@article{19822, abstract = {>Controlling spin wave excitations in magnetic materials underpins the burgeoning field of magnonics. Yet, little is known about how magnons interact with the conduction electrons of itinerant magnets, or how this interplay can be controlled. Via a surface-sensitive spectroscopic approach, we demonstrate a strong electron–magnon coupling at the Pd-terminated surface of the delafossite oxide PdCoO2, where a polar surface charge mediates a Stoner transition to itinerant surface ferromagnetism. We show how the coupling is enhanced sevenfold with increasing surface disorder, and concomitant charge carrier doping, becoming sufficiently strong to drive the system into a polaronic regime, accompanied by a significant quasiparticle mass enhancement. Our study thus sheds light on electron–magnon interactions in solid-state materials, and the ways in which these can be controlled.}, author = {Mazzola, F. and Yim, C. -M. and Sunko, Veronika and Khim, S. and Kushwaha, P. and Clark, O. J. and Bawden, L. and Marković, I. and Chakraborti, D. and Kim, T. K. and Hoesch, M. and Mackenzie, A. P. and Wahl, P. and King, P. D. C.}, issn = {2397-4648}, journal = {npj Quantum Materials}, publisher = {Springer Nature}, title = {{Tuneable electron–magnon coupling of ferromagnetic surface states in PdCoO2}}, doi = {10.1038/s41535-022-00428-8}, volume = {7}, year = {2022}, } @inbook{19984, abstract = {The first part of this paper is a survey of mathematical results on mirror symmetry phenomena between Hitchin systems for Langlands dual groups. The second part introduces and discusses multiplicity algebras of the Hitchin system on Lagrangians, and considers corresponding conjectural structures on their mirror.}, author = {Hausel, Tamás}, booktitle = {International Congress of Mathematicians}, isbn = {9783985470587}, location = {virtuel}, pages = {2228--2249}, publisher = {EMS Press}, title = {{Enhanced mirror symmetry for Langlands dual Hitchin systems}}, doi = {10.4171/icm2022/164}, year = {2022}, } @inbook{20062, abstract = {This article presents two fine-grained complexity lower bounds with relevance to algorithmic problems in computer aided verification. We have chosen these lower bounds as the proofs are relatively simple, but the techniques can be extended to give lower bounds for many more algorithmic problems. The goal is to present the bounds with minimal notation, making the results accessible to a broad community and stimulating further research in the area. Specifically, we first describe a lower bound on the symbolic complexity of computing strongly connected components, which can be extended to show lower bounds for fundamental model-checking questions in graphs, published in [CDHL16b]. Second we present a conditional lower bound for disjunctive safety problems on graphs from [CDHL18] in the RAM model of computation. This bound can be modified to give conditional lower bounds for disjunctive objectives for reachability, Büchi, coBüchi and Rabin objectives in MDPs. We also present various open questions.}, author = {Henzinger, Monika H}, booktitle = {Principles of Systems Design}, editor = {Raskin, Jean-François and Chatterjee, Krishnendu and Doyen, Laurent and Majumdar, Rupak}, isbn = {9783031223365}, issn = {1611-3349}, pages = {292--305}, publisher = {Springer Nature Switzerland}, title = {{Fine-Grained Complexity Lower Bounds for Problems in Computer Aided Verification}}, doi = {10.1007/978-3-031-22337-2_14}, volume = {13660}, year = {2022}, } @article{20616, abstract = {We establish two WDVV-style relations for the disk invariants of real symplectic fourfolds by implementing Georgieva’s suggestion to lift homology relations from the Deligne–Mumford moduli spaces of stable real curves. This is accomplished by lifting judiciously chosen cobordisms realizing these relations. The resulting lifted relations lead to the recursions for Welschinger invariants announced by Solomon in 2007 and have the same structure as his WDVV-style relations, but differ by signs from the latter. Our topological approach provides a general framework for lifting relations via morphisms between not necessarily orientable spaces.}, author = {Chen, Xujia}, issn = {1420-8970}, journal = {Geometric and Functional Analysis}, number = {3}, pages = {490--567}, publisher = {Springer Nature}, title = {{Steenrod pseudocycles, lifted cobordisms, and Solomon’s relations for Welschinger invariants}}, doi = {10.1007/s00039-022-00596-6}, volume = {32}, year = {2022}, } @article{20617, abstract = {Our previous paper describes a geometric translation of the construction of open Gromov–Witten invariants by Solomon and Tukachinsky from a perspective of $A_{\infty }$-algebras of differential forms. We now use this geometric perspective to show that these invariants reduce to Welschinger’s open Gromov–Witten invariants in dimension 6, inline with their and Tian’s expectations. As an immediate corollary, we obtain a translation of Solomon–Tukachinsky’s open WDVV equations into relations for Welschinger’s invariants.}, author = {Chen, Xujia}, issn = {1687-0247}, journal = {International Mathematics Research Notices}, number = {9}, pages = {7021--7055}, publisher = {Oxford University Press}, title = {{Solomon-Tukachinsky’s versus Welschinger’s open Gromov-Witten invariants of symplectic six-folds}}, doi = {10.1093/imrn/rnaa318}, volume = {2022}, year = {2022}, } @article{20620, abstract = {The 2016 papers of J. Solomon and S. Tukachinsky use bounding chains in Fukaya's $A_{\infty}$-algebras to define numerical disk counts relative to a Lagrangian under certain regularity assumptions on the moduli spaces of disks. We present a (self-contained) direct geometric analogue of their construction under weaker topological assumptions, extend it over arbitrary rings in the process, and sketch an extension without any assumptions over rings containing the rationals. This implements the intuitive suggestion represented by their drawing and P. Georgieva's perspective. We also note a curious relation for the standard Gromov-Witten invariants readily deducible from their work. In a sequel, we use the geometric perspective of this paper to relate Solomon-Tukachinsky's invariants to Welschinger's open invariants of symplectic sixfolds, confirming their belief and G. Tian's related expectation concerning K. Fukaya's earlier construction.}, author = {Chen, Xujia}, journal = {Peking Mathematical Journal }, pages = {279--348}, publisher = {Springer Nature}, title = {{A geometric depiction of Solomon-Tukachinsky's construction of open GW-invariants}}, doi = {10.1007/s42543-021-00044-8}, volume = {5}, year = {2022}, } @inproceedings{20627, abstract = {The modern control model of the two-wheeled balancing vehicle is established by rational simplification and linearization and selection of appropriate state space variables. The state space expressions in modern control theory are used to make up for some deficiencies in the classical inverted pendulum model. By constructing the mathematical model of the LQR controller in MATLAB, using Simulink for model design and theoretical simulation analysis according to the actual application scenario, the results show that the improved LQR controller can be used in the autonomous balance control and anti-external interference of the two-wheeled self-balancing vehicle model. Has excellent performance.}, author = {Yuan, Jiemin and Chen, Haiyun and Yong, Tao and Lai, Xi and Chen, Xujia}, booktitle = {6th Advanced Information Technology, Electronic and Automation Control Conference}, location = {Beijing, China}, publisher = {IEEE}, title = {{Research on two-wheeled balance car based on improved LQR controller}}, doi = {10.1109/iaeac54830.2022.9930026}, year = {2022}, } @article{20763, abstract = {Compared with peripheral late-stage transformations mainly focusing on carbon–hydrogen functionalizations, reliable strategies to directly edit the core skeleton of pharmaceutical lead compounds still remain scarce despite the recent flurry of activity in this area. Herein, we report the skeletal editing of indoles through nitrogen atom insertion, accessing the corresponding quinazoline or quinoxaline bioisosteres by trapping of an electrophilic nitrene species generated from ammonium carbamate and hypervalent iodine. This reactivity relies on the strategic use of a silyl group as a labile protecting group that can facilitate subsequent product release. The utility of this highly functional group-compatible methodology in the context of late-stage skeletal editing of several commercial drugs is demonstrated.}, author = {Reisenbauer, Julia and Green, Ori and Franchino, Allegra and Finkelstein, Patrick and Morandi, Bill}, issn = {1095-9203}, journal = {Science}, number = {6610}, pages = {1104--1109}, publisher = {American Association for the Advancement of Science}, title = {{Late-stage diversification of indole skeletons through nitrogen atom insertion}}, doi = {10.1126/science.add1383}, volume = {377}, year = {2022}, } @article{20764, abstract = {Hydrocyanation reactions enable access to synthetically valuable nitriles from readily available alkene precursors. However, hydrocyanation reactions using hydrogen cyanide (HCN) or similarly toxic reagents on laboratory scale can be particularly challenging due to their hazardous nature. In addition, such processes typically require air- and temperature-sensitive Ni(0) precatalysts, further reducing the operational simplicity of this transformation. Herein, we report a HCN-free transfer hydrocyanation of alkenes and alkynes that employs commercially available aliphatic nitriles as sacrificial HCN donors in combination with a catalytic amount of air-stable and inexpensive NiCl2 as a precatalyst and a cocatalytic Lewis acid. The scalability and robustness of the catalytic process were demonstrated by the hydrocyanation of α-methylstyrene on a 100 mmol scale (11.4 g of product obtained) using 1 mol % of the Ni catalyst. In addition, the feasibility of the dehydrocyanation protocol using the air-stable Ni(II) precatalyst and norbornadiene as a sacrificial acceptor was showcased by the selective conversion of an aliphatic nitrile into the corresponding alkene.}, author = {Reisenbauer, Julia and Bhawal, Benjamin N. and Jelmini, Nicola and Morandi, Bill}, issn = {1520-586X}, journal = {Organic Process Research & Development}, number = {4}, pages = {1165--1173}, publisher = {American Chemical Society}, title = {{Development of an operationally simple, scalable, and HCN-free transfer hydrocyanation protocol using an air-stable nickel precatalyst}}, doi = {10.1021/acs.oprd.1c00442}, volume = {26}, year = {2022}, } @inproceedings{18876, abstract = {Convolutional neural networks were the standard for solving many computer vision tasks until recently, when Transformers of MLP-based architectures have started to show competitive performance. These architectures typically have a vast number of weights and need to be trained on massive datasets; hence, they are not suitable for their use in low-data regimes. In this work, we propose a simple yet effective framework to improve generalization from small amounts of data. We augment modern CNNs with fully-connected (FC) layers and show the massive impact this architectural change has in low-data regimes. We further present an online joint knowledge-distillation method to utilize the extra FC layers at train time but avoid them during test time. This allows us to improve the generalization of a CNN-based model without any increase in the number of weights at test time. We perform classification experiments for a large range of network backbones and several standard datasets on supervised learning and active learning. Our experiments significantly outperform the networks without fully-connected layers, reaching a relative improvement of up to 16% validation accuracy in the supervised setting without adding any extra parameters during inference.}, author = {Kocsis, Peter and Súkeník, Peter and Brasó, Guillem and Niessner, Matthias and Leal-Taixé, Laura and Elezi, Ismail}, booktitle = {36th Conference on Neural Information Processing Systems}, issn = {1049-5258}, location = {New Orleans, LA, United States}, pages = {1896--1908}, publisher = {Neural Information Processing Systems Foundation}, title = {{The unreasonable effectiveness of fully-connected layers for low-data regimes}}, volume = {35}, year = {2022}, } @article{19490, abstract = {Abstract. We study integral points on the quadratic twists ED : y2 = x3 − D2x of the congruent number curve. We give upper bounds on the number of integral points in each coset of 2ED(Q) in ED(Q) and show that their total is (3.8)rank ED(Q). We further show that the average number of non-torsion integral points in this family is bounded above by 2. As an application we also deduce from our upper bounds that the system of simultaneous Pell equations aX2 − bY 2 = d, bY 2 − cZ2 = d for pairwise coprime positive integers a, b, c, d, has at most (3.6)ω(abcd) integer solutions.}, author = {Chan, Yik Tung}, issn = {1088-6850}, journal = {Transactions of the American Mathematical Society}, number = {9}, pages = {6675--6700}, publisher = {American Mathematical Society}, title = {{Integral points on the congruent number curve}}, doi = {10.1090/tran/8732}, volume = {375}, year = {2022}, } @article{19491, abstract = {Using a recent breakthrough of Smith [18], we improve the results of Fouvry and Klüners [4, 5] on the solubility of the negative Pell equation. Let D denote the set of positive squarefree integers having no prime factors congruent to 3 modulo 4 . Stevenhagen [19] conjectured that the density of d in D such that the negative Pell equation x2−dy2=−1 is solvable with x,y∈Z is 58.1% , to the nearest tenth of a percent. By studying the distribution of the 8 -rank of narrow class groups Cl+(d) of Q(√d) , we prove that the infimum of this density is at least 53.8% .}, author = {Chan, Yik Tung and Koymans, Peter and Milovic, Djordjo and Pagano, Carlo}, issn = {2050-5094}, journal = {Forum of Mathematics, Sigma}, publisher = {Cambridge University Press}, title = {{The 8-rank of the narrow class group and the negative Pell equation}}, doi = {10.1017/fms.2022.40}, volume = {10}, year = {2022}, } @article{15131, abstract = {RNA modifications are widespread in biology and abundant in ribosomal RNA. However, the importance of these modifications is not well understood. We show that methylation of a single nucleotide, in the catalytic center of the large subunit, gates ribosome assembly. Massively parallel mutational scanning of the essential nuclear GTPase Nog2 identified important interactions with rRNA, particularly with the 2′-O-methylated A-site base Gm2922. We found that methylation of G2922 is needed for assembly and efficient nuclear export of the large subunit. Critically, we identified single amino acid changes in Nog2 that completely bypass dependence on G2922 methylation and used cryoelectron microscopy to directly visualize how methylation flips Gm2922 into the active site channel of Nog2. This work demonstrates that a single RNA modification is a critical checkpoint in ribosome biogenesis, suggesting that such modifications can play an important role in regulation and assembly of macromolecular machines.}, author = {Yelland, James N. and Bravo, Jack Peter Kelly and Black, Joshua J. and Taylor, David W. and Johnson, Arlen W.}, issn = {1545-9985}, journal = {Nature Structural & Molecular Biology}, keywords = {Molecular Biology, Structural Biology}, pages = {91--98}, publisher = {Springer Nature}, title = {{A single 2′-O-methylation of ribosomal RNA gates assembly of a functional ribosome}}, doi = {10.1038/s41594-022-00891-8}, volume = {30}, year = {2022}, } @article{15132, abstract = {Clustered regularly interspaced short palindromic repeats - CRISPR-associated protein (CRISPR-Cas) systems are a critical component of the bacterial adaptive immune response. Since the discovery that they can be reengineered as programmable RNA-guided nucleases, there has been significant interest in using these systems to perform diverse and precise genetic manipulations. Here, we outline recent advances in the mechanistic understanding of CRISPR-Cas9, how these findings have been leveraged in the rational redesign of Cas9 variants with altered activities, and how these novel tools can be exploited for biotechnology and therapeutics. We also discuss the potential of the ubiquitous, yet often-overlooked, multisubunit CRISPR effector complexes for large-scale genomic deletions. Furthermore, we highlight how future structural studies will bolster these technologies.}, author = {Bravo, Jack Peter Kelly and Hibshman, Grace N and Taylor, David W}, issn = {0958-1669}, journal = {Current Opinion in Biotechnology}, keywords = {Biomedical Engineering, Bioengineering, Biotechnology}, publisher = {Elsevier}, title = {{Constructing next-generation CRISPR–Cas tools from structural blueprints}}, doi = {10.1016/j.copbio.2022.102839}, volume = {78}, year = {2022}, } @article{15133, abstract = {In the evolutionary arms race against phage, bacteria have assembled a diverse arsenal of antiviral immune strategies. While the recently discovered DISARM (Defense Island System Associated with Restriction-Modification) systems can provide protection against a wide range of phage, the molecular mechanisms that underpin broad antiviral targeting but avoiding autoimmunity remain enigmatic. Here, we report cryo-EM structures of the core DISARM complex, DrmAB, both alone and in complex with an unmethylated phage DNA mimetic. These structures reveal that DrmAB core complex is autoinhibited by a trigger loop (TL) within DrmA and binding to DNA substrates containing a 5′ overhang dislodges the TL, initiating a long-range structural rearrangement for DrmAB activation. Together with structure-guided in vivo studies, our work provides insights into the mechanism of phage DNA recognition and specific activation of this widespread antiviral defense system.}, author = {Bravo, Jack Peter Kelly and Aparicio-Maldonado, Cristian and Nobrega, Franklin L. and Brouns, Stan J. J. and Taylor, David W.}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}, publisher = {Springer Nature}, title = {{Structural basis for broad anti-phage immunity by DISARM}}, doi = {10.1038/s41467-022-30673-1}, volume = {13}, year = {2022}, } @article{15134, abstract = {CRISPR-Cas systems are adaptive immune systems that protect prokaryotes from foreign nucleic acids, such as bacteriophages. Two of the most prevalent CRISPR-Cas systems include type I and type III. Interestingly, the type I-D interference proteins contain characteristic features of both type I and type III systems. Here, we present the structures of type I-D Cascade bound to both a double-stranded (ds)DNA and a single-stranded (ss)RNA target at 2.9 and 3.1 Å, respectively. We show that type I-D Cascade is capable of specifically binding ssRNA and reveal how PAM recognition of dsDNA targets initiates long-range structural rearrangements that likely primes Cas10d for Cas3′ binding and subsequent non-target strand DNA cleavage. These structures allow us to model how binding of the anti-CRISPR protein AcrID1 likely blocks target dsDNA binding via competitive inhibition of the DNA substrate engagement with the Cas10d active site. This work elucidates the unique mechanisms used by type I-D Cascade for discrimination of single-stranded and double stranded targets. Thus, our data supports a model for the hybrid nature of this complex with features of type III and type I systems.}, author = {Schwartz, Evan A. and McBride, Tess M. and Bravo, Jack Peter Kelly and Wrapp, Daniel and Fineran, Peter C. and Fagerlund, Robert D. and Taylor, David W.}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}, publisher = {Springer Nature}, title = {{Structural rearrangements allow nucleic acid discrimination by type I-D Cascade}}, doi = {10.1038/s41467-022-30402-8}, volume = {13}, year = {2022}, } @article{15136, abstract = {CRISPR–Cas9 as a programmable genome editing tool is hindered by off-target DNA cleavage1,2,3,4, and the underlying mechanisms by which Cas9 recognizes mismatches are poorly understood5,6,7. Although Cas9 variants with greater discrimination against mismatches have been designed8,9,10, these suffer from substantially reduced rates of on-target DNA cleavage5,11. Here we used kinetics-guided cryo-electron microscopy to determine the structure of Cas9 at different stages of mismatch cleavage. We observed a distinct, linear conformation of the guide RNA–DNA duplex formed in the presence of mismatches, which prevents Cas9 activation. Although the canonical kinked guide RNA–DNA duplex conformation facilitates DNA cleavage, we observe that substrates that contain mismatches distal to the protospacer adjacent motif are stabilized by reorganization of a loop in the RuvC domain. Mutagenesis of mismatch-stabilizing residues reduces off-target DNA cleavage but maintains rapid on-target DNA cleavage. By targeting regions that are exclusively involved in mismatch tolerance, we provide a proof of concept for the design of next-generation high-fidelity Cas9 variants.}, author = {Bravo, Jack Peter Kelly and Liu, Mu-Sen and Hibshman, Grace N. and Dangerfield, Tyler L. and Jung, Kyungseok and McCool, Ryan S. and Johnson, Kenneth A. and Taylor, David W.}, issn = {1476-4687}, journal = {Nature}, number = {7900}, pages = {343--347}, publisher = {Springer Nature}, title = {{Structural basis for mismatch surveillance by CRISPR–Cas9}}, doi = {10.1038/s41586-022-04470-1}, volume = {603}, year = {2022}, } @article{15144, author = {Bravo, Jack Peter Kelly}, issn = {1937-8661}, journal = {Genetic Engineering & Biotechnology News}, keywords = {Management of Technology and Innovation, Biomedical Engineering, Bioengineering, Biotechnology}, number = {4}, pages = {12}, publisher = {Mary Ann Liebert}, title = {{SuperFi-Cas9 exceeds fidelity, matches speed of original Cas9}}, doi = {10.1089/gen.42.04.03}, volume = {42}, year = {2022}, } @article{15203, abstract = {The first X-ray pulsar, Cen X-3, was discovered 50 yr ago. Radiation from such objects is expected to be highly polarized due to birefringence of plasma and vacuum associated with propagation of photons in the presence of the strong magnetic field. Here we present results of the observations of Cen X-3 performed with the Imaging X-ray Polarimetry Explorer. The source exhibited significant flux variability and was observed in two states different by a factor of ∼20 in flux. In the low-luminosity state, no significant polarization was found in either pulse phase-averaged (with a 3σ upper limit of 12%) or phase-resolved (the 3σ upper limits are 20%–30%) data. In the bright state, the polarization degree of 5.8% ± 0.3% and polarization angle of 49fdg6 ± 1fdg5 with a significance of about 20σ were measured from the spectropolarimetric analysis of the phase-averaged data. The phase-resolved analysis showed a significant anticorrelation between the flux and the polarization degree, as well as strong variations of the polarization angle. The fit with the rotating vector model indicates a position angle of the pulsar spin axis of about 49° and a magnetic obliquity of 17°. The detected relatively low polarization can be explained if the upper layers of the neutron star surface are overheated by the accreted matter and the conversion of the polarization modes occurs within the transition region between the upper hot layer and a cooler underlying atmosphere. A fraction of polarization signal can also be produced by reflection of radiation from the neutron star surface and the accretion curtain.}, author = {Tsygankov, Sergey S. and Doroshenko, Victor and Poutanen, Juri and Heyl, Jeremy and Mushtukov, Alexander A. and Caiazzo, Ilaria and Di Marco, Alessandro and Forsblom, Sofia V. and González-Caniulef, Denis and Klawin, Moritz and La Monaca, Fabio and Malacaria, Christian and Marshall, Herman L. and Muleri, Fabio and Ng, Mason and Suleimanov, Valery F. and Sunyaev, Rashid A. and Turolla, Roberto and Agudo, Iván and Antonelli, Lucio A. and Bachetti, Matteo 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 Costa, Enrico and Rosa, Alessandra De and Del Monte, Ettore and Gesu, Laura Di and Lalla, Niccolò Di 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 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 Pavlov, George G. and Peirson, Abel L. 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 Romani, Roger W. and Sgrò, Carmelo and Slane, Patrick and Soffitta, Paolo and Spandre, Gloria 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 Vink, Jacco and Weisskopf, Martin C. and Wu, Kinwah and Xie, Fei and Zane, Silvia}, issn = {2041-8213}, journal = {The Astrophysical Journal Letters}, keywords = {Space and Planetary Science, Astronomy and Astrophysics}, number = {1}, publisher = {American Astronomical Society}, title = {{The x-ray polarimetry view of the accreting pulsar Cen X-3}}, doi = {10.3847/2041-8213/aca486}, volume = {941}, year = {2022}, } @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}, }