Pub Date : 2026-03-03DOI: 10.3847/1538-4357/ae3aa5
Kunihiko Tanaka, Makoto Nagai and Kazuhisa Kamegai
We present Atacama Large Millimeter/submillimeter Array [C i] 3P1–3P0 imaging of the central 6.6 × 4.2 pc2 region of the Galaxy encompassing the circumnuclear disk (CND). The data reveal low-density ( cm−3) molecular gas with inward motion, widespread both inside and outside the CND. The normalized [C i] to CS 7–6 intensity difference decreases inwardly from R = 4 pc to 1.7 pc and azimuthally along the CND’s rotation, likely tracing paths of low-density gas inflow. By projecting spaxels into orbital coordinates assuming a velocity field model, we identify four kinematic features: a pair of spiral outer streamers toward the CND, inner streamers extending to 0.5 pc from Sgr A*, an outer disk at R ∼ 3–6 pc, and the rotating ring at R = 2 pc. P–P–V correlation between the inner streamers and H42α indicates gas supply to the mini-spiral through the western arc (WA) and northern arm (NA). The total inflowing mass is 1.5 × 104M⊙, 1.7 times the mass of the rotating ring. The identified flows can be organized into two main pathways connecting the CND exterior and interior: “WA flow” feeding the mini-spiral WA via the CND, and “NA flow” bypassing the purely rotating orbit. The inflow rate along the former is approximately constant (0.1–0.16 M⊙ yr−1), implying a CND dwelling time comparable to its orbital period and supporting the CND’s transient nature. We also identify two [C i]-bright clumps (CBCs) lacking dense-gas counterparts near the contact point between the northern outer streamer and the CND. Apparently intact against tidal disruption despite subcritical densities, the CBCs may represent a chemically young phase shortly after formation in colliding flows.
{"title":"ALMA [C I] Image of the Circumnuclear Disk of the Milky Way: Inflowing Low-density Molecular Gas","authors":"Kunihiko Tanaka, Makoto Nagai and Kazuhisa Kamegai","doi":"10.3847/1538-4357/ae3aa5","DOIUrl":"https://doi.org/10.3847/1538-4357/ae3aa5","url":null,"abstract":"We present Atacama Large Millimeter/submillimeter Array [C i] 3P1–3P0 imaging of the central 6.6 × 4.2 pc2 region of the Galaxy encompassing the circumnuclear disk (CND). The data reveal low-density ( cm−3) molecular gas with inward motion, widespread both inside and outside the CND. The normalized [C i] to CS 7–6 intensity difference decreases inwardly from R = 4 pc to 1.7 pc and azimuthally along the CND’s rotation, likely tracing paths of low-density gas inflow. By projecting spaxels into orbital coordinates assuming a velocity field model, we identify four kinematic features: a pair of spiral outer streamers toward the CND, inner streamers extending to 0.5 pc from Sgr A*, an outer disk at R ∼ 3–6 pc, and the rotating ring at R = 2 pc. P–P–V correlation between the inner streamers and H42α indicates gas supply to the mini-spiral through the western arc (WA) and northern arm (NA). The total inflowing mass is 1.5 × 104M⊙, 1.7 times the mass of the rotating ring. The identified flows can be organized into two main pathways connecting the CND exterior and interior: “WA flow” feeding the mini-spiral WA via the CND, and “NA flow” bypassing the purely rotating orbit. The inflow rate along the former is approximately constant (0.1–0.16 M⊙ yr−1), implying a CND dwelling time comparable to its orbital period and supporting the CND’s transient nature. We also identify two [C i]-bright clumps (CBCs) lacking dense-gas counterparts near the contact point between the northern outer streamer and the CND. Apparently intact against tidal disruption despite subcritical densities, the CBCs may represent a chemically young phase shortly after formation in colliding flows.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330288","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 : 2026-03-03DOI: 10.3847/1538-4357/ae3f06
Juliana S. M. Karp, David J. Schlegel, Xiaosheng Huang, Nikhil Padmanabhan, Adam S. Bolton, Christopher J. Storfer, J. Aguilar, S. Ahlen, S. Bailey, D. Bianchi, D. Brooks, F. J. Castander, T. Claybaugh, A. Cuceu, A. de la Macorra, J. Della Costa, P. Doel, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, G. Gutierrez, K. Honscheid, M. Ishak, J. Jimenez, R. Joyce, S. Juneau, D. Kirkby, A. Kremin, C. Lamman, M. Landriau, L. Le Guillou, M. Manera, P. Martini, A. Meisner, R. Miquel, J. Moustakas, S. Nadathur, W. J. Percival, C. Poppett, F. Prada, I. Pérez-Ràfols, G. Rossi, E. Sanchez, M. Schubnell, D. Sprayberry, G. Tarlé, B. A. Weaver, R. Zhou and and The DESI Collaboration
We present 4110 strong gravitational lens candidates, 3887 of which are new discoveries, selected from a sample of 5,837,154 luminous red galaxies (LRGs) observed with the Dark Energy Spectroscopic Instrument (DESI). Candidates are identified via the presence of background ionized oxygen [O ii] nebular emission lines in the foreground LRG spectra, which may originate from the lensing of higher-redshift star-forming galaxies. Using the measured foreground redshift, background redshift, and integrated flux of the background [O ii] doublet, we integrate over impact parameters to compute the probability that each candidate is a lens. We expect 53% of candidates to be true lenses with Einstein radii ranging from 0 1–4″, which can be confirmed with high-resolution imaging. Confirmed strong lenses from this sample will form a valuable cosmological data set, as strong gravitational lensing is the only method to directly measure dark matter halo substructure at cosmological distances. We independently recover the host of the multiply imaged gravitationally lensed type Ia supernova iPTF16geu. Monitoring these lenses for future multiply lensed transients will enable (a) H0 measurements via time-delay cosmography and (b) substructure measurements via flux ratios.
{"title":"The DESI Single Fiber Lens Search. I. Four Thousand Spectroscopically Selected Galaxy–Galaxy Gravitational Lens Candidates","authors":"Juliana S. M. Karp, David J. Schlegel, Xiaosheng Huang, Nikhil Padmanabhan, Adam S. Bolton, Christopher J. Storfer, J. Aguilar, S. Ahlen, S. Bailey, D. Bianchi, D. Brooks, F. J. Castander, T. Claybaugh, A. Cuceu, A. de la Macorra, J. Della Costa, P. Doel, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, G. Gutierrez, K. Honscheid, M. Ishak, J. Jimenez, R. Joyce, S. Juneau, D. Kirkby, A. Kremin, C. Lamman, M. Landriau, L. Le Guillou, M. Manera, P. Martini, A. Meisner, R. Miquel, J. Moustakas, S. Nadathur, W. J. Percival, C. Poppett, F. Prada, I. Pérez-Ràfols, G. Rossi, E. Sanchez, M. Schubnell, D. Sprayberry, G. Tarlé, B. A. Weaver, R. Zhou and and The DESI Collaboration","doi":"10.3847/1538-4357/ae3f06","DOIUrl":"https://doi.org/10.3847/1538-4357/ae3f06","url":null,"abstract":"We present 4110 strong gravitational lens candidates, 3887 of which are new discoveries, selected from a sample of 5,837,154 luminous red galaxies (LRGs) observed with the Dark Energy Spectroscopic Instrument (DESI). Candidates are identified via the presence of background ionized oxygen [O ii] nebular emission lines in the foreground LRG spectra, which may originate from the lensing of higher-redshift star-forming galaxies. Using the measured foreground redshift, background redshift, and integrated flux of the background [O ii] doublet, we integrate over impact parameters to compute the probability that each candidate is a lens. We expect 53% of candidates to be true lenses with Einstein radii ranging from 0 1–4″, which can be confirmed with high-resolution imaging. Confirmed strong lenses from this sample will form a valuable cosmological data set, as strong gravitational lensing is the only method to directly measure dark matter halo substructure at cosmological distances. We independently recover the host of the multiply imaged gravitationally lensed type Ia supernova iPTF16geu. Monitoring these lenses for future multiply lensed transients will enable (a) H0 measurements via time-delay cosmography and (b) substructure measurements via flux ratios.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147358808","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 : 2026-03-02DOI: 10.3847/1538-4357/ae3950
Rhyan Sawyer and Jasper Halekas
The lunar surface exhibits small-scale crustal magnetic fields that can give rise to various interactions when subjected to the incident solar wind plasma. These lunar crustal magnetic fields exhibit scale lengths that are much smaller than the typical convected ion gyroradius within the solar wind, leading to an effective demagnetization of the ions. Thus, these lunar crustal magnetic fields provide a natural environment within which Hall electric fields and various current structures may be generated. This study reports observations from THEMIS–ARTEMIS during a periselene of 14 km to the lunar surface and examines the plasma environment within the vicinity of various crustal magnetic fields. The reported observations suggest a Hall interaction region that extends downstream of prominent regions of crustal magnetization. Within these extended interaction regions we report a Hall electric field of 2–3 mV m−1 and oriented upward and sunward, as well as a northward current carried by southward ExB drifting electrons. Lastly, Hall electric fields were observed above the lunar crustal magnetic fields oriented downward and antisunward, as well as parallel currents directed toward the lunar surface, and were consistently observed when the magnetic footpoint was within the cusp region.
{"title":"New Observations of an Extended Hall Interaction Region Downstream of Lunar Crustal Magnetic Fields","authors":"Rhyan Sawyer and Jasper Halekas","doi":"10.3847/1538-4357/ae3950","DOIUrl":"https://doi.org/10.3847/1538-4357/ae3950","url":null,"abstract":"The lunar surface exhibits small-scale crustal magnetic fields that can give rise to various interactions when subjected to the incident solar wind plasma. These lunar crustal magnetic fields exhibit scale lengths that are much smaller than the typical convected ion gyroradius within the solar wind, leading to an effective demagnetization of the ions. Thus, these lunar crustal magnetic fields provide a natural environment within which Hall electric fields and various current structures may be generated. This study reports observations from THEMIS–ARTEMIS during a periselene of 14 km to the lunar surface and examines the plasma environment within the vicinity of various crustal magnetic fields. The reported observations suggest a Hall interaction region that extends downstream of prominent regions of crustal magnetization. Within these extended interaction regions we report a Hall electric field of 2–3 mV m−1 and oriented upward and sunward, as well as a northward current carried by southward ExB drifting electrons. Lastly, Hall electric fields were observed above the lunar crustal magnetic fields oriented downward and antisunward, as well as parallel currents directed toward the lunar surface, and were consistently observed when the magnetic footpoint was within the cusp region.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329664","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 : 2026-03-02DOI: 10.3847/1538-4357/ae42c2
Elvira Cruz-Cruz and Christopher S. Kochanek
The supernova remnant (SNR) S147 contains the pulsar PSR J0538+2817 and a likely unbound binary companion, HD 37424. It is the only good Galactic candidate for a binary unbound by a core-collapse supernova. Using Gaia DR3 parallaxes and photometry, we select the stars local to SNR S147 ( ) in a cylinder with a projected radius of 100 pc and a parallax range of 0.614 < ϖ < 0.787 mas (a length of ≃360 pc). We individually model the most luminous of these stars. The two most luminous single stars are the unbound binary companion, HD 37424, and HD 37367, with estimated masses of (13.51 ± 0.05) M⊙ and (14.30 ± 0.09) M⊙, respectively. The two most luminous binary systems are the spectroscopic binary HD 37366 and the eclipsing binary ET Tau, which have primary masses of (20.9 ± 0.12) and (16.7 ± 0.09) M⊙, respectively. We model the Gaia color–magnitude diagram of this local stellar population using both single stars and a model consisting of noninteracting binaries using solar metallicity PARSEC v2.0 isochrones. For both models, the estimated age distributions of the 439 MG < 0 mag stars favor a high-mass progenitor of 21.5–41.1 M⊙ for the supernova.
{"title":"The Progenitor of the S147 Supernova Remnant","authors":"Elvira Cruz-Cruz and Christopher S. Kochanek","doi":"10.3847/1538-4357/ae42c2","DOIUrl":"https://doi.org/10.3847/1538-4357/ae42c2","url":null,"abstract":"The supernova remnant (SNR) S147 contains the pulsar PSR J0538+2817 and a likely unbound binary companion, HD 37424. It is the only good Galactic candidate for a binary unbound by a core-collapse supernova. Using Gaia DR3 parallaxes and photometry, we select the stars local to SNR S147 ( ) in a cylinder with a projected radius of 100 pc and a parallax range of 0.614 < ϖ < 0.787 mas (a length of ≃360 pc). We individually model the most luminous of these stars. The two most luminous single stars are the unbound binary companion, HD 37424, and HD 37367, with estimated masses of (13.51 ± 0.05) M⊙ and (14.30 ± 0.09) M⊙, respectively. The two most luminous binary systems are the spectroscopic binary HD 37366 and the eclipsing binary ET Tau, which have primary masses of (20.9 ± 0.12) and (16.7 ± 0.09) M⊙, respectively. We model the Gaia color–magnitude diagram of this local stellar population using both single stars and a model consisting of noninteracting binaries using solar metallicity PARSEC v2.0 isochrones. For both models, the estimated age distributions of the 439 MG < 0 mag stars favor a high-mass progenitor of 21.5–41.1 M⊙ for the supernova.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329692","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 : 2026-03-02DOI: 10.3847/1538-4357/ae42ca
Gissel P. Montaguth, Claudia Mendes de Oliveira, Ciria Lima-Dias, Antonela Monachesi, Sergio Torres-Flores, Eduardo Telles, Fábio R. Herpich, Yolanda Jiménez-Teja, Antonio Kanaan, Tiago Ribeiro and William Schoenell
The stellar mass–size relation is a sensitive probe of how environment shapes galaxy structure. We analyse this relation in the local Universe for galaxies in compact groups (CGs), low-mass groups (Mvir ≤ 1013M⊙), and high-mass groups, comparing them to field galaxies using data from the Southern Photometric Local Universe Survey. Galaxies are classified as early-type galaxies (ETGs; n ≥ 2.5, (u − r)0 ≥ 2.2), late-type galaxies (LTGs; n < 2.5, (u − r)0 <2.2), transition galaxies (TGs; n < 2.5, (u − r)0 ≥ 2.2), and other galaxies (OGs; n ≥ 2.5, (u − r)0 <2.2). We find that ETGs and OGs show no significant environmental dependence: their mass–size slopes and intercepts are statistically consistent across CGs, groups, and the field. LTGs also follow similar relations in the field and in most groups, with only a modest tendency for LTGs in CGs to be smaller at fixed stellar mass. By contrast, TGs display a clear environmental signal: in groups the slope steepens to α ∼ 0.4 (versus α ∼ 0.2 in the field) and their sizes are smaller than in the field, with nonoverlapping 95% posterior intervals. These trends suggest that TGs in denser environments are more structurally evolved, likely owing to enhanced bulge prominence and fading of the outer disk, consistent with the Sérsic-index distributions, which show an excess of TGs with nr ≳ 1.5 in groups and CGs. Our findings highlight TGs as an environmentally sensitive population, providing insight into the structural transformation of galaxies in group environments.
恒星质量-大小关系是环境如何塑造星系结构的一个敏感探测器。我们分析了紧凑群（CGs）、低质量群（Mvir≤1013M⊙）和高质量群星系在局部宇宙中的这种关系，并使用南方光度局部宇宙调查的数据将它们与场星系进行了比较。星系分为早期型星系（ETGs, n≥2.5,(u−r)0≥2.2）、晚期型星系（LTGs, n < 2.5, (u−r)0 <2.2）、过渡星系（tgg, n < 2.5, (u−r)0≥2.2）和其他星系（OGs, n≥2.5,(u−r)0 <2.2）。我们发现ETGs和OGs没有明显的环境依赖性：它们的质量尺寸斜率和截距在cg、群和油田之间具有统计学上的一致性。在野外和大多数群体中，ltg也遵循类似的关系，只有在固定恒星质量下，cg中的ltg有较小的趋势。相比之下，TGs显示出清晰的环境信号：在组中，斜率陡增至α ~ 0.4（与野外的α ~ 0.2相比），它们的大小比野外小，95%的后置间隔不重叠。这些趋势表明，在密度较大的环境中，tg在结构上更进化，可能是由于凸起突出和外盘的衰落，这与ssamrsic指数分布一致，ssamrsic指数分布表明，在群和群中，tg的nr≥1.5是过量的。我们的发现强调了tg是一个对环境敏感的群体，为群体环境中星系的结构转变提供了见解。
{"title":"Galaxies Caught in Transition: The Role of Group Environment in Shaping the Mass–Size Relation in the Local Universe","authors":"Gissel P. Montaguth, Claudia Mendes de Oliveira, Ciria Lima-Dias, Antonela Monachesi, Sergio Torres-Flores, Eduardo Telles, Fábio R. Herpich, Yolanda Jiménez-Teja, Antonio Kanaan, Tiago Ribeiro and William Schoenell","doi":"10.3847/1538-4357/ae42ca","DOIUrl":"https://doi.org/10.3847/1538-4357/ae42ca","url":null,"abstract":"The stellar mass–size relation is a sensitive probe of how environment shapes galaxy structure. We analyse this relation in the local Universe for galaxies in compact groups (CGs), low-mass groups (Mvir ≤ 1013M⊙), and high-mass groups, comparing them to field galaxies using data from the Southern Photometric Local Universe Survey. Galaxies are classified as early-type galaxies (ETGs; n ≥ 2.5, (u − r)0 ≥ 2.2), late-type galaxies (LTGs; n < 2.5, (u − r)0 <2.2), transition galaxies (TGs; n < 2.5, (u − r)0 ≥ 2.2), and other galaxies (OGs; n ≥ 2.5, (u − r)0 <2.2). We find that ETGs and OGs show no significant environmental dependence: their mass–size slopes and intercepts are statistically consistent across CGs, groups, and the field. LTGs also follow similar relations in the field and in most groups, with only a modest tendency for LTGs in CGs to be smaller at fixed stellar mass. By contrast, TGs display a clear environmental signal: in groups the slope steepens to α ∼ 0.4 (versus α ∼ 0.2 in the field) and their sizes are smaller than in the field, with nonoverlapping 95% posterior intervals. These trends suggest that TGs in denser environments are more structurally evolved, likely owing to enhanced bulge prominence and fading of the outer disk, consistent with the Sérsic-index distributions, which show an excess of TGs with nr ≳ 1.5 in groups and CGs. Our findings highlight TGs as an environmentally sensitive population, providing insight into the structural transformation of galaxies in group environments.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329694","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 : 2026-03-02DOI: 10.3847/1538-4357/ae434d
Aaron Werlen, Edward D. Young, Hilke E. Schlichting, Caroline Dorn and Anat Shahar
Sub-Neptunes with hydrogen-rich envelopes are expected to sustain long-lived magma oceans that continuously exchange volatiles with their overlying atmospheres. Capturing these interactions is key to understanding the chemical evolution and present-day diversity of sub-Neptunes, super-Earths, and terrestrial planets, particularly in light of new JWST observations and upcoming missions. Recent advances in both geochemistry and astrophysics now allow for the integration of experimental constraints and thermodynamic models across melt, metal, and gas phases. Here we extend a global chemical equilibrium model to include non-ideal behavior in all three phases. Our framework combines fugacity corrections for gas species with activity coefficients for silicate and metal species, enabling a fully coupled description of volatile partitioning. We show that for planetary embryos (0.5 M⊕ at 2350 K), non-ideality introduces only modest corrections to atmosphere–magma ocean interface (AMOI) pressures, volatile inventories, and interior compositions. In contrast, for sub-Neptunes with higher temperatures (≈3000 K) and pressures, non-ideal effects are more pronounced, though still modest in absolute terms—typically within 20% and at most a factor of 2. Including activity and fugacity coefficients simultaneously increases the AMOI pressure, and enhances water retention in the mantle and the envelope. Our results demonstrate that non-ideality must be treated globally: applying corrections to only one phase leads to incomplete or even misleading trends. These findings highlight the importance of self-consistent global thermodynamic treatments for interpreting atmospheric spectra and interior structures of sub-Neptunes and super-Earths.
{"title":"The Effects of Non-ideal Mixing in Planetary Magma Oceans and Atmospheres","authors":"Aaron Werlen, Edward D. Young, Hilke E. Schlichting, Caroline Dorn and Anat Shahar","doi":"10.3847/1538-4357/ae434d","DOIUrl":"https://doi.org/10.3847/1538-4357/ae434d","url":null,"abstract":"Sub-Neptunes with hydrogen-rich envelopes are expected to sustain long-lived magma oceans that continuously exchange volatiles with their overlying atmospheres. Capturing these interactions is key to understanding the chemical evolution and present-day diversity of sub-Neptunes, super-Earths, and terrestrial planets, particularly in light of new JWST observations and upcoming missions. Recent advances in both geochemistry and astrophysics now allow for the integration of experimental constraints and thermodynamic models across melt, metal, and gas phases. Here we extend a global chemical equilibrium model to include non-ideal behavior in all three phases. Our framework combines fugacity corrections for gas species with activity coefficients for silicate and metal species, enabling a fully coupled description of volatile partitioning. We show that for planetary embryos (0.5 M⊕ at 2350 K), non-ideality introduces only modest corrections to atmosphere–magma ocean interface (AMOI) pressures, volatile inventories, and interior compositions. In contrast, for sub-Neptunes with higher temperatures (≈3000 K) and pressures, non-ideal effects are more pronounced, though still modest in absolute terms—typically within 20% and at most a factor of 2. Including activity and fugacity coefficients simultaneously increases the AMOI pressure, and enhances water retention in the mantle and the envelope. Our results demonstrate that non-ideality must be treated globally: applying corrections to only one phase leads to incomplete or even misleading trends. These findings highlight the importance of self-consistent global thermodynamic treatments for interpreting atmospheric spectra and interior structures of sub-Neptunes and super-Earths.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329696","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}
To investigate the origin of the dependence of the covering factor on the Eddington ratio suggested by X-ray observations, we examined the angular distribution of H i and H ii based on two-dimensional radiative hydrodynamic simulations. To calculate the Compton-thin covering factor C22 and Compton-thick covering factor C24 of H i alone, we performed one-dimensional photoionization equilibrium calculations with the XSTAR code based on radiative hydrodynamic simulations. The results obtained are as follows. (1) The Compton-thin covering factor C22 of H i and H ii is independent of the Eddington ratio and is approximately 70%, while C22 of H i alone is also independent of the Eddington ratio and is approximately 30%. (2) The Compton-thick covering factor C24 of H i has the same value as C22 of H i. (3) Our C24 is consistent with that obtained from X-ray observations. (4) Our C22 agrees with that obtained from X-ray observations in a high Eddington ratio, while our C22 is smaller than that from X-ray observations in a low Eddington ratio. (5) To explain the difference between C22 obtained from theoretical calculations and that inferred from X-ray observations, a Compton-thin gas is required in regions extending at least 10 pc beyond the current computational regions.
为了研究覆盖因子依赖于x射线观测的Eddington比的来源，我们基于二维辐射流体动力学模拟研究了H i和H ii的角分布。为了单独计算H的康普顿-薄覆盖因子C22和康普顿-厚覆盖因子C24，我们基于辐射流体动力学模拟，利用XSTAR程序进行了一维光电离平衡计算。所得结果如下：(1) H i和H ii的康普顿-薄覆盖因子C22与Eddington比无关，约为70%，而H i单独的C22也与Eddington比无关，约为30%。(2) H i的康普顿厚覆盖因子C24与H i的C22值相同。(3)我们的C24与x射线观测结果一致。(4) C22与高Eddington比下的x射线观测值一致，而C22小于低Eddington比下的x射线观测值。(5)为了解释从理论计算得到的C22与从x射线观测推断出的C22之间的差异，在当前计算区域之外至少延伸10%的区域需要康普顿薄气体。
{"title":"Unification Model of Active Galactic Nuclei by Photoionization Equilibrium Calculation Based on Radiative Hydrodynamic Simulations","authors":"Atsushi Tanimoto, Keiichi Wada, Yuki Kudoh, Nozomu Kawakatu, Mariko Nomura and Hirokazu Odaka","doi":"10.3847/1538-4357/ae4514","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4514","url":null,"abstract":"To investigate the origin of the dependence of the covering factor on the Eddington ratio suggested by X-ray observations, we examined the angular distribution of H i and H ii based on two-dimensional radiative hydrodynamic simulations. To calculate the Compton-thin covering factor C22 and Compton-thick covering factor C24 of H i alone, we performed one-dimensional photoionization equilibrium calculations with the XSTAR code based on radiative hydrodynamic simulations. The results obtained are as follows. (1) The Compton-thin covering factor C22 of H i and H ii is independent of the Eddington ratio and is approximately 70%, while C22 of H i alone is also independent of the Eddington ratio and is approximately 30%. (2) The Compton-thick covering factor C24 of H i has the same value as C22 of H i. (3) Our C24 is consistent with that obtained from X-ray observations. (4) Our C22 agrees with that obtained from X-ray observations in a high Eddington ratio, while our C22 is smaller than that from X-ray observations in a low Eddington ratio. (5) To explain the difference between C22 obtained from theoretical calculations and that inferred from X-ray observations, a Compton-thin gas is required in regions extending at least 10 pc beyond the current computational regions.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329699","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 : 2026-03-02DOI: 10.3847/1538-4357/ae3fa0
Bangzheng Sun, Haojing Yan, Wei Leong Tee and Feige Wang
Variability detected in galaxies is usually attributed to their active galactic nuclei (AGNs). While all AGNs are intrinsically variable, the AGN unification model predicts that Type 2 AGNs rarely vary because their engines are blocked by dust tori. Previous UV to near-IR variability studies largely support this expectation. Here, we present a variability study with the James Webb Space Telescope (JWST) that reveals a more subtle picture. Using NIRCam imaging data from three surveys over ∼140 arcmin2 in the COSMOS field, we found 117 galaxies with ≥4σ variability in the F356W band across an ∼2 yr baseline. Crossmatching with existing JWST spectroscopic data, we identified five of them at z = 0.19–3.69 (F356W corresponding to rest-frame λ ≈ 0.76–2.97 μm), which were all coincidentally observed by an NIRSpec program almost contemporaneously with the last imaging epoch. One additional variable was identified at z = 0.90 using archival Keck telescope data. These six objects form our spectroscopic subsample. Interestingly, two reside in close-pair environments, while two others form a close pair themselves. Most of their light curves can hardly be explained by nuclear transients, and AGN variability is a more plausible cause. However, among these six objects (1) only one shows broad Bracket and Pfund series permitted lines (Δv > 1000 km s−1) indicative of a Type 1 AGN; (2) two show narrow permitted lines (Hα and/or He I λ10830) consistent with Type 2 AGNs, with another one likely Type 2 based on the host galaxy properties; and (3) two others, which form a pair, show no emission lines. Our results add more challenges to the unification model.
在星系中检测到的变异性通常归因于它们的活动星系核（agn）。虽然所有的AGN本质上都是可变的，但AGN统一模型预测，2型AGN很少变化，因为它们的发动机被灰尘环阻挡。以前的紫外到近红外变异性研究在很大程度上支持了这一预期。在这里，我们用詹姆斯韦伯太空望远镜（JWST）进行了一项变异性研究，揭示了一个更微妙的画面。利用来自宇宙场约140 arcmin2的三次调查的NIRCam成像数据，我们发现117个星系在F356W波段具有≥4σ的变异性，跨越约2年的基线。与已有的JWST光谱数据进行交叉匹配，我们在z = 0.19-3.69 （F356W对应静止帧λ≈0.76-2.97 μm）处发现了5个，它们都与NIRSpec程序几乎同时观测到。利用凯克望远镜的档案数据，在z = 0.90处发现了一个额外的变量。这六个物体构成了我们的光谱子样本。有趣的是，其中两种生活在亲密的成对环境中，而另外两种则形成亲密的成对。它们的大多数光曲线很难用核瞬变来解释，而AGN变异性是一个更合理的原因。然而，在这6个对象中(1)，只有一个显示出宽的支架和Pfund系列允许线（Δv > 1000 km s−1），表明1型AGN；(2)两个agn显示出与2型agn一致的窄线（Hα和/或He I λ10830），另一个根据宿主星系的性质可能是2型agn；(3)形成一对的另外两个没有发射线。我们的结果给统一模型增加了更多的挑战。
{"title":"New Insight from the James Webb Space Telescope on Variable Active Galactic Nuclei","authors":"Bangzheng Sun, Haojing Yan, Wei Leong Tee and Feige Wang","doi":"10.3847/1538-4357/ae3fa0","DOIUrl":"https://doi.org/10.3847/1538-4357/ae3fa0","url":null,"abstract":"Variability detected in galaxies is usually attributed to their active galactic nuclei (AGNs). While all AGNs are intrinsically variable, the AGN unification model predicts that Type 2 AGNs rarely vary because their engines are blocked by dust tori. Previous UV to near-IR variability studies largely support this expectation. Here, we present a variability study with the James Webb Space Telescope (JWST) that reveals a more subtle picture. Using NIRCam imaging data from three surveys over ∼140 arcmin2 in the COSMOS field, we found 117 galaxies with ≥4σ variability in the F356W band across an ∼2 yr baseline. Crossmatching with existing JWST spectroscopic data, we identified five of them at z = 0.19–3.69 (F356W corresponding to rest-frame λ ≈ 0.76–2.97 μm), which were all coincidentally observed by an NIRSpec program almost contemporaneously with the last imaging epoch. One additional variable was identified at z = 0.90 using archival Keck telescope data. These six objects form our spectroscopic subsample. Interestingly, two reside in close-pair environments, while two others form a close pair themselves. Most of their light curves can hardly be explained by nuclear transients, and AGN variability is a more plausible cause. However, among these six objects (1) only one shows broad Bracket and Pfund series permitted lines (Δv > 1000 km s−1) indicative of a Type 1 AGN; (2) two show narrow permitted lines (Hα and/or He I λ10830) consistent with Type 2 AGNs, with another one likely Type 2 based on the host galaxy properties; and (3) two others, which form a pair, show no emission lines. Our results add more challenges to the unification model.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"90 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329700","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 : 2026-03-02DOI: 10.3847/1538-4357/ae355b
Hyunwook Ro, Motoki Kino, Kazuhiro Hada, Yosuke Mizuno, Yuzhu Cui, Kunwoo Yi, Tomohisa Kawashima, Jongho Park and Bong Won Sohn
We present an in-depth analysis of the transverse oscillations in the M87 jet, as identified in our previous study, which reported oscillatory patterns with a characteristic period of ∼1 yr in the edge-brightened jet structure extending up to 12 mas from the core. This work is based on high-cadence KaVA 22 GHz observations conducted from 2013 December to 2016 June. By analyzing the transverse velocity profiles and the spatial evolution of the oscillations, we find that the oscillations propagate downstream along the jet, with a wavelength of ∼9–10 mas. A single-mode sinusoidal wave model applied to the ridgelines successfully reproduces the observed transverse oscillations and yields superluminal wave speeds of ∼2.7–2.9c, consistent with the bulk jet velocity in this region. These findings suggest that the transverse oscillations may be interpreted either as transverse MHD waves—possibly excited by jet precession, nutation, or quasiperiodic magnetic flux eruptions near the central engine—or as manifestations of jet instabilities, such as current-driven instabilities. Further investigation is required to distinguish between these scenarios and to clarify the dominant physical mechanism.
{"title":"Transverse Oscillations and Wave Propagation in the Magnetically Dominated M87 Jet","authors":"Hyunwook Ro, Motoki Kino, Kazuhiro Hada, Yosuke Mizuno, Yuzhu Cui, Kunwoo Yi, Tomohisa Kawashima, Jongho Park and Bong Won Sohn","doi":"10.3847/1538-4357/ae355b","DOIUrl":"https://doi.org/10.3847/1538-4357/ae355b","url":null,"abstract":"We present an in-depth analysis of the transverse oscillations in the M87 jet, as identified in our previous study, which reported oscillatory patterns with a characteristic period of ∼1 yr in the edge-brightened jet structure extending up to 12 mas from the core. This work is based on high-cadence KaVA 22 GHz observations conducted from 2013 December to 2016 June. By analyzing the transverse velocity profiles and the spatial evolution of the oscillations, we find that the oscillations propagate downstream along the jet, with a wavelength of ∼9–10 mas. A single-mode sinusoidal wave model applied to the ridgelines successfully reproduces the observed transverse oscillations and yields superluminal wave speeds of ∼2.7–2.9c, consistent with the bulk jet velocity in this region. These findings suggest that the transverse oscillations may be interpreted either as transverse MHD waves—possibly excited by jet precession, nutation, or quasiperiodic magnetic flux eruptions near the central engine—or as manifestations of jet instabilities, such as current-driven instabilities. Further investigation is required to distinguish between these scenarios and to clarify the dominant physical mechanism.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329663","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 : 2026-03-02DOI: 10.3847/1538-4357/ae3f05
A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, R. Aloisio, J. Alvarez-Muñiz, A. Ambrosone, J. Ammerman Yebra, L. Anchordoqui, B. Andrada, L. Andrade Dourado, L. Apollonio, C. Aramo, E. Arnone, J. C. Arteaga Velázquez, P. Assis, G. Avila, E. Avocone, A. Bakalova, A. Baluta, F. Barbato, A. Bartz Mocellin, C. Berat, M. E. Bertaina, M. Bianciotto, P. L. Biermann, V. Binet, K. Bismark, T. Bister, J. Biteau, J. Blazek, J. Blümer, M. Boháčová, D. Boncioli, C. Bonifazi, N. Borodai, J. Brack, P. G. Brichetto Orchera, A. Bueno, S. Buitink, M. Büsken, A. Bwembya, K. S. Caballero-Mora, S. Cabana-Freire, L. Caccianiga, F. Campuzano, J. Caraça-Valente, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon, M. Cerda, B. Čermáková, A. Cermenati, K. Cerny, J. A. Chinellato, J. Chudoba, L. Chytka, R. W. Clay, A. C. Cobos Cerutti, R. Colalillo, R. Conceição, G. Consolati, M. Conte, F. Convenga, D. Correia dos Santos, P. J. Costa, C. E. Covault, M. Cr..
Deflections in the propagation of charged ultra-high-energy cosmic rays (UHECRs) caused by magnetic fields make the identification of their sources challenging. On the other hand, the arrival directions at Earth of neutrons point directly to their origin. The emission of UHECRs from a source is expected to be accompanied by the production of neutrons in its vicinity through interactions with ambient matter and radiation. Since free neutrons travel a mean distance d kpc−1 = 9.2 (E EeV−1) before decaying, a neutron flux in the EeV range could be detected on Earth from sources of UHECRs in our Galaxy. Using cosmic-ray data from Phase I of the Surface Detector of the Pierre Auger Observatory, we search for neutron fluxes from Galactic candidate sources. We select more than 1000 objects of astrophysical interest, stacking them into target sets. The targets all have decl. within the exposure of the Observatory, ranging from −90° up to +45° for energies above 1 EeV (and up to +20° for energies down to 0.1 EeV). Given that a neutron air shower is indistinguishable from a proton one, there is a significant background due to cosmic rays. A neutron flux from the direction of a candidate source would be identified by a celestial density of events that significantly exceeds the expected density of cosmic rays for that direction. No significant excess is found at any tested target direction, and an upper limit on the neutron flux is calculated for each candidate source.
由磁场引起的带电超高能量宇宙射线（uhecr）传播中的偏转使其来源的识别具有挑战性。另一方面，中子到达地球的方向直接指向它们的起源。从一个源发射uhecr时，预计会在其附近通过与环境物质和辐射的相互作用产生中子。由于自由中子在衰变前的平均距离为d kpc−1 = 9.2 (E EeV−1)，因此可以从银河系的uhecr源在地球上探测到EeV范围内的中子通量。利用皮埃尔·奥格天文台表面探测器第一阶段的宇宙射线数据，我们寻找来自银河系候选源的中子通量。我们选择了1000多个天体物理学感兴趣的物体，将它们堆叠成目标集。目标都有衰减。在天文台的照射范围内，能量高于1 EeV时为- 90°至+45°（能量低于0.1 EeV时为+20°）。考虑到中子气雨与质子气雨难以区分，由于宇宙射线的存在，有一个重要的背景。来自候选源方向的中子通量将通过天体事件密度来确定，该事件密度大大超过该方向宇宙射线的预期密度。在任何测试的目标方向上都没有发现明显的过剩，并为每个候选源计算了中子通量的上限。
{"title":"Search for Ultra-high-energy Neutrons from Galactic Sources with the Pierre Auger Observatory","authors":"A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, R. Aloisio, J. Alvarez-Muñiz, A. Ambrosone, J. Ammerman Yebra, L. Anchordoqui, B. Andrada, L. Andrade Dourado, L. Apollonio, C. Aramo, E. Arnone, J. C. Arteaga Velázquez, P. Assis, G. Avila, E. Avocone, A. Bakalova, A. Baluta, F. Barbato, A. Bartz Mocellin, C. Berat, M. E. Bertaina, M. Bianciotto, P. L. Biermann, V. Binet, K. Bismark, T. Bister, J. Biteau, J. Blazek, J. Blümer, M. Boháčová, D. Boncioli, C. Bonifazi, N. Borodai, J. Brack, P. G. Brichetto Orchera, A. Bueno, S. Buitink, M. Büsken, A. Bwembya, K. S. Caballero-Mora, S. Cabana-Freire, L. Caccianiga, F. Campuzano, J. Caraça-Valente, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon, M. Cerda, B. Čermáková, A. Cermenati, K. Cerny, J. A. Chinellato, J. Chudoba, L. Chytka, R. W. Clay, A. C. Cobos Cerutti, R. Colalillo, R. Conceição, G. Consolati, M. Conte, F. Convenga, D. Correia dos Santos, P. J. Costa, C. E. Covault, M. Cr..","doi":"10.3847/1538-4357/ae3f05","DOIUrl":"https://doi.org/10.3847/1538-4357/ae3f05","url":null,"abstract":"Deflections in the propagation of charged ultra-high-energy cosmic rays (UHECRs) caused by magnetic fields make the identification of their sources challenging. On the other hand, the arrival directions at Earth of neutrons point directly to their origin. The emission of UHECRs from a source is expected to be accompanied by the production of neutrons in its vicinity through interactions with ambient matter and radiation. Since free neutrons travel a mean distance d kpc−1 = 9.2 (E EeV−1) before decaying, a neutron flux in the EeV range could be detected on Earth from sources of UHECRs in our Galaxy. Using cosmic-ray data from Phase I of the Surface Detector of the Pierre Auger Observatory, we search for neutron fluxes from Galactic candidate sources. We select more than 1000 objects of astrophysical interest, stacking them into target sets. The targets all have decl. within the exposure of the Observatory, ranging from −90° up to +45° for energies above 1 EeV (and up to +20° for energies down to 0.1 EeV). Given that a neutron air shower is indistinguishable from a proton one, there is a significant background due to cosmic rays. A neutron flux from the direction of a candidate source would be identified by a celestial density of events that significantly exceeds the expected density of cosmic rays for that direction. No significant excess is found at any tested target direction, and an upper limit on the neutron flux is calculated for each candidate source.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329682","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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