Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae4ec2
Thomas A. Schad, Paul Bryans, André Fehlmann, Sarah Gibson, David M. Harrington, Lucas A. Tarr, Steven Tomczyk and Jeffrey G. Yepez
Atmospheric aerosols strongly influence daytime sky quality for solar coronal imaging, yet few studies directly link aerosol properties and sky brightness measurements within ∼2° of the Sun. Here, we compare externally occulted coronagraphic measurements of near-Sun radiance with aerosol-constrained inferences derived from direct-Sun and sky photometry. Our analysis focuses on Mauna Loa Observatory, a well-characterized high-altitude site for atmospheric and solar observations. We present coronagraphic measurements of near-Sun radiance at 1 54 ± 0 77 from the solar disk center acquired between 2006 and 2007 by an ATST sky brightness monitor (SBM). These data are directly compared with circumsolar radiances inferred at 1 54 using Aerosol Robotic Network (AERONET) almucantar measurements and aerosol optical retrievals. We find quantitative agreement between these two approaches, enabling extension to multidecadal analyses of circumsolar radiance and its relationship to aerosol properties and related proxies (e.g., the Ångström exponent) using AERONET data from 2000 to 2025. Near-Sun radiances are expressed relative to the solar disk-center radiance, facilitating direct comparison to related studies. Finally, we synthesize physically based true-color images of the circumsolar sky under representative aerosol conditions as an observational aid, in part to illustrate that visually enhanced solar aureoles do not necessarily imply poor infrared coronal observing conditions. This methodology provides an extended framework for assessing daytime coronal sky quality at existing and future observing sites, including DKIST and the proposed Coronal Solar Magnetism Observatory facility.
{"title":"Joint Diagnostics of Circumsolar Sky Brightness Using Coronagraphic Measurements and Aerosol Optical Inversions at Maunaloa","authors":"Thomas A. Schad, Paul Bryans, André Fehlmann, Sarah Gibson, David M. Harrington, Lucas A. Tarr, Steven Tomczyk and Jeffrey G. Yepez","doi":"10.3847/1538-4357/ae4ec2","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4ec2","url":null,"abstract":"Atmospheric aerosols strongly influence daytime sky quality for solar coronal imaging, yet few studies directly link aerosol properties and sky brightness measurements within ∼2° of the Sun. Here, we compare externally occulted coronagraphic measurements of near-Sun radiance with aerosol-constrained inferences derived from direct-Sun and sky photometry. Our analysis focuses on Mauna Loa Observatory, a well-characterized high-altitude site for atmospheric and solar observations. We present coronagraphic measurements of near-Sun radiance at 1 54 ± 0 77 from the solar disk center acquired between 2006 and 2007 by an ATST sky brightness monitor (SBM). These data are directly compared with circumsolar radiances inferred at 1 54 using Aerosol Robotic Network (AERONET) almucantar measurements and aerosol optical retrievals. We find quantitative agreement between these two approaches, enabling extension to multidecadal analyses of circumsolar radiance and its relationship to aerosol properties and related proxies (e.g., the Ångström exponent) using AERONET data from 2000 to 2025. Near-Sun radiances are expressed relative to the solar disk-center radiance, facilitating direct comparison to related studies. Finally, we synthesize physically based true-color images of the circumsolar sky under representative aerosol conditions as an observational aid, in part to illustrate that visually enhanced solar aureoles do not necessarily imply poor infrared coronal observing conditions. This methodology provides an extended framework for assessing daytime coronal sky quality at existing and future observing sites, including DKIST and the proposed Coronal Solar Magnetism Observatory facility.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae486d
P. A. R. Ade, Z. Ahmed, M. Amiri, D. Barkats, R. Basu Thakur, C. A. Bischoff, D. Beck, J. J. Bock, H. Boenish, V. Buza, K. Carter, J. R. Cheshire, J. Connors, J. Cornelison, L. Corrigan, M. Crumrine, S. Crystian, A. J. Cukierman, E. Denison, L. Duband, M. Echter, M. Eiben, B. D. Elwood, S. Fatigoni, J. P. Filippini, A. Fortes, M. Gao, C. Giannakopoulos, N. Goeckner-Wald, D. C. Goldfinger, J. A. Grayson, A. Greathouse, P. K. Grimes, G. Hall, G. Halal, M. Halpern, E. Hand, S. A. Harrison, S. Henderson, J. Hubmayr, H. Hui, K. D. Irwin, J. H. Kang, K. S. Karkare, S. Kefeli, J. M. Kovac, C. Kuo, K. Lau, M. Lautzenhiser, A. Lennox, T. Liu, K. G. Megerian, M. Miller, L. Minutolo, L. Moncelsi, Y. Nakato, H. T. Nguyen, R. O’Brient, S. Paine, A. Patel, M. A. Petroff, A. R. Polish, T. Prouve, C. Pryke, C. D. Reintsema, T. Romand, D. Santalucia, A. Schillaci, B. Schmitt, E. Sheffield, B. Singari, K. Sjoberg, A. Soliman, T. St Germaine, A. Steiger, B. Steinbach, R. Sudiwala, K. L. Thompso..
Millimeter-wave refracting telescopes targeting the degree-scale structure of the cosmic microwave background (CMB) have recently grown to diffraction-limited apertures of over 0.5 m. These instruments are entirely housed in vacuum cryostats to support their subkelvin bolometric detectors and to minimize radiative loading from thermal emission due to absorption loss in their transmissive optical elements. The large vacuum window is the only optical element in the system at ambient temperature, and therefore minimizing loss in the window is crucial for maximizing detector sensitivity. This motivates the use of low-loss polymer materials and a window as thin as practicable. However, the window must simultaneously meet the requirement to keep a sufficient vacuum, and therefore must limit gas permeation and remain mechanically robust against catastrophic failure under pressure. We report on the development of extremely thin composite polyethylene window technology that meets these goals. Two windows have been deployed for two full observing seasons on the BICEP3 and the 150 GHz BICEP Array receiver CMB telescopes at the South Pole. On BICEP3, the window has demonstrated a 6% improvement in detector sensitivity.
{"title":"BICEP/Keck. XIX. Extremely Thin Composite Polymer Vacuum Windows for BICEP and Other High-throughput Millimeter-wave Telescopes","authors":"P. A. R. Ade, Z. Ahmed, M. Amiri, D. Barkats, R. Basu Thakur, C. A. Bischoff, D. Beck, J. J. Bock, H. Boenish, V. Buza, K. Carter, J. R. Cheshire, J. Connors, J. Cornelison, L. Corrigan, M. Crumrine, S. Crystian, A. J. Cukierman, E. Denison, L. Duband, M. Echter, M. Eiben, B. D. Elwood, S. Fatigoni, J. P. Filippini, A. Fortes, M. Gao, C. Giannakopoulos, N. Goeckner-Wald, D. C. Goldfinger, J. A. Grayson, A. Greathouse, P. K. Grimes, G. Hall, G. Halal, M. Halpern, E. Hand, S. A. Harrison, S. Henderson, J. Hubmayr, H. Hui, K. D. Irwin, J. H. Kang, K. S. Karkare, S. Kefeli, J. M. Kovac, C. Kuo, K. Lau, M. Lautzenhiser, A. Lennox, T. Liu, K. G. Megerian, M. Miller, L. Minutolo, L. Moncelsi, Y. Nakato, H. T. Nguyen, R. O’Brient, S. Paine, A. Patel, M. A. Petroff, A. R. Polish, T. Prouve, C. Pryke, C. D. Reintsema, T. Romand, D. Santalucia, A. Schillaci, B. Schmitt, E. Sheffield, B. Singari, K. Sjoberg, A. Soliman, T. St Germaine, A. Steiger, B. Steinbach, R. Sudiwala, K. L. Thompso..","doi":"10.3847/1538-4357/ae486d","DOIUrl":"https://doi.org/10.3847/1538-4357/ae486d","url":null,"abstract":"Millimeter-wave refracting telescopes targeting the degree-scale structure of the cosmic microwave background (CMB) have recently grown to diffraction-limited apertures of over 0.5 m. These instruments are entirely housed in vacuum cryostats to support their subkelvin bolometric detectors and to minimize radiative loading from thermal emission due to absorption loss in their transmissive optical elements. The large vacuum window is the only optical element in the system at ambient temperature, and therefore minimizing loss in the window is crucial for maximizing detector sensitivity. This motivates the use of low-loss polymer materials and a window as thin as practicable. However, the window must simultaneously meet the requirement to keep a sufficient vacuum, and therefore must limit gas permeation and remain mechanically robust against catastrophic failure under pressure. We report on the development of extremely thin composite polyethylene window technology that meets these goals. Two windows have been deployed for two full observing seasons on the BICEP3 and the 150 GHz BICEP Array receiver CMB telescopes at the South Pole. On BICEP3, the window has demonstrated a 6% improvement in detector sensitivity.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae4961
John Groger, Frits Paerels, Slavko Bogdanov, Eric V. Gotthelf, David J. Helfand, Ivan Hubeny, Thierry Lanz and Thomas A. Gomez
We present evidence for atomic absorption lines in the high-resolution 4–30 Å X-ray spectrum of the neutron star RX J0822−4300 in the supernova remnant Puppis A. A comparison with model atmosphere calculations shows that features in the observed spectrum can be uniquely associated with redshifted and pressure-broadened transitions in highly ionized oxygen and neon. We also spectroscopically confirm the previously estimated strength of the surface magnetic dipole field; we detect both the linear and the quadratic Zeeman effect. We derive values for both the gravitational redshift and the acceleration of gravity at the stellar surface, yielding the first purely spectroscopic estimates for the radius and mass of a neutron star.
我们在超新星遗迹Puppis A的中子星RX J0822−4300的高分辨率4-30 Å x射线光谱中提供了原子吸收谱线的证据。与模式大气计算的比较表明，观测到的光谱特征与高电离氧和氖的红移和压加宽跃迁有独特的联系。我们还从光谱上证实了先前估计的表面磁偶极子场的强度；我们检测了线性和二次塞曼效应。我们推导出了恒星表面的引力红移和重力加速度的值，从而得出了中子星半径和质量的第一个纯光谱估计。
{"title":"Evidence for Atomic Absorption Features in the High-resolution X-Ray Spectrum of the Neutron Star in Puppis A","authors":"John Groger, Frits Paerels, Slavko Bogdanov, Eric V. Gotthelf, David J. Helfand, Ivan Hubeny, Thierry Lanz and Thomas A. Gomez","doi":"10.3847/1538-4357/ae4961","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4961","url":null,"abstract":"We present evidence for atomic absorption lines in the high-resolution 4–30 Å X-ray spectrum of the neutron star RX J0822−4300 in the supernova remnant Puppis A. A comparison with model atmosphere calculations shows that features in the observed spectrum can be uniquely associated with redshifted and pressure-broadened transitions in highly ionized oxygen and neon. We also spectroscopically confirm the previously estimated strength of the surface magnetic dipole field; we detect both the linear and the quadratic Zeeman effect. We derive values for both the gravitational redshift and the acceleration of gravity at the stellar surface, yielding the first purely spectroscopic estimates for the radius and mass of a neutron star.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae4c53
Liam O. Dubay, Jennifer A. Johnson, James W. Johnson and John D. Roberts
Stars in the Milky Way disk exhibit a clear separation into two chemically distinct populations based on their [α/Fe] ratios. This α-bimodality is not a universal feature of simulated disk galaxies and may point to a unique evolutionary history. A popular and well-studied explanation is the two-infall scenario, which postulates that two periods of substantial accretion rates dominate the assembly history of the Galaxy. Thanks to recent advances in stellar age measurements, we can now compare this model to more direct measurements of the Galaxy’s evolutionary timescales across the disk. We run multizone galactic chemical evolution models with a two-infall-driven star formation history and compare the results against abundance patterns from APOGEE DR17, supplemented with stellar ages estimated through multiple methods. Although the two-infall scenario offers a natural explanation for the α-bimodality, it struggles to explain several features of the age–abundance structure in the disk. First, our models generically require a massive and long-lasting dilution event, but the data show that stellar metallicity is remarkably constant across much of the lifetime of the disk. This apparent age-independence places considerable restrictions upon the two-infall parameter space. Second, most local metal-rich stars in APOGEE have intermediate ages, yet our models predict these stars should either be very old or very young. Some of these issues can be mitigated, but not completely resolved, by pre-enriching the accreted gas to low metallicity. These restrictions also place limits on the role of merger events in shaping the chemical evolution of the thin disk.
{"title":"Challenges to the Two-infall Scenario by Large Stellar Age Catalogs","authors":"Liam O. Dubay, Jennifer A. Johnson, James W. Johnson and John D. Roberts","doi":"10.3847/1538-4357/ae4c53","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4c53","url":null,"abstract":"Stars in the Milky Way disk exhibit a clear separation into two chemically distinct populations based on their [α/Fe] ratios. This α-bimodality is not a universal feature of simulated disk galaxies and may point to a unique evolutionary history. A popular and well-studied explanation is the two-infall scenario, which postulates that two periods of substantial accretion rates dominate the assembly history of the Galaxy. Thanks to recent advances in stellar age measurements, we can now compare this model to more direct measurements of the Galaxy’s evolutionary timescales across the disk. We run multizone galactic chemical evolution models with a two-infall-driven star formation history and compare the results against abundance patterns from APOGEE DR17, supplemented with stellar ages estimated through multiple methods. Although the two-infall scenario offers a natural explanation for the α-bimodality, it struggles to explain several features of the age–abundance structure in the disk. First, our models generically require a massive and long-lasting dilution event, but the data show that stellar metallicity is remarkably constant across much of the lifetime of the disk. This apparent age-independence places considerable restrictions upon the two-infall parameter space. Second, most local metal-rich stars in APOGEE have intermediate ages, yet our models predict these stars should either be very old or very young. Some of these issues can be mitigated, but not completely resolved, by pre-enriching the accreted gas to low metallicity. These restrictions also place limits on the role of merger events in shaping the chemical evolution of the thin disk.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae4ecd
Shinyu Kim, Minjin Kim, Suyeon Son and Luis C. Ho
We assess the systematics and efficiency of an active galactic nucleus (AGN) selection method based on mid-infrared (MIR) variability. To this end, we utilize various types of active and inactive galaxies from the Sloan Digital Sky Survey, matching them with multiepoch photometric data from the NEOWISE mission. Using W1 and W2 band light curves with a ∼10 yr baseline, we find that combining the likelihood of deviation from nonvariability with the correlation coefficient between the W1 and W2 bands reliably identifies AGNs. Specifically, this MIR-based method recovers ∼28.2% of optically selected AGNs. Applying the same technique to inactive galaxies, we identify AGN candidates at fractions ranging from 0.4% to 11.8%, indicating that MIR variability allows us to detect AGN candidates even in optically inactive hosts. While some variable sources exhibit transient-like light curves, possibly originating from tidal disruption events or supernovae, their contribution to the total variable population is less than a few percent, indicating a minimal impact on our results. Across all subsamples, the AGN fraction marginally increases with star formation activity, implying coordinated evolution between central black hole growth and star formation. Finally, the AGN fraction inferred from our method drops dramatically in classical LINERs, consistent with their low accretion rates and absence of a dusty torus.
{"title":"Mid-infrared Variability-based Active Galactic Nucleus Selection Using the Multiepoch Photometric Data from WISE","authors":"Shinyu Kim, Minjin Kim, Suyeon Son and Luis C. Ho","doi":"10.3847/1538-4357/ae4ecd","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4ecd","url":null,"abstract":"We assess the systematics and efficiency of an active galactic nucleus (AGN) selection method based on mid-infrared (MIR) variability. To this end, we utilize various types of active and inactive galaxies from the Sloan Digital Sky Survey, matching them with multiepoch photometric data from the NEOWISE mission. Using W1 and W2 band light curves with a ∼10 yr baseline, we find that combining the likelihood of deviation from nonvariability with the correlation coefficient between the W1 and W2 bands reliably identifies AGNs. Specifically, this MIR-based method recovers ∼28.2% of optically selected AGNs. Applying the same technique to inactive galaxies, we identify AGN candidates at fractions ranging from 0.4% to 11.8%, indicating that MIR variability allows us to detect AGN candidates even in optically inactive hosts. While some variable sources exhibit transient-like light curves, possibly originating from tidal disruption events or supernovae, their contribution to the total variable population is less than a few percent, indicating a minimal impact on our results. Across all subsamples, the AGN fraction marginally increases with star formation activity, implying coordinated evolution between central black hole growth and star formation. Finally, the AGN fraction inferred from our method drops dramatically in classical LINERs, consistent with their low accretion rates and absence of a dusty torus.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae4c39
Keitaro Takahashi
The discovery of many Earth-like planets has renewed interest in whether life and technological civilizations exist elsewhere. The Search for Extraterrestrial Intelligence (SETI) seeks evidence for technological civilizations via technosignatures across the electromagnetic spectrum. Here, focusing on artificial radio emissions with extremely narrowband signals, we model Earth as a distant, unresolved source and simulate its narrowband transmissions as observed with current and forthcoming radio facilities. Planetary rotation induces small but coherent Doppler drifts (maximum fractional shift of order 10−6) that imprint a characteristic, time-varying pattern on the spectrum. We develop a forward-inverse framework that exploits this modulation: adopting a population-weighted model for terrestrial transmitters, we compute time-resolved spectra and then apply a new inversion method that reconstructs the underlying transmitter distribution from the temporal pattern of fractional frequency offsets. In noise-added tests, the method recovers the low-order spherical-harmonic structure of the map and retrieves major population centers despite the north–south degeneracy of unresolved observations. The recovered distribution is expected to correlate with continents, climate zones, and population density. This approach moves SETI beyond mere detection, enabling quantitative cartography of a civilization’s activity and inference of host-planet properties through sustained, time-resolved spectroscopy.
{"title":"Rotational Doppler Cartography of Technosignatures on Unresolved Planets","authors":"Keitaro Takahashi","doi":"10.3847/1538-4357/ae4c39","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4c39","url":null,"abstract":"The discovery of many Earth-like planets has renewed interest in whether life and technological civilizations exist elsewhere. The Search for Extraterrestrial Intelligence (SETI) seeks evidence for technological civilizations via technosignatures across the electromagnetic spectrum. Here, focusing on artificial radio emissions with extremely narrowband signals, we model Earth as a distant, unresolved source and simulate its narrowband transmissions as observed with current and forthcoming radio facilities. Planetary rotation induces small but coherent Doppler drifts (maximum fractional shift of order 10−6) that imprint a characteristic, time-varying pattern on the spectrum. We develop a forward-inverse framework that exploits this modulation: adopting a population-weighted model for terrestrial transmitters, we compute time-resolved spectra and then apply a new inversion method that reconstructs the underlying transmitter distribution from the temporal pattern of fractional frequency offsets. In noise-added tests, the method recovers the low-order spherical-harmonic structure of the map and retrieves major population centers despite the north–south degeneracy of unresolved observations. The recovered distribution is expected to correlate with continents, climate zones, and population density. This approach moves SETI beyond mere detection, enabling quantitative cartography of a civilization’s activity and inference of host-planet properties through sustained, time-resolved spectroscopy.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae4d37
T. Cabrera, A. Palmese and M. Fishbach
While the LIGO/Virgo/KAGRA (LVK) gravitational-wave (GW) detectors have detected over 300 binary black hole (BBH) mergers to date, the first confirmation of an electromagnetic (EM) counterpart to such an event remains elusive. Previous works have performed searches for counterpart candidates in transient catalogs and have identified active galactic nucleus (AGN) flares coincident with GW events; existing theory predicts that such flares may arise from the interaction of the merger remnant with the embedding accretion disk environment. We apply a statistical formalism to measure the significance of coincidence for the catalog as a whole, measuring that less than 3% (90% credible interval) of LVK BBH mergers give rise to observable AGN flares. This result still allows up to ∼40% of BBH mergers to originate in AGN disks. We also examine the individual coincidences of each merger–flare pairing, determining that in all cases the flares are more likely to belong to a background population of flares not associated with GW events. Our results are consistent with theoretical predictions accounting for the observability of EM counterparts in AGN disks, as well as based on the fact that the most massive/luminous AGNs (such as those included in the search) are not expected to harbor the majority of the BBHs. We emphasize that developing both the means to distinguish BBH counterpart flares from background AGN flares and an understanding of which BBHs are most likely to produce AGN flares as counterparts is critical to optimizing the use of follow-up resources.
{"title":"Multimessenger Constraints on LIGO/Virgo/KAGRA Gravitational-wave Binary Black Holes Merging in Active Galactic Nucleus Disks","authors":"T. Cabrera, A. Palmese and M. Fishbach","doi":"10.3847/1538-4357/ae4d37","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4d37","url":null,"abstract":"While the LIGO/Virgo/KAGRA (LVK) gravitational-wave (GW) detectors have detected over 300 binary black hole (BBH) mergers to date, the first confirmation of an electromagnetic (EM) counterpart to such an event remains elusive. Previous works have performed searches for counterpart candidates in transient catalogs and have identified active galactic nucleus (AGN) flares coincident with GW events; existing theory predicts that such flares may arise from the interaction of the merger remnant with the embedding accretion disk environment. We apply a statistical formalism to measure the significance of coincidence for the catalog as a whole, measuring that less than 3% (90% credible interval) of LVK BBH mergers give rise to observable AGN flares. This result still allows up to ∼40% of BBH mergers to originate in AGN disks. We also examine the individual coincidences of each merger–flare pairing, determining that in all cases the flares are more likely to belong to a background population of flares not associated with GW events. Our results are consistent with theoretical predictions accounting for the observability of EM counterparts in AGN disks, as well as based on the fact that the most massive/luminous AGNs (such as those included in the search) are not expected to harbor the majority of the BBHs. We emphasize that developing both the means to distinguish BBH counterpart flares from background AGN flares and an understanding of which BBHs are most likely to produce AGN flares as counterparts is critical to optimizing the use of follow-up resources.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae4ebb
Min Bao, Zhenyu Tang, Yanmei Chen, Yong Shi and Qiusheng Gu
The gas accretion process can fuel both star formation and black hole activity, playing a critical role in galaxy evolution. The counter-rotating structures are believed to originate from gas accretion, serving as an ideal laboratory to study its impact on galaxy evolution. Based on the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we built a sample of 147 galaxies with counter-rotating stellar disks (CRDs). This is the largest CRD sample to date, accounting for ∼1.5% of the MaNGA survey. For a subset of 138 CRDs, global stellar mass (M*) and star formation rate (SFR) were measured in reference. We constructed a control sample with similar M* and SFR but lacking counter-rotating structures. The CRDs relatively exhibit more bulge-dominated morphology, lower molecular gas mass fraction, and reside in a less dense environment, supporting the hypothesis that they primarily originate from gas accretion. We classified 96 out of 138 CRDs into four types based on their stellar and gas kinematics following the criteria from M. Bao et al. There are two additional CRD types: eight CRDs show misalignment between both stellar disks and gas disk, indicating multiple gas accretion events with differing angular momentum directions; while 34 CRDs lack ionized gas emission, showing the highest M* among all the CRD types, which may represent a final stage of CRD evolution. We compared the radial gradients of gas-phase metallicity and stellar population properties between CRD types and found that the impact of gas accretion on galaxy evolution primarily depends on the abundance of pre-existing gas in progenitors.
{"title":"Properties of Galaxies with Counter-rotating Stellar Disks in the MaNGA Survey","authors":"Min Bao, Zhenyu Tang, Yanmei Chen, Yong Shi and Qiusheng Gu","doi":"10.3847/1538-4357/ae4ebb","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4ebb","url":null,"abstract":"The gas accretion process can fuel both star formation and black hole activity, playing a critical role in galaxy evolution. The counter-rotating structures are believed to originate from gas accretion, serving as an ideal laboratory to study its impact on galaxy evolution. Based on the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we built a sample of 147 galaxies with counter-rotating stellar disks (CRDs). This is the largest CRD sample to date, accounting for ∼1.5% of the MaNGA survey. For a subset of 138 CRDs, global stellar mass (M*) and star formation rate (SFR) were measured in reference. We constructed a control sample with similar M* and SFR but lacking counter-rotating structures. The CRDs relatively exhibit more bulge-dominated morphology, lower molecular gas mass fraction, and reside in a less dense environment, supporting the hypothesis that they primarily originate from gas accretion. We classified 96 out of 138 CRDs into four types based on their stellar and gas kinematics following the criteria from M. Bao et al. There are two additional CRD types: eight CRDs show misalignment between both stellar disks and gas disk, indicating multiple gas accretion events with differing angular momentum directions; while 34 CRDs lack ionized gas emission, showing the highest M* among all the CRD types, which may represent a final stage of CRD evolution. We compared the radial gradients of gas-phase metallicity and stellar population properties between CRD types and found that the impact of gas accretion on galaxy evolution primarily depends on the abundance of pre-existing gas in progenitors.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"229 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae459e
Patrick S. Kamieneski, Rogier A. Windhorst, Brenda L. Frye, Min S. Yun, Kevin C. Harrington, Simon D. Mork, Nicholas Foo, Nikhil Garuda, Massimo Pascale, Belén Alcalde Pampliega, Timothy Carleton, Seth H. Cohen, Carlos Garcia Diaz, Rolf A. Jansen, Eric F. Jiménez-Andrade, Anton M. Koekemoer, James D. Lowenthal, Allison Noble, Justin D. R. Pierel, Amit Vishwas, Q. Daniel Wang and Ilsang Yoon
More than 60 years have passed since the first formal suggestion to use strongly lensed supernovae (SNe) to measure the expansion rate of the Universe through time-delay cosmography. Yet, fewer than 10 such objects have ever been discovered. We consider the merits of a targeted strategy focused on lensed hyperluminous infrared galaxies, which are among the most rapidly star-forming galaxies known in the Universe. With star formation rates (SFRs) ∼200–6000 M⊙ yr−1, the ∼30 objects in the Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts are excellent candidates for a case study, in particular, and have already led to the discovery of the multiply imaged SN H0pe. Considering their lens model-corrected SFRs, we estimate their intrinsic SN rates to be an extraordinary 1.8–65 yr−1 (core-collapse) and 0.2–6.4 yr−1 (Type Ia). Moreover, these massive starbursts typically have star-forming companions which are unaccounted for in this tally. We demonstrate a strong correlation between Einstein radius and typical time delays, with cluster lenses often exceeding several months (and therefore most favorable for high-precision H0 inferences). A multivisit monitoring campaign with a sensitive infrared telescope (namely, JWST) is necessary to mitigate dust attenuation. Nevertheless, a porous interstellar medium and clumpy star formation in these extreme galaxies might produce favorable conditions for detecting SNe as transient point sources. Targeted campaigns of known lensed galaxies to discover new lensed SNe can greatly complement wide-area cadenced surveys. Increasing the sample size helps to realize the potential of SN time-delay cosmography to elucidate the Hubble tension through a single-step measurement, independent of other H0 techniques.
自从第一次正式建议使用强透镜超新星（SNe）通过时间延迟宇宙学来测量宇宙的膨胀率以来，60多年已经过去了。然而，迄今为止发现的这样的天体还不到10个。我们考虑了聚焦于透镜超发光红外星系的目标策略的优点，这些星系是宇宙中已知的恒星形成最快的星系之一。由于恒星形成速率（SFRs）为~ 200-6000 M⊙yr−1，普朗克全天调查中分析引力透镜极端星暴的~ 30个天体特别适合进行案例研究，并且已经导致发现了多重成像的SN ho0pe。考虑到它们的透镜模型校正的SFRs，我们估计它们的内在SN率为1.8-65 yr - 1（核心坍缩）和0.2-6.4 yr - 1 （Ia型）。此外，这些巨大的恒星爆发通常有恒星形成的伴星，这些伴星在这个统计中是没有解释的。我们证明了爱因斯坦半径和典型的时间延迟之间有很强的相关性，星系团透镜通常超过几个月（因此最有利于高精度的H0推断）。使用灵敏的红外望远镜（即JWST）进行多次监测活动是必要的，以减轻尘埃衰减。然而，在这些极端星系中，多孔的星际介质和块状恒星的形成可能为探测作为瞬态点源的SNe创造有利条件。对已知透镜星系进行有针对性的运动，以发现新的透镜型SNe，可以极大地补充广域有节奏的调查。增加样本量有助于实现SN时间延迟宇宙学的潜力，通过单步测量来阐明哈勃张力，独立于其他H0技术。
{"title":"Forecasting the Observable Rates of Gravitationally Lensed Supernovae for the PASSAGES Dusty Starbursts","authors":"Patrick S. Kamieneski, Rogier A. Windhorst, Brenda L. Frye, Min S. Yun, Kevin C. Harrington, Simon D. Mork, Nicholas Foo, Nikhil Garuda, Massimo Pascale, Belén Alcalde Pampliega, Timothy Carleton, Seth H. Cohen, Carlos Garcia Diaz, Rolf A. Jansen, Eric F. Jiménez-Andrade, Anton M. Koekemoer, James D. Lowenthal, Allison Noble, Justin D. R. Pierel, Amit Vishwas, Q. Daniel Wang and Ilsang Yoon","doi":"10.3847/1538-4357/ae459e","DOIUrl":"https://doi.org/10.3847/1538-4357/ae459e","url":null,"abstract":"More than 60 years have passed since the first formal suggestion to use strongly lensed supernovae (SNe) to measure the expansion rate of the Universe through time-delay cosmography. Yet, fewer than 10 such objects have ever been discovered. We consider the merits of a targeted strategy focused on lensed hyperluminous infrared galaxies, which are among the most rapidly star-forming galaxies known in the Universe. With star formation rates (SFRs) ∼200–6000 M⊙ yr−1, the ∼30 objects in the Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts are excellent candidates for a case study, in particular, and have already led to the discovery of the multiply imaged SN H0pe. Considering their lens model-corrected SFRs, we estimate their intrinsic SN rates to be an extraordinary 1.8–65 yr−1 (core-collapse) and 0.2–6.4 yr−1 (Type Ia). Moreover, these massive starbursts typically have star-forming companions which are unaccounted for in this tally. We demonstrate a strong correlation between Einstein radius and typical time delays, with cluster lenses often exceeding several months (and therefore most favorable for high-precision H0 inferences). A multivisit monitoring campaign with a sensitive infrared telescope (namely, JWST) is necessary to mitigate dust attenuation. Nevertheless, a porous interstellar medium and clumpy star formation in these extreme galaxies might produce favorable conditions for detecting SNe as transient point sources. Targeted campaigns of known lensed galaxies to discover new lensed SNe can greatly complement wide-area cadenced surveys. Increasing the sample size helps to realize the potential of SN time-delay cosmography to elucidate the Hubble tension through a single-step measurement, independent of other H0 techniques.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-26DOI: 10.3847/1538-4357/ae47de
G. Livadiotis and D. J. McComas
This paper explores the thermodynamics of fluctuating polytropic processes and their connection to turbulence. It is shown that random fluctuations of polytropic processes produce a nonzero overall heating of a particle system, e.g., solar wind plasma flowing out through the heliosphere; while any nonturbulent heating can be thermodynamically described by typical nonfluctuating polytropic processes, turbulent heating can be thermodynamically described through fluctuating polytropic processes. First, we derive the expression of the overall process and find that polytropic fluctuations lead to heat entering the system even if the respective nonfluctuating process is adiabatic. The temperature of the solar wind plasma protons decreases with heliospheric distance less than the adiabatic cooling, again, similar to when heating enters the system; this subadiabatic cooling is proportional to the variance of the fluctuations. We derive the heliospheric radial profiles of the thermodynamic expressions of the polytropic index, temperature, and heating rates. Then, we show that the analytical profiles of heating of fluctuating polytropic processes and of turbulent heating are identical, suggesting that turbulence heats plasma particle populations by fluctuating their polytropic processes. We apply the thermodynamics of fluctuating polytropic processes to the energy transfer from pickup ions (PUIs) to solar wind plasma protons, and derive the analytical expressions of PUI turbulent and nonturbulent heating rates, which are well fitted to the respective observations. Finally, we apply the thermodynamic model to the radial profile of PUI energy transfer to solar wind plasma protons, where we derive the portion of PUI turbulent versus nonturbulent heating rates.
{"title":"Fluctuating Polytropic Processes, Turbulence, and Heating","authors":"G. Livadiotis and D. J. McComas","doi":"10.3847/1538-4357/ae47de","DOIUrl":"https://doi.org/10.3847/1538-4357/ae47de","url":null,"abstract":"This paper explores the thermodynamics of fluctuating polytropic processes and their connection to turbulence. It is shown that random fluctuations of polytropic processes produce a nonzero overall heating of a particle system, e.g., solar wind plasma flowing out through the heliosphere; while any nonturbulent heating can be thermodynamically described by typical nonfluctuating polytropic processes, turbulent heating can be thermodynamically described through fluctuating polytropic processes. First, we derive the expression of the overall process and find that polytropic fluctuations lead to heat entering the system even if the respective nonfluctuating process is adiabatic. The temperature of the solar wind plasma protons decreases with heliospheric distance less than the adiabatic cooling, again, similar to when heating enters the system; this subadiabatic cooling is proportional to the variance of the fluctuations. We derive the heliospheric radial profiles of the thermodynamic expressions of the polytropic index, temperature, and heating rates. Then, we show that the analytical profiles of heating of fluctuating polytropic processes and of turbulent heating are identical, suggesting that turbulence heats plasma particle populations by fluctuating their polytropic processes. We apply the thermodynamics of fluctuating polytropic processes to the energy transfer from pickup ions (PUIs) to solar wind plasma protons, and derive the analytical expressions of PUI turbulent and nonturbulent heating rates, which are well fitted to the respective observations. Finally, we apply the thermodynamic model to the radial profile of PUI energy transfer to solar wind plasma protons, where we derive the portion of PUI turbulent versus nonturbulent heating rates.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147507948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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