-Neptunian binaries (TNBs) provide rare opportunities to measure the physical and orbital properties of small bodies in the outer solar system. However, successful observations of these events have been limited by uncertain predictions. Here, we present probabilistic predictions of TNB mutual events occurring through the 2030s, using high-precision non-Keplerian orbit solutions from the Beyond Point Masses project combined with a Bayesian framework that propagates orbital and size uncertainties. Our methods generate distributions of event timing, duration, depth, and probability of occurrence, enabling direct assessment of observability. We provide predictions for five systems with ongoing or imminent mutual event seasons, including (38628) Huya, (58534) LogosZoe, (148780) Altjira, (469705) Kagara-!Haunu, and (524366) 2001 XR₂₅₄. Preparing for upcoming events with long-baseline light-curve monitoring is vital, as events may be difficult to distinguish from a regular rotational light curve. Rapid dissemination of event detections will benefit the entire community, allowing predictions to be updated, ensuring that these rare mutual event opportunities can be fully exploited.

9. Shaw, R., Novacescu, J., Weissman, S., Berger, T., Brasseur, C., Chamblee, J., Cherinka, B., Claytor, Z., Dower, T., Edeani, C., Falk, B., Fleming, S., Hargis, J., Imig, J., Januario, T., Kimball, T., Kotler, J., Levay, K., Lewis, H., Lubow, S., Lucy, A., McLean, B., Malla, S., Matuskey, J., Miller, S., Mullally, S., Murray, C., Peek, J., Phillip, C., Rafelski, M., Rodriguez, D., Snyder, G., Usha, A., White, R., Wilkinson, C., Yoon, J., 2026, PASP, 138, 034502, The Impact of the MAST Data Archive
   Abstract

   The Barbara A. Mikulski Archive for Space Telescopes (MAST) hosts science-ready data products from over 20 NASA missions plus community-contributed data collections and other select surveys. The data support forefront research in the ultraviolet, optical, and near-infrared wavelength bands. We have constructed bibliographies for each mission from publications in nearly 40 professional journals and identified more than 37,000 refereed articles where investigators made a science usage of data hosted in MAST. The publication rate over the last 50 yr shows that most MAST missions have had very high productivity during their in-service lifetimes and have remained so for years or decades afterward. Annual citations of these publications, a measure of impact on research, are robust for most missions, with citations that grow over more than a decade. Most of the citations come from about 10% of the articles within each mission. We examined the bibliographies of the active missions Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) in greater detail. For HST, the rate of archival publications exceeded those authored by the original observing teams within a decade of launch and is now more than 3 times higher. Early indications hint that JWST archival articles could dominate the publication rate even sooner. The production of articles resulting from any given observing program can extend for decades. Programs with small and very large allocations of observing time tend to be particularly productive per unit of observing time. For HST in general, a first publication appears within 1.5 yr for 50% of observing programs and within 3.8 yr for 80% of programs. We discuss various external factors that affect publication metrics, their strengths and limitations for measuring scientific impact, and the challenges of making meaningful comparisons of publication metrics across missions.

10. Devogele, M., Hainaut, O., Micheli, M., Pravec, P., Cano, J., Ocana, F., Conversi, L., Moskovitz, N., de Leon, J., Gray, Z., Granvik, M., Fedorets, G., Bourdelle de Micas, J., Ieva, S., Dotto, E., Beuden, T., Fuls, C., Kareta, T., Bagnulo, S., Barucci, M., Birlan, M., Farina, A., Hornoch, K., Fatka, P., Kusnirak, P., Ferri, F., Fulchignoni, M., Lazzarin, M., La Forgia, F., Mazzotta Epifani, E., Mura, A., Perna, D., Bendjoya, P., Rivet, J., Cellino, A., 2026, JAnSc, 73, 31, Rapid-Response Characterization of Near-Earth Asteroid 2024 YR₄ During a Torino Scale 3 Alert
    Abstract

    On 27 December 2024, near-Earth object (NEO) 2024 $$\hbox {YR}_4$$ was discovered by the ATLAS survey and identified as a virtual impactor. A few weeks later, it eventually reached level 3 on the Torino Scale and was the first and only asteroid to be ever classified at that level. Here we report an intensive observational campaign combining time-series photometry in the visible, broadband visible and near-infrared colors, and low-resolution visible reflectance spectroscopy to assess its physical properties. Fourier analysis of the lightcurves yields a synodic rotation period of $$P = 19.46341 \pm 0.00008$$ min, placing 2024 $$\hbox {YR}_4$$ among the fast rotators, even if such rotation is common for objects of similar H magnitude. Its visible and near-infrared colors and spectra are most consistent with an Sq or K taxonomic classification, though some ambiguity remains. Finally, its phase curve exhibits a notably shallow slope ($$G = 0.51 \pm 0.11$$), from which we derive an absolute magnitude of $$H_\textrm{R} = 23.82\pm 0.09$$ mag. After color correction and taking into account other models for the phase function, we report an absolute magnitude of $$H_\textrm{V} = 24.14\pm 0.25$$ mag. These characterizations, rotation period, taxonomy, and surface properties, would have been crucial for risk assessment and mitigation planning had the initially high impact probability scenario been confirmed, underscoring the importance for planetary defense of a rapid, coordinated international response.

11. Tan, C., Drlica-Wagner, A., Pace, A., Cerny, W., Nadler, E., Doliva-Dolinsky, A., Anbajagane, D., Li, T., Simon, J., Vivas, A., Walker, A., Adamow, M., Bechtol, K., Carlin, J., Casey, Q., Chang, C., Chaturvedi, A., Cheng, T., Chiti, A., Choi, Y., Crnojevic, D., Ferguson, P., Gruendl, R., Ji, A., Limberg, G., Medina, G., Mutlu-Pakdil, B., Noel, N., Overdeck, K., Placco, V., Riley, A., Sand, D., Sharp, J., Sherman, N., Stringfellow, G., Wechsler, R., Aguena, M., Allam, S., Alves, O., Bacon, D., Brooks, D., Burke, D., Camilleri, R., Carballo-Bello, J., Carnero Rosell, A., Carretero, J., da Costa, L., da Silva Pereira, M., Davis, T., de Vicente, J., Desai, S., Everett, S., Flaugher, B., Frieman, J., Garcia-Bellido, J., Gruen, D., Gutierrez, G., Herner, K., Hinton, S., Hollowood, D., James, D., Kuehn, K., Lahav, O., Lee, S., Marshall, J., Martinez-Vazquez, C., Massana, P., Mena-Fernandez, J., Miquel, R., Muir, J., Myles, J., Ogando, R., Plazas Malagon, A., Porredon, A., Sanchez, E., Sanchez Cid, D., Sevilla-Noarbe, I., Smith, M., Suchyta, E., Swanson, M., To, C., Tollerud, E., Tucker, D., Vikram, V., Weaverdyck, N., Yamamoto, M., Zenteno, A., Delve Collaboration, Des Collaboration, 2026, ApJ, 1000, 87, DELVE Milky Way Satellite Galaxy Census. I. Satellite Population and Survey Selection Function in DES, DELVE, and Pan-STARRS
    Abstract

    The properties of Milky Way satellite galaxies have important implications for galaxy formation, reionization, and the fundamental physics of dark matter. However, the population of Milky Way satellites includes the faintest known galaxies, and current observations are incomplete. To understand the impact of observational selection effects on the known satellite population, we perform rigorous, quantitative estimates of the Milky Way satellite galaxy detection efficiency in three wide-field survey datasets: the Dark Energy Survey Year 6, the DECam Local Volume Exploration Data Release 3, and the Pan-STARRS1 Data Release 1. Together, these surveys cover 13,600 deg² to g 24.0 and 27,700 deg² to g 22.5, spanning 91% of the high-Galactic-latitude sky (b 15). We apply multiple detection algorithms over the combined footprint and recover 49 known satellites above a strict census detection threshold. To characterize the sensitivity of our census, we run our detection algorithms on a large set of simulated galaxies injected into the survey data, which allows us to develop models that predict the detectability of satellites as a function of their properties. We then fit an empirical model to our data and infer the luminosity function, radial distribution, and sizeluminosity relation of Milky Way satellite galaxies. Our empirical model predicts a total of 26547+79 satellite galaxies with 20 M_V 0, half-light radii of 15 r_1/2, (pc) 3000, and galactocentric distances of 10 D_GC(kpc) 300. We also identify a mild anisotropy in the angular distribution of the observed galaxies, at a significance of 2, which can be attributed to the clustering of satellites associated with the LMC.

12. Zhang, Q., Knight, M., Ye, Q., Schmidt, C., Battams, K., 2026, RNAAS, 10, 57, Preliminary Nucleus Size Estimate for Kreutz Sungrazer C/2026 A1 (MAPS)
    Abstract

    JWST imagery of the approaching Kreutz sungrazer C/2026 A1 (MAPS) appears sufficient to distinguish the comet's nucleus from the surrounding dust. Coma model fitting indicates the morphology is compatible with a 0.4 km diameter nucleuslikely larger than those of the minor Kreutz fragments routinely discovered with coronagraphs, and comparable to or slightly smaller than that of C/2011 W3 (Lovejoy). However, since C/2026 A1 is the only Kreutz sungrazer whose nucleus has been directly observed, these comparisons should be treated with caution.

13. Kilic, Y., Braga-Ribas, F., Pereira, C., Ortiz, J., Sicardy, B., Santos-Sanz, P., Erece, O., Rizos, J., Gomez-Limon, J., Margoti, G., Souami, D., Morgado, B., Gomes-Junior, A., Catani, L., Desmars, J., Kretlow, M., Rommel, F., Duffard, R., Alvarez-Candal, A., Camargo, J., Kaplan, M., Morales, N., Herald, D., Assafin, M., Benedetti-Rossi, G., Sfair, R., Savalle, R., Arcas-Silva, J., Bernasconi, L., Blank, T., Bonavita, M., Carlson, N., Christophe, B., Colesanti, C., Collins, M., Columba, G., Dunford, R., Dunham, D., Dunham, J., Emilio, M., Ferrante, W., George, T., Hanna, W., Isopi, G., Jones, R., Kenyon, D., Kerr, S., Kouprianov, V., Maley, P., Mallia, F., Mattei, J., Meunier, M., Napoleao, T., Peixoto, V., Pollock, J., Snodgrass, C., Stechina, A., Thomas, W., Venable, R., Viscome, G., Zapparata, A., Bardecker, J., Castro, N., Cebral, C., Chapman, A., Gao, C., Green, K., Guimaraes, A., Jacques, C., Jehin, E., Konishi, M., Leiva, R., Liberato, L., Magliano, C., Mammana, L., Melita, M., Moura, V., Olivera-Cuello, Y., Peiro, L., Spagnotto, J., Stuart, P., Vanzi, L., Wilberger, A., Malacarne, M., 2026, A&A, 707, A70, Constraining the size, shape, and albedo of the large trans-Neptunian object (28978) Ixion with multi-chord stellar occultations
    Abstract

    Context. Trans-Neptunian objects (TNOs) are among the most primitive remnants of the early Solar System. Determining their sizes, shapes, albedos, and surface properties is essential for understanding their origin and evolution. Stellar occultations provide highly accurate size and shape information for TNOs, while photometry constrains their albedo and surface colours. (28978) Ixion is one of the largest TNOs and a prominent Plutino, making it a key target for comparative studies. Aims. The aim of this work is to constrain Ixion's projected size, shape, absolute magnitude, geometric albedo, and surface colours, and to search for evidence of an atmosphere or circum-object material. Methods. We conducted a series of campaigns targeting stellar occultations by Ixion between 2020 and 2023 as part of the Lucky Star collaboration, gathering 51 observations from eight events, including 30 positive detections. Five multi-chord events were used for a global limb fit, enabling an accurate reconstruction of Ixion's projected shape. Calibrated photometric data, including new and archival measurements, were analysed to derive its absolute magnitude, phase-curve parameters, and broadband colours. Results. The multi-chord occultations reveal a slightly elongated limb that is well represented by a single projected ellipse with semi-axes a = 363.42_3.85^+3.53 km and b = 333.98_4.96^+7.07 km, yielding R_equiv = 348.39_4.43^+5.37 km (D_equiv = 696.78_8.87^+10.75 km), and an apparent oblateness ' = 0.081_0.010^+0.004. The geometry is consistent with a moderately flattened, nearly spheroidal body that may show slight departures from axial symmetry. The typical radial residuals (~10 km) support a largely stable shape across the observed epochs, with modest epoch-dependent variations. The phase-curve fit gives H_V = 3.845 0.006, = 0.1301 0.0078 mag deg¹, and p_V = 0.106_0.003^+0.003. Multi-band photometry yields B V = 1.06 0.03, V R = 0.61 0.02, and R I = 0.54 0.03, which is consistent with moderately red TNO surfaces. No atmosphere or circum-object material was detected down to our sensitivity limits. The best-sampled event (13 October 2020) also allowed us to measure the angular diameter of the occulted star Gaia DR3 4056440205544338944, = 0.670 0.010 mas, which corresponds to R = 128 10 R at the Gaia distance.

14. Tan, C., Cerny, W., Pace, A., Sharp, J., Overdeck, K., Drlica-Wagner, A., Simon, J., Mutlu-Pakdil, B., Sand, D., Senkevich, A., Erkal, D., Ferguson, P., Sobreira, F., Atzberger, K., Carlin, J., Chiti, A., Crnojevic, D., Ji, A., Johnson, L., Li, T., Limberg, G., Martinez-Vazquez, C., Medina, G., Placco, V., Riley, A., Tollerud, E., Vivas, A., Abbott, T., Aguena, M., Alves, O., Bacon, D., Bocquet, S., Brooks, D., Burke, D., Camilleri, R., Carballo-Bello, J., Carnero Rosell, A., Carretero, J., Cheng, T., Choi, Y., da Costa, L., da Silva Pereira, M., Davis, T., de Vicente, J., Desai, S., Doel, P., Everett, S., Flaugher, B., Frieman, J., Garcia-Bellido, J., Gruen, D., Gutierrez, G., Hinton, S., Hollowood, D., James, D., Kuehn, K., Lee, S., Marshall, J., Mena-Fernandez, J., Menanteau, F., Miquel, R., Myles, J., Navabi, M., Nidever, D., Noel, N., Ogando, R., Plazas Malagon, A., Porredon, A., Samuroff, S., Sanchez, E., Sanchez Cid, D., Sevilla-Noarbe, I., Smith, M., Stringfellow, G., Suchyta, E., Swanson, M., Vikram, V., Walker, A., Zenteno, A., Delve Collaboration, Des Collaboration, 2026, ApJ, 1000, 46, Ultra-faint Milky Way Satellites Discovered in Carina, Phoenix, and Telescopium with DELVE Data Release 3
    Abstract

    We report the discovery of three Milky Way satellite candidates: Carina IV, Phoenix III, and DELVE 7, in the third data release of the DECam Local Volume Exploration survey (DELVE). The candidate systems were identified by cross-matching results from two independent search algorithms. All three are extremely faint systems composed of old, metal-poor stellar populations ( 10 Gyr, [Fe/H] 1.4). Carina IV (M_V = 2.8; r_1/2 = 40 pc) and Phoenix III (M_V = 1.2; r_1/2 = 19 pc) have half-light radii that are consistent with the known population of dwarf galaxies, while DELVE 7 (M_V = 1.2; r_1/2 = 2 pc) is very compact and seems more likely to be a star cluster, though its nature remains ambiguous without spectroscopic follow-up. The Gaia proper motions of stars in Carina IV ( M=2250830+1180M ) indicate that it is unlikely to be associated with the LMC, while DECam CaHK photometry confirms that its member stars are metal poor. Phoenix III ( M=520290+660M ) is the faintest known satellite in the extreme outer stellar halo (D_GC > 100 kpc), while DELVE 7 ( M=6040+120M ) is the faintest known satellite with D_GC > 20 kpc.

15. Godoy-Rivera, D., Grossmann, D., Richey-Yowell, T., Santos, A., Mathur, S., Garcia, R., 2026, RNAAS, 10, 53, Mining the Kepler Field: Atmospheric Parameters, Bolometric Corrections, and Luminosities
    Abstract

    The 200,000 stars observed by the Kepler mission have provided unprecedented constraints across astrophysics. With the advent of modern spectroscopic and photometric surveys, new limits in stellar characterizations are within reach. In this work, we report a compilation of atmospheric parameters (T_eff, log(g) , and [M/H]) for the Kepler stars by crossmatching with several spectroscopic and spectro-photometric surveys. We use these to calculate bolometric corrections, which combined with colormagnitude diagram information from Gaia yield self-consistent luminosities on a survey-by-survey basis. These properties will aid in future explorations of Kepler data toward new astrophysical insights. We make our catalog publicly available online in Zenodo (doi:10.5281/zenodo.18620911).

16. Brasseur, C., Jardine, M., Daley-Yates, S., Donati, J., Morin, J., 2026, MNRAS, 546, stag042, Electron cyclotron maser emission from ejected stellar prominences on V374 Peg
    Abstract

    We investigate a possible origin for bursty radio emission observed on the active M dwarf V374 Peg, combining data-driven magnetic field modelling with archival radio light curves. We examine whether stellar prominence ejection can plausibly account for the observed radio bursts that have been attributed to electron cyclotron maser (ECM) emission. Our analysis shows that ejected prominences can produce the required energy range to drive the emission, and that modelled ECM visibility exhibits a rotational phase dependence consistent with the limited observational data (four observed bursts). The results support prominence ejection as a viable mechanism for ECM generation on V374 Peg and motivate further observational campaigns to constrain this process.

17. Hoppe, R., Bergemann, M., Eitner, P., Ellwarth, M., Nordlund, A., Leenaarts, J., Plez, B., Serenelli, A., 2026, MNRAS, 546, staf2085, Solar carbon abundance from 3D non-LTE modelling of the diagnostic lines of the CH molecule
    Abstract

    The spectral lines of the CH molecule are a key carbon (C) abundance diagnostic in FGKM-type stars. These lines are detectable in metal-rich and, in contrast to atomic C lines, also in metal-poor late-type stars. However, only 3D LTE analyses of the CH lines have been performed so far. We test the formation of CH lines in the solar spectrum, using for the first time, 3D Non-LTE (NLTE) models. We also aim to derive the solar photospheric abundance of C, using the diagnostic transitions in the optical (4218$4356 \,\rm{\mathring{\rm A}}$) and infrared (33025$37944 \,\rm{\mathring{\rm A}}$). We use the updated NLTE model molecule from S. A. Popa et al. (2023) and different solar 3D radiation-hydrodynamics model atmospheres. The models are contrasted against new spatially resolved optical solar spectra, and the centre-to-limb variation (CLV) of CH lines is studied. We find generally small ($\sim$0.01 dex) NLTE effects in the optical and IR diagnostic CH AX lines in the solar atmosphere. Both 3D NLTE and 3D LTE spectral modelling yield an excellent fit to the solar intensity observations at all viewing angles. The 1D LTE and 1D NLTE models fail to describe the line CLV, and lead to underestimated solar C abundances. The 3D NLTE modelling of diagnostic lines in the optical and IR yields a carbon abundance of A(C) = $8.52\pm 0.07$ dex. The estimate is in agreement with recent results based on neutrino fluxes measured by Borexino. 3D NLTE modelling and tests on spatially resolved solar data are essential to derive robust solar abundances. The analysis presented here focuses on CH, but we expect that similar effects will be present for other molecules of astrophysical interest.

18. Quitral-Pierart, A., Leigh, N., Mathieu, R., Latham, D., Sandquist, E., Horch, E., 2026, A&A, 706, A177, Mass-luminosity anomalies: Plausible evidence of recent stellar interaction in the extraordinary blue straggler S1082
    Abstract

    Context. We present an observational and theoretical study of the complex stellar system S1082 in the open cluster M67. This system consists of at least four stars: a blue straggler in a 1.07-day eclipsing binary with a main sequence star (binary A) and another blue straggler in a 1185-day orbit with an unknown companion (binary B). Aims. We analyzed observational data to obtain the orbital and stellar parameters of the components of the eclipsing system. We then explored mass transfer and dynamical encounter scenarios that could explain the derived properties of all of the components of S1082. Methods. We combined high-precision photometry from K2 and TESS with archival light curves, new radial-velocity measurements, and speckle imaging to refine the orbital and physical parameters of the system. To explore the formation pathways, we conducted binary evolution simulations with MESA and dynamical scattering experiments with FEWBODY, followed by a tidal evolution modeling procedure. Results. Our revised radial-velocity solutions yield significantly changed dynamical masses for binary A, reducing the tension with the cluster turnoff mass compared to previous studies. Speckle imaging shows two resolved components separated by 390 AU in projection and, in combination with the two spectroscopic orbits, this is suggestive of a hierarchical quadruple configuration. Our results suggest that the two blue stragglers formed separately, with later dynamical encounters assembling the present configuration. This work underscores the importance of stellar dynamics in shaping the evolution of complex stellar systems within cluster environments such as M67.

19. Zhao, L., Fischer, D., Szymkowiak, A., Brewer, J., Llama, J., 2026, ApJS, 282, 71, Uncovering Hidden Systematics in Extreme-precision Radial Velocity Measurements
    Abstract

    We identify and correct for small but coherent instrumental drifts in 7 yr of radial velocity (RV) data from the EXtreme PREcision Spectrograph (EXPRES). The systematics are most notable for the six months before and after 2022 January, when EXPRES experienced larger temperature variations, and we see a systematic trough-to-peak amplitude of 2.8 m s¹ in the radial velocities. This is large enough to mimic or obscure planetary signatures. To isolate and correct these effects, we develop a suite of diagnostics that track two-dimensional echellogram shifts, scalings, and rotation, as well as line bisector spans derived from laser frequency comb lines. By combining these empirical tracers with instrument telemetry in a multidimensional regression, we reduce the EXPRES instrument trend traced with solar RVs from an rms of 1.320.43 m s¹, a 67% improvement, and the aggregate of 12 chromospherically quiet stars shows a 26% reduction in velocity scatter. Our injection/recovery simulations further demonstrate a doubling in sensitivity to low-amplitude planetary signals after correction. When applied to the stellar time series of Coronae Borealis (CrB), the correction removes a spurious planet d signal, restoring the integrity of the data. These results highlight the need for long-term monitoring and multidimensional calibration diagnostics on the path toward true centimeter-per-second precision in next-generation extreme precision RV instruments.

20. Zhang, Q., Ye, Q., Battams, K., Knight, M., Boonplod, W., Kracht, R., 2026, PSJ, 7, 31, Covertly Active Comet (139359) 2001 ME1
    Abstract

    On 2018 November 18, coronagraphs onboard the Solar and Heliospheric Observatory (SOHO) captured an unrecognized comet crossing its fields of view. We identified this comet to be the minor planet (139359) 2001 ME₁, whose previously unnoticed dust activity near perihelion became optically amplified by efficient forward scattering of sunlight as the comet crossed between the Sun and SOHO/Earth at up to 175.6 phase angle. Simultaneous backscattering observations by the Solar Terrestrial Relations Observatory (STEREO) precisely constrain the comet's 7 mag forward scattering brightening, enabling a direct comparison with the 3 mag brightening of the more active but optically dust-poor comet 2P/Encke seen by SOHO and STEREO under similar geometry in 2017. Earlier STEREO observations from 2014 additionally show the newly recognized activity to be recurrentconsistent with a reanalysis of the comet's associated meteor activityand has likely only been previously overlooked due to the comet's faintness and proximity to the Sun while active. Orbital integrations show the comet has likely followed a near-Earth orbit for at least the past 10 kyr, suggesting that the weakness of its observed activity evolved through its continued depletion of accessible volatiles.

21. Sandford, N., Li, T., Koposov, S., Hayashi, K., Pace, A., Erkal, D., Bovy, J., Da Costa, G., Cullinane, L., Ji, A., Kuehn, K., Lewis, G., Zucker, D., Limberg, G., Medina, G., Simon, J., Yang, Y., (S, 2026, ApJ, 998, 47, Chemodynamics of Bootes I with S⁵: Revised Velocity Gradient, Dark Matter Density, and Galactic Chemical Evolution Constraints
    Abstract

    We combine new spectroscopic observations of the ultrafaint dwarf (UFD) galaxy Bootes I (Boo I) from the Southern Stellar Stream Spectroscopic Survey (S⁵) with 15 yr of archival spectroscopic data to create the largest sample of stellar kinematics and metallicities to date for any Milky Way UFD. Our combined sample includes 148 members extending out to 7 half-light radii (r_h), including 24 newly confirmed members, 18 binary candidates, 15 RR Lyrae stars, and 92 [Fe/H] measurements. Using this larger and more spatially extended sample, we provide updated constraints on Boo I's systemic properties, including its radial population gradients. Properly accounting for perspective rotation effects in a UFD for the first time, we detect a 4 line-of-sight velocity gradient of 1.2 0.3 km s¹ rh1 aligned along Boo I's orbit and discuss its potential tidal origins. We also infer a metallicity gradient of 0.10 0.02 dex rh1 in agreement with previous studies. Using an axisymmetric Jeans model, we provide updated constraints on Boo I's dark matter density profile, which weakly favors a cusped ( =1.00.6+0.5 ) dark matter profile. Lastly, we reanalyze Boo I's metallicity distribution function with a one-zone galactic chemical evolution model and place new constraints on its rapid, inefficient star formation and strong galactic outflows.

22. Webber, K., Hansen, T., Marshall, J., Ji, A., Li, T., Da Costa, G., Cullinane, L., Erkal, D., Koposov, S., Kuehn, K., Lewis, G., Mackey, D., Martell, S., Pace, A., Shipp, N., Simpson, J., Wan, Z., Zucker, D., Alvarado, V., Bland-Hawthorn, J., Limberg, G., Medina, G., Usman, S., 2026, ApJ, 998, 114, Detailed Chemical Abundance Analysis of the Brightest Stars in the Turranburra and Willka Yaku Stellar Streams
    Abstract

    We present a detailed chemical abundance analysis of the three brightest known stars from each of the Turranburra and Willka Yaku stellar streams using high-resolution Magellan/Magellan Inamori Kyocera Echelle spectra. Abundances for 27 elements, ranging from carbon to dysprosium, were derived. Our results support the original classification that Turranburra, with a low average metallicity of [Fe/H] = 2.45 0.07, likely originates from a dwarf galaxy progenitor. Willka Yaku has a low average metallicity of [Fe/H] = 2.35 0.03 with a small scatter in the abundances, consistent with a globular cluster progenitor as suggested by previous studies. Both streams exhibit mild enhancements in neutron-capture elements, with averages of [Eu II/Fe] = 0.47 0.09 for Turranburra and 0.44 0.05 for Willka Yaku, consistent with enrichment from an r-process event. A similar enrichment is observed in other stellar streams, and we further discuss this signature as it relates to the potential enrichment histories of these two streams. *This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

23. Bechtol, K., Sevilla-Noarbe, I., Drlica-Wagner, A., Yanny, B., Gruendl, R., Sheldon, E., Rykoff, E., De Vicente, J., Adamow, M., Anbajagane, D., Becker, M., Bernstein, G., Carnero Rosell, A., Gschwend, J., Gorsuch, M., Hartley, W., Jarvis, M., Jeltema, T., Kron, R., Manning, T., O'Donnell, J., Pieres, A., Rodriguez-Monroy, M., Sanchez Cid, D., Tabbutt, M., Tan, C., Toribio San Cipriano, L., Tucker, D., Weaverdyck, N., Yamamoto, M., Abbott, T., Aguena, M., Alarcon, A., Allam, S., Amon, A., Andrade-Oliveira, F., Avila, S., Bernardinelli, P., Bertin, E., Blazek, J., Brooks, D., Burke, D., Carretero, J., Castander, F., Cawthon, R., Chang, C., Choi, A., Conselice, C., Costanzi, M., Crocce, M., da Costa, L., Davis, T., Desai, S., Diehl, H., Dodelson, S., Doel, P., Doux, C., Ferte, A., Flaugher, B., Fosalba, P., Frieman, J., Garcia-Bellido, J., Gatti, M., Gaztanaga, E., Giannini, G., Gruen, D., Gutierrez, G., Herner, K., Hinton, S., Hollowood, D., Honscheid, K., Huterer, D., Jeffrey, N., Krause, E., Kuehn, K., Lahav, O., Lee, S., Lidman, C., Lima, M., Lin, H., Marshall, J., Mena-Fernandez, J., Miquel, R., Mohr, J., Muir, J., Myles, J., Ogando, R., Palmese, A., Plazas Malagon, A., Porredon, A., Prat, J., Raveri, M., Romer, A., Roodman, A., Samuroff, S., Sanchez, E., Scarpine, V., Smith, M., Soares-Santos, M., Suchyta, E., Tarle, G., Troxel, M., Vikram, V., Walker, A., Weller, J., Wiseman, P., Zhang, Y., DES Collaboration, 2026, ApJS, 282, 62, Dark Energy Survey Year 6 Results: Photometric Dataset for Cosmology
    Abstract

    We describe the photometric dataset assembled from the full 6 yr of observations by the Dark Energy Survey (DES) in support of static-sky cosmology analyses. DES Y6 Gold is a curated dataset derived from DES Data Release 2 (DR2) that incorporates improved measurement, photometric calibration, object classification and value-added information. Y6 Gold comprises nearly 5000 deg² of grizY imaging in the south Galactic cap and includes 669 million objects with a depth of i_AB 23.4 mag at a signal-to-noise ratio 10 for extended objects and a top-of-the-atmosphere photometric uniformity <2 mmag. Y6 Gold augments DES DR2 with simultaneous fits to multiepoch photometry for more robust galaxy shapes, colors, and photometric redshift estimates. Y6 Gold features improved morphological stargalaxy classification with an efficiency of 98.6% and a contamination of 0.8% for galaxies with 17.5 < i_AB < 22.5. Additionally, it includes per-object quality information, and accompanying maps of the footprint coverage, masked regions, imaging depth, survey conditions, and astrophysical foregrounds that are used for cosmology analyses. After quality selections, benchmark samples contain 448 million galaxies and 120 million stars. This publication is complemented by data access and documentation.

24. Hang, Q., Jeffrey, N., Whiteway, L., Lahav, O., Williamson, J., Gatti, M., DeRose, J., Kovacs, A., Alarcon, A., Amon, A., Bechtol, K., Becker, M., Bernstein, G., Campos, A., Rosell, A., Kind, M., Chang, C., Chen, R., Choi, A., Dodelson, S., Doux, C., Drlica-Wagner, A., Elvin-Poole, J., Everett, S., Ferte, A., Gruen, D., Gruendl, R., Harrison, I., Jarvis, M., MacCrann, N., McCullough, J., Myles, J., Navarro-Alsina, A., Pandey, S., Prat, J., Raveri, M., Rollins, R., Rykoff, E., Sanchez, C., Secco, L., Sevilla-Noarbe, I., Sheldon, E., Shin, T., Troxel, M., Tutusaus, I., Wechsler, R., Yanny, B., Yin, B., Aguena, M., Alves, O., Andrade-Oliveira, F., Bacon, D., Blazek, J., Bocquet, S., Brooks, D., Carretero, J., Cawthon, R., Crocce, M., da Costa, L., Pereira, M., Davis, T., Desai, S., Diehl, H., Doel, P., Flaugher, B., Frieman, J., Gutierrez, G., Hinton, S., Hollowood, D., Honscheid, K., Kuehn, K., Lee, S., Marshall, J., Mena-Fernandez, J., Miquel, R., Malagon, A., Porredon, A., Roodman, A., Samuroff, S., Sanchez, E., Cid, D., Smith, M., Suchyta, E., Swanson, M., To, C., Vikram, V., 2026, MNRAS, 546, stag006, Biasing from galaxy trough and peak profiles with the DES Y3 redMaGiC galaxies and the weak lensing mass map
    Abstract

    We measure the correspondence between the distribution of galaxies and matter around troughs and peaks in the projected galaxy density, by comparing redMaGiC galaxies ($0.15< z<0.65$) to weak lensing mass maps from the Dark Energy Survey (DES) Y3 data release. We obtain stacked profiles, as a function of angle $\theta$, of the galaxy density contrast $\delta _{\rm g}$ and the weak lensing convergence $\kappa$, in the vicinity of these identified troughs and peaks, referred to as 'void' and 'cluster' superstructures. The ratio of the profiles depend mildly on $\theta$, indicating good consistency between the profile shapes. We model the amplitude of this ratio using a function $F(\boldsymbol{\eta }, \theta)$ that depends on cosmological parameters $\boldsymbol{\eta }$, scaled by the galaxy bias. We construct templates of $F(\boldsymbol{\eta }, \theta)$ using a suite of N-body (Gower Street) simulations forward-modelled with DES Y3-like noise and systematics. We discuss and quantify the caveats of using a linear bias model to create galaxy maps from the simulation dark matter shells. We measure the galaxy bias in three lens tomographic bins (near to far): $2.32^{+0.86}_{-0.27}, 2.18^{+0.86}_{-0.23}, 1.86^{+0.82}_{-0.23}$ for voids, and $2.46^{+0.73}_{-0.27}, 3.55^{+0.96}_{-0.55}, 4.27^{+0.36}_{-1.14}$ for clusters, assuming the best-fitting Planck cosmology. Similar values with $\sim 0.1\sigma$ shifts are obtained assuming the mean DES Y3 cosmology. The biases from troughs and peaks are broadly consistent, although a larger bias is derived for peaks, which is also larger than those measured from the DES Y3 $3\times 2$-point analysis. This method shows an interesting avenue for measuring field-level bias that can be applied to future lensing surveys.

25. Elmegreen, B., Hunter, D., Corbelli, E., 2026, ApJ, 997, 235, Pressure and Star Formation in LITTLE THINGS Dwarf Irregular Galaxies
    Abstract

    The surface densities of star formation, _SFR, in 24 dwarf irregular (dIrr) galaxies from the LITTLE THINGS survey are combined with gas surface densities and midplane pressures to examine the correlations found previously for spiral galaxies. The pressure is the weight of the disk inside the gas layer, including gas, stars, and dark matter, which usually dominates disk gravity in dIrrs. We compare the results to the outer part of M33, which has similar local properties but a slightly higher metallicity, enabling the detection of CO. All the data are convolved to the H I beam, but to study the effects of resolution, the galaxies are examined first with average radial profiles, and then with maps having 1 . 5 pixels and 244 pc pixels. The correlations are found to be independent of resolution from 24 to 424 pc. The average ratio of molecular to atomic surface density is estimated to be 0.23 0.1, from the H₂ surface density in M33 compared to the H I surface density at the same _SFR in the dIrrs. With this ratio, the average star formation rate per molecule is about the same for all the dIrrs, and a factor of 2 less than the rate in M33. The pressure in dIrrs is so low that CO is essentially a dense gas tracer, with the same surface density threshold at the low metallicities of dIrrs as HCN has in spiral galaxies. As a result, CO regions in dIrrs should be strongly self-gravitating.

26. Farrah, D., Ejercito, K., Efstathiou, A., Leisawitz, D., Engholm, A., Shivaei, I., Bonato, M., Clements, D., Petty, S., Pitchford, L., Varnava, C., Afonso, J., Gruppioni, C., Hatziminaoglou, E., Hoffman, A., Lacy, M., Matthews, B., Nixon, C., Pearson, C., Ricketti, B., Rigopoulou, D., Robinson, L., Spencer, L., Wang, L., Sanders, D., van Belle, G., 2026, ApJ, 997, 150, How Accurately Can Obscured Galaxy Luminosities Be Measured Using Spectral Energy Distribution Fitting of Near- through Far-infrared Observations?
    Abstract

    Infrared-luminous galaxies are important sites of stellar and black hole mass assembly at most redshifts. Their luminosities are often estimated by fitting spectral energy distribution (SED) models to near- to far-infrared data, but the dependence of these estimates on the data used is not well understood. Here, using observations simulated from a well-studied local sample, we compare the effects of wavelength coverage, signal-to-noise ratio, flux calibration, angular resolution, and redshift on the recovery of starburst, active galactic nucleus (AGN), and host luminosities. We show that the most important factors are wavelength coverage that spans the peak in a SED, and dense wavelength sampling. Such observations recover starburst and AGN infrared luminosities with systematic bias below 20%. Starburst luminosities are best recovered with far-infrared observations, while AGN luminosities are best recovered with near- and mid-infrared observations, though the recovery of both are enhanced with near/mid-infrared and far-infrared observations, respectively. Host luminosities are best recovered with near/far-infrared observations, but are usually biased low, by 20%. The recovery of starburst and AGN luminosity is enhanced by observing at high angular resolution. Starburst-dominated systems show more biased recovery of luminosities than do AGN-dominated systems. As redshift increases, far-infrared observations become more capable and mid-infrared observations less capable at recovering luminosities. Our results highlight the transformative power of a far-infrared instrument with dense wavelength coverage, from tens to hundreds of microns, for studying infrared-luminous galaxies. We tabulate estimates of systematic bias and random error for use with JWST and other observatories.

27. Zhang, Q., Battams, K., 2026, PASP, 138, 014403, Rapid Brightening of 3I/ATLAS Ahead of Perihelion
    Abstract

    Interstellar comet 3I/ATLAS has been approaching its 2025 October 29 perihelion while opposite the Sun from Earth, hindering ground-based optical observations over the preceding month. However, this geometry placed the comet within the fields of view of several space-based solar coronagraphs and heliospheric imagers, enabling its continued observation during its final approach toward perihelion. We report photometry from STEREO-A's SECCHI HI1 and COR2, SOHO's LASCO C3, and GOES-19's CCOR-1 instruments in 2025 SeptemberOctober, which show a rapid rise in the comet's brightness scaling with heliocentric distance r as r^7.51.0. CCOR-1 also resolves the comet as an extended source with an apparent coma of 4' in diameter. Furthermore, LASCO/CCOR-1 color photometry shows the comet to be distinctly bluer than the Sun, consistent with gas emission contributing a substantial fraction of the visible brightness near perihelion.

28. Micheli, M., Devogele, M., Denneau, L., Ryan, E., Ryan, W., Pravec, P., Hornoch, K., Kucakova, H., Fatka, P., Brucker, M., Lejoly, C., Moskovitz, N., Granvik, M., Gray, Z., Fedorets, G., Djupvik, A., Fuls, C., Rankin, D., Wierzchos, K., Gray, B., Lister, T., Wainscoat, R., Weryk, R., Hainaut, O., Spoto, F., Veres, P., Rivkin, A., Holler, B., Burdanov, A., de Wit, J., Farnocchia, D., Rudawska, R., Alonso Peleato, E., Ocana, F., Tonry, J., Audenaert, J., Faggioli, L., Gianotto, F., Fenucci, M., Conversi, L., Moissl, R., 2026, JAnSc, 73, 8, Astrometric Follow-up of Near-Earth Asteroid 2024 YR₄ During a Torino Scale Level 3 Alert
    Abstract

    The discovery of 2024 YR₄ presented the planetary defense community with the most significant impact threat in almost two decades, reaching level 3 on the Torino scale. The community, now mature and well-organized, responded with a global observational effort. Astrometric measurements, forming the basis for orbital refinement and impact prediction, were a central component of this response. In this paper, we present the astrometric data collected by the international community, from the time of discovery until the object became too faint for all existing observational assets, including JWST. We also discuss the coordination role played by the International Asteroid Warning Network, and the importance of publicly available image archives to enable precovery searches.

29. Hsieh, H., Usher, H., Lister, T., Chandler, C., Frissell, M., Thirouin, A., Sheppard, S., Micheli, M., Kelley, M., Holt, C., Gomez, E., Chatelain, J., Greenstreet, S., 2026, RNAAS, 10, 1, Early Observations of New Active Asteroid 2025 VZ₈
    Abstract

    We report observations of main-belt asteroid 2025 VZ₈ using multiple telescopes from UT 2025 November 24 to UT 2025 December 23 that confirm the presence of visible comet-like activity. These observations were motivated by online reports that an abrupt brightening event may have led to the object's discovery on UT 2025 November 9. In all observations reported here, the object displays a tapered tail approximately 3 long aligned with the antisolar direction. The object has an asteroidal Tisserand parameter value with respect to Jupiter (T_J = 3.371), and is thus considered an active asteroid. We measure an average apparent r' -band magnitude of m_r 21.6 mag over the reported observing period. Due to the sudden appearance of activity far from perihelion, we suggest that the activity is more likely due to an impact or rotational destabilization, rather than sublimation.

30. Prat, J., Gatti, M., Doux, C., Pranav, P., Chang, C., Jeffrey, N., Whiteway, L., Anbajagane, D., Sugiyama, S., Thomsen, A., Alarcon, A., Amon, A., Bechtol, K., Bernstein, G., Campos, A., Chen, R., Choi, A., Davis, C., DeRose, J., Dodelson, S., Eckert, K., Elvin-Poole, J., Everett, S., Ferte, A., Gruen, D., Huff, E., Harrison, I., Herner, K., Jarvis, M., Kuropatkin, N., Leget, P., MacCrann, N., McCullough, J., Myles, J., Navarro-Alsina, A., Pandey, S., Raveri, M., Rollins, R., Roodman, A., Sanchez, C., Secco, L., Sheldon, E., Shin, T., Troxel, M., Tutusaus, I., Varga, T., Yanny, B., Yin, B., Zhang, Y., Zuntz, J., Abbott, T., Aguena, M., Allam, S., Andrade-Oliveira, F., Blazek, J., Bocquet, S., Brooks, D., Carretero, J., Carnero Rosell, A., Cawthon, R., De Vicente, J., Desai, S., da Silva Pereira, M., Diehl, H., Flaugher, B., Frieman, J., Garcia-Bellido, J., Gruendl, R., Gutierrez, G., Hinton, S., Hollowood, D., Honscheid, K., James, D., Kuehn, K., da Costa, L., Lahav, O., Lee, S., Marshall, J., Mena-Fernandez, J., Miquel, R., Mohr, J., Ogando, R., Plazas Malagon, A., Porredon, A., Samuroff, S., Sanchez, E., Santiago, B., Sevilla-Noarbe, I., Smith, M., Suchyta, E., Swanson, M., Thomas, D., To, C., Vikram, V., Walker, A., Weaverdyck, N., Weller, J., 2026, MNRAS, 545, staf2152, Dark Energy Survey Year 3 results: wCDM cosmology from simulation-based inference with persistent homology on the sphere
    Abstract

    We present cosmological constraints from Dark Energy Survey Year 3 (DES Y3) weak lensing data using persistent homology, a topological data analysis technique that tracks how features like clusters and voids evolve across density thresholds. For the first time, we apply spherical persistent homology to galaxy survey data through the algorithm TOPOS2, which is optimized for curved-sky analyses and HEALPIX compatibility. Employing a simulation-based inference framework with the Gower Street simulation suite specifically designed to mimic DES Y3 data properties we extract topological summary statistics from convergence maps across multiple smoothing scales and redshift bins. After neural network compression of these statistics, we estimate the likelihood function and validate our analysis against baryonic feedback effects, finding minimal biases (under $0.3\sigma$) in the $\Omega _\mathrm{m}-S_8$ plane. Assuming the wCold Dark Matter model, our combined Betti numbers and second moments analysis yields $S_8 = 0.821 \pm 0.018$ and $\Omega _\mathrm{m} = 0.304\pm 0.037$ constraints 70 per cent tighter than those from cosmic shear two-point statistics in the same parameter plane. Our results demonstrate that topological methods provide a powerful and robust framework for extracting cosmological information, with our spherical methodology readily applicable to upcoming Stage IV wide-field galaxy surveys.

30 publications and 155 citations in 2026.

30 publications and 155 citations total.