# Most-cited Physics and Astronomy papers of 2019, with free PDFs

The 25 most-cited Physics and Astronomy research papers published in 2019, ranked by citations in OpenAlex, with their original abstracts and free PDFs where available.

1. [Double-slit photoelectron interference in strong-field ionization of the neon dimer](https://nerdi.pages.dev/paper/W3105982350) · 8,194 citations
2. [From Louvain to Leiden: guaranteeing well-connected communities](https://nerdi.pages.dev/paper/W2897249806) · 5,602 citations · Free PDF
3. [GFN2-xTB─An Accurate and Broadly Parametrized Self-Consistent Tight-Binding Quantum Chemical Method with Multipole Electrostatics and Density-Dependent Dispersion Contributions](https://nerdi.pages.dev/paper/W2911997094) · 4,432 citations
4. [First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole](https://nerdi.pages.dev/paper/W2936349953) · 4,206 citations · Free PDF
5. [Topological photonics](https://nerdi.pages.dev/paper/W4211161891) · 3,672 citations · Free PDF
6. [LSST: From Science Drivers to Reference Design and Anticipated Data Products](https://nerdi.pages.dev/paper/W2159714423) · 3,556 citations · Free PDF
7. [GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs](https://nerdi.pages.dev/paper/W2971836485) · 3,531 citations · Free PDF
8. [Machine Learning for Fluid Mechanics](https://nerdi.pages.dev/paper/W2973119841) · 2,887 citations · Free PDF
9. [Planck 2018 results](https://nerdi.pages.dev/paper/W4211141710) · 2,423 citations · Free PDF
10. [New Basis Set Exchange: An Open, Up-to-Date Resource for the Molecular Sciences Community](https://nerdi.pages.dev/paper/W2979795026) · 2,339 citations
11. [Optical vortices 30 years on: OAM manipulation from topological charge to multiple singularities](https://nerdi.pages.dev/paper/W2978556994) · 2,286 citations · Free PDF
12. [Exceptional points in optics and photonics](https://nerdi.pages.dev/paper/W2908266731) · 2,222 citations
13. [Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics beyond ΛCDM](https://nerdi.pages.dev/paper/W2921829748) · 1,992 citations · Free PDF
14. [A generally applicable atomic-charge dependent London dispersion correction](https://nerdi.pages.dev/paper/W2936033307) · 1,943 citations
15. [QuantumATK: an integrated platform of electronic and atomic-scale modelling tools](https://nerdi.pages.dev/paper/W2944119246) · 1,934 citations · Free PDF
16. [Overview of the DESI Legacy Imaging Surveys](https://nerdi.pages.dev/paper/W2799047820) · 1,865 citations · Free PDF
17. [Wannier90 as a community code: new features and applications](https://nerdi.pages.dev/paper/W2982683571) · 1,841 citations · Free PDF
18. [Colloquium : Many-body localization, thermalization, and entanglement](https://nerdi.pages.dev/paper/W2914454605) · 1,828 citations · Free PDF
19. [PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter](https://nerdi.pages.dev/paper/W2995381361) · 1,796 citations · Free PDF
20. [Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation](https://nerdi.pages.dev/paper/W2918550948) · 1,781 citations · Free PDF
21. [Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems](https://nerdi.pages.dev/paper/W2787226197) · 1,713 citations · Free PDF
22. [Planck 2018 results](https://nerdi.pages.dev/paper/W3098899650) · 1,644 citations · Free PDF
23. [A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation](https://nerdi.pages.dev/paper/W2995178730) · 1,632 citations · Free PDF
24. [First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole](https://nerdi.pages.dev/paper/W2936095933) · 1,630 citations · Free PDF
25. [The Simons Observatory: science goals and forecasts](https://nerdi.pages.dev/paper/W2888259247) · 1,527 citations · Free PDF

Canonical page: https://nerdi.pages.dev/papers/physics-and-astronomy/most-cited-2019