@article{18867,
  abstract     = {In an accreting X-ray pulsar, a neutron star accretes matter from a companion star through an accretion disk. The magnetic field of the rotating neutron star disrupts the inner edge of the disk, funnelling the gas to flow onto the poles on its surface. Hercules X-1 is a prototypical persistent X-ray pulsar about 7 kpc from Earth. Its emission varies on three distinct timescales: the neutron star rotates every 1.2 s, it is eclipsed by its companion each 1.7 d, and the system exhibits a superorbital period of 35 d, which has remained stable since its discovery. Several lines of evidence point to the source of this variation as the precession of the accretion disk or that of the neutron star. Despite the many hints over the past 50 yr, the precession of the neutron star itself has yet not been confirmed or refuted. X-ray polarization measurements (probing the spin geometry of Her X-1) with the Imaging X-ray Polarimetry Explorer suggest that free precession of the neutron star crust sets the 35 d period; this has the important implication that its crust is somewhat asymmetric by a few parts per ten million.},
  author       = {Heyl, Jeremy and Doroshenko, Victor and González-Caniulef, Denis and Caiazzo, Ilaria and Poutanen, Juri and Mushtukov, Alexander and Tsygankov, Sergey S. and Kirmizibayrak, Demet and Bachetti, Matteo and Pavlov, George G. and Forsblom, Sofia V. and Malacaria, Christian and Suleimanov, Valery F. and Agudo, Iván and Antonelli, Lucio Angelo and Baldini, Luca and Baumgartner, Wayne H. and Bellazzini, Ronaldo and Bianchi, Stefano and Bongiorno, Stephen D. and Bonino, Raffaella and Brez, Alessandro and Bucciantini, Niccolò and Capitanio, Fiamma and Castellano, Simone and Cavazzuti, Elisabetta and Chen, Chien-Ting and Ciprini, Stefano and Costa, Enrico and De Rosa, Alessandra and Del Monte, Ettore and Di Gesu, Laura and Di Lalla, Niccolò and Di Marco, Alessandro and Donnarumma, Immacolata and Dovčiak, Michal and Ehlert, Steven R. and Enoto, Teruaki and Evangelista, Yuri and Fabiani, Sergio and Ferrazzoli, Riccardo and Garcia, Javier A. and Gunji, Shuichi and Hayashida, Kiyoshi and Iwakiri, Wataru and Jorstad, Svetlana G. and Kaaret, Philip and Karas, Vladimir and Kislat, Fabian and Kitaguchi, Takao and Kolodziejczak, Jeffery J. and Krawczynski, Henric and La Monaca, Fabio and Latronico, Luca and Liodakis, Ioannis and Maldera, Simone and Manfreda, Alberto and Marin, Frédéric and Marinucci, Andrea and Marscher, Alan P. and Marshall, Herman L. and Massaro, Francesco and Matt, Giorgio and Mitsuishi, Ikuyuki and Mizuno, Tsunefumi and Muleri, Fabio and Negro, Michela and Ng, C.-Y. and O’Dell, Stephen L. and Omodei, Nicola and Oppedisano, Chiara and Papitto, Alessandro and Peirson, Abel Lawrence and Perri, Matteo and Pesce-Rollins, Melissa and Petrucci, Pierre-Olivier and Pilia, Maura and Possenti, Andrea and Puccetti, Simonetta and Ramsey, Brian D. and Rankin, John and Ratheesh, Ajay and Roberts, Oliver J. and Romani, Roger W. and Sgrò, Carmelo and Slane, Patrick and Soffitta, Paolo and Spandre, Gloria and Swartz, Douglas A. and Tamagawa, Toru and Tavecchio, Fabrizio and Taverna, Roberto and Tawara, Yuzuru and Tennant, Allyn F. and Thomas, Nicholas E. and Tombesi, Francesco and Trois, Alessio and Turolla, Roberto and Vink, Jacco and Weisskopf, Martin C. and Wu, Kinwah and Xie, Fei and Zane, Silvia},
  issn         = {2397-3366},
  journal      = {Nature Astronomy},
  pages        = {1047--1053},
  publisher    = {Springer Nature},
  title        = {{Complex rotational dynamics of the neutron star in Hercules X-1 revealed by X-ray polarization}},
  doi          = {10.1038/s41550-024-02295-8},
  volume       = {8},
  year         = {2024},
}

@article{15204,
  abstract     = {Using observations of X-ray pulsar Hercules X-1 by the Imaging X-ray Polarimetry Explorer we report a highly significant (>17σ) detection of the polarization signal from an accreting neutron star. The observed degree of linear polarization of ~10% is far below theoretical expectations for this object, and stays low throughout the spin cycle of the pulsar. Both the degree and angle of polarization exhibit variability with the pulse phase, allowing us to measure the pulsar spin position angle 57(2) deg and the magnetic obliquity 12(4) deg, which is an essential step towards detailed modelling of the intrinsic emission of X-ray pulsars. Combining our results with the optical polarimetric data, we find that the spin axis of the neutron star and the angular momentum of the binary orbit are misaligned by at least ~20 deg, which is a strong argument in support of the models explaining the stability of the observed superorbital variability with the precession of the neutron star.},
  author       = {Doroshenko, Victor and Poutanen, Juri and Tsygankov, Sergey S. and Suleimanov, Valery F. and Bachetti, Matteo and Caiazzo, Ilaria and Costa, Enrico and Di Marco, Alessandro and Heyl, Jeremy and La Monaca, Fabio and Muleri, Fabio and Mushtukov, Alexander A. and Pavlov, George G. and Ramsey, Brian D. and Rankin, John and Santangelo, Andrea and Soffitta, Paolo and Staubert, Rüdiger and Weisskopf, Martin C. and Zane, Silvia and Agudo, Iván and Antonelli, Lucio A. and Baldini, Luca and Baumgartner, Wayne H. and Bellazzini, Ronaldo and Bianchi, Stefano and Bongiorno, Stephen D. and Bonino, Raffaella and Brez, Alessandro and Bucciantini, Niccolò and Capitanio, Fiamma and Castellano, Simone and Cavazzuti, Elisabetta and Ciprini, Stefano and De Rosa, Alessandra and Del Monte, Ettore and Di Gesu, Laura and Di Lalla, Niccolò and Donnarumma, Immacolata and Dovčiak, Michal and Ehlert, Steven R. and Enoto, Teruaki and Evangelista, Yuri and Fabiani, Sergio and Ferrazzoli, Riccardo and Garcia, Javier A. and Gunji, Shuichi and Hayashida, Kiyoshi and Iwakiri, Wataru and Jorstad, Svetlana G. and Karas, Vladimir and Kitaguchi, Takao and Kolodziejczak, Jeffery J. and Krawczynski, Henric and Latronico, Luca and Liodakis, Ioannis and Maldera, Simone and Manfreda, Alberto and Marin, Frédéric and Marinucci, Andrea and Marscher, Alan P. and Marshall, Herman L. and Matt, Giorgio and Mitsuishi, Ikuyuki and Mizuno, Tsunefumi and Ng, Chi-Yung and O’Dell, Stephen L. and Omodei, Nicola and Oppedisano, Chiara and Papitto, Alessandro and Peirson, Abel L. and Perri, Matteo and Pesce-Rollins, Melissa and Pilia, Maura and Possenti, Andrea and Puccetti, Simonetta and Ratheesh, Ajay and Romani, Roger W. and Sgrò, Carmelo and Slane, Patrick and Spandre, Gloria and Sunyaev, Rashid A. and Tamagawa, Toru and Tavecchio, Fabrizio and Taverna, Roberto and Tawara, Yuzuru and Tennant, Allyn F. and Thomas, Nicolas E. and Tombesi, Francesco and Trois, Alessio and Turolla, Roberto and Vink, Jacco and Wu, Kinwah and Xie, Fei},
  issn         = {2397-3366},
  journal      = {Nature Astronomy},
  keywords     = {Astronomy and Astrophysics},
  number       = {12},
  pages        = {1433--1443},
  publisher    = {Springer Nature},
  title        = {{Determination of X-ray pulsar geometry with IXPE polarimetry}},
  doi          = {10.1038/s41550-022-01799-5},
  volume       = {6},
  year         = {2022},
}

@article{17544,
  abstract     = {Large cosmological datasets have been probing the properties of our Universe and constraining the parameters of dark matter and dark energy with increasing precision. Deep learning techniques have shown potential to be smarter than — and greatly outperform — human-designed statistics.},
  author       = {Haiman, Zoltán},
  issn         = {2397-3366},
  journal      = {Nature Astronomy},
  number       = {1},
  pages        = {18--19},
  publisher    = {Springer Science and Business Media LLC},
  title        = {{Learning from the machine}},
  doi          = {10.1038/s41550-018-0623-9},
  volume       = {3},
  year         = {2018},
}

@article{17667,
  abstract     = {The Direct Collapse Black Hole (DCBH) scenario provides a solution for forming the massive black holes powering bright quasars observed in the early Universe. A prerequisite for forming a DCBH is that the formation of (much less massive) Population III stars be avoided - this can be achieved by destroying H2 via Lyman-Werner (LW) radiation (ELW = 12.6 eV). We find that two conditions must be met in the proto-galaxy that will host the DCBH. First, prior star formation must be delayed; this can be achieved with a background LW flux of JBG≳100 J21. Second, an intense burst of LW radiation from a neighbouring star-bursting proto-galaxy is required, just before the gas cloud undergoes gravitational collapse, to finally suppress star formation completely. We show here for the first time using high-resolution hydrodynamical simulations, including full radiative transfer, that this low-level background, combined with tight synchronisation and irradiation of a secondary proto-galaxy by a primary proto-galaxy, inevitably moves the secondary proto-galaxy onto the isothermal atomic cooling track, without the deleterious effects of either photo-evaporating the gas or polluting it by heavy elements. These, atomically cooled, massive proto-galaxies are expected to ultimately form a DCBH of mass 104−105M⊙.},
  author       = {Regan, John A. and Visbal, Eli and Wise, John H. and Haiman, Zoltán and Johansson, Peter H. and Bryan, Greg L.},
  issn         = {2397-3366},
  journal      = {Nature Astronomy},
  number       = {4},
  publisher    = {Springer Science and Business Media LLC},
  title        = {{Rapid formation of massive black holes in close proximity to embryonic protogalaxies}},
  doi          = {10.1038/s41550-017-0075},
  volume       = {1},
  year         = {2017},
}