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The evolution of satellite galaxies is shaped by their constant interaction with the circumgalactic medium surrounding central galaxies, which in turn may be affected by gas and energy ejected from the central supermassive black hole.sup.1-6. The nature of such a coupling between black holes and galaxies is, however, much debated.sup.7-9 and observational evidence remains scarce.sup.10,11. Here we report an analysis of archival data on 124,163 satellite galaxies in the potential wells of 29,631 dark matter halos with masses between 10.sup.12 and 10.sup.14 solar masses. We find that quenched satellite galaxies are relatively less frequent along the minor axis of their central galaxies. This observation might appear counterintuitive given that black hole activity is expected to eject mass and energy preferentially in the direction of the minor axis of the host galaxy. We show, however, that the observed anisotropic signal results precisely from the ejective nature of black hole feedback in massive halos, as outflows powered by active galactic nuclei clear out the circumgalactic medium, reducing the ram pressure and thus preserving star formation in satellite galaxies. This interpretation is supported by the IllustrisTNG suite of cosmological numerical simulations, even though the model's sub-grid implementation of black hole feedback is effectively isotropic.sup.12. An analysis of archival data from the Sloan Digital Sky Survey finds that star-forming satellite galaxies are relatively more common along the minor axis of central galaxies owing to the effect of black hole feedback., Author(s): Ignacio Martín-Navarro [sup.1] [sup.2] [sup.3] , Annalisa Pillepich [sup.3] , Dylan Nelson [sup.4] [sup.5] , Vicente Rodriguez-Gomez [sup.6] , Martina Donnari [sup.3] , Lars Hernquist [sup.7] , Volker Springel [...]

About ten per cent of 'massive' stars (those of more than 1.5 solar masses) have strong, large-scale surface magnetic fields.sup.1-3. It has been suggested that merging of main-sequence and pre-main-sequence stars could produce such strong fields.sup.4,5, and the predicted fraction of merged massive stars is also about ten per cent.sup.6,7. The merger hypothesis is further supported by a lack of magnetic stars in close binaries.sup.8,9, which is as expected if mergers produce magnetic stars. Here we report three-dimensional magnetohydrodynamical simulations of the coalescence of two massive stars and follow the evolution of the merged product. Strong magnetic fields are produced in the simulations, and the merged star rejuvenates such that it appears younger and bluer than other coeval stars. This can explain the properties of the magnetic 'blue straggler' star [tau] Sco in the Upper Scorpius association that has an observationally inferred, apparent age of less than five million years, which is less than half the age of its birth association.sup.10. Such massive blue straggler stars seem likely to be progenitors of magnetars, perhaps giving rise to some of the enigmatic fast radio bursts observed.sup.11, and their supernovae may be affected by their strong magnetic fields.sup.12. Simulated mergers of two massive stars provide a solution to the long-standing puzzle of the origin of strong magnetic fields in a subset of massive stars., Author(s): Fabian R. N. Schneider [sup.1] [sup.2] [sup.3] , Sebastian T. Ohlmann [sup.2] [sup.4] , Philipp Podsiadlowski [sup.3] , Friedrich K. Röpke [sup.2] [sup.5] , Steven A. Balbus [sup.3] , [...]

Author(s): Volker Springel (corresponding author) [1]; Carlos S. Frenk [2]; Simon D. M. White [1] The past two and a half decades have seen enormous advances in the study of [...]

Author(s): Volker Springel (corresponding author) [1]; Simon D. M. White [1]; Adrian Jenkins [2]; Carlos S. Frenk [2]; Naoki Yoshida [3]; Liang Gao [1]; Julio Navarro [4]; Robert Thacker [5]; [...]

Author(s): Tiziana Di Matteo (corresponding author) [1, 3]; Volker Springel [1]; Lars Hernquist [2] In the early Universe, while galaxies were still forming, black holes as massive as a billion [...]

Author(s): Volker Springel [1] by DanHooper Smithsonian Institution: 2006. 256 pp. $24.95 [illus. 1] Since the discoveries of Copernicus, astronomy has taught us that there is nothing special about the [...]