Pub Date : 2026-02-06DOI: 10.1038/s41550-025-02768-4
{"title":"JWST reveals hydrocarbon-rich material in a buried galactic nucleus","authors":"","doi":"10.1038/s41550-025-02768-4","DOIUrl":"https://doi.org/10.1038/s41550-025-02768-4","url":null,"abstract":"","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"34 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.1038/s41550-026-02781-1
Eleonora Di Valentino, Jackson Levi Said, Emmanuel N. Saridakis
{"title":"Tensions in Cosmology 2025","authors":"Eleonora Di Valentino, Jackson Levi Said, Emmanuel N. Saridakis","doi":"10.1038/s41550-026-02781-1","DOIUrl":"https://doi.org/10.1038/s41550-026-02781-1","url":null,"abstract":"","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"384 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.1038/s41550-026-02785-x
Chenxuan Zhang, Qingwen Wu, Xiao Fan, Luis C. Ho, Jiancheng Wu, Huanian Zhang, Bing Lyu, Xinwu Cao, Jianmin Wang
{"title":"The composite spectrum of little red dots from a standard inner disk and an unstable outer disk","authors":"Chenxuan Zhang, Qingwen Wu, Xiao Fan, Luis C. Ho, Jiancheng Wu, Huanian Zhang, Bing Lyu, Xinwu Cao, Jianmin Wang","doi":"10.1038/s41550-026-02785-x","DOIUrl":"https://doi.org/10.1038/s41550-026-02785-x","url":null,"abstract":"","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"18 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.1038/s41550-026-02782-0
Yifan Chen, Matthias Daniel, Daniel J. D’Orazio, Xuanye Fan, Andrea Mitridate, Laura Sagunski, Xiao Xue, , Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Jeremy G. Baier, Paul T. Baker, Bence Bécsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Heling Deng, Lankeswar Dey, Timothy Dolch, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Emiko C. Gardiner, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, Bjorn Larsen, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Chiara M. F. Mingarelli, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Jessie C. Runnoe, Alexander Saffer, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Sophia V. Sosa Fiscella, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Jacob E. Turner, Caner Ünal, Michele Vallisneri, Rutger van Haasteren, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, David Wright, Olivia Young
{"title":"Inference on inner galaxy structure via gravitational waves from supermassive binaries","authors":"Yifan Chen, Matthias Daniel, Daniel J. D’Orazio, Xuanye Fan, Andrea Mitridate, Laura Sagunski, Xiao Xue, , Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Jeremy G. Baier, Paul T. Baker, Bence Bécsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Heling Deng, Lankeswar Dey, Timothy Dolch, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Emiko C. Gardiner, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Kayhan Gültekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, Bjorn Larsen, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Chiara M. F. Mingarelli, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Jessie C. Runnoe, Alexander Saffer, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Sophia V. Sosa Fiscella, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Jacob E. Turner, Caner Ünal, Michele Vallisneri, Rutger van Haasteren, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, David Wright, Olivia Young","doi":"10.1038/s41550-026-02782-0","DOIUrl":"https://doi.org/10.1038/s41550-026-02782-0","url":null,"abstract":"","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"162 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.1038/s41550-025-02771-9
Shmuel Bialy, Amit Chemke, David A. Neufeld, James Muzerolle Page, Alexei V. Ivlev, Sirio Belli, Brandt A. L. Gaches, Benjamin Godard, Thomas G. Bisbas, Paola Caselli, Arshia M. Jacob, Marco Padovani, Christian Rab, Kedron Silsbee, Troy A. Porter, Ekaterina I. Makarenko
Stars and planets form within cold, dark molecular clouds. In these dense regions, where starlight cannot penetrate, cosmic rays (CRs) are the dominant source of ionization—driving interstellar chemistry, setting the gas temperature and enabling coupling to magnetic fields. Together, these effects regulate the collapse of clouds and the onset of star formation. Despite this importance, the CR ionization rate, ζ, has never been measured directly. Instead, this fundamental parameter has been loosely inferred from indirect chemical tracers and uncertain assumptions, limiting our understanding of star formation physics. Here we report the direct detection of CR-excited vibrational H2 emission, using James Webb Space Telescope observations of the starless core Barnard 68 (B68). The observed emission pattern matches theoretical predictions for CR excitation precisely, confirming a decades-old theoretical proposal long considered observationally inaccessible. This result enables direct measurement of ζ, effectively turning molecular clouds into natural, light-year-sized, CR detectors. It opens a transformative observational window into the origin, propagation and role of CRs in star formation and galaxy evolution.
{"title":"Direct detection of cosmic-ray-excited H2 in interstellar space","authors":"Shmuel Bialy, Amit Chemke, David A. Neufeld, James Muzerolle Page, Alexei V. Ivlev, Sirio Belli, Brandt A. L. Gaches, Benjamin Godard, Thomas G. Bisbas, Paola Caselli, Arshia M. Jacob, Marco Padovani, Christian Rab, Kedron Silsbee, Troy A. Porter, Ekaterina I. Makarenko","doi":"10.1038/s41550-025-02771-9","DOIUrl":"https://doi.org/10.1038/s41550-025-02771-9","url":null,"abstract":"Stars and planets form within cold, dark molecular clouds. In these dense regions, where starlight cannot penetrate, cosmic rays (CRs) are the dominant source of ionization—driving interstellar chemistry, setting the gas temperature and enabling coupling to magnetic fields. Together, these effects regulate the collapse of clouds and the onset of star formation. Despite this importance, the CR ionization rate, ζ, has never been measured directly. Instead, this fundamental parameter has been loosely inferred from indirect chemical tracers and uncertain assumptions, limiting our understanding of star formation physics. Here we report the direct detection of CR-excited vibrational H2 emission, using James Webb Space Telescope observations of the starless core Barnard 68 (B68). The observed emission pattern matches theoretical predictions for CR excitation precisely, confirming a decades-old theoretical proposal long considered observationally inaccessible. This result enables direct measurement of ζ, effectively turning molecular clouds into natural, light-year-sized, CR detectors. It opens a transformative observational window into the origin, propagation and role of CRs in star formation and galaxy evolution.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"8 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1038/s41550-026-02777-x
Eli Galanti, Maria Smirnova, Maayan Ziv, Matteo Fonsetti, Andrea Caruso, Dustin R. Buccino, William B. Hubbard, Burkhard Militzer, Scott J. Bolton, Tristan Guillot, Ravit Helled, Steven M. Levin, Marzia Parisi, Ryan S. Park, Paul Steffes, Paolo Tortora, Paul Withers, Marco Zannoni, Yohai Kaspi
Jupiter, the fastest-rotating planet in the Solar System, exhibits a pronounced equatorial bulge, with its equatorial radius exceeding the polar radius by approximately 7%. This oblate shape reflects the combined effects of rapid rotation, complex internal structure and atmospheric winds. Existing estimates of Jupiter’s shape, with uncertainties of about 4 km, are based on a single analysis of Voyager and Pioneer radio occultations from nearly five decades ago and do not account for the influence of Jupiter’s strong winds. The Juno spacecraft has recently returned numerous high-precision radio-occultation measurements, enabling a more accurate determination. Here, incorporating the effects of zonal winds, we derive Jupiter’s shape with an order-of-magnitude reduction in uncertainty. At the 1-bar pressure level, we find a polar radius of 66,842 ± 0.4 km, an equatorial radius of 71,488 ± 0.4 km and a mean radius of 69,886 ± 0.4 km, which are 12 km, 4 km and 8 km smaller than previous estimates, respectively. The results indicate that winds above the visible cloud tops are largely barotropic, showing minimal vertical variation. The updated shape has important implications for interior structure models, supporting a metal-enriched and cooler atmosphere, thereby helping reconcile discrepancies between models, Galileo probe measurements and Voyager-derived temperatures. The refined radius profile also improves spatial referencing for pressure-dependent measurements, offering a more precise context for interpreting Jupiter’s atmospheric dynamics.
{"title":"The size and shape of Jupiter","authors":"Eli Galanti, Maria Smirnova, Maayan Ziv, Matteo Fonsetti, Andrea Caruso, Dustin R. Buccino, William B. Hubbard, Burkhard Militzer, Scott J. Bolton, Tristan Guillot, Ravit Helled, Steven M. Levin, Marzia Parisi, Ryan S. Park, Paul Steffes, Paolo Tortora, Paul Withers, Marco Zannoni, Yohai Kaspi","doi":"10.1038/s41550-026-02777-x","DOIUrl":"https://doi.org/10.1038/s41550-026-02777-x","url":null,"abstract":"Jupiter, the fastest-rotating planet in the Solar System, exhibits a pronounced equatorial bulge, with its equatorial radius exceeding the polar radius by approximately 7%. This oblate shape reflects the combined effects of rapid rotation, complex internal structure and atmospheric winds. Existing estimates of Jupiter’s shape, with uncertainties of about 4 km, are based on a single analysis of Voyager and Pioneer radio occultations from nearly five decades ago and do not account for the influence of Jupiter’s strong winds. The Juno spacecraft has recently returned numerous high-precision radio-occultation measurements, enabling a more accurate determination. Here, incorporating the effects of zonal winds, we derive Jupiter’s shape with an order-of-magnitude reduction in uncertainty. At the 1-bar pressure level, we find a polar radius of 66,842 ± 0.4 km, an equatorial radius of 71,488 ± 0.4 km and a mean radius of 69,886 ± 0.4 km, which are 12 km, 4 km and 8 km smaller than previous estimates, respectively. The results indicate that winds above the visible cloud tops are largely barotropic, showing minimal vertical variation. The updated shape has important implications for interior structure models, supporting a metal-enriched and cooler atmosphere, thereby helping reconcile discrepancies between models, Galileo probe measurements and Voyager-derived temperatures. The refined radius profile also improves spatial referencing for pressure-dependent measurements, offering a more precise context for interpreting Jupiter’s atmospheric dynamics.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"90 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30DOI: 10.1038/s41550-025-02760-y
Csanád Horváth, Nanda Rea, Natasha Hurley-Walker, Samuel J. McSweeney, Richard A. Perley, Emil Lenc
{"title":"A binary model of long-period radio transients and white dwarf pulsars","authors":"Csanád Horváth, Nanda Rea, Natasha Hurley-Walker, Samuel J. McSweeney, Richard A. Perley, Emil Lenc","doi":"10.1038/s41550-025-02760-y","DOIUrl":"https://doi.org/10.1038/s41550-025-02760-y","url":null,"abstract":"","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"14 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146089328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1038/s41550-025-02757-7
Cyril Tasse, Philippe Zarka, Martin J. Hardcastle, Alan Loh, Tim W. Shimwell, Joseph R. Callingham, Benjamin Hugo, Oleg Smirnov, Harish Vedantham, Hertzog L. Bester, Alexander Drabent, Julien Girard, Jean-Mathias Grießmeier, Laurent Lamy, Corentin K. Louis, Emilie Mauduit, Talon Myburgh, Hamish A. S. Reid, Huub Röttgering, Jake D. Turner, Dominik J. Schwarz, Reinout J. van Weeren, Xiang Zhang
In the Solar System, low-frequency radio emission at frequencies ≲200 MHz is produced by acceleration processes in the Sun and in planetary magnetospheres. Such emission has been actively searched for in other stellar systems, as it could potentially enable the study of the interactions between stars and the magnetospheres of their exoplanets. Here we present radio interferometric multiplexed spectroscopy (RIMS), a method designed to measure the variability of the flux density in an arbitrary number of directions from interferometric datasets. Using it, we synthesized ~200,000 dynamic spectra of stars and exoplanetary systems from an ~1.4 years’ long, multi-petabytes dataset from the Low-Frequency Array (LOFAR) at 150 MHz. This extra diagnostic shows that ~25% of the 68 targets previously identified in the LOFAR circularly polarized images also show significant variability on timescales of a few hours. The improved instantaneous sensitivity led to the detection of eight more weak bursts from low-mass stars, most of which varied on ~0.5–1-h timescales. We argue that some are fully compatible with radio emission generated by star–planet interactions, although an intrinsic stellar origin is still a possible explanation. Our results demonstrate the potential of the method for studying stellar and star–planet interactions with the Square Kilometre Array.
{"title":"The detection of circularly polarized radio bursts from stellar and exoplanetary systems","authors":"Cyril Tasse, Philippe Zarka, Martin J. Hardcastle, Alan Loh, Tim W. Shimwell, Joseph R. Callingham, Benjamin Hugo, Oleg Smirnov, Harish Vedantham, Hertzog L. Bester, Alexander Drabent, Julien Girard, Jean-Mathias Grießmeier, Laurent Lamy, Corentin K. Louis, Emilie Mauduit, Talon Myburgh, Hamish A. S. Reid, Huub Röttgering, Jake D. Turner, Dominik J. Schwarz, Reinout J. van Weeren, Xiang Zhang","doi":"10.1038/s41550-025-02757-7","DOIUrl":"https://doi.org/10.1038/s41550-025-02757-7","url":null,"abstract":"In the Solar System, low-frequency radio emission at frequencies ≲200 MHz is produced by acceleration processes in the Sun and in planetary magnetospheres. Such emission has been actively searched for in other stellar systems, as it could potentially enable the study of the interactions between stars and the magnetospheres of their exoplanets. Here we present radio interferometric multiplexed spectroscopy (RIMS), a method designed to measure the variability of the flux density in an arbitrary number of directions from interferometric datasets. Using it, we synthesized ~200,000 dynamic spectra of stars and exoplanetary systems from an ~1.4 years’ long, multi-petabytes dataset from the Low-Frequency Array (LOFAR) at 150 MHz. This extra diagnostic shows that ~25% of the 68 targets previously identified in the LOFAR circularly polarized images also show significant variability on timescales of a few hours. The improved instantaneous sensitivity led to the detection of eight more weak bursts from low-mass stars, most of which varied on ~0.5–1-h timescales. We argue that some are fully compatible with radio emission generated by star–planet interactions, although an intrinsic stellar origin is still a possible explanation. Our results demonstrate the potential of the method for studying stellar and star–planet interactions with the Square Kilometre Array.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"42 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1038/s41550-025-02770-w
Ewoud Wempe, Simon D. M. White, Amina Helmi, Guilhem Lavaux, Jens Jasche
Our Galaxy, Andromeda and their companion dwarf galaxies form the Local Group. Most of the mass in and around it is believed to be dark matter rather than gas or stars, so its distribution must be inferred from the effect of gravity on the motion of visible objects. Modelling efforts have long struggled to reproduce the quiet Hubble flow around the Local Group, as they require unrealistically little mass beyond the haloes of the two main galaxies. Here we revisit this using ΛCDM simulations of Local Group analogues with initial conditions constrained to match the observed dynamics of the two main haloes and the surrounding flow. The observations are reconcilable within ΛCDM, but only if mass is strongly concentrated in a plane out to 10 Mpc, with the surface density rising away from the Local Group and with deep voids above and below. This configuration, dynamically inferred, mirrors known structures in the nearby galaxy distribution. The resulting Hubble flow is quiet yet strongly anisotropic, a fact obscured by the paucity of tracers at high supergalactic latitude. This flattened geometry reconciles the dynamical mass estimates of the Local Group with the surrounding velocity field, thus demonstrating full consistency within the standard cosmological model.
{"title":"The mass distribution in and around the Local Group","authors":"Ewoud Wempe, Simon D. M. White, Amina Helmi, Guilhem Lavaux, Jens Jasche","doi":"10.1038/s41550-025-02770-w","DOIUrl":"https://doi.org/10.1038/s41550-025-02770-w","url":null,"abstract":"Our Galaxy, Andromeda and their companion dwarf galaxies form the Local Group. Most of the mass in and around it is believed to be dark matter rather than gas or stars, so its distribution must be inferred from the effect of gravity on the motion of visible objects. Modelling efforts have long struggled to reproduce the quiet Hubble flow around the Local Group, as they require unrealistically little mass beyond the haloes of the two main galaxies. Here we revisit this using ΛCDM simulations of Local Group analogues with initial conditions constrained to match the observed dynamics of the two main haloes and the surrounding flow. The observations are reconcilable within ΛCDM, but only if mass is strongly concentrated in a plane out to 10 Mpc, with the surface density rising away from the Local Group and with deep voids above and below. This configuration, dynamically inferred, mirrors known structures in the nearby galaxy distribution. The resulting Hubble flow is quiet yet strongly anisotropic, a fact obscured by the paucity of tracers at high supergalactic latitude. This flattened geometry reconciles the dynamical mass estimates of the Local Group with the surrounding velocity field, thus demonstrating full consistency within the standard cosmological model.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"73 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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